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diff --git a/78386-0.txt b/78386-0.txt new file mode 100644 index 0000000..0241642 --- /dev/null +++ b/78386-0.txt @@ -0,0 +1,9282 @@ +*** START OF THE PROJECT GUTENBERG EBOOK 78386 *** + + + + +[Illustration: THE PLATYPUS. DRAWN BY J. W. LEWIN IN 1810. + +After the original watercolour in the Mitchell Library, Sydney.] + + + + + THE PLATYPUS + + ITS DISCOVERY, ZOOLOGICAL POSITION, + FORM AND CHARACTERISTICS, HABITS, + LIFE HISTORY, ETC. + + BY + HARRY BURRELL, C.M.Z.S. + + Co-author of + _The Wild Animals of Australasia_ + + _With 35 Plates_ + + AUSTRALIA: + ANGUS & ROBERTSON LIMITED + 89 CASTLEREAGH STREET, SYDNEY + 1927 + + + + + Wholly set up and printed in Australia by + Eagle Press Ltd., Allen Street, Waterloo + 1927 + + Registered by the Postmaster-General for + transmission through the post as a book + + + + + TO MY WIFE + + Without whose help and encouragement this book + would probably not have been written. + + + + +PREFACE + + +This book is the result of nearly twenty years’ personal observation of +the platypus in its haunts, carried on while I was collecting specimens +for the University of Sydney and the Commonwealth National Museum; but +the limitations under which the work has had to be carried on, and +the impossibility of obtaining official sanction to work as a private +collector, have prevented me from exploring certain branches of the +subject and have brought my field work practically to a standstill. +Earlier observers, working without restraint, had opportunities +of discovering details which I have been debarred from studying; +nevertheless, I have not hesitated to criticize their observations +where they differ from my own, and I have ventured to suggest several +directions in which scientific investigators may proceed. + +All my descriptions have been written from living specimens or from +material freshly collected; museum specimens and records have been +deliberately ignored. The illustrations also show living platypus, with +the exception of a few photographs taken from fresh carcasses; and none +of the photographs reproduced have been touched up in any way. + +As the book is intended mainly for general readers, measurements have +been given in inches where possible; but for scientific purposes it has +sometimes been necessary to give them in millimetres. Roughly, 25 mm. +equal 1 inch; therefore 3 mm. equal ⅛in., 12 mm. equal ½in., etc. + + H.B. + + + + +CONTENTS + + + PREFACE vii + + I. INTRODUCTORY 1 + + II. DISCOVERY AND EARLY DESCRIPTIONS 16 + + III. CONTROVERSY ON THE ZOOLOGICAL POSITION 26 + + IV. CONTROVERSY ON THE LAYING OF EGGS 33 + + V. GENERAL CHARACTERISTICS 46 + + VI. NERVOUS ORGANIZATION AND SENSORY PERCEPTIONS 63 + + VII. THE SPUR AND CRURAL GLAND 76 + + VIII. THE NESTING-BURROW 105 + + IX. DISTRIBUTION AND HAUNTS 139 + + X. HABITS 147 + + XI. BREEDING HABITS AND LIFE HISTORY 167 + + XII. PRESERVATION AND ECONOMICS 193 + + XIII. THE PLATYPUS IN CAPTIVITY 202 + + BIBLIOGRAPHY 219 + + INDEX 223 + + + + +ILLUSTRATIONS + + + THE PLATYPUS _Frontispiece_ + + THE AUTHOR 6 + + MRS. HARRY BURRELL FONDLING TWIN NESTLINGS 6 + + UPPER AND LOWER JAWS FORCED WIDE OPEN 10 + + SKELETON OF PLATYPUS 11 + + JAWBONES, SHOWING DIVIDED EXTREMITIES 14 + + “AN AMPHIBIOUS ANIMAL OF THE MOLE KIND” 18 + + MALE PLATYPUS FLOATING 18 + + MALE PLATYPUS WATCHING INTENTLY 30 + + FEMALE PLATYPUS LISTENING INTENTLY 30 + + VENTRAL VIEW OF MALE PLATYPUS 34 + + HEAD OF FEMALE PLATYPUS, SHOWING DIRECT DORSAL VISION 46 + + VENTRAL VIEW OF LIPS 46 + + PLATYPUS PAWS, EXPANDED FOR SWIMMING, AND CONTRACTED FOR + WALKING 50 + + FEMALE PLATYPUS SUCKLING YOUNG 54 + + FEMALE PLATYPUS 54 + + TOP OF LEFT HIND FOOT, WITH SWIMMING MEMBRANE FULLY + EXTENDED 58 + + SOLE OF RIGHT HIND FOOT 58 + + HEAD OF INFURIATED MALE PLATYPUS 62 + + NESTLING PLATYPUS, ABOUT FIVE WEEKS OLD 62 + + EXPERIMENTS ON SENSORY PERCEPTIONS OF PLATYPUS BENEATH + WATER 66 + + POISON GLAND CONNECTED BY DUCT TO WELL AT BASE OF SPUR 94 + + GENERAL VIEW OF MALE PLATYPUS 94 + + SOLE OF RIGHT HIND FOOT, SHOWING SPUR NORMALLY SHEATHED 98 + + SOLE OF LEFT HIND FOOT, SHOWING SPUR IN ACTION 98 + + UNEARTHING PLATYPUS, RETREAT STATION, MACDONALD RIVER, + N.S.W. 110 + + A NEWLY-OPENED NESTING-CAVITY 114 + + NEST COMPOSED OF GUM-LEAVES AND GRASS STEMS 118 + + BROODING FEMALE PLATYPUS 118 + + MODELS OF NESTING-BURROW 122, 124 + + NESTING-BURROW WITH TWO OPENINGS 126 + + VARIETY IN NESTS 126 + + MALE PLATYPUS (1) 130 + + MALE PLATYPUS (2) 130 + + BURROW WITH FOUR NESTS 134 + + PLATYPUS EGGS AND YOUNG 134 + + MACDONALD RIVER, N.S.W. 138 + + “BLUE HOLE,” NAMOI RIVER, N.S.W. 138 + + PLATYPUS MANOEUVRING ALONG A SANDY BOTTOM 142 + + MALE PLATYPUS RUNNING AT TOP SPEED (1) 146 + + MALE PLATYPUS RUNNING AT TOP SPEED (2) 146 + + VENTRAL VIEW OF MALE PLATYPUS 158 + + FEMALE PLATYPUS TAKEN DIRECTLY FROM NEST AND PERSUADED TO + ADOPT SLEEPING POSITION 162 + + TWIN EGGS IN NEST COMPOSED ENTIRELY OF REED ROOTS 174 + + TRIPLET NESTLINGS ABOUT FOUR DAYS OLD. NEST COMPOSED OF + GUM-LEAVES AND GRASS 174 + + FEMALE PLATYPUS IN NEST OF GUM-LEAVES AND GRASS 178 + + MILK GLAND FROM LEFT SIDE 182 + + BROODING FEMALE STEALTHILY GROVELLING HER WAY FROM HER NEST + WHICH HAS BEEN EXPOSED 186 + + TWIN NESTLINGS ABOUT FOUR WEEKS OLD, DIRECT FROM BURROW 206 + + NESTLING PLATYPUS, ABOUT THREE WEEKS OLD, SHOWING + “MILK-LIPS” 206 + + EXHIBITING A PLATYPUS IN AN EXPERIMENTAL “PLATYPUSARY,” + CONSTRUCTED IN 1910 210 + + PORTABLE “PLATYPUSARY,” DESIGNED FOR TRAVELLING 210 + + INTERIOR OF PORTABLE “PLATYPUSARY” 214 + + +[Illustration: THE AUTHOR.] + +[Illustration: MRS. HARRY BURRELL FONDLING TWIN NESTLINGS, IN CAMP.] + + + + +CHAPTER I + +INTRODUCTORY + + +The first printed description of the platypus appeared in the tenth +volume of the _Naturalist’s Miscellany_ (1799) under the name _Platypus +anatinus_ and was written by Dr. George Shaw, of the British Museum, +where the original skin, received in 1798, is still preserved. +In 1800 the German anatomist Blumenbach received a skin from Sir +Joseph Banks (one of two sent by Governor Hunter), and described +it as _Ornithorhynchus paradoxus_. Shaw’s generic name _Platypus_ +was not permissible, it having been used in 1793 by Herbst for a +genus of beetles. The correct name of the animal therefore became +_Ornithorhynchus anatinus_ Shaw; but ‘platypus’ has survived in the +vernacular, to the exclusion of ‘duck-bill’ and ‘water-mole,’ which +were in general use among the earlier colonists. + +No animal has given rise to so much controversy among both laymen and +professed zoologists. The first specimens which reached England were +regarded with suspicion. Shaw’s account, quoted on page 17, shows +clearly enough his doubts and fears, which were dissolved by the +arrival of further specimens; Home’s anatomical research in 1802 put +the genuineness of these beyond all question. But the general feeling +is summed up by Knox (1823, p. 27), who writes:-- + + “It is well known that the specimens of this very extraordinary + animal first brought to Europe were considered by many as + impositions. They reached England by vessels which had navigated + the Indian seas, a circumstance in itself sufficient to rouse the + suspicions of the scientific naturalist, aware of the monstrous + impostures which the artful Chinese had so frequently practised on + European adventurers; in short, the scientific felt inclined to class + this rare production of nature with eastern mermaids and other works + of art; but these conjectures were immediately dispelled by an appeal + to anatomy.” + +The ‘eastern mermaid’ so mentioned is still to be seen occasionally in +curiosity shops, and consists of the skin of the fore-part of a monkey +skilfully sewn to the tail-part of a fish. + +The singular nature of the platypus was not, however, confined to its +external form, and the proof that its duck-like bill really belonged to +it by no means ended the troubles of contemporary zoologists. A furred +animal should obviously be a mammal--that is to say, it should have +a uterus to contain its foetal young, and milk glands with external +nipples for the suckling of the young when born. + +But Home (1802) found no uterus, no mammary glands, and no nipples. Was +the platypus a mammal? Home discovered that the oviducts of the female, +instead of uniting to form a uterus as in the majority of mammals, +opened separately into a cloaca, as in birds and reptiles. + +Here was material for two further controversies. Should +_Ornithorhynchus_ be included in the mammalian class, or must a new +vertebrate class be added for its inclusion? We know now that we may +fairly include the platypus and its only near relative, the echidna, +in a sub-class of the Mammalia (the Ornithodelphia), which, though so +insignificant numerically, is the equivalent, zoologically, of the +larger marsupial sub-class, Didelphia, and of the infinitely greater +sub-class Monodelphia, which comprises all other mammals. But it was +long before this point was settled. The varying opinions will be +detailed in due course. + +The second controversy concerned the method of reproduction. Persistent +reports came from New South Wales that the platypus laid eggs, but +definite evidence was lacking. Sir John Jamison, writing from Sydney +on March 18, 1817 (Jamison, 1818, p. 585) states categorically:--“The +female is oviparous, and lives in burrows in the ground.” But he +offers no proof. Lesson (1839, p. 302) writes:-- + + “It is in New South Wales that one meets those singular and fantastic + creatures to which naturalists have not been able to assign a + position: the _ornithorhynchuses_ or _paradoxals_ with a duck’s + beak, which live in the waters of the rivers, and which lay eggs, + creatures set across the path of the scientific method to show its + worthlessness.” + +These statements were not, however, acceptable to European zoologists, +with one or two exceptions, such as Etienne Geoffroy St.-Hilaire. At +first two alternatives only were considered. _Ornithorhynchus_ was +either oviparous (egg-laying) or ovi-viviparous, that is, producing +eggs which hatch within the parent body. But with the discovery in 1824 +by Meckel, the great German anatomist, of the mammary glands, a third +possibility was manifested. Did the platypus produce its young alive? +Blainville and Meckel thought so. Home, and after him the great Richard +Owen, stood out for ovi-viviparity. The St.-Hilaires in France, more +especially Etienne Geoffroy, fought determinedly for oviparity. The +controversy raged for eighty years, significant evidence being rejected +from time to time because it did not fit in with the preconceived +notions of the person to whose notice it came; and the question was not +settled until 1884, when Caldwell reported his finding of the eggs. + +Yet another controversy, which can scarcely be said to have been +settled even yet, has been concerned with the spur which is found upon +the hind limb of the male. This was first described by Shaw (1799), who +includes it as a sixth digit, but mentions that it resembles a strong, +sharp spur. Home, who also described it, suggested that it was used +for holding the female in the sexual embrace. Jamison (1818) first +mentioned the serious results of wounds inflicted by it. A number of +independent observers in the early twenties--Hill, Traill, Blainville, +Knox and others--described the spur and its duct and gland with varying +degrees of completeness. Martin and Tidswell made a fairly exact +investigation of the nature of the fluid secreted by the gland, and of +its physiological effects. Numerous writers have quoted cases of severe +wounds, while others, including Dr. George Bennett, who handled large +numbers of male platypus, never knew the animal to attempt the use of +its spurs for offensive purposes. + +The mammary glands differ from those of mammals in general, and may be +considered as modified sweat-glands. They open by a number of pores +upon a small area of skin, there being no teats. After the end of the +breeding-season they become so small as to be easily overlooked, and +will apparently yield no milk at the time when the young are just +hatched from the egg. In these respects they differ very markedly +from the milk glands of ordinary mammals, and have afforded ground +for further lively arguments. The fiercest opponent of their mammary +function was Etienne Geoffroy; he was prepared to take any view other +than the obvious one, which seemed fatal to his oviparity hypothesis. + +The nesting habits of _Ornithorhynchus_ have also taken a long time to +elucidate. The early accounts of the nests are derived from information +supplied at secondhand, and their fantastic nature may be due to +misunderstanding on the part of the recorder. Hill (1822, p. 622) +writes:-- + + “... a female _Ornithorhynchus_ had been brought in alive, having + been found on its nest in a lagoon near Campbell’s River, by Mr. + Rawley, who says that he was obliged to tear the nest to pieces + before he could get the animal out, the nest being formed of reeds + and rushes, with a long tube or entrance into it, out of which the + bill of the animal only was visible.” + +It is easy to imagine that what Mr. Rawley really said was that he had +to dig out the long tube, or burrow, and that, when he came to the +nesting-chamber itself, the nest was made of reeds and rushes, out of +which only the bill of the animal was visible. Maule (1832) gave the +first account of the burrow, which was more fully described by Dr. +George Bennett a little later. G. F. Bennett (1877) and Kershaw (1912) +have increased our knowledge of the nesting habits. + +Although at least the natural habits of the platypus have been +ascertained, its life history and development are incompletely known. +Development in the egg prior to the laying has been dealt with by +Wilson and Hill (1908). Similar material obtained by Caldwell in 1883 +was never described. A small number of ‘mammary foetus’ stages from +the burrow have been dealt with by Owen, Parker, Poulton, Wilson, and +others. + +Finally, the habits of the platypus have been variously reported by +different observers, some of whom would seem to have drawn upon a +lively imagination for many of their ‘facts;’ moreover, the original +accounts have become garbled in repetition. Most of the tales might +have been disproved once for all by one or two published statements +from colonists who were familiar with the animal. Curiously enough, +however, there are no local accounts--at any rate, I have not been +able to find any--during the first half of the nineteenth century. We +owe all our early knowledge to English officials and visiting French +naturalists. While scientific Europe thirsted for enlightenment, the +colonist went blandly on with his pioneering. Fletcher (1901) has +pointed out the main reasons for the apparent neglect of zoology in the +early days of the colony. Sir Joseph Banks, who organized the early +collecting, was more interested in botany; also, that study seemed more +likely to have an economic value. So, while the flora was assiduously +collected, catalogued, and described, the fauna was practically +neglected. Nevertheless, such was the interest in _Ornithorhynchus_ +that in 1840 Broderip was able to write:-- + + “The form is now as familiar to us as most of our European animals, + and with regard to its organization and natural history, it is + perhaps better known than many.” + +Bennett (1860, p. 94) writes:-- + + “Of all the Australian mammalia, none has excited so much attention + as the Platypus or Water-Mole (_Ornithorhynchus paradoxus_ Blum.), + both from its peculiar form, and the great desire evinced to + ascertain the habits and economy of so singular a creature.” + +Lesson’s opinion has been quoted above. Shaw (1800, p. 229) says:--“Of +all the Mammalia yet known it seems the most extraordinary in its +conformation”; and again (1809, p. 80):-- + + “This most extraordinary and dubious quadruped is a native + of Australasia.... If there be no mistake in the anatomical + disquisitions hitherto made on the Duckbill, its internal structure + is not less extraordinary than its external....” + +Verreaux (1848, p. 128) commences his account:-- + + “The _Ornithorhynchus_ is an animal bizarre of structure, and offers + numerous analogies with a host of different species and even classes. + In its external form it resembles in some degree the mole as to its + body, the beaver as to its tail, and the duck as to its beak. Its + internal structure, more astonishing still, resembles that of certain + reptiles, and appears to form a link between the Mammals and Lizards.” + +Every writer upon the platypus begins with an expression of wonder. +Never was there such a disconcerting animal! This wonder finds a +very curious expression in the determined efforts made to retain +Blumenbach’s name _paradoxus_, against all the rules of zoological +nomenclature. Even Everard Home, the English anatomist, writing less +than two years after the publication of Shaw’s original description, +uses the name given by the German author. + +An amusing and barefaced attempt to justify the use of Blumenbach’s +name is that made by Chenu (1879). On p. 349, after mentioning that +Shaw in 1792 had described the echidna under the name of _Myrmecophaga +aculeata_, he continues:-- + + “... four years later, Blumenbach, in 1796, having observed a skin + of a curious animal which Banks had sent him, was struck by the + resemblance of the curious kind of beak which terminates it to that + of a duck, and made it the type of a new genus, which he called, + because of this, _Ornithorhynchus_ ...; he applied also appropriately + to the species the name _paradoxus_.... Shaw, not knowing + Blumenbach’s work, made the same animal the type of his _Platypus + anatinus_.” + +Shaw could scarcely have been expected to know Blumenbach’s work, +since it did not appear until the year after his own description. In +1796, the year to which Chenu attributes Blumenbach’s observations, +the platypus had not been discovered in Australia. But Chenu has not +finished, and on p. 352 he writes:-- + + “As we have said in our general account of the Monotremes, the + genus _Ornithorhynchus_ was created, in 1800, by Blumenbach; + this name, most happily chosen since it recalls one of the best + characters of the included species, has nevertheless been changed + by some zoologists. _About the same time as Blumenbach_, Shaw has + named it _Platypus_, and Wiedemann, _Dermipus_; but the name of + _Ornithorhynchus_ has generally prevailed.” + +Despite this brave effort to establish Blumenbach’s priority, Shaw’s +specific name is now in general scientific use, though popular works on +natural history frequently use the _paradoxus_ of Blumenbach. + +Before considering the platypus in all its aspects, a few general +considerations may help to a better understanding of this ‘mystery +mammal.’ To begin with, it must be borne in mind that existing +monotremes are the survivors of a group which once formed the +aristocracy of the animal kingdom. The Tertiary is commonly referred +to as the Age of Mammals; but in late Mesozoic times there existed +mammalian forms which must have been the first wearers of hair and +drinkers of milk, and which were, in their day and according to their +manner, the lords of creation. They were mammals of a relatively +simple type and of a low grade of organization; but there was nothing +above them. In great part, however, they almost literally rose on +stepping-stones of their dead selves. The higher types to which they +gave origin easily defeated them in the competition for existence--ate +them, starved them out, thrust them into corners--and themselves went +forward to still higher destinies. + +The family trees of man and the platypus probably have a common origin +in this group of primitive Mesozoic mammals. At the time, however, +there was not even the faintest foreshadowing of man--not so much +as an insignificant tree-shrew, which is supposed by many to be the +kind of stock from which he sprang. But the anatomical features which +the platypus and the echidna possess in common, and by virtue of +which they differ from all other mammals, were, it is fairly certain, +characteristic of the whole primitive group of Mesozoic mammals; in +regard to these structural features the monotremes have not evolved at +all. + +Professor W. K. Parker, in his _Mammalian Descent_ (1885), writes:-- + + “At present, I have only partially worked out the young of one of + these kinds--the _Ornithorhynchus_; but although tolerably familiar + with the structure of the Vertebrata generally, I am at a loss, even + in this early stage of research, to see the meaning of many things in + that type. + + “Here is a beast--a primary kind of beast, a _Prototherian_--whose + general structure puts it somewhere on the same level as low + reptiles, and old sorts of birds; but in which there are characters + much more archaic than anything seen in Serpents, Lizards, Tortoises, + Crocodiles, or in Emeus. Therefore the existing reptiles and birds + must stand aside as having nothing to do with the family tree of the + Monotremes, although in some things they are like these beasts, and + many of their organs are formed on a similar pattern; they are all + equally below the morphological level of the nobler Mammalia.” + +Apart from its primitive simplicity, however, the platypus is a very +highly specialized animal--a statement not so self-contradictory as it +may seem at first sight. Man himself owes his dominant position to the +simplicity of his hand and the specialization of his brain. Kipling’s +jungle folk, wanting a name for the human infant which has strayed into +their midst, cannot find one among the mammals, and are forced back to +the Amphibia--to Mowgli the frog. Man has retained a simple body, which +has escaped the need for specialization because his evolution has been +projected outside himself into an evolution of tools and weapons. Other +animals in need of tools and weapons must evolve them from their own +bodily parts; we therefore frequently find a specialized adaptation to +environmental needs grafted on to primitive simplicity of structure. + +Without troubling about its internal anatomy, which presents many +archaic features, let us shortly balance the primitive external +features against others which show specialization to the peculiar +environment and mode of life of _Ornithorhynchus_. The platypus is an +aquatic mammal, but its bodily form shows no very marked adaptation +to aquatic conditions. During countless ages of life in the water it +has not developed the ‘stream-lines’ of porpoises and seals. Its body +is squat, clumsy, and reptilian, as are its short, thick limbs. The +adaptations to aquatic life are mainly two: the enormous webbing of the +fore-foot or paw, which is the actual swimming-organ, and the flattened +tail, which is used as a rudder and helps in diving. Its habits in the +water can be judged accurately enough from its form. It is not a rapid +swimmer, nor an especially graceful one. It has quiet and leisurely +ways, the quick dive when alarmed constituting its one speedy movement. + +The arrangement of the hair is primitive. It lies straight along +the back and belly and the upper and under surfaces of the limbs; +but falls away gradually on the sides, following the slope of the +surface. There are none of the special sensory hairs (vibrissae) +which are almost universal in mammals,--the ‘whiskers’ of the cat +will serve as an example. Against this simplicity we must set the +extraordinary specialization of the muzzle,[1] with its innumerable +special nerve-endings and its remarkable shape. It is easy and usual +to compare this muzzle to the beak of a duck. Superficially, the two +are much alike; in underlying structure, however, they are totally +unlike, and it is with the muzzle of the lower mammals that comparison +must be made. The integument is not horny, like that of a bird’s beak, +but soft, moist, flexible, and extremely sensitive. The under-water +life of the platypus is that of a blind animal. Keeping its eyes and +ears tightly shut, it feels its way by means of the touch-corpuscles +arranged all over the surface of its muzzle; by touch, combined +probably with its “sixth sense,” it also finds its food. Altogether, +the muzzle of the platypus is possibly the most remarkable organ for +sensory perception found in the Mammalia. The resemblance to the beak +of a duck has resulted from the similarity of the feeding habits of the +two animals. The common use of terms such as ‘horny’ or ‘leathery’ is +due to the fact that in stuffed specimens the soft, moist integument +dries, hardens, and becomes thinner; but this circumstance is very +misleading, as an examination of the living animal will show. + +[Illustration: UPPER AND LOWER JAWS FORCED WIDE OPEN. + +The normal opening does not exceed about 45 deg. + +1. Nostril; 2 & 3. Secateuring ridges; 4. Serrated portion of lower +lip; 5. Free end of tongue. + +(_From a fresh carcass_) + +_Plate 3_] + +[Illustration: JAWBONES, SHOWING DIVIDED EXTREMITIES. + +From same specimen as Plate 3, after drying. + +_Plate 4_] + +It will be seen in Plates 3 and 4 that both the upper and lower +jawbones of _Ornithorhynchus_ are divided at their anterior ends. They +are also pliable and permit of the lips being puckered to the extent +of forming thereby a small central suction tube. It seems probable +that, by pressing the sides of the lower lip tightly against the upper +jawbones, the maximum of food-matter is sucked in with the minimum +of so-called mud. Most observers agree that the animal feeds to some +extent on minute matter, such as the eggs and larvae of aquatic fauna +found on the bed of the river. A suction system such as that described +would be by far the surest method of obtaining such delicacies, as less +sediment and foodstuffs would be disturbed by the gentle methodical +probing of closed jaws than by abrupt champing or puddling. + +The small, bright eyes are remarkable only for their position high up +on the head. Since they are not used for vision under water, they have +come to be placed where they will be of most service to the animal +as it floats at the surface, munching its catch. The absence of an +external ear would seem to be a primitive character; in its place there +is a curious modification of the orifice of the auditory meatus. This +orifice lies at the posterior end of a facial furrow, the eye lying at +the anterior end, while the furrow is incompletely divided into two +by an oblique fold of skin. The edges of this furrow act as a long +pair of lids, by means of which both eye and ear may be tightly closed +at the will of the animal. The aural aperture can also be dilated and +contracted while the eyes are open, and can be “cocked” to catch sound +(see Plate 6, fig. 2). The arrangement of the lids serves also to keep +out water while the animal is submerged, and earth while it is engaged +in burrowing. + +The limbs are primitive and reptilian in general form, and progression +on land is clumsy, shuffling, and sinuous, like that of a heavy-bodied +lizard. The platypus can, however, raise its body off the ground when +moving fast, though it does so only occasionally. The fore-paws serve +both as the chief organ of locomotion in the water and as the burrowing +tool. The extensive web is used only for swimming, and is folded away +under the palms during running and digging operations. Being used +for digging, the claws of the fore-paws are straighter, broader, and +stouter than those of the hind feet. Both paw and foot have preserved +the full primitive number of five digits. The feet are also very useful +and versatile. Apart from their ordinary functions, when burrowing they +can be reversed for backward progression; in self-defence they are used +to grip the foe before applying the spurs; and during copulation they +are indispensable. They are also used for toilet purposes. + +The mouth exhibits a high degree of specialization. The true teeth +(which are, in any case, reduced in number to a few molars and +premolars) are lost early, and their place is taken by horny plates. +Anteriorly occur two pairs of horny ridges, which are not preceded by +teeth, and which serve to hold and kill the slippery prey; this is +then passed back and kept segregated by the large bulb which forms +the hinder part of the tongue. Two peculiar tooth-like projections, +directed forward from the anterior border of this swollen portion, +are of service in guiding the food to one side or the other as may be +necessary, and possibly for manoeuvring the grit, etc., contained in +the pouches. + +My observations on the cheek-pouches of the platypus have led me to +think that what has been written about their use for storing foodstuffs +must be wrong, and in order to test my theory I secured (by concussion) +three specimens of feeding platypus immediately on their appearance at +the surface of the river. I found grit, mud, sediment, and the broken +remains (including legs, wings, and hard coverings) of small aquatic +fauna, not only cramming the pouches, but covering, in quantity, each +set of grinders also. In their entrails, however, mud was the only one +of these traceable. + +Never yet have I found in the pouches sufficient remains of any one +creature to determine its specific kind. I confess myself no expert +in that branch of research; nevertheless, one would certainly expect +to find at least something recognizable if the pouching of foodstuff +beneath water was usual. Because of their bulk, adult shrimps and +other large-sized prey cannot possibly be pouched whole, nor can +they be passed through to the grinders before being dissected by the +secateuring ridges of the bill; this I have frequently observed while +feeding platypus in captivity. The necessary act of dissection, prior +to mastication, takes place while the animal is floating with its bill +skimming the water; therefore large prey must be carried up to the +surface in the bill-like section of the capacious jaws. + +These observations suggest to me that the purpose of the cheek-pouches +is to act as containers of grit rather than as receptacles for food. +The pouches open out at each side directly on to the grinders, which +project very little above the level of the jaws, and my opinion is that +the coarse grit aids considerably in their functioning as teeth, and, +further, tends to toughen the gums and thus convert them into grinders, +maintaining these essential conditions after the true teeth of the +nestling stage have disappeared. + +The fact that only the hard remains of foodstuff are found mixed with +the grit may mean that this mixture is drawn upon and repouched, +as occasion demands, over and over again; but whether the grit is +deliberately pouched before meals, or collected haphazard, or even +accidentally, with the food, I cannot say. It probably depends on the +class of food offering at any particular time and on the frequently +changing conditions of river beds--from mud to sand and shingle or +otherwise--according to varying seasonal changes by which platypus and +its many forms of living prey are naturally ruled. + +It should be understood that the platypus, from choice or necessity, +consumes various kinds of food, that some kinds are normally available +only at certain times of the year, and that in abnormal seasons the +variety, as well as the quantity, would be affected. At such times +one finds platypus gorging themselves with inferior muddy matter, +which would not, by preference, be included in their bill of fare. The +various statements made on this subject by observers may, therefore, +all be correct, though each is sceptical of the accuracy of the others. + +Finally, mention must be made of the curious integumentary flap which +projects backwards from the base of the naked muzzle, both above and +below. This is not altogether, as has sometimes been suggested, a +shield for the protection of the head during feeding and burrowing. +It is an extension of the area for sensory perception, and from its +position would appear to serve much the same function as the “whiskers” +about the mouths of other mammals. + +To this mixture of old and new physical characteristics there must +correspond a somewhat similar mixture of psychological characteristics. +Much of the behaviour of the platypus cannot be adequately explained +by its present conditions of life, and there is no obvious reason why +it adopted its present extraordinary precautions for the safety both +of itself and of its young. The Murray cod and the monitor lizards may +have eaten the platypus out of certain rivers, since there seems to +be nothing that they will not eat; but of this there is no reliable +evidence. The instinct for caution must be a heritage from some olden +time, when it had to contend with conditions much more strenuous. +During that period, which our imagination cannot reconstruct, the +ancestral platypus may have used its cerebral cortex to the full for +the winning of a livelihood in open competition, and for keeping +safe, not only itself, but its young. It has a large brain for its +size, proportionately much larger than those of many of the lower +Didelphia and Monodelphia. Its brain does not show any of the furrowed +convolutions which are looked upon as indicating a high degree of +mental development, but the smooth condition may have been acquired. +The brain of echidna, which is in general a much more stupid creature, +is convoluted, and indicates that this animal still has enough worries +to produce wrinkles on its cortical surface. + + +[Illustration: SKELETON OF PLATYPUS. + +Sketched from specimen in the Australian Museum, Sydney.] + + + + +CHAPTER II + +DISCOVERY AND EARLY DESCRIPTIONS + + +In the second volume of Collins’s _Account of the English Colony in +New South Wales_ (1802, p. 62), under date ‘November, 1797,’ there +occurs the following account of what was apparently the first platypus +captured by a European:-- + + “The Kangaroo, the Dog, the Opossum, the Flying Squirrel, the + Kangaroo Rat, a spotted Rat, the common Rat, and the large Fox-bat + (if entitled to a place in this society), made up the whole catalogue + of animals that were known at this time, with the exception which + must now be made of an amphibious animal, of the mole species, one + of which had been lately found on the banks of a lake near the + Hawkesbury. In size it was considerably larger than the land mole. + The eyes were very small. The fore-legs, which were shorter than + the hind, were observed, at the feet, to be provided with four + claws, and a membrane, or web, that spread considerably beyond them, + while the feet of the hind legs were furnished, not only with this + membrane or web, but with four long and sharp claws, that projected + as much beyond the web, as the web projected beyond the claws of the + fore-feet. The tail of this animal was thick, short, and very fat; + but the most extraordinary circumstance observed in its structure + was, its having, instead of the mouth of an animal, the upper and + lower mandibles of a duck. By these it was enabled to supply itself + with food, like that bird, in muddy places, or on the banks of the + lakes, in which its webbed feet enabled it to swim; while on shore + its long and sharp claws were employed in burrowing; nature thus + providing for it in its double or amphibious character. These little + animals had been frequently noticed rising to the surface of the + water, and blowing like the turtle.” + +Collins also included an engraving of the animal “from a drawing made +on the spot by Governor Hunter”, which appears on p. 63, with the +following legend:-- + + “AN AMPHIBIOUS ANIMAL of the MOLE KIND _which Inhabits the Banks + of the fresh water Lagoons in New South Wales--its fore-feet are + evidently their principal assistance in Swimming and their hind + feet having the Claws extending beyond the Web’d part are useful in + burrowing_.” + +A reproduction of this engraving is given on Plate 5. + +[Illustration: ORNITHORHYNCUS PARADOXUS + +Reproduced from the engraving in Collins’ _New South Wales_ (1802). + + The inference to be drawn from Collins’ description, read in + conjunction with the reference (under the engraving) to the hind + feet being useful in burrowing, is that the burrowing is done with + the hind feet. If that meaning was intended, Collins was evidently + misled by anatomical probabilities in assuming the function of the + projecting hind-claws for that purpose and ignoring the possibility + of the projecting web of the fore-paws being “palmed” to admit of the + claws being used for burrowing. The actual method of burrowing is + described on pages 112 and 120. + +_Plate 5_] + +It has not been possible to trace with certainty the subsequent history +of this individual platypus. In the following year (1798), however, a +specimen came into the hands of an English naturalist named Dobson, +and--as already mentioned on page 1--was described by George Shaw. +Shaw’s description was illustrated by two plates--Pl. 385, giving a +view of the whole animal, and Pl. 386, on which are figured three +aspects of the “bill”, and the fore-paw and hind foot. These are the +first published figures. The work in which Shaw’s original description +occurs is not easily accessible to the general reader, which fact is +some justification for quoting the full text. But the surprise of the +zoologist at the novel nature of the animal before him, and his uneasy +doubt whether he is not being deceived by a clever taxidermist’s wiles, +render the description too delightful to be omitted:-- + + “The animal exhibited on the present plate constitutes a new and + singular genus, which, in the Linnaean arrangement of Quadrupeds, + should be placed in the order _Bruta_, and should stand next to the + genus Myrmecophaga. + + “Of all the Mammalia yet known it seems the most extraordinary in + its conformation, exhibiting the perfect resemblance of the beak + of a Duck engrafted on the head of a quadruped. So accurate is the + similitude, that, at first view, it naturally excites the idea of + some deceptive preparation by artificial means: the very epidermis, + proportion, serratures, manner of opening, and other particulars + of the beak of a shoveler, or other broad-billed species of duck, + presenting themselves to the view: nor is it without the most minute + and rigid examination that we can persuade ourselves of its being the + real beak or snout of a quadruped. + + “The body is depressed, and has some resemblance to that of an Otter + in miniature: it is covered with a very thick, soft, and beaver-like + fur, and is of a moderately dark brown above, and of a subferruginous + white beneath. The head is flattish, and rather small than large: + the mouth or snout, as before observed, so exactly resembles that + of some broad-billed species of duck that it might be mistaken for + such: round the base is a flat, circular membrane, somewhat deeper + or wider below than above; viz. below near the fifth of an inch, and + above about an eighth. The tail is flat, furry like the body, rather + short, and obtuse, with an almost bifid termination: it is broader + at the base, and gradually lessens to the tip, and is about three + inches in length: its colour is similar to that of the body. The + length of the whole animal from the tip of the beak to that of the + tail is thirteen inches: of the beak an inch and a half. The legs + are very short, terminating in a broad web, which on the fore-feet + extends to a considerable distance beyond the claws; but on the hind + feet reaches no farther than the roots of the claws. On the fore-feet + are five claws, straight, strong, and sharp-pointed: the two exterior + ones somewhat shorter than the three middle ones. On the hind feet + are six claws, longer and more inclining to a curved form than those + on the fore-feet: the exterior toe and claw are considerably shorter + than the four middle ones: the interior or sixth is seated much + higher up than the rest, and resembles a strong, sharp spur. All the + legs are hairy above: the fore-feet are naked both above and below; + but the hind feet are hairy above, and naked below. The internal + edges of the under mandible, (which is narrower than the upper) are + serrated or channelled with numerous striae, as in a duck’s bill. The + nostrils are small and round, and are situated about a quarter of an + inch from the tip of the bill, and are about an eighth of an inch + distant from each other. There is no appearance of teeth: the palate + is removed, but seems to have resembled that of a duck: the tongue + also is wanting in the specimen. The ears or auditory foramina are + placed about half an inch beyond the eyes; they appear like a pair + of oval holes of the eighth of an inch in diameter, there being no + external ear. On the upper part of the head, on each side, a little + beyond the beak, are situated two smallish, oval, white spots; in + the lower part of each of which are imbedded the eyes, or at least + the parts allotted to the animal for some kind of vision; for from + the thickness of the fur and the smallness of the organs they seem + to have been but obscurely calculated for distinct vision, and are + probably like those of Moles, and some other animals of that tribe; + or perhaps even subcutaneous; the whole apparent diameter of the + cavity in which they were placed not exceeding the tenth of an inch. + + [Illustration: MALE PLATYPUS FLOATING. + + Of the upper surface, the only portions wholly submerged are the root + and tip of the tail. + + _Plate 5_] + + “When we consider the general form of this animal, and particularly + its bill and webbed feet, we shall readily perceive that it must be + a resident in watery situations; that it has the habits of digging + or burrowing in the banks of rivers, or under ground; and that its + food consists of aquatic plants and animals. This is all that can at + present be reasonably guessed at: future observations, made in its + native regions, will, it is hoped, afford us more ample information, + and will make us fully acquainted with the natural history of an + animal which differs so widely from all other quadrupeds, and which + verifies in so striking a manner the observation of Buffon; viz. + that whatever was possible for Nature to produce has actually been + produced. + + “On a subject so extraordinary as the present, a degree of scepticism + is not only pardonable, but laudable; and I ought perhaps to + acknowledge that I almost doubt the testimony of my own eyes with + respect to the structure of this animal’s beak; yet must confess that + I can perceive no appearance of any deceptive preparation; and the + edges of the rictus, the insertion, &c., when tried by the test of + maceration in water, so as to render every part completely moveable + seem perfectly natural; nor can the most accurate examination of + expert anatomists discover any deception in this particular. + + “The Platypus is a native of Australasia or New Holland, and is at + present in the possession of Mr. Dobson, so much distinguished by his + exquisite manner of preparing specimens of vegetable anatomy.” + +Two years later Shaw repeated this description in his _General Zoology_ +(1800, Vol. 1, pp. 228-232), with the following remarks as preface:-- + + “Of this most extraordinary genus the first description appeared + in the _Naturalist’s Miscellany_; but as the individual there + described was the only one which had been seen, it was impossible + not to entertain some distant doubts as to the genuine nature of the + animal, and to surmise, that, though in appearance perfectly natural, + there might still have been practised some arts of deception in + its structure. I, therefore, hesitated as to admitting it into the + present History of Quadrupeds. Two more specimens, however, having + been very lately sent over from New Holland, by Governor Hunter, to + Sir Joseph Banks, the suspicions before mentioned are now completely + dissipated.” + +It is clear from this that up to 1800 only three specimens had come +under Shaw’s notice. Whether from the words “as the individual there +described was the only one which has been seen” we are justified in +concluding that this individual was identical with that mentioned by +Collins, is another matter; but it seems at least probable. Little is +known of the subsequent history of the skin which served as the type +for Shaw’s description, but it was ultimately presented by Latham to +the British Museum, where it is now preserved. Mr. Oldfield Thomas +writes:-- + + “I have lying in front of me the original type skin of Shaw’s + _Platypus anatinus_, but I am afraid I can give you practically + no details of its history more than is printed in my Catalogue of + Mammalia. + + “It is an immature male with the spurs cut off (No. 110c of Gray’s + List of Mammalia in the British Museum, 1843) 343 millimetres in + extreme length. There were no registers in those days.” + +Mr. Tom Iredale has directed attention to the fact that Hunter, besides +the specimens which he had forwarded to London, also sent to Newcastle +a platypus which reached the Literary and Philosophical Society of +that city in 1798, together with a wombat, probably the first to reach +England. These two animals were described by Bewick in an addendum +to the fourth and all subsequent editions of his _General History of +Quadrupeds_. I have not seen the fourth edition, but quote from the +seventh (1820, p. 524):-- + + “We are favoured by the Literary and Philosophical Society of + Newcastle upon Tyne, with the figures and descriptions of two very + rare animals, sent to them from New South Wales, by James Hunter, + Esq. governor of that settlement.... The other seems to be an animal + _sui generis_; it appears to possess a threefold nature, that of a + fish, a bird, and a quadruped, and is related to nothing that we + have hitherto seen: we shall not attempt to arrange it in any of the + usual modes of classification, but content ourselves with giving + the description of both these curious animals as they have been + transmitted to us.” + +On p. 528 appears a woodcut of the platypus with a legend--“An +Amphibious Animal”--and the following description:-- + + “is found in freshwater lakes, and is about the size of a small + Cat; it chiefly frequents the banks of the lakes; its bill is very + similar to that of a Duck, and it probably feeds in muddy places in + the same way; its eyes are very small; it has four short legs; the + fore-legs are shorter than those of the hind, and their webs spread + considerably beyond the claws, which enables it to swim with great + ease; the hind legs are also webbed, and the claws are long and + sharp. They are frequently seen on the surface of the water, where + they blow like a turtle: their tail is thick, short, and very fat. + + “The natives say they sometimes see them of a very large size.” + +Bewick made no attempt to name the animal, and it appears in his index +simply as “An Amphibious Animal of New South Wales.” + +The first four specimens sent to England were in the form of dried +skins. Home (1802, p. 69), writing after he had received specimens +(in spirit) of the integumentary flap which surrounds the base of the +muzzle, uses the following words:-- + + “In dried specimens that have been brought to England, the flap has + been contracted in drying, and stands up perpendicularly. This, + however, is now ascertained not to be its natural situation.” + +As Home received from Banks the material which he described, it is +reasonably certain that he refers to the two individuals sent by +Hunter. One of these was sent to Blumenbach at Göttingen, who records +(1800, p. 206) that he has received a stuffed specimen from “the Hon. +Baronet Banks,” the first that had been sent from England to the +Continent. This individual he described as _Ornithorhynchus paradoxus_. +Weidemann, who also described the platypus in 1800 (as _Dermipus +anatinus_), apparently had no specimen, and merely gave a German +version of Shaw’s description with an indifferent copy of his figure. + +Blumenbach (1801, p. 724) published an extract from a letter from Banks +in which he stated that he now had a couple of spirit specimens, and +gave a short description of them. These specimens formed the basis +of the first anatomical description by Home (1802). The official +correspondence in the _Historical Records of New South Wales_ shows +that one of these was sent by Governor King, who succeeded Hunter. +King writes to Banks on 28 September, 1800:--“I send you by the +hands of Capt. Kent, who is nephew to Governor Hunter, and commands +the _Buffalo_, which he takes home with him, a cask in which is a +water-mole ... (_Historical Records of N.S.W._, IV., p. 205), which +I hope will all get safe, particularly the mole, which you desired.” +In due course Kent writes from on board the _Buffalo_ in Portsmouth +harbour, on 1 July, 1801:--“The keg containing the water-mole and other +articles in spirits ... I have still on board” (_loc. cit._, p. 427). +We can find no record of the other spirit specimen sent about this +time, but it is probable that this also was sent by King. A pencil +note in Banks’s handwriting records that two animals were received. + +A further spirit specimen is that of which Home (1802, p. 356) +writes:--“... had I not been favoured by Sir Joseph Banks with a +specimen of the paradoxus, brought from New South Wales by Mr. +Belmain.” Balmain came out as assistant surgeon with the First Fleet, +succeeded John White as head surgeon in 1796, and returned to England +on leave by the _Albion_, arriving in March, 1802. A box of specimens +was placed by King in his personal charge for delivery to Banks +(_Historical Records of N.S.W._, IV, pp. 514-5). + +It is of interest to note in passing that King uses the name +‘water-mole’ in the letter quoted above, but in a later letter to Banks +(dated 5th June, 1802) writes:--“I do not recollect what things I sent +by the Buffalo besides the duckbill....” (_loc. cit._, p. 784). These +are the first mentions noted of the two names which were in vernacular +use for many decades. + +The first account of the habits of the platypus is that given to Home +by Hunter. Home writes (1802, p. 67):-- + + “Governor Hunter, who has lately returned from New South Wales, where + he had opportunities of seeing them alive, has favoured me with the + following particulars respecting them. + + “The _Ornithorhynchus_ is only found in freshwater lakes, of + which there are many in the interior parts of the country, some + three-quarters of a mile long, and several hundred yards broad. + This animal does not swim upon the surface of the water, but comes + up occasionally to breathe, which it does in the same manner as the + turtle. The natives sit upon the banks, with small wooden spears, + and watch them every time they come to the surface, till they get + a proper opportunity of striking them. This they do with much + dexterity; and frequently succeed in catching them in this way. + + “Governor Hunter saw a native watch one for above an hour before he + attempted to spear it, which he did through the neck and fore leg; + when on shore, it used its claws with so much force, that they were + obliged to confine it between two pieces of board, while they were + cutting off the barbs of the spear, to disengage it. When let loose, + it ran upon the ground with as much activity as a land tortoise; + which is faster than the structure of its fore-feet would have led us + to believe. It inhabits the banks of the lakes, and is supposed to + feed in the muddy places which surround them; but the particular kind + of food on which it subsists, is not known.” + +As the second volume of Collins’s _New South Wales_ was not published +until 1802--by which time Home’s paper had appeared, and a copy had +been sent by him to Collins--the author was able to include a further +account of the platypus (1802, pp. 321-8), abstracted from Home. + +Hunter’s account forms the basis of most statements concerning the +economy of the animal which appear in European works on natural history +during the next three decades. Since the first discovery was made ‘on +the banks of a lake near the Hawkesbury,’ the platypus is invariably +described as a dweller on the banks of lakes, and its more customary +habitat in rivers is not mentioned. Mr. Henry Selkirk, who has a +long-standing familiarity with the Hawkesbury district, informs me that +he thinks it probable that the lake mentioned as the site of the first +discovery is one of several lagoons close to the town of Richmond. He +himself, as a boy, made his first acquaintance with the platypus in +those waters. + +These meagre particulars are all that I have been able to gather +concerning the discovery of the platypus. In view of the interest which +it excited in Europe, and of the keen demand for specimens that must +have followed immediately upon the first description, it is rather +remarkable that contemporary journals and official documents should be +so barren of reference to it. White and Tench, who would surely have +told us more had they been in the colony at the time, had unfortunately +returned to England before the discovery. Hunter, to whom we owe the +first drawing of the animal, as well as the first description of its +habits, appears to have taken his recall very much to heart. Little is +known of his subsequent history, and he made no effort to continue his +journal over the period of years which included the first finding of +the platypus. + +It is certain, however, that there was a brisk traffic in specimens. +When the great controversy as to the zoological position of the +platypus, and its method of reproduction, began in the second decade +of the nineteenth century, most European museums were in possession +of material. Much of this was, doubtless, brought back by the various +French scientific expeditions of which mention is made hereafter; +but a great deal must have passed through English hands, and records +of this may be presumed to exist somewhere. They have not, however, +been revealed, and the only other contemporary account which I can +find is in Barrington’s _History of New South Wales_ (1804), which is +substantially reproduced, without acknowledgment, from Home. + + + + +CHAPTER III + +CONTROVERSY ON THE ZOOLOGICAL POSITION + + +Vertebrate animals are now divided into five classes--Fishes, Amphibia, +Reptiles, Birds, and Mammals--distinguished from one another by such +obvious characters that no zoological knowledge is required to classify +any normal member of one of these great groups. When, however, the +position of _Ornithorhynchus_ first came under discussion, Amphibia +were usually included with Reptilia, making four classes only. + +To Shaw, the first zoologist to handle a platypus, the animal was +obviously a mammal, since it had a furry covering; he placed it in +the lowest Linnean Order, Bruta, which included what we know now as +the Edentata, or toothless mammals (though not all are toothless), +anteaters, sloths, and the like. Shaw had only a stuffed skin, and +could know nothing of the anatomy. Yet he was fully seized of its +remarkable character, as may be judged by his reference to Buffon’s +aphorism in the passage quoted in the preceding chapter. + +Blumenbach (1800) made anatomical observations on the bones contained +within the skin sent him by Banks, but his paper is not available in +Australia. The first account of the anatomy of specimens preserved in +spirit is that by Home (1802), who received a male and female from Sir +Joseph Banks, both probably sent by Governor King. + +Home was an anatomist, not a systematist; in his first paper he does +not concern himself with the systematic position of the animal whose +anatomy he was describing. He notes the remarkable character of the +organs of reproduction both in male and female, and remarks (1802, p. +81):-- + + “This structure of the female organs is unlike anything hitherto met + with in quadrupeds; since, in all of them that I have examined, there + is the body of the uterus, from which the horns go off as appendages. + The opossum differs from all other animals in the structure of these + parts, but has a perfectly formed uterus; nor can I suppose it + wanting in any of the class Mammalia.” + +Finding that these organs were not comparable with those of mammals, +Home was led to examine the corresponding parts in birds and reptiles, +and found most resemblance to the organs of ovi-viviparous lizards. He +concludes (p. 82) + + “There is therefore every reason to believe that this animal also is + ovi-viviparous in its mode of generation.” + +Later in the same year Home examined the anatomy of the echidna (Spiny +Anteater), which Shaw has described in 1792 as _Myrmecophaga aculeata_. +He at once recognized its close affinity to the platypus, and included +it in the same genus as _Ornithorhynchus hystrix_ (1802, p. 356). He +sums up on p. 360 as follows:-- + + “The peculiar characters of the _Ornithorhynchus_, as a genus, or + more properly a tribe of animals, are: + + “The male having a spur upon the two hind legs, close to the heel. + + “The female having no nipples. + + “The beak being smooth, while the rest of the animal is covered with + hair. + + “The tongue having horny processes, answering the purposes of teeth. + + “The penis of the male being appropriated to the passage of semen; + and its external orifice being subdivided into several openings, so + as to scatter the semen over an extent of surface, while the urine + passes by a separate canal into the rectum. + + “The female having no common uterus; and the tubes, which correspond + to the horns of the uterus in other quadrupeds, receiving the semen + immediately from the penis of the male. + + “These characters distinguish the _Ornithorhynchus_, in a very + remarkable manner, from all other quadrupeds, giving _this new tribe_ + a resemblance in some respects to birds, in others to the Amphibia; + so that it may be considered as an intermediate link between the + classes Mammalia, Aves, and Amphibia.... + + “Between it and the bird, no link of importance seems to be wanting.” + +In a later paper (1819, p. 237) he returns to this linkage with birds:-- + +“The mode of formation of the ova in the ornithorhynchi, constitutes +the intermediate link between that of the American opossum and the +bird.” + +This talk of “links” between classes, long before the advent of +Charles Darwin, is interesting. Home may not have used the word in an +evolutionary sense, but it seems likely that he did. In reading these +early discussions on the platypus, one is naturally struck by the +implied acceptance of the evolutionary idea which permeates them. + +Home’s opinion was, then, that the genus _Ornithorhynchus_ constituted +a new tribe of animals, to which, however, he gave no designation. +This opinion was based chiefly upon the structure of the organs of +reproduction in the female, and a brief explanation of the importance +of these organs may prove helpful to general readers. In birds and +reptiles the female organs consist of a pair of ovaries placed on the +dorsal wall of the body cavity, one on each side of the middle line. +In close relation to the ovaries are the wide funnel-shaped mouths of +a pair of tubes, the oviducts, which receive the ova shed from the +ovaries, invest them with additional coats, albumen, shell-membranes, +and shell, and pass them backwards to the cloaca--the common terminal +chamber, into which the alimentary canal and urinary organs also open. +In birds, the gradual development of a large-yolked egg, and the danger +to the mother involved in the production of such large eggs in both +oviducts simultaneously, has led to the reduction of the right ovary +and oviduct to functionless vestiges, those of the left side alone +remaining functional. + +In the higher mammals the organs are essentially the same, but with +certain marked differences. There is no longer a cloaca, the terminal +aperture of the food-canal being quite separate from that of the +urinogenital organs. Both ovaries and both oviducts are functional, +since the mammalian ovum is very small. But, except in a few lower +forms, the oviducts are no longer separate tubes; a varying amount of +fusion has taken place, the fused portion being the uterus, or womb. +This may be a single cavity, its double origin indicated only by the +horns of which Home speaks and into the apices of which open the upper +portions of the oviducts; or it may be more or less divided by a septum +and thus afford more obvious evidence of its double nature. Within this +uterus the young develop and are nourished until birth, being attached +to the maternal wall by a placenta. Where no placenta exists, as in +most marsupials, the young are born in a very immature condition; they +become attached to an external teat, and are nourished by milk, which +they cannot suck but which is impelled into them by muscular reaction +on the mammary glands of the mother. + +Turning again to _Ornithorhynchus_, we find that the oviducts open +separately into a cloaca, that the left ovary and oviduct alone are +functional, and, as will be shown later, that a shelled egg is laid, +which is hatched outside the body of the mother. This last fact was +not, of course, known to the naturalists who first discussed the +position of the platypus in zoological systems. In all these features +the platypus agrees with birds and reptiles, rather than with mammals. +It must also be held in mind that its mammary glands, the outstanding +characteristic of the mammalian class, had not yet been discovered; it +was not until 1824 that Meckel announced their discovery--which was +not, even then, accepted by all zoologists. + +It is hardly to be wondered at that zoologists were in doubt as to +the systematic position of this weird animal. Etienne Geoffroy (1803, +p. 125) included it with the echidna in a new order, Monotremata, +characterized by:--“Digits clawed; no true teeth; a common cloaca +opening to the exterior by a single orifice;” but he did not give any +precise indication as to where this order should be placed. Tiedemann +(1808) evaded the difficulty by placing it in an appendix. Lamarck +(1809) created a new class, Prototheria, for platypus and echidna, +deciding that they were not mammals, for they had no mammary glands and +were probably oviparous; they were not birds, for their lungs differed, +and they had no wings; and they were not reptiles, for they possessed +a four-chambered heart. Illiger (1811) placed them in a division +Reptantia, intermediate between reptiles and mammals. Blainville +(1812), on the other hand, was convinced that they were mammals, though +belonging to a separate order, Ornithodelphia. He was the first to +indicate their many close points of agreement with the marsupials, and +gave a long list of mammalian resemblances. + +Etienne Geoffroy was convinced from the outset that the platypus was +oviparous, and was not a mammal. He entered into a controversy with +Blainville which lasted for many years. Van der Hoeven and Latreille +were on his side, while Cuvier and Meckel supported Blainville. Isidore +Geoffroy, in his article on _Ornithorhynchus_ in the _Dictionnaire +Classique d’Histoire Naturelle_ (1827) includes the animal in Mammalia, +with a query, and gives a good summary of the position at that date, +just after Meckel’s discovery of the mammary glands. He supports +his father’s views, and argues that, even if the glands discovered +by Meckel are true mammary glands (which he doubts), this does not +necessarily make _Ornithorhynchus_ a mammal. He cites (p. 395) his +father, who claims (1826) that the so-called mammary glands are +homologous with the flank glands of shrews. They differ remarkably +in structure from any known milk-producing gland, and particularly +from those of marsupials, to which one would expect to find most +resemblance. Besides, how can one conceive of an animal with a horny +beak sucking, especially when the supposed milk gland has no teat? It +may be a scent-gland; or perhaps its secretion serves to coat the fur +and render it less permeable by water. The crux of the whole matter +is--Does _Ornithorhynchus_ lay eggs, or does it not? + +Meckel reported the discovery of the mammary glands in 1824, but it +was not until 1826 that his full description of them was published. +The glands lie between the main abdominal muscles and the muscular +sheet (_panniculus carnosus_) lining the skin. They are two in number, +each consisting of a considerable number of tubules which open by +minute pores upon a small area of skin; there is no teat. They are +large during the suckling period, but become very much reduced after +it is over, and this accounts for their being so long overlooked. We +now know that they are of the nature of modified sweat-glands, and so +differ from the mammary glands of mammals in general; there was thus +some justification for Geoffroy’s doubts. He returns to the charge +again in 1829, and first traverses the conclusions he had reached and +published in 1827. Monotremes, he maintained, were not mammals, as was +thought, and as was apparently indicated by the identity of several +important organs, e.g. limbs, hair, lungs, blood-vessels, heart with +two ventricles, closure of the chest by a diaphragm, etc. They must +be removed from the Mammalia, because their reproductive organs and +several other parts placed them amongst the oviparous classes. They +could not be included in the birds, because they had neither wings nor +feathers. Nor could they be placed amongst the reptiles, for their +blood was warm, and their lungs were enclosed in pleurae, and shut +off from the abdomen by a diaphragm. Still less were they fish, which +breathe by means of gills. They were therefore mammals without the +mammalian character, without the special organization of viviparous +animals, without all the consequences and functions of an apparatus +capable of producing a placental foetus. Rejected on all sides, they +did not belong to any recognized class of vertebrates; they must have a +special class to themselves. + +In spite of all this, Meckel presumes to discover mammary glands, and +announces the fact in 1824. For two years scientific men were kept +in suspense; then in 1826 appeared his wonderful description in which +Blainville found confirmation of the notions which he had published in +1808. But Meckel writes (1826, pp. 159-160):-- + + “I thought, and I said, that the new elements introduced into this + controversy were not what they had been announced to be. It is true + that a richly glandular apparatus had been discovered on each side of + the abdomen of an _Ornithorhynchus_; but it was a little too hasty to + decide and declare that it was a mammary gland. I examined the facts + again in a specimen preserved in spirit which formed part of Baron + Cuvier’s collections; I saw a glandular structure, but simple, and + merely composed of a considerable number of ampullae with long necks. + There were none of the characters which distinguish a milk gland.” + +Geoffroy proceeds to announce the discovery of eggs, the sad story of +which will be told in another place, and concludes (p. 164):-- + + “We may to-day regard it as certain that the first zoological + division, comprising vertebrate animals, should henceforth be divided + into the five following types: Mammals, Monotremes, Birds, Reptiles, + and Fishes.” + +Despite these strenuous efforts, however, the monotremes were generally +considered to be mammals, although the actual method of reproduction +was not definitely known until 1884, and although there are still some +doubtful points about the lactatation. + +In this connection Etienne Geoffroy’s final desperate effort to +disprove the mammary nature of the glands may be mentioned. He compared +them to the so-called mammary glands of whales and porpoises, which +secrete not milk but mucus. This coagulates on being ejected into the +water, and is then devoured by the young. Unfortunately, just as he had +elaborated this hypothesis, he had the ill-fortune to secure a nursing +porpoise, and found that the glands secreted milk. Nevertheless, this +endeavour may account for a statement by Verreaux which we shall have +to consider later. + +The production of milk by _Ornithorhynchus_ was definitely recorded by +Maule (1832) and by Bennett (1833). + +[Illustration: MALE PLATYPUS WATCHING INTENTLY. + +Note brightness of eye when on the alert. + +_Plate 6_] + + +[Illustration: FEMALE PLATYPUS LISTENING INTENTLY. + +Note end of top lid “cocked” for catching sound. Eye comparatively +inert. + +_Plate 6_] + + + + +CHAPTER IV + +CONTROVERSY ON THE LAYING OF EGGS + + +Home (1802), the first anatomist to examine the platypus, suggested +that, from the nature of the reproductive organs in the female, it +might be ovi-viviparous. In 1819 (p. 238) he makes a categorical +statement, without giving any evidence in support, as follows:-- + + “In the ornithorhynchi the yelk-bags are formed in the ovaria; + received into the oviducts, in which they acquire the albumen, and + are impregnated afterwards; the foetus is aerated by the vagina, and + hatched in the oviduct, after which the young provides for itself, + the mother not giving suck.” + +Had this been put forward as merely the probable course of events, +there would perhaps have been some justification for it. But it is +given as a statement of fact, and it is hard to imagine how a worker +of Home’s standing could have committed himself to so dogmatic a +statement--which time has proved to be entirely erroneous, and for +which not one jot of actual evidence existed at the time it was written. + +Blumenbach (1801), after a study of the skull, suggested that the +platypus might be oviparous; but although this long shot ultimately +received confirmation, it hardly seems necessary to credit the +Göttingen anatomist with any very remarkable acumen. + +Those zoologists who considered the platypus to be definitely a mammal, +of course believed that it brought forth its young alive. Among these +we may include Blainville, Cuvier, and Oken. The last-named suggested +(1817) that the mammary glands might occupy some unusual situation, +and so might have escaped notice; later (1823), commenting on the +ovarian ovum described by Dr. Patrick Hill (see below), he points out +its resemblance to the mammalian Graafian follicle, and concludes by +saying that the tales of oviparity and ovi-viviparity have all arisen +from failure to observe the mammary glands. Oken’s assurance of the +existence of mammary glands was justified, as we have seen, by the +discovery of these glands by Meckel, announced in 1824. + + +[Illustration: VENTRAL VIEW OF MALE PLATYPUS. + +The spurs are concealed behind the heels. In this specimen the hair is +almost entirely worn off the under surface of the tail. + +_Plate 7_] + +It seemed likely, then, that despite the opposition of Etienne Geoffroy +and the extraordinary form of the animal itself and of its reproductive +apparatus, _Ornithorhynchus_ would turn out to be quite an ordinary +mammal, which produced its young alive. But persistent statements came +from the colonists of New South Wales that it laid eggs. Sir John +Jamison (1818, p. 585) wrote, without comment, and as if citing an +established fact:--“The female is oviparous, and lives in burrows in +the ground.” This would seem to indicate that nesting-burrows and eggs +had been definitely observed. But no actual evidence was forthcoming to +calm the agitation of European zoologists. + +Dr. Patrick Hill (1822, p. 623) examined what he believed to be an +impregnated female, in the left ovary of which was a large Graafian +follicle. This specimen was taken to England by a Mr. Scott, and, as +is recorded in a footnote, was presented to the University of Oxford. +Hill’s error as to the nature of the ovum gave rise to a considerable +misunderstanding. Fleming (1822, p. 215) stated that the eggs of +_Ornithorhynchus_ had been transmitted to London; although he was aware +that these ‘eggs’ were merely ovarian ova, this statement was repeated +in several French works. Hill concluded his letter with the following +words:--“Cookoogong a native, chief of the Boorah-Boorah tribe, says, +that it is a fact well known to them, that this animal lays two eggs, +about the size, shape, and colour of those of a hen; ...” As the egg +of the platypus measures only three-quarters of an inch in length, +Cookoogong’s estimate of the size is rather wide of the mark; but this +may have been due to misunderstanding on the part of Hill. + +In 1824 an anonymous article, “Quelques observations nouvelles sur +l’Ornithorhynque,” appeared in the _Annales des Sciences Naturelles_, +(Vol. II). Quite possibly it was written by Geoffroy St.-Hilaire. On +p. 75 the following words appear:--“On a vu à la Nouvelle-Hollande +des oeufs d’Ornithorhynque, et c’est M. Jameson, l’un des principaux +propriétaires et habitans de Botany-Bay, qui guarantit ce +renseignement.” Jamison’s statement that the platypus lays eggs has +here been converted into a definite assertion that the eggs have been +seen. + +In Vol. X of the same journal (1827) a second unsigned article +appears:--“Sur les Habitudes de l’Ornithorhynque”--the account +of the habits being quoted from the _Antologia di Firenze_, +XXIV, p. 305, where also it appears anonymously. On p. 193 we +read--“_Ornithorhynchus_ inhabits the marshes of New Holland. It makes +among tufts of reeds bordering the water a nest composed of down +and interlaced roots, in which it deposits two white eggs, smaller +than those of ordinary fowls: it broods on them for a long time, +hatches them like a bird, and only abandons them when threatened by a +formidable enemy.” The author of the article comments (pp. 194-5):--“We +regret that the _Antologia_ usually omits to make known the source +whence it borrows the curious facts which it communicates to its +readers. What we have just read bears a tolerably faithful resemblance +to an account by Patrick Hill, ... but it differs in being more +precise; which leads us to believe that it may be borrowed from another +and a newer source.” It is quite obvious that the account was drawn +from Hill, the greater precision being due to the journalistic sense of +the writer. + +However, these statements about eggs stirred Etienne Geoffroy to +make enquiries, and the article closes with a quotation from a +letter written by Southwood Smith to Milne Edwards in reply to +Geoffroy:--“There are no eggs of _Ornithorhynchus_ with the Linnean +Society, nor in any other collection in London. One preparation had +been seen, and was said to be furnished with an egg; Sir Everard Home +had examined it, and was convinced that this was a mistake. This man +of science added that no one had taken more trouble than himself to +resolve all doubts on the subject of _Ornithorhynchus_, and that he had +hopes of doing so, having interested the Secretary of State for the +Colonies in this research.” This is a fairly literal translation of +the French, as it appears in the _Annales_. The letter may have been +written in English, in which case the re-translation of a translation +would be certain to differ considerably from the original. + +Lesson, writing in the _Annales_, Vol. VI (1825), says on p. 249:-- + + “Mr. Murdoch, superintendent of the farm at Emu Plains, assured me + that he had found the eggs of _Ornithorhynchus_, and that they are of + the size of those of a domestic fowl.” + +In Vol. XVIII (1829) Etienne Geoffroy, flushed with triumph, produced a +description and figure of veritable eggs. He writes on pp. 160-164:-- + + “But this fact, the more decisive as it is a fortunate confirmation + of old stories, has just been sent to me by the learned Professor of + Comparative Anatomy and Zoology in the free university lately founded + in London, Mr. Robert E. Grant: this is, that _Ornithorhynchus_ + certainly lays eggs. I publish the full text of the letter which this + savant has sent me; it is written from London, from the headquarters + of the new university, under the date 14th September, 1829. + + “Mr. Grant’s Letter. + + “Sir,-- + + “My return to London has been delayed, as I stopped at Calais, + Boulogne, Dover, and other places in England for the purpose of + making zoological investigations on the coasts; but having now + arrived here, I experience very great pleasure in communicating to + you the information which I have just received, and which I have + obtained from Mr. Leadbeater, concerning the eggs which he possesses, + and which are said to be those of _Ornithorhynchus_. + + “Mr. Holmes, well known to most naturalists in London as a gatherer + of natural history collections, has lived for some years in New + Holland. One day while hunting on the banks of the Hawkesbury, a + river in the interior of the country, he saw very distinctly, some + feet away, an _Ornithorhynchus_ leave a sandbank and escape in the + river. On examining the place where the animal had rested, Mr. Holmes + saw a hollow in the sand about nine inches in diameter, and in this + open cavity were some small twigs and the eggs in question. + + “He found there four eggs:--all were brought to England, together + with a collection of birds of the country. Mr. Holmes has since + returned to New Holland, with his wife and family. Two of these + eggs are in the Manchester Museum; the other two were given to Mr. + Leadbeater, who will not part with them, neither for cash nor for any + other consideration: he has refused to sell them to Sir Everard Home, + to various other naturalists, and to myself. + + “At the same time, despite the remarkable agreement of these facts + with the results of your profound studies, you will only accord to + this evidence such confidence as is due. + + “These eggs seem to me to differ, in form and texture, from those of + birds; they are remarkable for their regular spheroidal-oblong shape, + of an equal width at both ends; they measure 1⅜ inches in length, by + a breadth of ¾-inch; the shell is thin, fragile, semi-transparent, + and of a uniform flat white colour; its external surface, under a + lens, shows a wonderfully woven network; the calcareous matter forms + the white walls of its innumerable and very minute cavities, which do + not prevent the surface from remaining somewhat polished. One of the + eggs was broken, and I examined its inner surface, which seemed also + to be formed by the deposition of very small grains of calcareous + matter. + + “The size and shape of these eggs recall the eggs of lizards and + snakes, reptiles which have not, however, a tenth of the bulk of an + _Ornithorhynchus_. + + “My friend Mr. Yarrell, who has also examined the eggs, thinks that + they differ as much from those of birds as from those of reptiles. + Other travellers have told me that the Hawkesbury River, on the banks + of which these eggs were found, is reputed in that country to harbour + great numbers of _Ornithorhynchus_. + + “Mr. Holmes has been back in New Holland for nearly a year: and he + will again be directing his attention to this matter. + + “I regret being reduced to so few facts for communication to you on + this subject of so great interest to science. + + “I place at the bottom of my letter a drawing, made with the greatest + care, of the entire egg which I saw at Mr. Leadbeater’s; it is shown + natural size, and with the precise detail of its shape. + + “Robert E. Grant.” + +But, alas for the hopes of M. Geoffroy, this drawing, which he +reproduces in Plate 3, is so faithfully done that an Australian +zoologist has no difficulty in recognizing it as the egg of the common +long-necked tortoise (_Chelodina longicollis_). Geoffroy was, of +course, unaware of this. When, however, he came to consider the size +of the egg, he realized that it could not possibly pass through the +pelvic ring of the female platypus, the diameter of which was but +five-twelfths of an inch, while that of the egg was nine-twelfths. +Nothing daunted, Geoffroy first supposed that the egg passed to the +cloaca in a not fully developed condition, and that it underwent +further development there, but so rapidly as not to cause serious +obstruction. Later, however, in 1833, he discarded this view, and +believed that it remained in the oviduct until hatching took place, +since it could not pass through the small pelvis. He would seem to have +conveniently forgotten that the eggs were found laid in a nest in the +sand. + +Though, in support of oviparity, Geoffroy fell so often into error, he +ultimately proved right. The great Richard Owen, on the other hand, +through too firm and convinced a belief in ovi-viviparity, rejected +evidence which, in the light of our later knowledge, was convincing +enough; in the upshot he was proved wrong. The first piece of positive +evidence was given by Lieutenant the Hon. Lauderdale Maule, of the +39th regiment, in a letter to Dr. Weatherhead, extracts from which were +communicated to the Zoological Society of London and printed on pp. +145-6 of the volume for 1832. Maule writes:-- + + “During the spring of 1831, being detached in the interior of New + South Wales, I was at some pains to discover the truths of the + generally accepted belief, namely, that the female Platypus lays eggs + and suckles its young.” + +He goes on to say that he found and opened up a number of +nesting-burrows, of which he gives a summary description. He obtained +young which were forwarded to Dr. Weatherhead, and described by Owen; +but “no eggs were found in a perfect state, but pieces of a substance +resembling egg-shell were picked out of the debris of the nest” (p. +155). There is no reason to doubt that these were actually egg-shells, +but Owen ignores this statement altogether, and Broderip (1840) writes +in the _Penny Cyclopaedia_:--“The supposed portions of egg-shell found +by Lieutenant Maule in the nest were probably portions of excrement, +coated, as in birds, with the salts of the urine, that secretion and +the faeces being expelled by the same orifice.” + +It is probable that Owen based his views on the evidence of Dr. George +Bennett, who spent many years in endeavouring to penetrate the secrets +of the furtive and mysterious platypus. Bennett obtained impregnated +females, and forwarded uteri containing ova to Owen, who described them +in 1834. He also found young, but did not succeed in getting eggs, and +became convinced that the young were brought forth alive. He tried +to get precise information from the aborigines, but, again probably +through lack of understanding, failed. We read on pp. 122-3 of his +_Gatherings of a Naturalist_:-- + + “The various contradictory accounts that have been given, on the + authority of the aborigines (who might be supposed, from their so + often seeking these animals for food, to be able to state their + habits correctly), as to the animal laying eggs and hatching them, + induced me to take some pains to find out the cause of such an error, + and being now perfectly satisfied as to the contents of the uteri, + I could the more readily determine the accuracy or inaccuracy of + the accounts which I might receive from the natives. I determined, + however, not to ask any person who had been repeatedly questioned + before on the same subject; but some time after, when I visited the + out-stations in the Tumat country, where such questions had never + been previously asked, I made inquiries among the most intelligent. + The Yas natives at first asserted that the animals lay eggs, but + very shortly afterwards contradicted themselves. To ascertain what + dependence could be placed on them, I made a drawing of an oval egg, + which was recognized to be like that of the Mallangong. I then made + a drawing of a round egg, and that also was declared to be ‘cabango’ + (egg) of the Mallangong. It was also declared that ‘old woman have + eggs there in so many days’ (the number of which they did not know), + that the young ones ‘tumble down,’ and that two eggs are laid in one + day. An account subsequently obtained from a native, who appeared + anxious to explain the fact, would lead to the belief that the + animal is ovi-viviparous; but yet, from the difficulty they find in + expressing themselves in our language, we often misunderstand them. + He asserted the animal to be oviparous; but when desired to procure + the egg, he replied, ‘Bel cabango (no egg) tumble down; pickaninny + tumble down.’ + + “In the Tumat country the answers were readily and satisfactorily + given; and afterwards, more minute questions being put to them + through my interpreter, the result was the same. ‘Tambreet no make + egg (corbuccor) tumble down; pickaninny make tumble down,’ was their + reply. This accorded with my observations; for it was at the season + when this inquiry was made that the young platypi were found in the + burrow, as if just brought forth.” + +Had Dr. Bennett relied more on individual effort instead of on +aboriginal information, this vexed question could have been settled +there and then. + +The next account is that given by M. Jules Verreaux, of the Paris +Museum, who spent some time in Tasmania; he wrote an article +“Observations sur l’_Ornithorhynque_” in the _Revue Zoologique_ for +1848. This article contains a curious admixture of fancy with some +of which we shall have to deal later. The only point that interests +us here is that on p. 130 Verreaux declares himself quite sure that +the animal is ovi-viviparous, without giving any justification for his +assertion. Owen (1848) reviews this article, and on p. 318 comments +on Verreaux’s statement, which, apparently, he is quite prepared to +accept, suggesting that it is based upon the same kind of evidence +that has led to his own conclusions. He deplores the lack of absolute +proof, but sets out in a footnote the reason for his belief: “It is to +the absence of this proof that Dr. Carpenter appears to refer, where +he remarks, in his excellent _Principles of Human Physiology_, 1842, +p. 40, ‘No _positive_ evidence has yet been obtained that its young +are born alive.’ The minute size of the ovarian ovum and consequently +of the vitellus; the presence of small ova with a delicate chorion and +without chalazae or shell, in the uterine portion of the oviduct; the +absence of any shell-forming portion of the oviduct--all are elements +of a body of _positive_ evidence in favour of the ovi-viviparity of the +_Ornithorhynchus_, which needs only the discovery of the foetus _in +utero_ for decisive confirmation.” + +In 1865 (1865, pp. 683-4) Owen published, with comment, two interesting +letters from Australia, which are worth quoting in full:-- + + “Wood’s Point, September 21st, 1864. + + “To Professor R. Owen. + + “Sir,--I have great pleasure in being able to inform you of a + very interesting discovery in the economy of the _Ornithorhynchus + paradoxus_, and one which I have no doubt you will hail with delight. + About ten months ago, a female Platypus was captured in the River + Goulburn by some workman who gave it to the Gold-Receiver of this + district. He, to prevent its escape, tied a cord to its leg and put + it into a gin-case, where it remained during the night. The next + morning, when he came to look at it, he found that it had laid two + eggs. They were about the size of a crow’s egg, and were white, soft, + and compressible, being without shell or anything approaching to a + calcareous covering. + + “I had an opportunity of examining them externally, and I found no + evidence of their having had any recent vascular connexion with the + maternal organs; but I am sorry to say that I never had a chance of + examining their contents, as, on inquiring for them a day or two + afterwards, I found they had been thrown away, much to my chagrin and + disappointment. + + “The animal itself was afterwards killed (next day), and I was told + that numerous ova (in the words of my informant ‘eggs’) were found in + it, in various stages of development, which in the aggregate somewhat + resembled a bunch of grapes; but this I cannot personally vouch for. + + “It may appear to you a matter of surprise that I did not examine + more minutely this interesting animal; but I am sorry to say that the + same spirit that dictated the throwing away of the eggs, prevented me + making a more detailed investigation. + + “I am in hopes that I shall be able to get another pregnant specimen; + if so, I shall have much pleasure in sending it to you for your + inspection. + + “I have the honour to be, Sir, + “Your obedient Servant, + “Jno. Nicholson, M.D., etc.” + “Wood’s Point, Victoria, Australia.” + +By a later mail Owen received from Dr. Mueller a letter from the +“Gold-Receiver” referred to by Dr. Nicholson. It had been written in +reply to enquiries, which vague reports of the occurrence had induced +Dr. Mueller to make. + + “Woods’ Point, September 25, 1864. + + “Dear Sir,--In reply to your enquiries relative to the + _Ornithorhynchus paradoxus_, I must in the first place correct an + erroneous impression which the newspaper paragraph has conveyed. + + “The Platypus is not now in my possession, and the eggs were laid the + day after its capture. The animal was captured in the Goulburn and + given to me. It was then fastened by a cord in a gin-case, and on + examining it the next morning the two eggs were found in the bottom + of the box, both of them having undoubtedly been laid during the + night. In the course of the day the creature was killed by a _would + be_ scientific friend of mine, with the intention of preserving its + skin; and on opening the body the ovaries were found to be clustered + with ova in different stages of growth; but none of them so large as + the eggs which were laid. These eggs were white, soft, and without + shell, easily compressible, and about the size of a crow’s egg. + + “Not being sufficiently versed in the subject I am not prepared to + say whether these eggs might not have been abortions caused by fear, + but there was no appearance on the surface of their ever having been + vascularly connected with the maternal uterus, and reviewing all the + facts observed I should undoubtedly say that the animal was oviparous. + + “I am, dear Sir, + “Yours faithfully, + (Signed) “Geo. J. Rumby.” + +Owen comments as follows upon these letters:-- + + “Assuming the fact of the oviposition in the month of December 1863 + (Dr. Nicholson writes of the occurrence as having happened ‘about + ten months’ before the date of his letter, September 21, 1864) by a + female _Ornithorhynchus_, of two ova, about the size of a crow’s egg, + ‘white, soft, compressible, without shell or anything approaching to + a calcareous covering,’ the question is--What did they contain? Had + the unvascular chorion been cut or torn open, an embryo or a yelk + might have been seen. Better still would it have been if both ova had + been at once immersed in a bottle of whatever colourless alcoholic + liquor might be at hand. Probably no medical man had ever an + opportunity or a chance of settling a point in comparative physiology + of more interest, and with less trouble, than the gentleman who was + privileged to be the first person to see and handle the new-laid eggs + of the _Ornithorhynchus paradoxus_.” + +I can sympathize with Owen in his disappointment. It would indeed be +interesting to know what was inside those eggs. Probably young birds! +However, without that knowledge it is not possible to decide whether +they were the first eggs known to have been laid by a platypus. If the +size mentioned by both Nicholson and Rumby is correct, they could not +have been the eggs of _Ornithorhynchus_, which have but a third of +the length and a tenth of the bulk of any Australian bird’s egg that +could justifiably be referred to as that of a crow. The words “soft” +and “compressible” in their descriptions are perplexing; if correct, +then the size was wrong, and, if incorrect, the probability is that a +practical joker introduced birds’ eggs. + +At the outset Owen appears to have accepted this account at proving +that _Ornithorhynchus_ was oviparous; but later he inclined to the +belief that the eggs might have been “abortions due to fear,” and was +still enquiring for definite evidence. + +In the _Australian Journal of Education_ (vol. ii, 1869) there is +a series of articles on the fauna of Australia, most of which are +unsigned. That on the platypus appears on pages 104-5, under the +pseudonym “Five Dock;” it contains nothing of any particular interest +except a statement that the egg-laying idea is “exploded.” + +On p. 16 of the _Proceedings of the Royal Society of Tasmania_ (1878) +we read:-- + + “Some members having expressed their opinion that the question as to + the animal being oviparous had long been settled in the negative, Mr. + E. D. Swan remarked that Professor McCoy, who would be recognized by + all as an authority of the greatest weight, had recently written to + the effect that he had received evidence of a most reliable character + that the _Ornithorhynchus_ was oviparous.” + +But I cannot find that McCoy ever published this evidence. + +In the same journal for 1879 Dr. Crowther makes some interesting +observations on the platypus, and remarks on p. 96:--“when I tell you +that the foetus has been found in utero, and in a hairless condition +in the burrow ... (The former of these startling facts I hope to +demonstrate to this society soon.)” It is hardly necessary to point out +that this hope was never fulfilled. + +The matter was not finally settled until 1884. In that year W. H. +Caldwell, a Cambridge zoologist who came to Australia specially to +investigate the reproduction of monotremes and marsupials, obtained +eggs of both platypus and echidna in the Burnett River district of +Queensland. He writes (1887, p. 464):--“In the second week of August I +had similar stages in _Ornithorhynchus_,[2] but it was not until the +third week that I got the laid eggs from the pouch of _Echidna_. In the +following week (August 24) I shot an _Ornithorhynchus_ whose first egg +had been laid; her second egg was in a partially dilated _os uteri_. +This egg, of similar appearance to, though slightly larger than, that +of _Echidna_, was at a stage equal to a 36-hour chick. On the 29th +I sent in the telegram ‘Monotremes oviparous, ovum meroblastic’ to +a neighbouring station, where it would meet the passing mail-man, +addressed to my friend Professor Liversidge, of the Sydney University, +asking him to forward it to the British Association at Montreal.” + +Caldwell’s cable was read before the Montreal meeting of the British +Association for the Advancement of Science in September, 1884, and +the scientific world at last had the solution of a question which had +troubled it for more than eighty years. Monotremes laid eggs. By a +curious coincidence, W. Haacke found on 25 August, 1884, an egg-shell +in the pouch of an echidna, and exhibited it before the Royal Society +of South Australia on 2 September, the very day on which Caldwell’s +cable was read in Montreal. Haacke has made the claim that he first +discovered the oviparous nature of the monotremes, but there can be no +question that Caldwell has priority. + + + + +CHAPTER V + +GENERAL CHARACTERISTICS + + +The general form of the platypus is by now familiar to all. It appears +stuffed and mounted in all natural history museums, and illustrations +of it adorn all ordinary natural history books. Yet, strange as it may +seem, I have never seen a correctly mounted specimen in a museum, nor a +correct figure of the whole animal in a book. + +The most conspicuous feature about the bodily form of the platypus is +its prevailing flatness. The naked muzzle is broad and flat; the head +is so much depressed that the eyes have become more dorsal than lateral +in position; the trunk is broad and flat, though in profile its outline +rises from the shoulders to a point a little behind the middle of its +length, and then falls towards the tail; a cross-section has the form +of a low arch, a good deal more broad than high; finally, the tail is +broad and flat, with a broadly rounded tip. + +The skin, kimono-like, is over-large for the size of the body, and, +except at all the animal’s extremities, it appears to be entirely +dissociated from the primary nervous system. That is to say, a platypus +will readily respond to the slightest touch on either feet, paws, bill, +lips, or tail, but will not shrink from being soothingly stroked, from +forehead to rump, along the fur. This characteristic is most apparent +while the animal is submerged in water, where it is unable to see, +hear, or smell the experimentalist. + +[Illustration: (1) HEAD OF FEMALE PLATYPUS, SHOWING DIRECT DORSAL +VISION. + +In this instance the eyes, which are situated above the white patches, +are closed. + +_Plate 8_] + +[Illustration: (2) VENTRAL VIEW OF LIPS. + +Note how sides of lower lip are pressed tightly against upper jaws, +leaving space in centre for sucking in foodstuff. + +_Plate 8_] + +The muzzle with its backward-projecting flaps is naked, as also are +the upper surfaces of the digits of paws and feet, and the palms and +soles. All the rest of the body is covered with hair, which is of +two main kinds. Closely investing all the body except the tail +and extremities of the limbs is a fine dense under-fur, beyond which +project the ends of a much longer and harsher kind of hair, with highly +polished tips. The under-fur is woolly, grey at the base, inclining to +brownish at the outer ends. The longer hairs are remarkable in that +their projecting portions are flattened, giving them a lance-like +appearance, and are generally curved so that the ends turn in to the +fur. On the animal’s back and sides these hairs are usually dark +brown in colour, but the tips are frequently silvery white, or, in +reddish individuals, golden yellow. The prevailing paler colour of +the under surface is due to the absence of dark pigment from the ends +of these hairs, which have grey basal portions and tips ranging from +silver-white through yellow to chestnut and (in some cases) deep +ferruginous brown. + +This longer fur determines the animal’s colour, which is variable +within fairly narrow limits. The usual coloration is deep umber-brown +on the back and sides of head and body and upon the exposed surfaces of +the limbs; but reddish individuals are not uncommon, and some examples +are almost black. The ends of the long hairs are frequently curly, and +the prevailing ground-colour becomes powdered, as it were, with silver +or gold, in consequence of the different colour of the tips. + +The hair on the dorsal surface of the tail is coarse, and without +flattened tips. Owing to the constant dragging of the under-side over +the ground, this surface is usually denuded of hair, but in young +individuals a delicate silky fur is present, usually of a golden +colour, but ranging to warm brown. + +The ventral surface of the body is described by Thomas (1888, p. 389) +as ‘dirty greyish white’, which hardly does justice to the beauty +of the fur on this part. It ranges from silver through yellow to +warm chestnut, being lightest on the chest and throat, and darkening +posteriorly. Old males sometimes have the whole ventral surface a warm +brown in colour, with darker markings about the chin, limbs, and vent. +The colour is, in all instances, due to the highly polished tips of +the longer hairs, which have a brilliant sheen comparable with that +of the breast-feathers of the tippet grebe (see Plate 7). An albino +is recorded by Bennett, and one is exhibited in the Mammal Gallery of +the Australian Museum, Sydney. Sometimes, too, the black skin of the +extremities is mottled with white. + +The coat of the platypus is devoid of stripes, bars, spots, or +pattern of any description, save for a small yellowish-white to +yellowish-brown spot placed just beneath the eye. Bennett (1860, p. +98) correctly described this spot, and noted that it occurred, with +a single exception, in all specimens of either sex which had come +under his observation. Thomas (1888, p. 389) dismisses it briefly +as ‘a spot round each eye white or yellowish.’ Wood Jones (1923, p. +46) remarks--“There is said to be a ‘white or yellowish’ area around +each eye; but this area, though almost always emphasized in text-book +accounts of the animal, is not invariably present.” + +To describe this spot as ‘around the eye’ is misleading. In some +individuals the very slightly differentiated upper eyelashes certainly +are light in colour, but it is only to this extent that the spot may be +said to surround the eye. It is, as Bennett describes it, immediately +below the inner angle. It is, moreover, present in all the platypus +I have seen, including specimens from Queensland and Tasmania in the +Australian Museum collections. That it is not invariably present is +indicated by Bennett’s observation of an individual without it. Home +(1802, p. 70) also records its absence in a male which he examined; +he judged from its presence in the female that it was a character for +the distinction of the sexes. This is not so, since it is commonly +present in males. In dried skins, if the head be not fully filled out, +it sometimes becomes involved in the facial furrow, and thus escapes +notice; in spirit specimens, as well as in those wet with water, it is +often curiously inconspicuous. Thus, out of ten photographs of the one +animal illustrating the articles of Hornaday and Joseph (1922) which +show the eye, only two (on pages 108 and 109) show the spot clearly. In +one or two of the others it can just be made out, but in most it is not +visible. Yet it is ordinarily a conspicuous mark, whether on dry land +or under water, as may be judged from both subjects shown on Plate 6. + +The hair of the platypus, as has been mentioned in the first chapter, +has a general fore-and-aft direction, and, apart from the different +kinds of hair described above, the only differentiation is to be found +in the region of the facial furrow. Here the hair surrounding the eye +is slightly modified to form eyelashes of a rudimentary nature, and the +aural orifice is lined with short fine hairs, which help to prevent +water and particles of soil from gaining admittance. There are no +specialized sensory hairs in any part. + +The muzzle, which shows some resemblance to a duck’s bill in the dry +condition, is very different in the living animal. The naked skin is +thick, but soft, moist, and flexible, very unlike the horny beak of +a bird. On the upper surface it is slate-coloured; on the under, of +a yellowish flesh-colour, often broadly mottled with greenish slate. +From the base of each mandible a cuticular flap projects backwards +over the fur of forehead and throat. The dorsal flap is longest in the +middle line of the head, varying from 17 to 20 mm. in length, and is +shorter at each side. The ventral flap is wider at its base than the +dorsal, and has a shallow emargination in the middle of its posterior +border. Although described separately as dorsal and ventral flaps, +these really form round the base of the muzzle one continuous collar, +which is only partially divided into dorsal and ventral portions by +deep dorso-lateral emarginations. The nostrils open upon the upper +mandible at about a third of its length from the anterior end. They are +oval apertures with a slight rim-like border, set close together at +each side of the middle line. Their anterior borders lie very close to +each other, but they diverge obliquely behind. The dorsal portion of +the muzzle measures, in an individual of average size, 60 mm. long by +50 mm. wide; it considerably overlaps the ventral portion, which in the +same individual measures 42 mm. by 38 mm. (see Plate 8). + +The muzzle, with its flaps, is a highly specialized sense-organ. The +whole of its exposed surface, both above and below, is pitted with +minute pores, which extend on to the cuticular flaps and mark the sites +of the highly specialized touch-corpuscles. When under water, the +animal depends principally on its delicate sense of touch for finding +its way about, and it is fairly certain that the same condition obtains +in the burrow. Even when in the open air, it probably depends largely +upon the muzzle, since its eyes are so placed that it cannot easily see +objects straight in front of it on the ground. The anterior border of +the upper mandible is, from its position, the part most brought into +use for testing objects, and would seem to be especially sensitive, +for the platypus strongly resents its being touched, notwithstanding +that it is used for shovelling away loose earth and for upturning +river shingle. But the general distribution of touch-corpuscles over +the whole of the naked area indicates that all parts are sensitive; +and their continuation on to the flaps carries a sure implication that +these, too, subserve a sensory function. Many dangers threaten an +animal nosing about blindly under water; and it seems probable that +the extension of the tactile area in this way is a provision against +entering crevices and crannies in which it might be caught. It is +well known that it can squeeze through very narrow spaces, and it is +possible that the flaps are used as a gauge by means of which it can +tell whether it is safe to go on, or wiser to withdraw. Whether this be +so or not, the flaps are assuredly a part of the great tactile organ, +and not a mechanical shield. In some of the earlier figures, drawn from +dried skins, these flaps are shown standing up at right angles from the +surface of the head; in the living animal they are always laid back +upon the fur, nor does it seem able to raise and depress them to any +appreciable extent. + +[Illustration: PLATYPUS PAWS, EXPANDED FOR SWIMMING, AND CONTRACTED FOR +WALKING AND BURROWING. + +Note impressions in membrane caused by coming into contact with claw +tips. + +(_From fresh carcass_) + +_Plate 9_] + +The eye and ear are peculiarly arranged. In the half-grown young, +running across the front of the head, just under the border of the +dorsal flap, there is a groove which on each side turns backwards over +the area occupied by the eye and ear (see Plate 12). In the adult +the transverse portion of this groove has disappeared, but the lateral +portions remain as the facial furrows, in which the eye and ear are +situated. The eye, which has suffered most at the hands of artists +and taxidermists, is placed at the anterior end of the groove, very +close to the dorsal flap, by which it would be partly hidden were +not the flap emarginated a little at each side. It is rather small, +but exceedingly bright and beady, and has a dark brown iris almost +indistinguishable from the pupil. Because of its position it can see +only upwards and outwards, and its sole function would appear to be +that of detecting moving objects when the beast is at the surface of +the water or on the bank. In illustrations the eye is usually placed +in the middle portion of the furrow, that is to say, between its true +position and that of the ear. Even Gould’s plate exhibits this error. +Moreover, the eye is generally depicted too large, and often with a +light iris. The plates of Peron and Lesuer (1807) and of Lesson (1839) +show a yellow iris, and Waterhouse (1846) in his black-and-white figure +shows the iris white. A light iris has been given to many of the +specimens mounted in museums, and in these, too, the eye is usually +wrongly placed. In life the upper and lower eyelids are not well marked +off from the borders of the furrow, but may be distinguished by a +slight differentiation of the hair on their margins to form eyelashes. +There is a nictitating membrane capable of covering the whole cornea, +but I have never seen this employed by the living animal. + +The portion of the furrow which contains the eye is partially separated +from the auricular part by a fold of skin running obliquely upwards and +backwards from the lower border. There is no auricle (external ear). +The aural opening is in the form of a deep pit, occupying most of the +posterior half of the furrow. The margin is lined inside with short, +soft hairs, which prevent the entry of foreign bodies. The opening +can be dilated and contracted at the will of the animal, and is in a +constant state of motion when it is alarmed or excited. Under water, +or while burrowing, the whole furrow is closed by the apposition of +its upper and lower margins, and remains so until the head once more +emerges. The dorsal position of the eyes, in conjunction with the +bulging of the cheeks (due partly to the grit in the pouches) give the +sides of the head a heavy-jowled appearance. + +The head is joined to the trunk by means of a short and not very +well-defined neck. The shape of the trunk varies according to the +degree to which the animal is extended. When it is fully stretched in +walking, the body appears oblong, and twice as long as it is wide. When +squatting, the trunk appears both broader and higher in the posterior +region. + +The limbs are approximately equal in length, and are highly +specialized. The metacarpal region of the fore-paw is covered with +hair dorsally; the digits are naked, and are united by a black web, +which is extended beyond the tips of the claws for a distance of +15 mm. (in spirit specimens), the extension being supported upon +leathery thickenings which take origin from the under surface of the +ungual phalanges. Each of the three middle digits has two of these +thickenings, arranged symmetrically, but the two outer digits have only +one each, placed towards the lateral margin of the paws. The claws are +short, straight, and compressed. The palm is black and naked, finely +wrinkled, but without any pads such as usually occur on mammalian feet. +The fore-paw is the chief swimming-organ, its web being capable of +considerable extension in the living creature. On land, that portion +which extends beyond the finger-tips is folded under the palm, so that +the stout claws may be used for walking and burrowing. The adaptation +to two such totally diverse functions is very extraordinary. According +to Wood Jones (1923, p. 48) the digital formula is 4 3 2 5 1; but +the three middle digits are practically equal in length. In mounted +specimens, and in illustrations, the web is always shown in the +extended condition, but the animal when on land always has the web +tucked under its palms. It is, moreover, never flat, as usually shown, +but is always arched, with a dorsal convexity, even when extended. + +A somewhat remarkable transformation of the fore-claws is essential +before a young platypus can fend for itself. In the nestling stage, the +slender claws curve downwards and are grooved beneath. The reason for +this curvature is, apparently, to give the nestlings a firm grip of +the mother’s abdominal fur when vigorously nuzzling to induce a free +flow of milk (see Plate 10). As the nestling grows, the claws gradually +become straighter and broader, and instead of remaining grooved, the +nails become slightly convex below. By this time the paw is adequately +webbed for swimming, and consequently the young one is free to forage +alone (see Plate 9). + +With each vigorous sweep of the paw when swimming, there is necessarily +a severe pressure of the claws against the delicate webbing, and if +the claws were not broad and regularly rounded off beneath they would +undoubtedly puncture the swimming membrane. The same thing might +happen during the toilet process. On examining living adult specimens +I have found that, not only is the under surface of the claws convex, +but the tips are slightly tilted and there is a considerable amount +of resiliency in the nails. Yet, notwithstanding all this, distinct +impressions of the tips may be clearly seen in the webbing (see Plate +9). It will thus be seen that although the platypus is a burrowing +mammal, the nails are not designed entirely for that particular +purpose. This supports my opinion that burrowing is normally attempted +only in soil where the sensitivity-lipped bill can also be used. + +The hind foot is less remarkable. On the upper side it is covered with +hair almost to the ends of the digits, which are webbed. The webbing +does not extend beyond the bases of the claws, except for a peculiar +narrow prolongation on the inner margin, which lies just within the +first digit, and looks like the shadow of its claw. The claws are +laterally compressed, and strongly curved outwards and backwards. The +digital formula, according to Wood Jones, is 4 5 3 2 1. This foot is +scarcely used at all in swimming, except to help tread water, and to +aid the tail in steering. On land, the main thrust is due to the +feet, but the paws pull with a fair degree of strength. The sole, like +the palm, is black, wrinkled, and naked, except for a fringe of hair +along its inner border (see Plate 11). In the male a horn-coloured +spur is set upon the heel, with a fleshy collar about its base; this +spur is movable, and is directed backwards and inwards. In Bennett’s +figure (1860, Pl. III), as well as in a number of others contained in +authoritative zoological works, the spur is shown on the outside of +the foot. This may have been due to a laudable desire to get the spur +in at all costs, but it is apt to disconcert the seeker after precise +knowledge. In the female, a depressed socket lined with wrinkled skin +occupies a position corresponding to that of the spur in the male. The +spur is developed in the young of both sexes; in the male it grows +normally, but in the female it gradually disappears. + +The tail is broad and flat, with the under surface usually a little +concave. It is about a third longer than it is wide, with sides +slightly converging as it passes backwards, and with broadly rounded +end. The hair of its upper surface is exceedingly coarse and harsh; +that of the under surface, when not entirely worn off, is softer +and lighter in colour. It is a powerful and muscular organ, and an +efficient aid in diving, as well as a somewhat less efficient rudder. +In nursing females the hair is usually found to be worn off the upper +surface. This is caused principally by pushing the pugs back into +position in the burrow. Against this view, Wood Jones (1923, p. 48) +writes:-- + + “On general lines, the form of the tail resembles that seen in the + Beaver; and this form is, in both animals, an adaptation to surface + swimming and rapid diving. It has nothing whatever to do (either in + the Platypus or the Beaver) with any supposed habit of puddling clay + or flattening down the floor of its burrow or nesting-chamber. When + Beavers are alarmed they suddenly smack the water with their flat + tails and dive beneath the surface. The loud sound made by the smack + of the diving Beaver acts as a warning note to other Beavers in the + neighbourhood, and it is probable that the same warning note is + produced by the Platypus. The animal has several times been described + as making a sound as it dives.” + +[Illustration: (1) FEMALE PLATYPUS SUCKLING YOUNG. + +Note young one clinging to fur and supported by the mother’s tail. + +_Plate 10_] + +[Illustration: (2) FEMALE PLATYPUS. + +Note extreme looseness of skin, and tail worn bare with pugging. + +_Plate 10_] + +Without supporting evidence, the categorical statement that the tail +of the platypus has nothing whatever to do with any supposed habit +of puddling clay is not convincing, and I prefer to rely on my own +field observations. I must disagree also as to the warning signals. +These are common enough among gregarious animals, and the beaver is a +gregarious animal. The platypus is not gregarious, but almost solitary, +and therefore has no one to warn. Wood Jones writes, it is true, of +‘a considerable colony,’ but I have had no experience of colonies +of platypus. The rare occasions when I have found two in company +have always caused me surprise. I see no justification, therefore, +for arguing by analogy from the herd habits of the beaver to the +semi-solitary behaviour of the platypus. When surprised, and beating a +hasty retreat, the animal certainly makes a noise in diving; but this +has no significance, as I shall explain later on. + +The only sure external mark of distinction between the sexes is the +spur. Full-grown males are considerably larger than full-grown females; +but the immature or young male may be smaller than the female. Ten +males taken by me during the spring over a period of several years +measured (mm.):--600, 529, 535, 538, 481, 533, 485, 475, 540, 510, +averaging 522 mm. Nine females measured (mm.):--406, 402, 414, 460, +475, 433, 451, 421, 407, averaging 430 mm. + +Measurements of spirit specimens and skins in the Australian Museum +are:-- + + MALE. FEMALE. + Spirit Specimens. 445 mm. 398 mm. + 405 mm. 392 mm. + 455 mm. -- + + Skins 561 mm. 483 mm. + 560 mm. 478 mm. + 510 mm. -- + 537 mm. -- + + Average of 7 = 496 mm. Average of 4 = 413 mm. + +Bennett (1860, p. 102) gives the average measurements of freshly-killed +males as from 19 to 20 inches (483 mm. to 508 mm.); and of females as +from 18 to 19 inches (457 mm. to 483 mm.). + +We may next consider the nature and heat of the blood. In amphibia, +reptiles, and birds, the red blood-corpuscles are oval, nucleated +discs. In mammals they are non-nucleated, and in all save the camels +are circular. The platypus has typical mammalian corpuscles, of about +the same size as those of man. Cold-blooded animals (amphibia and +reptiles) have no heat-regulating apparatus, and their temperature +tends to rise and fall in accordance with that of the surrounding +medium, whether it be earth, air, or water. In mammals and birds, +on the other hand, the heat-regulating mechanism tends to keep the +temperature constant within a degree or two, regardless of the external +medium. This difference in blood-heat causes striking differences +in habit. The cold-blooded animal is forced to hibernate during the +winter, at least in places where there is a considerable difference +between the mean winter and summer temperatures; the depression of +temperature renders it inactive. The warm-blooded animal, on the other +hand, eats more food, and moves about actively in order to produce the +heat necessary to keep up its body temperature. + +It has been claimed that the monotremes exhibit an intermediate +condition, and are not completely warm-blooded. On this point, however, +I am in full agreement with Wood Jones (1923, pp. 38-39), and quote his +discussion of the matter:-- + + “In the same way we must admit that the body temperature of the + Monotreme is unusually low; but that is not to agree that they are + akin to the Reptiles in failing to maintain their body temperatures + within certain fairly definite limits. + + “The temperatures of seven females of the Platypus were taken by Mr. + Burrell. These females were removed from their nesting chambers, and + the observations were made in September. The temperature of these + animals ranged between 30°C. and 33°C., and the average of all the + observations was 32.2°C. + + “Of _Echidna_ there are many temperature records, since it + is an animal which is easily kept and examined in captivity. + Miklouho-Maklay, in 1879, examined a series of ‘porcupines,’ and + concluded that their temperature ranged between such low figures as + from 26.95°C. and 28.3°C. In 1886, R. von Lendenfeld, as the result + of a series of observations, concluded that the body temperature + was higher, but more variable, and they give the extremes as 28°C. + and 35°C. Semon, in 1894, gave 26.5°C. to 34°C. as the range for + _Echidna_. Sutherland, in 1897, found it to be as wide as from 22°C. + to 36°C. Dr. C. J. Martin re-investigated the question in 1902, + and during the last few years Dr. Wardlaw has made innumerable + observations, and, thanks to his work, we may say that the + peculiarities of the body temperature of the Monotremes are now well + known. + + “The temperature of the higher Mammals varies within fairly wide + limits, and in the different species that have been examined it + ranges from about 36°C. upwards for a few degrees. It is therefore + obvious that both _Ornithorhynchus_, with its average of 32.2°C., and + _Echidna_, with its average of 31.1°C., are creatures of relatively + low temperature; but the difference between the Monotreme temperature + and that of other Mammals is not nearly so great as it is often + asserted to be. It must also be remembered that our knowledge of + the temperatures of some of the lower Monodelphia is scanty, and it + is possible that _Echidna_ and _Ornithorhynchus_ do not stand very + far apart from some of the more sluggish and least advanced of the + higher Mammals in the matter of their bodily heat. Again, the fact + that the temperature of the Monotremes varies at different times of + the day does not confer on them the distinction that some writers + have imagined. Dr. Wardlaw determined that the morning temperature + was always lower than the afternoon temperature; but the same is true + of the higher Mammals and of man. Semon noted this variation in the + temperature, but confessed that ‘a relation between these changes + and the changing temperature of the outer air could, however, not + be proved.’ That is to say, although the temperature of _Echidna_ + is variable, its rise and fall does not correspond with the rise + and fall of the temperature of its surroundings, as is the case + with the lower Vertebrates. There is, nevertheless, a time when the + temperature of _Echidna_ does tend to follow the temperature of the + outside air, and when the Monotreme can be said to behave somewhat + like a ‘cold-blooded’ or poikilothermic animal. This is during that + period of the year when the animal undergoes a partial hibernation + or aestivation. In the summer Dr. Wardlaw’s animals averaged 30°C. + in the morning and 32.6°C. in the afternoon; but in the winter the + morning temperature was 29.7°C. and the afternoon was 32.3°C.; but + this fall in winter temperature is found in all hibernating or + partially hibernating animals; and it can only be said that the + Monotremes are animals having a rather low body temperature, but, + nevertheless, being truly homoeothermic (or ‘warm-blooded’) within + certain limits of temperature, and in the non-hibernating period. + They have a typically good mammalian heat-regulating mechanism, + effective between 27.6°C. and 32.6°C.; and it is only when the + temperature is raised or lowered beyond these limits that the + regulation tends to break down, and they behave as poikilothermic + animals.” + +[Illustration: (1) TOP OF LEFT HIND FOOT, WITH SWIMMING MEMBRANE FULLY +EXTENDED. + +Note tip of spur projecting behind and above ankle. + +(_From fresh carcass_) + +_Plate 11_] + +[Illustration: (2) SOLE OF RIGHT HIND FOOT. + +Note base of spur unsheathed; this readily occurs after death, but +seldom during life. Compare with Plate 15 (1). + +(_From fresh carcass_) + +_Plate 11_] + +Following is a table of cloacal and atmospheric temperatures (Fahr.) +observed by me during five years of field work. + + MALE PLATYPUS. + + Cloacal Atmospheric + temp. shade temp. + 8/10/23 84° 53° + 18/9/25 82° 63° + 19/9/25 87° 79° + + FEMALE PLATYPUS. + + 20/9/20 88° 70° + 23/9/21 87° 82° + 5/10/21 88° 68° + 8/10/23 84° 53° + 15/9/24 84° -- + 7/10/24 82° -- + 8/10/24 90° 46° + 14/3/25* 90° -- + 24/8/25 86° 64° + 24/8/25 92° 64° + 28/8/25 94° -- + 3/9/25 82° 70° + 10/9/25 89° 74° + 18/9/25 82° 63° + 26/9/25 86° 66° + + March may be reckoned as midway between rutting periods. + + * With this exception, all the females were brooders taken from nests. + +Two temperature readings of wild echidna specimens, made directly after +collection in mid-September 1924 and 1925, were found by me to be +respectively:-- + + 1. Cloaca, 90° Fahr. Pouch, containing young, 84° Fahr. + 2. Cloaca, 79° Fahr. Pouch, containing young, 82° Fahr. + +I did not record the atmospheric temperature when the 1924 specimen +was taken; but I noted that it was an exceptionally cold day. When the +second was taken, it was 70°. + +By attaching an adult platypus to a spring scale I found that it +could pull steadily (on level ground) six pounds, and up to twelve +by jerking. The bottom jaw, when open, can pull seven pounds in the +gradual closing. + +Characteristics common to the platypus, to reptiles, and to birds are +the single aperture or vent into which the intestinal, urinary, and +reproductive systems open, and the laying of eggs. The “scientific” +name (_Ornithorhynchus_) together with its commonly-accepted early +vernacular name of “duckbill,” its webbed feet, and the discovery of +its eggs have contributed to the existing impression, except among +zoologists, that the platypus is essentially bird-like; but, as a +matter of fact, while it is clearly a mammal, its remote origin has +been proved to be reptilian. Apart from this scientific conclusion I +would like to outline for general readers some external characteristics +of the platypus which I consider to be possessed also by certain +reptiles. + +The study of an animal in its adult stage is apt to lead one to look +for its relations in more modern forms, whereas in its embryo and +nestling stage it is more likely to exhibit the characteristics of +its forbears. By looking backward we may, therefore, occasionally +detect a trait connecting the platypus with much earlier forms in the +evolutionary cycle--a trait which in the mature animal would easily +escape notice, even if it had not entirely disappeared. + +To begin with the egg--quite apart from the leathery texture of the +capsule, the fact that the foetus has developed to a considerable +extent before deposition is positively reptilian in character. + +The tortoise-like overturning of a platypus, though inconspicuous +in the adult, is, nevertheless, deliberately and systematically +accomplished by the unfurred nestling, and this at a stage when their +limbs are of little assistance. Like a tortoise, a young platypus, +when floundering on its back, pivots its snout firmly in the ground, +then arches its neck, throat uppermost, until, by such strenuous +leverage, the shoulders are sufficiently raised to allow the wriggler +to over-balance on to its abdomen. + +Another reptilian trait peculiar to the young of platypus is their +power of endurance when wholly submerged in water, and, strange though +it may appear, the younger the subject the greater that power. This is +described more fully in the chapter on the breeding-burrow. + +The male platypus and echidna are the only known mammals with poison +glands, and this forms another link with the reptiles. + +From a dorsal aspect, the fur-tracts of _Ornithorhynchus_ trend +uniformly towards the tail, in a manner similar to that of the scale +pattern conspicuous in snakes, etc. It is true that slight semi-whorls +or waves of fur occur ventrally, and about the cheek-pouches, but even +this is not entirely wanting in the scale pattern of reptiles. + +Spurs, or “hooks” as I prefer to call them here, are to be found on the +fore-flippers of the male Green Turtle; but whether they are used as +weapons of defence I cannot say. My opinion is that, like those of a +platypus, defence is one of their purposes. From personal observation +of both creatures, however, I know that their hooks are used for +gripping during copulation. Incidentally it may be remarked that both +of these creatures perform this function in water. It is of prolonged +duration in both cases; therefore an untiring grip is essential. + +The casual gait of a platypus is somewhat akin to that of a +Stump-tailed Lizard, while the chubby tails which both animals possess +are sufficiently near in design not to be overlooked in this matter. + +The small and beady bright eyes of _Ornithorhynchus_, also their +position and the direction of their vision, are similar to those of +certain reptiles, as is also the dorsal position of the rigid nostrils. + +Although represented in swimming birds, the webbing of the feet of the +platypus is found also in reptilian quadrupeds. + +The contorting ability of an adult platypus is quite remarkable. It +can extend its length six inches without raising its abdomen from the +ground. When it is in a crouching attitude, with the back conspicuously +humped, it is impossible to see daylight below, and the contour of +the whole body resembles that of a squatting echidna. When lying +fully extended on its back, the platypus can, by placing the lower +portion of its bill on its breast, and without raising its head to +any appreciable extent, double itself ventrally until its head passes +its tail, and that pliable member is itself doubled until the creature +becomes normally righted on all fours, dragging its tail behind it. +This act it can accomplish in a tunnel equal in circumference to the +performer so doubled. When balled-up, as in the sleeping position, +the tip of its tail will reach over the head to the scapular region. +In the reversed position the tail-tip reaches to the gullet, above +the back. In turning sideways, with abdomen on the ground the while, +tail and bill just make contact. The head can be turned sideways at a +right angle to the body, and the tail can be moved either to form a +right angle with the rump or to lie comfortably along the contour of +the back, except at the base, where one can just insert the tip of an +index finger. These few items are additional to the animal’s capacity +for muscular expansion and oscillating limb-functions, and they give +some notion of what the platypus is capable of when hard pressed or in +a tight corner. + +Finally, the platypus, like the reptiles, has no external ears and is +flealess, though ticks are common to both. One is known by the company +one keeps. + +[Illustration: (1) HEAD OF INFURIATED MALE PLATYPUS. + +Note serrated edge of bottom lip. + +_Plate 12_] + +[Illustration: (2) NESTLING PLATYPUS, ABOUT FIVE WEEKS OLD. + +Note swimming membrane extending beyond claw tips of fore-paw; grip +of hind foot and tick on thigh; also that the eye is closed and the +ear-hole open. + +_Plate 12_] + + + + +CHAPTER VI + +NERVOUS ORGANIZATION AND SENSORY PERCEPTIONS + + +A primitive kind of mammal, which is in some respects intermediate +between the higher mammals and the reptiles, might be expected to show +a low grade of nervous organization and limited powers of sensory +perception, as well as something of the characteristic reptilian +cold-bloodedness. Strangely enough, these characters are not found in +the platypus. + +The brain is surprisingly large--much larger in proportion to the +body-weight than that of any reptile. It is, moreover, definitely +mammalian in its structure, except that it lacks the definite band of +fibres, connecting one hemisphere of the brain with the other, which +is known as the _corpus callosum_. This deficiency is not, however, +confined to monotremes, but also characterizes marsupials. Wood Jones +(1923, p. 32) writes:-- + + “The corpus callosum is a cerebral commissure, or a nerve fibre + bundle, which keeps the higher centres of the right and left central + hemispheres in communication across the middle line of the brain. It + cannot be said that the living monotremes are deficient in the extent + of their cerebral hemispheres--they are indeed mysteriously well + endowed with cerebral cortex. But it may be asserted--borrowing an + expression from the electrician--that their brains are underwired.” + +In the size and structure of its brain, then, the platypus proves to be +an animal with a considerable degree of intelligence, with a cerebrum +better organized than that of the lower marsupials and even of some of +the lower Monodelphia. A well-organized brain and a large surface of +cerebral cortex indicate a degree of intelligence far removed from +that of the reptiles. + +The psychology and sensory perceptions of animals other than ourselves +present a very difficult field for investigation. Philosophers have +never tired of telling us that the world about us is, though not +exactly a figment of our imaginations, yet an illusion due to the +limitations of our sensory perceptions. The physicist further confuses +our simple minds by supporting the philosopher with a statement that +the trees and grass and bricks and mortar which we imagine we see +are mere buzzings of electrons. We have, it is true, a proper scorn +for these attempts to befog us; yet, when we come to inquire into +the mental attributes or sense-reactions of any animal other than +ourselves, we are brought up sharply by an uneasy suspicion that the +philosopher may be right. Fabre, describing the behaviour of a wasp, +may record all its visible actions with scrupulous accuracy; when +he comes to interpretation of them, he can interpret only in terms +of Henri Fabre. We cannot project our minds into the mind of any +other animal; nor can we be sure that any other animal sees, smells, +tastes, hears, or feels just what we see, smell, taste, hear, and +feel. In fact, we know that there are differences, that our eyesight +is much inferior to that of the vultures, our sense of smell to that +of predatory carnivorous mammals in general, and so on. There is also +plenty of evidence that other animals possess sensory perceptions +denied to us. This being a matter which seriously affects human +prestige, we hasten to reassure ourselves by means of a dogmatic +statement that _we_ reason, while the rest of the animal kingdom, +unable to indulge in this majestic process, is at the mercy of tropisms +and instincts. + +This digression is merely a warning that what we conclude about the +mentality and sensory processes of the platypus must be derived chiefly +from what we know of these processes in ourselves. We say ‘chiefly,’ +because we have, after all, an evolutionary history of the development +of brains and sense-organs, and a surety (since our own have been +derived through those of the lower Mammalia) that the two must have a +great deal in common. Bearing in mind the limitations of the method, we +may proceed to an examination, first of the sensory perceptions, and +later of the intelligence, of the platypus, so far as we know anything +about them. + +The eye of the platypus is small; on this account it has generally +been assumed that the animal’s vision is poor. The earlier observers, +obsessed by the small size of the organ and the burrowing habits of its +proprietor, were led to compare its powers of vision with those of the +mole. As a matter of fact, though small, the eye is extraordinarily +bright, and is during life not deep sunk (as is commonly reported +from examinations of spirit specimens) but fairly prominent. The eyes +are certainly placed high towards the dorsal surface of the head; +but, since they are used only for sub-aerial vision, this position +would seem to be a direct adaptation to the particular purpose. +Wood Jones has certainly written, and that quite recently (1923, p. +52):--“Although the eye of the living animal is said to be brilliant, +it is small and deep-set, and so situated that its range of vision +must be very limited. In any case, one would not expect the sense of +vision to be remarkably acute in an animal which spends so much of its +time in a dark burrow, or at the bottom of the water.” I know that the +animal does not use its eyes under water--an observation which was not +available to Wood Jones--and I believe, though I have no proof of this, +that they are not kept open in the burrow. Their whole purpose is that +of sub-aerial vision, and they are so situated as to have the widest +possible range of vision when the animal is floating at the surface +with just the top of the flat head exposed. + +Bennett (1860, p. 135) observes of his captive animals:--“When running, +they were exceedingly animated, their little eyes glistened, and the +orifices of their ears contracted and dilated with rapidity.... Their +eyes being placed so high on the head, they do not see objects well in +a straight line, and consequently run against everything in the room +during their perambulations, spreading confusion among all the light +and easily overturnable articles. I have occasionally seen them elevate +the head, as if to regard objects above or around them.” + +When the animal is swimming in the water, it often raises its head, +so that the short neck is vertical to, and the plane of the head +horizontal with, the surface. Anyone who has ever attempted to shoot a +platypus is soon made to realize the sharpness of its vision. Bennett, +Semon, and many others have shown how useless it is to move towards the +animal when it is at the surface. The slightest movement is enough to +send it down; and, when it dives in alarm, it rarely reappears during +the same feeding period. It will also dive at the flash of a gun. + +My own observations go to show that, while the vision is acute in +diffused daylight (e.g., at the usual crepuscular feeding-times), +bright sunlight seems to affect it very considerably. When the sun +is shining, I find that there is no need to take precautions against +abrupt movements, as these do not seem to be observed. A gun may be +raised and pointed at the animal without the slightest notice being +taken. I have on many occasions released, during the daytime, platypus +collected for purposes of photography, and noted that, while the +animal dashes hurriedly for the water, when once there it displays no +further alarm. Waving the arms does not frighten it. The softest clap +of the hands, however, is sufficient to cause it to dive instantly. I +therefore believe that the auditory sense is much more acute than the +visual, at least during bright sunlight. This observation may account +for the apparent tameness of the animals observed by Geoffrey Smith. + +[Illustration: EXPERIMENT ON SENSORY PERCEPTIONS OF PLATYPUS BENEATH +WATER. + +1. Touching top lip; 2. Retreat from danger; 3. Returning from the +surface; 4, 5, 6. Hands held still for testing sense of smell. + +_Cinematograph by J. S. P. Ramsay._ + +_Plate 13_] + +I cannot say what kind of image is formed upon its retina; but we +are not entitled to assume that its power of sight is limited to the +detection of objects in movement, though that would appear to be the +chief purpose subserved. My own experience tells me that moving objects +are more easily perceived than stationary ones; and anyone who has had +successful experience of approaching or taming wild animals well knows +that the thing to be avoided at all costs is abrupt movement. The +capacity for detecting this kind of movement is as fully developed in +the platypus as in any other mammal, at least over the short range +which is necessary for the animal’s safety and well-being. Apart from +this, we have no criteria for comparing its powers of sight with those +of other animals, and certainly no justification, apart from the small +size of the eye, for assuming that these are limited. + +The auditory sense is undoubtedly acute. The creature dives on hearing +an unaccustomed noise just as rapidly as on seeing an unaccustomed +movement. Bennett, in the quotation given above, remarks upon the +dilatation and contraction of the aural orifice, which, in spite of the +absence of a definite auricle, remind one irresistibly of the nervous +twitchings and twistings of the ear made by a spirited and fidgety +horse. No observer of the living animal could have any doubt that it +depends very largely upon auditory sensations. Semon (1894, p. 11) +writes:--“Every doubtful noise causes it to disappear. I saw one dive +immediately on the discharge of a gun a mile away. It appeared again +rather soon, which decidedly it would not have done had it been alarmed +by a sound at close quarters.” In this instance, however, I think +the diving and distant report were merely a coincidence. As regards +Bennett’s statement concerning the twitching of the facial furrow +at the region of the ear-hole, I find that the platypus is actually +capable at will, of “cocking” it to act as a temporary auricle to pick +up sounds (see Plate 6, fig. 2). + +The olfactory organs are more definitely reptilian in character than +the rest of the sense-organs. To determine the measure of this sense, a +careful experimental enquiry would be necessary, and the platypus has +not shown any inclination to become a tractable laboratory animal. The +large size of the olfactory nerves, however, and the development of +scent-glands, are sufficient proof that the platypus has the sense of +smell. + +The optic nerves are small; the olfactory relatively large, though +not so enormously developed as in the echidna. Those branches of the +trigeminal nerve which are distributed to the muzzle are, however, +relatively enormous, a mass of nerve-fibres passing out through the +infra-orbital foramen above, and the inferior dental and mental +foramina below, and dividing up to go to every part of the sensitive +naked skin. These nerves end in special tactile corpuscles, the sites +of which are marked by innumerable pores (or pits) thickly scattered +over the naked integument. The whole of this area forms, as has been +indicated before, a remarkably sensitive tactile apparatus without +parallel among the Mammalia. + +The most sensitive portion of this remarkable muzzle is undoubtedly the +anterior border of the upper lip. As Bennett has remarked, the animal +exhibits signs of acute discomfort when this lip is touched or pressed, +and struggles violently to withdraw. At the date of this statement +Bennett was evidently unaware of the fact that the sensitive lip of +a platypus is used vigorously as a shovel when burrowing. Of course, +this portion of the muzzle would be the first to come into contact with +those animals which serve as food. Verreaux (1848, p. 129) states that +in burrowing the beak is first used to dig the soil. + +The extension of the naked integument into dorsal and ventral flaps is +very remarkable, and there has been much surmise as to the function of +these. Bennett first suggested (1860, p. 100):-- + + “In the base of both the lower and upper mandibles is a transverse + loose fold or flap of the integument, always similar in colour to + the skin covering the mandibles, that is to say, of a dull dirty + greyish-black in the upper, and white or mottled in the lower. In + the upper mandible this is continued very nearly to the eyes, and + may perhaps afford some protection to those organs when the animal + is engaged in burrowing, or seeking its food in the mud. The upper + fold or flap is continuous with another portion arising from the + lower mandible, also at its base. Some consider the use of these + folds to be to prevent the beak from being pushed into the soft + mud beyond this part, which is so broad as completely to stop its + further progress. From careful observation of the actions of living + specimens, I can assign no other use to this part than that which I + have just mentioned.” + +Oldfield Thomas (1888, p. 388) states:-- + + “Beak smooth, evenly rounded, its junction with the head marked, both + above and below, by a projecting leathery flap, evidently developed + to save the face from injury when the head is plunged in mud or + gravel.” + +Since the platypus has been observed to bury itself up to half its +body-length in mud and gravel, it becomes obvious that the purpose of +these flaps cannot be that of preventing it from burying more than +its ‘beak.’ If the function of the flaps be to protect the eyes, it +is a remarkable fact that the dorsal flap is emarginated at each side +just in front of the eye, where the protection would be most needed. +Moreover, the ventral flap could take no part in such protection, +and the eyes and ear are already quite sufficiently protected by the +apposable lids of the facial furrow. I am thus forced to the conclusion +that the flaps subserve a function wholly tactile, a conclusion +supported by the fact that their anterior faces are studded with +touch-corpuscles. In the platypus, therefore, these flaps may be said +to take the place, and serve the purpose, of the facial vibrissae of +higher mammals (see Plate 12, fig. 1). + +Passing to the sense of taste, we again find ourselves without means +for determining the precise degree of gustatory perception possessed +by the platypus. Poulton (1883) has investigated the structure of the +tongue. The anterior portion, which is free from the floor of the +mouth for only a third of its length, and is therefore capable of +only very limited movement, is covered with rough papillae directed +backwards, between the bases of which lie many mucous glands. This part +of the tongue contains only tactile terminal organs, somewhat like the +Pacinian corpuscles of ducks, and is concerned with the passing of +food back to the grinders. The taste-areas occur upon the posterior, +swollen portion of the tongue, and are four in number. The anterior +pair are situated in deep antero-lateral grooves, the posterior in much +shallower postero-lateral depressions. All four grooves are crammed +with taste-buds, approximately of the same type as those occurring in +mammals in general. The platypus is a dainty feeder, and it would seem +that its taste-sense is an important feature in its general economy. It +prefers its food alive, although in captivity hunger will induce it to +accept dead food. This must, however, be fresh. + +In addition to the five commonly-accepted senses, which are provided +for by special sense-organs, I have referred elsewhere to the +remarkable development of a sense of direction which the platypus +displays in locating the nearest water, in detecting obstacles +beneath the earth (thus inducing it to alter the course of its +burrow), and in procuring its food. The first of these powers is the +common possession of many animals, but is not, so far as I am aware, +understood or accounted for in any of them. The second and third are +quite as remarkable. Even in man there are still traces of a sense of +perception of something solid in the immediate neighbourhood. This +so-called “sixth sense” is probably due to the intense development of +some extremely sensitive organ not yet accurately defined. The ability +to “sense” the proximity of certain objects may be exemplified in the +bat, which flits unharmed about the darkest caverns, aided probably +by highly-sensitized skin-folds situated on its snout, and in certain +fishes, in which the well-known lateral-line organs help to serve a +similar purpose. + +My observations of the platypus under water support the view that, of +the five senses ordinarily possessed by animals, the only one operative +while the platypus is gathering its food at the bottom of a river or +water-hole is that of touch. My opinion is that this animal must have +developed some extraordinary means of finding its prey, apart from the +sense of touch, and that the sensory apparatus through which this acts +is connected in some way with the fleshy nature of the bill. If this +“sixth sense” is not responsible, then we must fall back upon that +makeshift word “instinct,” which is referred to by Hornaday (1922, p. +9) when he says “Instinct often functions as a sixth sense.” + +In a recent controversy concerning its use of the senses of smell and +touch while searching for food at the bottom of a river, the question +arose as to whether it relied on either of these exclusively, or on +both. No attempt had previously been made to solve the problem, so I +there and then decided to investigate systematically, and had a glass +tank constructed, with an observation chamber (see Plate 13). I was +well aware at the outset that the intended captive would be nervous +and excited, but concluded that such unavoidable conditions might be +to some extent counterbalanced by liberating it suddenly into fifty +gallons of cool, fresh water. At least, I imagined that a sudden +stimulant of that nature would somewhat, if only temporarily, lessen +the shock, since my presence would be unsuspected. + +When all was in readiness for the try-out, I obtained an uninjured +adult female from a burrow near by, and, so as to give her ample +experience of the smell of human hands (to say nothing of the sight and +feel of them), I handled her repeatedly and deliberately, occasionally +rubbing my hands, back and front, over her sniffing nostrils, besides +frequently fingering her sensitive lips. I reasoned that, if her sense +of smell was only half as efficient below water as on top, she might be +expected to shy clear of the submerged hands that had just previously +overhauled her. But such was not the case; in fact, quite the reverse +occurred, and to the marked astonishment of several onlookers she +instantly sounded, and, after probing her way along the sandy bottom of +the test-tank, reclined leisurely beneath the unscrupulous hands which, +only a few minutes earlier, were beyond doubt the dread of her precious +life. Several times she swam to the surface for a timely blow and +repeated the first performance, notwithstanding that I had deliberately +interfered with her several times below, with the specific object of +forcing her into action (see Plate 13, fig. 3). + +While she was practically stationary on the sand beneath my hands, I +placed my finger directly above, and within an eighth of an inch of +her nostrils. But obviously she was quite unaware of my presence or +behaviour until my finger came in contact with the tip of her bill. +“Cat-like,” then, she arched her back, raised her tail, turned a kind +of twisting somersault, and swam away (see Plate 13, fig. 1). Again +she returned and casually nuzzled my hands as though nothing unusual +had happened. Possibly the tap on the snout did not seem to her to +be any more than the sudden flip of a startled shrimp. Nevertheless, +I am quite convinced that she did not return solely to satisfy her +curiosity, or purposely for shelter, as she had already taken advantage +of that elsewhere in the tank. + +Judging from all that occurred, I ultimately came to the conclusion +that, if the creature had any sense of smell at all beneath the water, +she certainly did not display it during my investigations. The supposed +abnormal sense of touch was also not nearly so keen as I had surmised, +at any rate in the detection of immediate danger (at least of an +unfamiliar nature), while she was wholly submerged. Still, the bill may +be extremely sensitive and quite indispensable while sifting mud and +selecting suitable foodstuffs below. In that case (which I think may be +assumed) it is probably safe to assert that an adult platypus has no +enemies of consequence to fear beneath the water. Otherwise the docile +_Ornithorhynchus_ would surely not have fared so well during the many +evolutionary phases since prehistoric times. + +What is it, then, that is responsible for the prolonged existence of +this primeval creature? Is it a sixth sense, or simply because such +creatures fare well--as they appear to do--on so-called mud? As regards +the five ordinary senses of a platypus when on land, or afloat, I have +nothing to add except direct confirmation, if necessary, of their +existence; but I suggest that, beneath the water, where mud is possibly +consumed regardless of taste, the sense of taste is without function, +and that it remains so until the animal swims to the surface and +leisurely masticates the food taken while below, at least in the case +of large prey. + +Of the senses of hearing and seeing, so far as I could observe, +both were rendered inoperative, while the creature remained +submerged, principally by means of a water-tight facial furrow which +simultaneously envelops the orifice of both ear and eye directly the +animal decides to sound. I endeavoured to attract its attention by +shouting at the top of my voice, while it groped about my submerged +hands and around the glass helmet enveloping my head, without +demonstrating the slightest symptoms of agitation. Testing the sense of +sight proved rather perplexing. However, I came to the conclusion that, +strictly speaking, the animal could not then see, although, whenever +it came to a part of the tank where the light was at all strong, it +immediately turned and sought the most shaded parts. + +As a guide to those interested in this subject, let me state that +it is practically impossible, owing to its timid nature, to test +accurately the sense of smell of a freshly-captured platypus beneath +water by introducing natural foods. Hence the omission of such an +attempt in this instance. Of course, a test could be made, and no doubt +successfully, with a contented and undisturbed captive, but I have +intentionally left that opening to other enthusiasts perchance intent +on checking my slender theoretical views. + +In a previous test case[3] I proved beyond doubt that a platypus in +captivity will devour in assorted foodstuffs (not including mud) half +its own weight nightly. Now, if similar quantities are consumed when +the creature is at large, then, as a platypus providore, it is beyond +my imagination to comprehend how it obtains such an enormous supply, +unless mud be included in the bill of fare as a kind of “fill-up” +necessity, if not as a staple food. + +Of the many platypus that I have had occasion to dissect, the +intestines and stomachs of most, especially the robust and +healthy-looking specimens, contained much mud, and apparently little +else, while the cheek-pouches of all bulged, crammed with grit, mud, +and crunched aquatic creatures, seemingly of minute forms. + +On one occasion, in the presence of the late Charles M. Hoy, who was +collecting in Australia for the Smithsonian Institution, I extracted a +small shrimp (entire) from the stomach of a foraging female platypus, +captured at noon. Possibly, the crustacean slipped down accidentally. +Nevertheless, that query does not upset my theory that platypus are +indiscriminate mud-suckers, but it tends rather to strengthen my +contention that the sense of taste is apt to cease functioning beneath +water. + +Live shrimps collected directly from the feeding-grounds of platypus +are readily devoured by _Ornithorhynchus_ in captivity. In fact most +specimens prefer them to indigenous river-bank worms or other varieties +of food supplied to them. From personal observation, I can vouch for +one male platypus in captivity that lived entirely on dead raw prawns +(salt-water variety) for eight months, and was then, apparently, in +splendid condition. Furthermore, it is said to have lived four months +longer, when unfortunately for the experimenters, it escaped from its +neglected enclosure. I have no hesitation in saying that platypus are +occasional mud-suckers, and that at least some part of their living +food is both discovered and secured by that sucking process. + +While under water, the sense of touch is apparently the only one of +the five ordinary senses functioning fully, and, in the procuring of +food, even that sense appears to be less effective than the animal’s +mysterious ability to track and secure living prey. + +Again, as mud is seemingly a necessity, if only to appease an enormous +appetite, why has the platypus such an abnormal nervous system of +touch? Surely the presence of mud could be readily determined by a +puddling platypus, without such special equipment as super-sensitized +abnormally-formed lips, etc. + +If a platypus must actually touch before being aware of the presence of +shrimps or other active prey that it so relishes and thrives upon in +captivity, then, to my mind, such wary creatures would be rarely taken +alive when at large. On the other hand, if a sixth sense functions to +assure direction, then it would be quite possible for a platypus to +collect half of its own weight in live animal foodstuffs nightly, but +not otherwise. + +The ease with which the platypus can be killed indicates that there is +something delicate in its organization. The ordinary method in shooting +is to fire a heavy rifle-bullet beneath the animal as it floats at the +surface of the water, and the concussion is usually sufficient to cause +its death. + +What I have written is scanty enough; but I think it shows, despite +our lack of more precise knowledge, that the platypus is an +animal possessed of acute sensory perceptions, a delicate nervous +organization, an active metabolism, and a degree of cunning which +must be based upon considerable intelligence and which is far from +justifying Professor W. K. Parker’s epithet of ‘frog-witted duckbill.’ + +A final point of distinction is that the platypus possesses a voice. +Vocal powers are somewhat curiously distributed among vertebrate +animals. Frogs are notorious for vocal ability, and the Australian +species can hold their own with those of other parts of the world both +in the variety and in the volume of their choruses. Reptiles, however, +are practically voiceless. Snakes and some lizards hiss, and some +geckoes can scream when disturbed or handled, but the vast majority are +silent under all circumstances. The songs of birds have called forth +many tributes. The lower orders of mammals are not famously vocal. The +echidna, so far as I am aware, has no voice at all, the only sound it +makes being a sniff through its nostrils. Marsupials are in general +silent animals, the cough of the wallaby and staccato snort of the +bandicoot affording examples of the sounds they do make. Phalangers can +scream, but do so only exceptionally. The lower Monodelphia, too, have +remarkably little in the way of voice. That the platypus should possess +a voice was unexpected, and certainly few have recorded it. The furred +young, when disturbed, keep up a continuous growling noise, which it is +usual to compare to that of a growling puppy. The adults make a noise +which can best be imitated by a tremulous snoring. + + + + +CHAPTER VII + +THE SPUR AND CRURAL GLAND + + +In both platypus and echidna there occurs on the inner side of each +hind limb of the male a movable spur. This is found in the young female +also; but in the full-grown female it has disappeared, leaving a +depression to mark the spot where it had been. This condition suggests +that the spur and depression are of the nature of secondary sexual +characters, and have something to do with reproduction. Such was the +general belief for twenty years after the first discovery of the +platypus. Then it was reported from Australia that the spur of the male +was capable of causing serious wounds, followed by dangerous symptoms +due to a venom expressed through the spur. Thus began a lengthy +controversy which has not yet been settled to the satisfaction of all. + +Shaw (1799) described the spur as a sixth digit, but pointed out that +it resembled a strong, sharp spur. Home (1801, p. 72) made the first +surmise as to its function, and described it in the following terms:-- + + “In the male, just at the setting on of the heel, there is a strong + crooked spur, half an inch long, with a sharp point, which has a + joint between it and the foot, and is capable of motion in two + directions. When the point of it is brought close to the leg, the + spur is almost completely concealed among the hair; when directed + outwards, it projects considerably, and is very conspicuous. It + is probably by means of these spurs, or hooks, that the female is + kept from withdrawing herself in the act of copulation, since they + are very conveniently placed for laying hold of her body on that + particular occasion. The female has no spur of this kind.”[4] + +In March 1817 extracts from a letter from Sir John Jamison, dated at +Regentville, New South Wales, September 10, 1816, were read before the +Linnean Society of London and published in the _Transactions_ for 1818 +(pp. 584-5). Jamison writes:-- + +“I cannot avoid relating to you an extraordinary peculiarity which I +have lately discovered in the _Ornithorhynchus paradoxus_. The male +of this wonderful animal is provided with spurs on the hind feet or +legs, like a cock. The spur is situated over a cyst of venomous fluid, +and has a tube or cannula up its centre, through which the animal can, +like a serpent, force the poison when it inflicts its wound. I wounded +one with small shot; and on my overseer’s taking it out of the water, +it stuck its spurs into the palm and back of his right hand with such +force, and retained them in with such strength, that they could not +be withdrawn until it was killed.[5] The hand instantly swelled to a +prodigious bulk; and the inflammation having rapidly extended to his +shoulder, he was in a few minutes threatened with locked-jaw, and +exhibited all the symptoms of a person bitten by a venomous snake. The +pain from the first was insupportable, and cold sweats and sickness +of the stomach took place so alarmingly, that I found it necessary, +besides the external application of oil and vinegar, to administer +large quantities of the volatile alkali with opium, which I really +think preserved his life. He was obliged to keep his bed for several +days, and did not recover the perfect use of his hand for nine weeks. +This unexpected and extraordinary occurrence induced me to examine +the spur of the animal; and on pressing it down on the leg the fluid +squirted through the tube: but for what purpose Nature has so armed +these animals is as yet unknown to me.” + +Blainville, also in 1817, described the canal in the spur and the cyst +at the base; as the specimen he examined was a skin only, he did not +find the gland. In the _Edinburgh Philosophical Journal_ (vol. vi, +1822, p. 184) it is mentioned that Dr. Traill confirmed the existence +of a canal through the spur, so small that he could not pass a +horse-hair through it, though a human hair passed. + +In the same year an extract of a letter from Mr. Patrick Hill, Surgeon +in the Royal Navy, dated Sydney, 3rd January, 1821, and addressed to +the Secretary of the Linnean Society of London, was read before the +Society and printed in the _Transactions_ for the year, pp. 622-4. Hill +writes:-- + + “You will be gratified to learn, that I have been completely + successful in establishing our friend Sir John Jamison’s account of + the spur of the _Ornithorhynchus paradoxus_. I subjoin an extract + from my notes: + + “_Sunday_, Oct. 1, 1820--On the banks of Campbell’s River. In the + morning shot a male _Ornithorhynchus_. On examination, soon after + it was killed, I observed near the extremity of the convex side + of the spur, a minute spot, like the orifice of a tube; and on + endeavouring to pass a bristle from this spot, three successive drops + of a limpid clear fluid issued from it. I then examined the other + spur with the same result. On dissecting the foot of the animal, I + found at the inner side of the root of the spur, immediately over + the articulation, a small cyst, which I cut into; it did not at that + time contain any fluid; but from it I, with great ease, passed a + horse-hair through the spur.[6] This preparation I have sent to you, + together with the dried cyst.” + +Farther on he quotes Cookoogong, chief of the Boorah-Boorah tribe, +as being “perfectly aware that a wound from the spur of the male is +followed by swelling and great pain; but although he has seen many +cases of it, he has never known it fatal.” + +Knox (1823, p. 38) describes and gives the first published figure +of the gland, duct, cyst, and spur _in situ_ in a dissection of the +leg. He opposes Home’s views as to the copulatory function, and is of +opinion that the spur must be a weapon of offence. In the same year +Home records the presence of the gland, and describes how Clift passed +mercury through the duct--an experiment which Knox also performed. The +specimen examined by Knox has a certain historic interest, it having +been sent to the Royal Museum of the University of Edinburgh by the +then Governor of New South Wales, Sir Thomas Brisbane. + +In an anonymous article in the _Annales des Sciences Naturelles_ (ii, +1824, pp. 75-6) from which I have previously quoted, the statement is +made that Jamison first announced the perforation of the spur, that Van +der Hoeven could not find it, but that Meckel confirmed its existence, +as well as that of the gland, in a letter to Brechet, the editor of the +_Annales_. + +In 1826 Knox recorded the presence of a rudimentary spur in the female +echidna, and claimed that this discovery disposed of Home’s suggestion +of a copulatory function. + +Isidore Geoffroy’s article on _Ornithorhynchus_ in the _Dictionnaire +Classique d’Histoire Naturelle_, published in 1827, refers to a +publication by Dr. Parmeter in Sydney:--“Cet auteur établit que les +mâles emploient leur ergots pour tenir les femelles immobiles dans +l’acte de la copulation, et il a publié sur ce sujet un petit Mémoire +imprimé dans la Gazette de Sidney.” + +Dr. Parmeter was in practice on the Hawkesbury River, and must have had +opportunities of observing the platypus, which was then so plentiful +there. A weary search through the pages of the _Sydney Gazette_ +brought to light only two occurrences of his name, apart from casual +attendances at the inquests which formed so prominent a feature of the +early days. One of these is at the foot of an advertisement deploring +the fact that his patients were not paying their bills, and threatening +drastic action unless they mended their ways; the second was the +advertisement of a forthcoming publication, _The History of Australia +by T. Parmeter, M.D._, with a list of a few advance subscribers--but +it would seem that the work was not published. In the _Gazette_ +of December 4, 1823, there does, however, appear a letter, signed +“Observator,” which is almost certainly the memoir referred to. + +Like most early statements about the platypus, it contains more +conjecture than observation. It is a comment on an excerpt concerning +Knox’s dissection of the spur and gland which had appeared in a +previous issue. Parmeter says:-- + + “I take leave to remark, that I have dissected this animal + particularly, to ascertain this much controverted point, and have + not been able to trace, either in the _living_ or _dead_ animal, the + virus supposed to be contained in the sac; and I am not _solitary_ in + my opinion, that _there is no poison_; nor is it, properly speaking, + a _gland_, which the spur is conjoined to.... That the plectrum + answers the particular purpose of a _prehensile_, is more rational + to conjecture, than that nature should have furnished the male with + a weapon (offensive or defensive), and not similarly provided the + female.” + +This can scarcely be said to justify Isidore Geoffroy’s statement that +Parmeter has established the fact that the males employ their spurs to +hold the females. Further on in Parmeter’s letter the following lines +occur:-- + + “I therefore invite any Member of this infant Association[7] to + correct me, from an _authenticated fact, of any individual having + been injured from the wound of this animal’s spur_.” + +This, from a medical practitioner who lived for many years among the +farming community on the banks of the Hawkesbury at a time when the +platypus was notoriously abundant in that river, and yet who had never +known of a case of injury from its spurs, points to the great rarity of +such an occurrence. The reason is that fully ninety per cent would be +drowned in the fish-nets, and the remainder killed before being handled. + +In 1829 there appeared in the _Edinburgh New Philosophical Journal_ +a letter from Thomas Axford, Esq., dated from Thorpe, Tasmania, 30th +June, 1828. He writes (p. 400):-- + + “It is my firm conviction that the animal has not the power of + instilling poison by its spur; and I believe this appendage is used + principally for securing the female in the season of love, though it + may also be useful in enabling the animal to climb the steep banks + of rivers. I have taken several large females, and I suppose old + ones, with the hair worn off, and only the fine fur left on their + rump; and although I have killed very large males, never found one in + that state.[8] The moment I saw the first old female thus denuded, it + struck me that the denudation must arise from the action of the spur + of the male in holding the female.” + +Verreaux (1848, pp. 130, 133) stated that the spurs were used to hold +the female in copulation, being applied to her posterior part; and +that, though he had handled many male platypus, none had ever attempted +to use its spurs as weapons of offence against him. Dr. Bennett records +the same experience. He endeavoured (1860, p. 107) to incite the animal +to use its spurs, placing it in a variety of positions, and teasing it +to make it angry, but without success. He was convinced that the spur +was not used for offensive purposes. Krefft (1871) writes:-- + + “It is possible that the spur has some poisonous properties during + certain seasons of the year, because we remember being cautioned + to handle a male Water-mole, by a gentleman who said that he once + had been wounded in the arm by one, and had suffered severely in + consequence.” + +Spicer (1876, pp. 162-3) records the case of Mr. Augustus Simson, of +Gould’s country in Tasmania, in a communication read before the Royal +Society of Tasmania on 13 November, 1876:-- + + “About three weeks ago, he and Mr. Stephens, the School Inspector, + were walking by the side of a lagoon, when their attention was + attracted by a Platypus, which had swum across from the other side, + and was on the point of making its way under the bank. Mr. Simson, + an active, energetic man, at once rushed down the bank, and secured + the animal. Now, I fancy, this fact alone is worthy of record; for of + all the shy wary animals in existence, Platypus is amongst the shiest + and most wary. Under ordinary circumstances, it is no easy matter to + catch even a passing sight of one; but here the creature was caught + in open daylight....’ The platypus was put safely in a bag, but + escaped. Mr. Stephens now takes up the story:-- + + + “After an exciting chase, Platypus was recaptured;[9] but this time + he revenged himself by giving my friend a severe wound on the hand, + one spur slightly tearing the palm, and the other the back of the + hand, making a deep puncture between the knuckles of (I think) the + first and second fingers. The pain from this was intense, and almost + paralysing. But for the administration of small doses of brandy, + he would have fainted on the spot. As it was, it was half an hour + before he could stand without support. By that time the arm was + swollen to the shoulder, and quite useless, and the pain in the hand + very severe. No ammonia was to be had; no medical assistance was + available; and the only treatment that could be adopted, was to keep + the whole arm for a night and a day in wet bandages, which seemed to + alleviate the pain a little, and to reduce the inflammation. + + “A week later I was informed by letter that the swelling had + subsided, the hand being still very tender, with a sensation as + of a severe bruise. From this time there was a slow but gradual + improvement.” + +A letter from the victim substantiates this statement, and he adds (p. +163):--“Some natives tell me they would rather lay hold of a snake than +a Platypus.” On the same page Stephens describes the mode of attack, +which was precisely the same in this case as in that described by +Jamison:-- + + “The mode of attack is not by scratching, but by a powerful lateral + and inward movement of the hind legs, the spurs being thus brought + together like the points of a pair of callipers.” + +The late Professor Sir Anderson Stuart, of the University of Sydney, +records further cases of poisoning in his Presidential Address to the +Royal Society of New South Wales, published in the Society’s _Journal_ +for 1894. His account, which occurs on pp. 5-9, is as follows:-- + + “I have no doubt whatever that it is, at least at certain seasons, + a powerful poison. I have from time to time made enquiry, and have + also advertised for information, and I have two good accounts from + very intelligent hunters of the animal, in widely separated parts of + the Colony, which coincide perfectly, so that I have no doubt myself + that they accurately represent the main features of the action of the + poison in dogs and as observable by laymen. + + “One account shows that the males fight very fiercely while in the + water during the pairing season, mostly applying themselves to each + other belly to belly. The scratches are mostly on the under surface + of the tail. The females are very seldom found scratched. One of the + hunters tells of a dog he had which was ‘stung’ on three different + occasions--each time both spurs were employed, and the wounds were + always on the dog’s cheeks. The wounds are always described as on + the head or face somewhere, because they are inflicted while the dog + is retrieving the wounded animal. The effects followed very quickly, + like the sting of a bee. Within a couple of minutes the head began + to swell, and on the first occasion had reached a ‘tremendous’ size + within a quarter of an hour. This swelling gradually disappeared, and + was gone in thirty-six, ten, and three hours on the first, second, + and third occasions respectively. The swelling and all the other + symptoms were less marked the second than they were the first time, + and the third than the second time. The swollen head was tender to + touch, for the dog ‘sang out’ when it was touched there. The eyes + were at first closed up by the swelling, and when again visible were + ‘wild-looking.’ The dog became sleepy, as if under the influence of + a strong narcotic, so that he had to be carried to the camp, and he + moaned from time to time. The dog would neither eat nor drink, but + there was no salivation, vomiting, diarrhoea, tremor, convulsions, + nor staggering. Breathing was difficult, but not very. This dog quite + recovered. + + “My other account is from one of two brothers who were both great + hunters of platypus, and he confesses to having been wicked enough + to have shot many thousands during his thirty-two years of work. + He had four valuable water-dogs that died from the ‘stings.’ On + one occasion he actually saw the platypus strike, heard the dog + whine, saw the wound, and the train of symptoms ending in death. + These were comparatively large dogs. He knew that after he himself + gave up hunting, his brother, who went on with it, lost dogs too. + The drowsiness was so intense that he has had to carry the dogs on + horseback with him for as long as three hours.” + +Here follow details of the accounts given by Jamison and Spicer, which +are quoted above. Anderson Stuart sums up (p. 9):-- + + “Now if we review these four accounts, we note that-- + + “1. They are all absolutely independent, not one writer knowing + anything of the other three, three hailing from different parts of + the colony of New South Wales, and one from Tasmania, and all from + different periods of time. + + “2. Two were in the human subject and the rest in dogs. + + “3. The train of symptoms, _mutatis mutandis_, agree most perfectly. + + “4. In all cases the poison was allowed to follow its natural course, + nothing but external applications, if anything at all, being ever + employed by way of treatment. + + “5. The symptoms were specific, and differed entirely from the + ordinary surgical effects of lacerated wounds.” + +He concludes that the gland secretes a powerful poison at certain +seasons, probably during pairing-time. + +Martin and Tidswell (1894) made a chemical examination of the fluid +secreted by the crural gland, and an inquiry into its physiological +effect when injected into rabbits. Their paper gives an excellent +summary of the history of the controversy, and mentions cases of +poisoning other than those given above. Thus on p. 476:-- + + “Under the heading: ‘The Poison of the Platypus’, the following + extract from the _Maitland Mercury_ is quoted in the _Australian + Journal of Education_ (1869):--‘On Tuesday, the 9th instant, when + Mr. E. was fishing in the river near his residence, he found that a + Platypus had got entangled in the net, and upon catching the animal + it immediately struck the two spurs attached to its floats or arms + into the forefinger of Mr. E.’s left hand, with such force that they + penetrated through the skin and into the muscles of the finger, + and it was with great difficulty that Mr. E. at last succeeded in + ridding himself of his unwelcome intruder and eventually killed + it. Mr. E. all the time suffered intense pain, and presently the + wounded finger, then the hand, and ultimately the whole arm up to the + shoulder swelled to a serious extent. The symptoms usually following + snake-bite also set in, and after a day or two Mr. E’s state became + so serious as to alarm his friends for his safety, and Dr. G. having + been sent for, he applied ammonia and the usual remedies against + snake poison, and we are glad to learn that Mr. E. has now entirely + recovered.’” + +On p. 479 Martin and Tidswell quote A. Nicols (_Zoological Notes_, +London, 1882, p. 116):-- + + “A. Nicols records having wounded and captured a Platypus which + was lively enough to scratch him with its sharp claws, but made no + attempt to use its spurs when handled. The native who accompanied + him, however, expressed fear of the spur. Nicols thought that + the spur and its gland might be ‘a remnant of conditions of life + very different from those under which the animal now exists.’ He + considered that, although it might possibly be used in contests + with its own kind, ‘there is no reason for attributing a poisonous + character to this weapon.’” + +On p. 480 the authors mention four more cases (two in men and two +in dogs) recorded by Dr. Lalor in a communication abstracted in the +_British Medical Journal_ for June, 1894, p. 1332. There is thus a +considerable body of evidence for the poisonous nature of the secretion. + +Martin and Tidswell proceed (pp. 482-487) to an examination of the +anatomy and histology of the gland and duct, which they figure on their +Plate XXVIII. The glands are more or less kidney-shaped bodies, with +the concave border outwards, symmetrically disposed on either side of +the vertebral column above the acetabulum and femur. Each gland lies +in a special compartment of the deep fascia, covered by the panniculus +carnosus and skin, between the muscles of the leg on the outer side, +and the gluteus maximus on the inner. An average gland measures 3 cm. +in length, 2 cm. in breadth at its widest part, and about 1.5 cm. in +thickness. The surface is lobulated. + +The duct emerges from the posterior half of the outer border, and +passes downwards, with the nerves and blood-vessels, on the posterior +aspect of the leg. It measures about 5 cm. in length, and, in an +undilated state, about 2 mm. in external diameter. After leaving the +gland it passes down under the biceps muscle, crosses the tendon of +the gastrocnemius, and reaches the spur. Here it becomes dilated into +a sac, which is so deeply embedded in the ligamentous tissue at the +back of the tarsus that its isolation is a matter of difficulty. From +this dilation a prolongation extends into the canal in the spur, which +is attached to a supernumerary tarsal ossicle, articulated to the +astragalus and tibia. + +The gland is enclosed in a capsule consisting of an outer layer of +unstriped muscle, three or four cells deep, and an inner coat of white +fibrous tissue, which is continued into the mass of the gland as a +stroma separating the alveoli. It is of the compound racemose type. +The duct, traced into the gland, divides repeatedly into smaller and +smaller branches; the final branches open into the alveoli, which are +dilated, and lined by a single layer of epithelial cells situated upon +a basement membrane. + +Sections across the duct show that it possesses a single lumen close +to the spur, which becomes multiple as it is traced backwards towards +the gland. The wall is composed of fibrous tissue, without any muscular +elements whatever, and is lined by an epithelium composed of four +layers of cells. The saccular dilatation at the base of the spur has +the same structure. + +The fluid secretion, which is described as ‘limpid and opalescent’ by +Martin and Tidswell, was chemically examined, with the following result +(p. 490):-- + + “Our conclusions as to the composition of the secretion drawn from + the above experiments are:-- + + (1) It is a solution of proteids. + + (2) That the greater portion is composed of a proteid belonging to + the class of albumins, and that in addition a small quantity of + proteose is present. + + (3) Nucleo-albumins are absent.” + +The authors remark that the toxicity of snake venom is known to be due +to its proteose content; but in their experiments with the platypus +fluid, because of the smallness of the quantity of material available, +it was not possible for them to separate the proteose from the albumin. +Consequently the limited number of experiments which were possible had +to be made with the mixture. + +_Experiment I_: A rabbit had .05 gramme of the ‘poison,’ dissolved in +5 cc. of .75-salt solution, injected under the skin of the abdomen. +Upon the following day a swelling the size of a duck’s egg had appeared +near the seat of the injection, which was tender to the touch. The +animal was sick, with dull eye, eating sparingly, and its temperature +had risen by one degree Fahrenheit. A day later, the swelling and +temperature were reduced, the animal was much livelier and taking food. +In a couple of days more it had completely recovered. + +_Experiment II_: 6 cc. of a solution of the dried poison in .75-salt +solution, of such strength that the dose actually contained .06 gramme +of the actual gland secretion, was injected through a cannula into the +jugular vein of an etherized rabbit. The experiment was arranged so +that a simultaneous record of blood-pressure, respiratory movement, +and time-rate was recorded upon a revolving drum covered with smoked +paper. Within three seconds from the commencement of the injection the +blood-pressure fell by 40 mm. of mercury, the heart-beats becoming +less frequent. At the same time the respiration became hurried and +exaggerated, and speedily terminated in a series of expiratory +convulsions, in the course of which the blood-pressure rose again, but +speedily fell. In a minute and a half the animal was dead. An immediate +post-mortem disclosed that the right side of the heart and the whole +of the venous system were full of clotted blood; the left chambers of +the heart and the pulmonary veins contained fluid blood, and there was +an extensive endocardial haemorrhage. Martin notes that this condition +is precisely similar to that induced in rabbits by the intra-venous +injection of snake venoms. + +Two further experiments were made similar to the latter of the two +above, but with smaller doses of poison. The dose for _Experiment III_ +on p. 494 of the paper is given as 0.4 gramme, but this obviously +should read 0.04 gramme. The former quantity was equal to the total +amount of poison held by the investigators (see p. 496). _Experiment +III_ gave the same ultimate result as _Experiment II_, but at a slower +rate; in _Experiment IV_ the blood was not clotted, but on being drawn +off coagulated at a rate much slower than the normal. + +The authors claim that these experiments prove the secretion of the +gland to contain some body capable of producing very considerable toxic +action when introduced into the bodies of rabbits. They admit that this +toxic agent may be of other than proteid nature, but do not think it +likely, since the results resemble those produced by proteid poisons. +The whole of the experiments, including the apparently contradictory +result obtained in _Experiment IV_, show a close agreement with results +obtained by use of snake venoms. The venom of snake is, however, 5000 +times as virulent as the preparation of platypus poison used. The +latter appears to be much more powerful in the production of local +oedema. + +Their final conclusions follow (pp. 498-9):-- + + “At the conclusion of our survey of the literature of this subject, + we pronounced the opinion that as far as the evidence adduced went, + it presented a very strong case in favour of the contention that + these glands, at any rate at some seasons, produce a poisonous + secretion. + + “We venture to think that the results of our experiments have + established the fact that the secretion is poisonous at some time of + the year. Whether the animal is capable of discharging a secretion + possessed of poisonous properties at all seasons of the year is not + at present determined. Creighton states definitely that the gland is + subject to seasonal variations in size just as is the case with the + mammary gland and testes (Bennett). We have been unable to find on + what evidence Creighton makes this statement; but the differences in + minute structure observed by us lend support to this view.[10] + + “The idea naturally occurs to one that this apparatus, which is + confined to the male sex, owes its peculiar development to the + operation of sexual selection. That it is a weapon used by the males + on one another when conflicting for the possession of the females, + is an idea which would become extremely probable if it could be + established that the gland is specially developed at or about the + pairing season. This is a point which could be settled without + difficulty, provided specimens could be obtained in sufficient number + at suitable periods of the year, say August and February. + + “Bennett found developing ova in the uterus as early as September, so + that in all probability the animals pair during the latter part of + August and earlier part of September. + + “That the secretion obtained by us from the glands of an animal + killed in June proved actively poisonous, whilst that from an animal + killed in April was innocuous, is interesting in this respect, + although June would indicate a somewhat early preparation for + pairing. We cannot, however, place much stress on this isolated + observation, as it is quite possible that the difference in + development was due to quite other causes. In the meantime the + biological significance of these extraordinary organs must remain an + open question.” + +The following interesting measurements and dates were recorded by me +after dissecting three robust adult male platypus during the rut of +1923. + + Testes Crural + Macdonald River, N. England, 8-10-’23 7 × 10 mm. 9 × 20 mm. + Namoi River, Manilla, 10-10-’23 22 × 30 mm. 15 × 44 mm. + Namoi River, Manilla, 23-10-’23 5 × 10 mm. 8 × 20 mm. + +The last two males were taken in the same locality. + +Although I omitted to measure the scent-glands, I observed that their +size was in proportion to that of the testes and crural glands. +This, then, suggests to me sexual affinity, so to speak, between all +three sets of glands in or out of season, and furthermore, that such +conditions prevail until all are gradually exhausted. This may occur +late or early during the rut, according to circumstances. + +An aboriginal once informed me that he had seen the male platypus +carrying nesting-material by means of its spurs. I do not, however, put +much trust in this story, for, so far as I have observed, the female +builds the nest unaided. As regards bachelor quarters (even during +the cold months), all the males that I have unearthed to date were in +cavities of bare earth. + +We have, then, a mass of evidence, contradictory in nature, yet adduced +by competent observers. It will be of interest to summarize the +suggestions which have been put forward as to the function of the spur, +and to see whether the apparent contradictions cannot be reconciled. +The suggestions made are five in number: + +(1). That put forward by several early naturalists (e.g. Axford), that +it aided the animal in climbing banks. This may be dismissed without +further comment, for it is quite obvious that the female has greater +need of bank-climbing apparatus--if such be necessary at all--than the +male. + +(2). The suggestion by Baden-Powell, quoted by Spicer, that the +secretion is simply a dressing for the fur, a function which, it will +be remembered, Geoffroy Saint-Hilaire once suggested for the mammary +gland. Here, again, if an oil for the fur be needed, the need of the +female is as great as that of the male. Moreover, although the hair is +combed principally by means of the claws of the hind foot, the spur is +not suitably placed for assisting in the operation. + +(3). The suggestion of Nicols, quoted by Martin and Tidswell, that the +spurs are a remnant of conditions of life very different from those +under which the animal now exists. Martin and Tidswell remark (p. 480) +that, while it is very difficult to show that the suggestion is false, +it does not appear to be reasonable. A complicated arrangement, in a +condition of functional perfection, would hardly be retained if it were +of no service to the individual or the species. With this I agree. + +(4). The position taken by Jamison, Knox, Spicer, Martin and Tidswell, +and others, that the spur and gland are weapons for the infliction of +poisonous wounds, either upon other males when fighting for possession +of the female, or upon enemies in general. The evidence for seasonal +variation in the functional activity of the gland is definite enough, +but is insufficient to rule out the notion that the spur is a weapon +of offence against enemies in general. The demand for protection from +enemies is not seasonal; it is an affair of all the year round, and the +spur is dangerous at all times. + +As one of the uses of the spur is almost certainly to inflict poisonous +wounds, it is probably directed against other males of its own species +as well as against natural enemies. One other observer besides myself +(Verreaux) has claimed to have seen the act of mating. Here at least I +have confirmatory evidence that this act takes place in the water. As +to whether Verreaux’s description of the event is in every particular +correct or otherwise, I am not concerned. There is, of course, no +doubt that the secretion, when introduced into the blood-stream of a +mammal, has a powerful toxic effect, and Martin and Tidswell claim no +more than this. When two males fight, I judge from the position which +they take up at first that the introduction of the venom is designed by +both combatants. Combats among mammals for possession of the female are +rarely fought to the death. They are, admittedly, at times severe, but +are tests of physical strength and endurance, in which the weaker goes +to the wall with nothing more than a few wounds. I have known platypus +males placed together in confinement disagree with, and sometimes kill, +one another, though I have no evidence that death was caused by poison +from the spurs. But I have always thought that such might be the case. + +Before solving the problem of keeping platypus in captivity for +exhibition purposes, I handled many freshly-trapped uninjured males, +first while collecting, and later with specimens imprisoned in a +contraption which I termed, at that time, a “Platypusary.” Realizing +that the less handling the animals received, the better for the test, I +did not ruffle their tempers more than was necessary. Not once during +manœuvrings did a male make any attempt to use his spurs on me. I +naturally came to the hasty conclusion (as others have done) that male +platypus are ridiculously docile, good-tempered creatures. + +Since then my opinion of them in this respect has changed, and for +this reason. I placed two freshly-caught adult males together (in the +breeding-season) in a large tub half-filled with water. After several +endeavours to crawl up the sides of the tub--which I prevented them +from doing--they became enraged, not only with me, but, apparently, +with themselves and one another. Presently a quarrel began in earnest; +they were floating side by side at the time, each with its head to its +opponent’s tail. As they became more and more tightly pressed together +for their full length, they circled around as one centrally-pivoted +concern. This was caused by each combatant, with gaping jaws, +strenuously endeavouring to catch hold of the other’s tail at the tip. +Each in turn eventually succeeded and hung on tenaciously as though all +depended on this remarkable grip. Both seemed so concerned that now my +presence appeared to be unheeded. Wriggling and paddling began with +vim, presumably with the object of one turning the other over without +being overturned itself. Had this fight been waged in deep water, it is +difficult to imagine what advantage either would obtain over the other. +Ultimately there was a great splash, and the antagonists were in firm +holds, heads to tails, for their full length, beneath the water; but on +bumping the foreign bottom they instantly released their holds and came +to the surface for a blow. As I could not induce them to battle again, +I released them into the Namoi River. + +It is worth noting here that, while under water in the locked position +as described, the vital external jugular veins of each (mentioned +by Martin and Tidswell) would be exposed, and nothing less than a +timely parry with the versatile fore-paws would suffice to prevent a +death-dealing puncture, if not actually in the jugular vein, then in +close proximity to it. In any case, if this did occur it could hardly +be called accidental. As in the case of all fauna in a fight to a +finish the combatants would probably receive many wounds in different +parts before one was totally disabled. + +This, then, brings me to another point. If the “dope” (as I term +it) is not of a deadly nature during the mating session, why is +it always ejected by the animal when it deliberately spurs at an +enemy? Hoy’s encounter with an infuriated male in the height of the +breeding-season[11] convinces me that the secretion is used for +offensive rather than for amatory purposes. + +Before placing the males together in the tub I experimented with +the larger of the two (weighing exactly four pounds) purposely to +explode my initial theory that males will not intentionally use their +spurs when being handled. Of course, I knew the truth even then, but +I required sufficient proof to satisfy the most sceptical. This is +what occurred: I first placed a special rubber gauntlet over my right +forearm, then gloved that hand adequately, leaving my left free for +minor purposes. After placing the robust male platypus on a table, +abdomen uppermost and tail towards me, with my bare hand I held the +wriggling creature by the head. Then, to exasperate him, I placed my +right arm on his tail and deliberately tantalized him by tickling him +from back legs to brisket with my fingers. Several times he raised his +spurs simultaneously as if sparring for a grip, but each time lowered +them again. Tiring of such monotonous behaviour, I removed my arm to +rearrange his position and to reverse my hand-holds temporarily. But, +while I was bringing my bare hand back to grasp his tail, the platypus, +as though aware that I was off my guard, like a flash struck with his +spur and ripped the edge of my left hand for a distance of over an inch +towards the little finger. This action was so quick and unexpected that +it certainly gave me a shock. After placing the platypus back in the +box, I repeatedly squeezed the wound and made it bleed very freely. + +My wife then took a hand, and flooded the wound with iodine twice +within half an hour; each time she did so, the pain was acute in the +extreme--far more so than when first inflicted. The rip, which was +jagged by my tearing away from the temporarily rigid spur, was 1⅛ +inch in length, and ⅛ inch in depth. Now, whether the pulling away of +my hand simultaneously with the striking of the spur saved me from +receiving a full dose of dope, or any at all, is questionable. But two +or three days later, when I had almost forgotten the event, I felt a +slight pain under the arm, and noticed a redness leading thereto from +the wound. Nothing more serious developed; but it occurred to me that, +as the iodine entered the wound, so the secretion administered with the +prod of a spur, during conflict, although not a deadly poison, might at +any rate cause sufficient pain, when injected into a wound, to cause +the rival at once to desist. If so, nothing more is necessary when +duelling for possession of the gentler sex. + +While on this subject, I will explain why and how the platypus is +capable of inflicting very severe wounds with its spurs. When the +animal is not anxious or prepared to grip, the spur may be lifted +back with one’s thumb and forefinger. This, I know, has led most +observers to suggest that the power of the grip would be insufficient +to penetrate the pelt of an adult platypus. If the spur were rigid like +that of a cock, and used in a like manner, all would readily agree +to such a possibility. Well, I can assure my readers that when the +platypus feels inclined, and is prepared to strike, the position of +the spur can be styled as rigid. That is to say, it is propped back to +the extreme point of erection, where, when striking, it will tear all +before it, or become dislocated in the attempt. But the driving power +then brought to bear is not alone in controlling the precise movements +of the spur. All the leg muscles concerned in the sudden twisting of an +ankle combine to force the weapon home. I am speaking from personal +experience with wild specimens in the field--not from pickled carcasses. + +[Illustration: (1) POISON GLAND CONNECTED BY DUCT TO WELL AT BASE OF +SPUR. DISSECTED SPURS AND THEIR INNER TUBES. + +(_From fresh carcass_) + +_Plate 14_] + +From experiment and observations made in connection with the actual +voluntary administration of poison by an enraged platypus, and also by +personally lifting to full-cock the clamped weapon of another fresh +carcass, I came to the conclusion that, in the erection of the spur +to a given point, say, from half-cock to full, the poison dose is +regulated accordingly. For instance, when the spur is fully cocked the +fluid will flow until a dew-like drop appears at the orifice near the +tip. Here, ready for immediate action, the weapon stands fully charged. +Its mission at this stage is first to puncture, with solid tip, the +skin of the opposing subject. By so doing, the tip readily tears a way, +thus preventing clogging of the orifice until the poison makes contact +with at least first blood. The desire of the animal is to strike at +a vulnerable spot, and the flow of poison would probably be stemmed +temporarily if the spur were embedded deeply; but whether the amount of +poison is measured automatically at the cocking of the spur, or whether +the platypus is able to control the flow after striking, has not been +determined. But the fact must be noted that, when the animal attempts +to insert the spur and misjudges the mark, the spur is carried on into +the fur of its own leg, and the dose spilt thereon is apparently in +greater quantity than that which the tube of the spur could possibly +hold with the one filling. Seemingly, then, the well at the base of the +heel is drained also with the complete clamping of the spur, having +been shut off from the main supply at the initial filling. It seems +reasonable to suppose that the spur must be re-cocked before a similar +operation can take place, otherwise there would probably be a constant +leakage while the spur is clamped normally out of action. + +[Illustration: (2) GENERAL VIEW OF MALE PLATYPUS, UNEARTHED FROM +CAMPING BURROW. + +_Plate 14_] + +Apart from the controversy as to whether the poison is deadly or not, +I strongly advise the uninitiated not to meddle recklessly with a male +platypus, in or out of season, for I am quite convinced that when once +the animal grips correctly, especially with both spurs, unless the +platypus releases voluntarily (which he is not likely to do readily) +the creature would surely have to be killed before the spurs could be +extracted. Failing this, there is obviously only one other way out of +it, and that is to lance or tear the tortured flesh of the victim. + +The sudden twist of the ankles, referred to above, may best be +illustrated thus. Clench both fists, place the hands side by side with +the fingers uppermost, then open the palms to the extreme, suddenly, +and note the rigid position of thumbs. While in that position, regard +the palms as the soles of platypus feet, and the extended thumbs as +“set-back” spurs. Of course, in the case of the platypus the incurved +shape would incline towards the finger-tips, but to follow this curve +with the thumbs the rigidity essential for striking purposes would +be lost. Very well, let that be understood. At this point, then, +imagine an enemy to be lodged in the palms, and held there firmly by +clutching talons. This may be represented by clamping the extremities +of the fingers tightly, without closing the palms. Then, with a jerk +simultaneously twist both wrists inwards to the full, finishing with +the backs of the hands uppermost, and thumbs clenched beneath. This +will serve to convey some idea as to the awkward position of the victim +so secured by an infuriated platypus. + +Of an endeavour to test the effect of platypus poison on a +freshly-trapped rabbit my report is as follows. Not being fully +equipped with the poison collected directly from the spurs of a living +specimen, because of its being swabbed up by the fur on the thigh of +the animal each time the fluid was ejected through the then clamped +spur, I was compelled to extract the secretion from the glands of a +freshly-killed specimen. Using a hypodermic syringe, I injected into +the thigh muscle (not a vital part) of the rabbit what I considered +to be a double dose of the poison, that is to say, as much as the +platypus would inject with both spurs simultaneously. I observed the +rabbit closely for two hours after, but did not notice any change in +its behaviour. My final examination, twenty-four hours later, found +the subject very quiet, but otherwise apparently well. On killing +the rabbit I found a discoloured swelling of the muscle surrounding +the punctured portion, and between the skin and muscle a frothy +cream-coloured corruption, quite foreign to the immediate conditions of +those parts. This then is slight evidence that, at least, the rabbit +suffered pain, but to what extent I could not estimate. Still, if the +effect is sudden, as I believe, then it would serve the essential +purpose of putting an opponent temporarily out of action at the desired +moment, and for a sufficient length of time. + +Where the method of striking has been observed and described, observers +agree that the hind legs are brought together, causing a wound on both +sides of the intervening object, which must be of comparatively small +dimensions--a finger, a hand on edge, or the sharp muzzle of a dog. The +animals concerned are wounded in several instances and badly frightened +in others. + +Taking warning from the mistakes of zoologists who have, in the past, +argued plausibly about the platypus, only to be proved wrong in the +end, one should refrain from argument unless armed with practical +experience and observation in the field. My observations of the method +of copulation were made without thought as to the function of the +spurs, and I think they prove clearly that that function is definitely +connected with copulation. This brings us to the fifth suggestion:-- + +(5). That the spurs are used for holding the female during the sexual +embrace. This suggestion was first put forward by Home in 1802. He +elaborated it in his _Lectures on Comparative Anatomy_ (1823), in which +he writes:-- + + “When I first saw the spur, I had no doubt from its situation but + that one of its purposes was to prevent the escape of the female + during the act of the coitus; in this I was confirmed when I found in + the female, exactly in the same situation, a regular socket, lined + with strong cuticle, adapted to the reception of the spur.... Having + ascertained that a secretion is emitted through the spur of the male + into this socket, and the parts being so minute as to require glasses + of considerable power, I got Mr. Bauer to examine the socket in the + female; and after overcoming considerable difficulties, the parts + being very much corrugated, and yet retaining their elasticity, he + made out the form of this socket, which corresponds exactly in shape + to the spur itself: so that, when completely introduced, it must be + so grasped that the male would be unable to withdraw it when coitus + was over; in this respect resembling the effect of suction. The + male, it would appear--at least this is the best conjecture I can + make by reasoning from analogy, there being no facts to guide us--by + throwing some of the secretion of the gland in the thigh into the + socket, dilates it, and releases the spur; the liquor injected being + acrimonious, will also irritate the female, and make her use efforts + to escape.”[12] + +Martin and Tidswell (_loc. cit._, p. 481) comment on the above as +follows:-- + + “Home’s suggestion, which had the powerful support of Dr. Bennett, + cannot be absolutely denied, as no one has, as far as we are aware, + ever seen these animals copulating. Home’s main reason for such an + hypothesis was that in the female there are situated in corresponding + situations slight hairless depressions. + + “It seems to us that for the male to apply its spurs to these + depressions during copulation in the manner suggested by Home + would involve an amount of gymnastic ability of which even an + _Ornithorhynchus_ is incapable. + + “Moreover, Knox and Owen have shown that these depressions in the + female are merely the rudiments of the male spur, and that the young + female, indeed, actually possesses a spur which disappears prior to + the dawn of sexual life.” + +The statement contained in the last paragraph seems capable of an +interpretation very different from that of Martin and Tidswell. The +young of both sexes have a genital protuberance of similar size; in +the male it develops into the intromittent organ and in the female it +is found in a reduced condition as the comparatively insignificant +clitoris, situated on the margin of an invagination. The history of the +spur affords an exact analogy. + +Until of late years I was under the impression that female platypus +might shed their spurs on attaining maturity, if not before leaving +the nest. On that account I was persistently on the look-out for +cast-offs among the nesting-material, where furred young were found. +Now, however, I have come to the conclusion that the spurs are retained +by the females, but that, instead of hardening like those of the male, +they soften and collapse within themselves to form the so-called socket +or calloused area about the ankles, which corresponds in dimensions +with the base of the male spur. This, then, would prevent the spur tip +from pricking, accidentally, the ankle of the female. + +[Illustration: (1) SOLE OF RIGHT HIND FOOT, SHOWING SPUR NORMALLY +SHEATHED. + +_Plate 15_] + +[Illustration: (2) SOLE OF LEFT HIND FOOT, SHOWING SPUR IN ACTION. + +Note trail of freshly-ejected venom on background. + +_Plate 15_] + +In my description of the method of copulation I think it is shown +conclusively that the platypus has the gymnastic ability to grip the +female with its spurs. Moreover, in the tail-to-tail position, which I +shall describe later as occurring throughout the greater part of the +coitus, the only possible grip the animals can have of one another is +by means of the spur and foot. That this use is feasible has been shown +by an experiment with recently killed animals, used while they were +still in a pliable condition. + +If we now turn to echidna, as we very well may--for an explanation +which is adequate for the platypus must be adequate also for the +echidna--what do we find? A gland is present, popliteal rather than +femoral in position (which leads Owen to prefer the word “crural” +as covering both), but much reduced in size, which is equal to that +of a small pea, with a reduced duct running to the spur. I rely on +Owen’s account in the _Penny Cyclopaedia_, confirmed by a recent +reinvestigation by Mackenzie and Owen (1919, p. 38), in which the +authors conclude:--“In our opinion this body shows evidence of +retrogression similar to that seen in the vermiform appendage and other +structures.” + +No case of venomous wound caused by the spur has been recorded against +the echidna. Semon (1894, p. 7) writes as follows:-- + + “There can be no doubt that the spur of the male, and the glandular + apparatus connected with it, is to be looked upon as an organ for + sexual excitation. Without at present bringing forward any theory as + to the function of the organ, I can at least completely substantiate + Bennett’s observation that the significance of the spur is not as a + poison weapon, nor, indeed, any kind of weapon at all. Not one of + the hundreds of echidnas which I have handled in a living state ever + tried to use its spur as a weapon.” + +It is generally believed that the echidna has evolved its spiny +covering for protective purposes, but it is obvious that spines are +useless as offensive weapons. Semon has apparently been influenced by +Home’s theory as to the use of the spur for sexual excitation, and by +Bennett’s opinion that the spur is not used as a poison weapon. His own +experience in handling hundreds of echidnas is not conclusive evidence +against the use of the spur as a weapon, for the reason that, when +handled, they tuck their legs within the protective covering of their +spines. The only way to prevent the echidna from rolling itself into a +ball is to place it on its back on a board, with straps at the corners +securing all its legs. In that position its spurs are out of action. +The animal apparently has no need of an offensive weapon against +enemies in general; but in all forms of animal life there is rivalry +among the males, and whether the echidna ever used, or still uses, its +spurs during copulation, or not, it would appear reasonable that the +spur is the natural weapon for males to use on each other, especially +as the only way in which they can possibly come together in combat is +on their hind legs, using the out-turned claws as supports, and with +the front of their bodies in contact for their full length. In this +position their spurs could be used on the only vulnerable portion of +each other, whereas, if the contest for possession of the female were +to be carried on in any other position, the result must be a stalemate +owing to the impregnable covering of spines. + +Bill Lancaster, of Manilla, N.S.W. (who has been my assistant in field +work), informed me that only once in his sixty years of bush experience +did he see the echidna in the act of copulating. It occurred on the +side of a mountain. He described the participators as forming one +large ball of quills with a pair of muzzles just protruding at one end, +the whole resembling a spiny melon with split stalk attached. After a +minute or two Lancaster rolled them over with his boot and, as this had +no effect, he deliberately kicked them down the mountain side, but even +this failed to separate them and they remained together for some time +after reaching the flat ground below. + +I have since examined many echidna specimens (both sexes) and noted +particularly the “cowlick” formation of their quills about the hinder +parts. These they are obviously unable to close down completely +even when walking in freedom in the bush, quite unaware of the +presence of an observer. I therefore consider it impossible for these +creatures to copulate in any other position than that described by +Lancaster--abdomen to abdomen, and head to head. Of course, they may +prefer to lie on their sides in the initial stages, but I consider +it more feasible for them to stand up on their hind legs, partly +supporting each other with their fore-paws until the desired position +is attained; after that, any attitude may be assumed; but, for the +sake of safety to both during the breakaway, the side-to-side movement +should prove the simplest. + +On August 11, 1919, I examined the spurs of an adult male echidna, and +found them embedded in a swollen fleshy sheath on the external portion +of its heels, or lower legs. On pressing the sheath down, the spurs +appeared to shoot up suddenly, like a splinter from festered flesh. +Here I discovered, around the base of both spurs, a creamy-coloured +discharge, which I consider, if applied to an open wound, would not +tend to heal the flesh. The condition appeared to be quite normal, but +I do not know of any previous record of a similar observation, and +cannot offer any opinion as to its purpose, or whether it was peculiar +to the mating season. + +If it is impossible for the male to make use of his spurs during +copulation while in the position described by Lancaster, the grip is +evidently obtained by the curiously-shaped long claws of both sexes. + +Wood Jones (1923, p. 37) sums up the position in regard to the platypus +in the following terms:-- + + “Thoroughly reliable observations, however, carry us this far. The + male _Ornithorhynchus_ can, and at times does, strike with its spurs + when handled. The spurs are capable of inflicting a wound, and this + wound is followed by definite symptoms. The symptoms are somewhat + akin to those present in cases of non-fatal snake-bite, and men and + dogs are equally affected when wounded by the spur. So far as I can + ascertain, no recorded observations have ever given support to any of + the various opinions that the apparatus has functions other than that + of an offensive and defensive weapon. That the recorded observations + show that the spur is not invariably made use of when the animal is + handled, is of little moment. + + “We may say, therefore, that the male Monotreme possesses a secreting + gland, a duct, and a hollow spur, as an anatomical entity; that the + gland undergoes seasonal changes in activity; that its secretion, + when injected into animals, is decidedly poisonous, and that its + composition, and its effects, are probably akin to those of snake + venom; that the symptoms produced by the experimental injection + of the secretion into animals are similar to those described in + well-authenticated cases of wounding of men, or dogs, by the spur of + the living male Platypus. + + “Because we have limited ourselves to the statement of certain + well-ascertained facts concerning its use as a weapon, it must not + be imagined that it is considered impossible that the animal may + put the spur to other uses. The Monotremes are not easy animals to + observe, and possibly many of their habits remain quite unknown for + lack of proper opportunities for observation. But there is little to + be gained by mere speculation as to the function of structures found + in living animals. Observation of the living creature is required.” + +Despite this judicial warning, I must plead guilty to indulgence in +speculation. It has, however, been based on observations which were +not available to Wood Jones. One concerns the method of copulation; +this observation is admittedly incomplete, and it will probably be +necessary to take a pair in the act of copulation to settle the matter. +The second may now be detailed. + +While drying a male platypus upon my knee with a towel, I felt an +increasing pressure of the soles of the animal’s feet upon my thigh, +and hurriedly raised it, thinking that it might be trying to use +its spurs. I then noticed that the spurs had penetrated through a +fold in the cloth of my trousers, which was moist from the expressed +secretion. On experimenting further with this animal, I noted that +there was no attempt to strike with the spurs, as does a cock. The +intervening object was first grasped with the hind feet, which were +then pressed firmly against it, and the spurs were brought together +with a deliberate probing motion, which may be likened to the process +of sewing with a packing-needle. + +Finally, there is the question of expression of the secretion. Several +observers have commented that they were unable to force it out by +pressure upon the gland and duct. Martin and Tidswell remark upon the +absence of muscular elements in the duct, and wonder how the secretion +is kept from wasting. The solution of the matter may be found in +Jamison’s observation--“This unexpected and extraordinary occurrence +induced me to examine the spur of the animal; and _on pressing it down +on the leg_ the fluid squirted through the tube” (1818, pp. 584-5). The +animal is, of course, able to bring this about by muscular action, and +is not dependent upon pressure against external objects for expression +of secretion. Plate 15 shows a photograph of the foot and spur of the +male referred to above. In preparation for taking the photograph, a +piece of card, in which a slit shaped like a button-hole had been +cut, was passed over the foot to serve as a background. In adjusting +this card so that the slit should not appear in the photograph, it +was revolved about a quarter turn, a process which caused continuous +irritation to the muscles above the base of the spur while the point +was resting on the card. The result was a trail of secretion which is +clearly visible in the illustration. + +After weighing all the evidence, and as the result of my own +observations, I have therefore come to the conclusion that the uses +of the spur of the male platypus are those set out in the fourth and +fifth suggestions, namely, as weapons and for holding the female during +copulation. + +[Illustration: UNEARTHING PLATYPUS, RETREAT STATION, MACDONALD RIVER, +N.S.W. + +Note excavated burrow commencing at water-level, between figure of +collector and oak-tree at right, then winding up the bank to black +patch (near tussock grass) where nest was found. + +_Plate 16_] + + + + +CHAPTER VIII + +THE NESTING-BURROW + + +The earliest statement concerning the burrowing habits of +_Ornithorhynchus_ that I have been able to find is contained in +Jamison’s brief sentence (1818, p. 585):--“The female is oviparous, +and lives in burrows in the ground, so that it is seldom seen either +on shore or in the water.” This would imply that the colonists were +familiar with the burrowing habits of the animal, and it seems strange +that no account of the nesting-burrow was published prior to that of +Maule in 1832. + +Hill (1822, p. 623) certainly gives a garbled account, of which we +have made mention before:--“On returning, however, we were gratified +in finding that a female _Ornithorhynchus_ had been brought in alive, +having been found on its nest in a lagoon near Campbell’s River, by +Mr. Rawley, who says that he was obliged to tear the nest to pieces +before he could get the animal out, the nest being formed of reeds and +rushes, with a long tube or entrance into it, out of which the bill of +the animal only was visible.” On the following page Hill gives us a +second piece of information, obtained from his aboriginal informant, +Cookoogong:--“... the female sits a considerable time on her eggs in +a nest which is always found among the reeds on the surface of the +water.” It seems probable that Hill misunderstood both his informants. +Rawley’s description is quite incomprehensible as it stands; that of +Cookoogong has no foundation at all in fact. + +In the anonymous article in the _Antologia di Firenze_, quoted in the +_Annales des Sciences Naturelles_ for 1827, we find on pp. 193-4:-- + + “_Ornithorhynchus_ inhabits the marshes of New Holland. It makes + among the tufts of reeds bordering the water a nest composed of down + and interlaced roots, in which it deposits two white eggs smaller + than those of ordinary fowls: it broods on them for a long time, + hatches them like a bird, and only abandons them when threatened by a + formidable enemy. It seems that during the whole time it eats neither + seed nor herb, but contents itself with mud, taken close at hand, + which serves to nourish it; at least, that is the only substance + found in its stomach.” + +With the exception of the reference to the mud, this account seems to +be a mixture of that given by Rawley and Cookoogong, with a dash of +Lesson, and seasoned to taste by the anonymous author’s imagination. It +is possible, however, that the writer had access to some account which +has escaped observation, and even that he had had personal experience. + +The first actual description of a platypus’ nesting-burrow is that +given by Lieutenant the Hon. Lauderdale Maule of the 39th Regiment +(P.Z.S., 1832, pp. 145-6):-- + + “By the care of a soldier of the 39th Regiment who was stationed at a + post on the Fish River, a mountain stream abounding with _Platypi_, + several nests of this shy and extraordinary animal were discovered. + + “The _Platypus_ burrows in the banks of rivers, choosing generally a + spot where the water is deep and sluggish, and the bank precipitous + and covered with reeds or overhung by trees. Considerably beneath + the level of the stream’s surface is the main entrance to a narrow + passage which leads directly into the bank, bearing away from the + river (at a right angle to it) and gradually rising above its highest + watermark. At a distance of some few yards from the river’s edge this + passage branches into two others, which, describing each a circular + course to the right and left, unite again in the nest itself, which + is a roomy excavation, lined with leaves and moss, and situated + seldom more than twelve yards from the water, or less than two feet + beneath the surface of the earth. Several of their nests were, with + considerable labour and difficulty, discovered.” + +Dr. George Bennett (1835, p. 248) published the first figure of a +burrow--a woodcut, of which the details were not very true to the facts +as we now know them. He also described the burrow, believing himself +to be the first European who had opened one. As he does not give the +precise date, one cannot speak with certainty; but it is most probable +that Maule was before him, as it is hardly likely that Bennett, had he +made such important observations during, or prior to, 1831, would have +withheld them from publication. Bennett’s description in _Gatherings +of a Naturalist_ (1860), is substantially the same as in the paper of +1835. Describing the first burrow discovered, he writes, commencing on +page 114:-- + + “The entrance or vestibule of the burrow was large, particularly when + compared with the width of the passage continued from it, measuring + 1 foot 3 inches in depth and 1 foot 1 inch in breadth. Instead of + laying the burrow entirely open from the entrance to the termination, + which would have been a laborious undertaking, holes were opened at + certain distances in the direction of its course, according to the + method adopted by the natives. Daraga assisted us by digging with a + sharp-pointed stick; and he was able to effect his object with much + greater rapidity by it than we with our spades. The burrow became + narrower as it receded from the entrance, its diameter being about + the usual breadth of the animal. We traced it for the distance of 10 + feet 4 inches; and having just delved down upon it again, so as to + perceive it still continuing its course up the bank, the beak and + head of a Water-Mole were seen protruding for an instant from the + upper part, as if it had been disturbed from its repose and had come + down to see what we were about. It only remained for an instant; for + as soon as it beheld us,--imagining, no doubt, that we could not be + making such a noise there for any benevolent purpose,--it immediately + turned up to take refuge in that part of the burrow which yet + remained unexplored. In turning round, however, it was seized by the + hind leg and dragged out. The animal appeared very much alarmed and + astonished when it was hauled out of its subterranean dwelling--that + is, if so paradoxical a creature could look surprised at anything.... + + “It was a great curiosity to the European residents in the vicinity, + who, though often seeing them dead, had never before had an + opportunity of observing one alive. Although they were supposed to be + burrowing animals, yet I believe this was the first burrow explored, + and the first living _Ornithorhynchus_ captured by a European.... + + “I found by measurement that the distance of the entrance of this + burrow from the water’s edge was 5 feet; it was on a moderately steep + bank, abounding with long wiry grass and shrubs, among which, and + concealed by them, was the opening of the subterranean dwelling. From + the judgment which I have been enabled to form from the examination + of this, as well as of several other burrows, I do not imagine + that the natives have ever seen, or that anyone could see (except + in a state of confinement), the mother in the act of suckling her + offspring; for in the tedious process of digging the old animal is + disturbed, and either endeavours to escape, or succeeds in escaping + long before the termination of the burrow is attained. I did not + observe any heaps of earth in the vicinity of the holes I examined; + nor can I form any opinion how, in the process of excavation, the + animal disposes of the loose mould. May we not suppose that the + animal carries away the earth collected during the excavation, in + order that the heap, which would otherwise be formed, may not point + out the situation of its retreat? The burrow we explored ran up the + bank in a serpentine course, approaching nearer to the surface of the + earth towards its termination, at which part the nest is situated. + + “No nest had yet been made in the termination of this burrow; for + that appears to be formed about the time of bringing forth the young, + and consists merely of dried grass, weeds, etc., strewed over the + floor of this part of the habitation. The whole extent of the burrow, + from the entrance to the termination, I found by measurement to be + 20 feet. The burrows of the _Ornithorhynchi_ are situated above the + usual river height, but do not appear to be out of the reach of the + extensive floods of the river which frequently take place during the + winter season.” + +On p. 126 of the same work there is another reference to the burrow:-- + + “I had previously remarked, that the situations where burrows of + these animals were known to exist, had been selected by their + instinct where the ponds of the river contained water even during + the dry summer season, and when other parts of the river were nearly + dry, or formed at best a mere trickling rivulet. Of course, where + the water remained the river-weeds flourished, and the flowers now + produced by them probably attracted insects, which would furnish + these animals with food, in addition to the minute shell-fish which + might also be found among the plants. Can they, I asked myself, + confine themselves to their holes during the period of gestation? To + ascertain this, two burrows were dug up, about the entrance of which + tracks had been seen: one was only half completed, the animal having + very probably been killed before the habitation had been finished; + the second was empty, the owner having probably met with the same + fate. The long grass and shrubs were very luxuriant and dense at + this, the summer season of the year, rendering the exploration or + even discovery of the burrows more difficult than we had before + experienced; and the thick grass afforded shelter for venomous + reptiles, among which black and brown snakes were numerous, rendering + the process not a little dangerous.” + +On pp. 130-131 another burrow is described:-- + + “I left Yas on the 23rd of December, and arrived at Lansdown Park, + Goulburn Plains, on the 24th. On the 28th of this month, with a + small party of aborigines, we visited a very beautiful part of the + Wollondilly River, which passes near this estate, and which has the + native name of Koroa. It was a noble sheet of water, extending to + some distance, and abounding in wild ducks of various species. We + then proceeded to explore the burrow of an _Ornithorhynchus_ which + had been discovered. The aborigines used their hard-pointed sticks, + called _kiar_ by them (the same name is applied to our spade in + their language); and although the ground was firm, they succeeded as + quickly as we could have done with our spades. The method of laying + open the burrow was by holes dug at about 4 or 5 feet apart, a stick + being passed up to ascertain the direction of the excavation. + + “As we proceeded in exploring, there were abundant good omens to + encourage us; for, besides fresh tracks of the feet of the animal, + pieces of grass, weeds, etc. (such as they strew at the bottom of + the termination of the burrow to form a warm nest for their young), + were seen. On every indication of the presence of the inmate, the + older blacks quietly passed either the earth from the under surface + of the burrow bearing recent impressions of its feet or tail, or the + pieces of grass, reeds, etc., to one another, for the opinion of + each, and if in favour of the presence of the occupant, the digging + up of the burrow was continued, the indications so well known to them + giving fresh hopes and renewed vigour to the diggers. The extent to + which this burrow was continued up the bank in a serpentine form + was very great; and after a most laborious task in exploring it, + in consequence of the hardness of the ground, the termination was + attained at a distance of 35 feet from the entrance. Extensive as + this may appear, burrows have been found of even 50 feet in length. + + “On arriving at the extremity of this very large burrow, a growling + was distinctly heard: this I at first thought proceeded from the old + one, which I now believed I should have an opportunity of viewing + with her young; but, on reconsideration, thinking it more probable + that the old one had forsaken them (as I noticed during the course + of laying open the burrow that we had not seen her come down, in + the usual manner, to ascertain why we destroyed her habitation), I + could not account for it, more especially when, on the termination + of the burrow being laid a little more open, the fur of the animal + or animals was seen. What then surprised me was, that although there + was abundance of growling, there was no movement of the animals to + escape. On being taken out, they were found to be full-furred young + ones, coiled up asleep, and they growled exceedingly at being exposed + to the light of day. There were two of them, a male and a female, + of the dimensions of 10 inches from the extremity of the beak to + that of the tail. They had a most beautiful, sleek and delicate + appearance, and seemed never to have left the burrow. The nest, if + it may be so termed, consisted of dry river-weeds, the epidermis of + reeds, and small dry fibrous roots, strewed over the floor of the + cavity, which was of sufficient size to contain the mother and her + young.” + +The only further reference to the burrow which need concern us here +occurs on p. 146:-- + + “I have no doubt the Water-Moles make their burrows high in the + banks--at such a height as to be out of the reach of the floods + which occasionally prevail: if they did not adopt some plan of the + kind, they would be destroyed, or drowned in their burrows by the + floods; for although very amphibious in their habits, they require to + repose on the dry land, and also to respire atmospheric air at short + intervals of time.” + +George Bennett maintained his interest to the very end of his long +life. But the pioneer discoverer rarely wins through to complete and +adequate knowledge of his discovery; and Bennett, owing to the fact +that he adopted the aboriginal method of opening up the burrows, and +did not follow them along their full length, missed several important +features in the structure of the burrow. + +The next description of the burrow is that of Verreaux (1848, pp. +128-9), who observed the platypus in Tasmania. His account is passably +accurate. He makes no specific claim to have opened up burrows himself, +but mentions (p. 131) that a Dr. Casy found two nests, one with one +young one, the other with two; so it may be that his description is +founded on Casy’s observation rather than on his own. However that may +be, the translation of the account is as follows:-- + + “The _Ornithorhynchus_ dwells by preference in marshy places, but + is nevertheless not so wholly aquatic as one might suppose from its + structure. It digs deep burrows, that is to say, of considerable + extent, which are at most fifteen to eighteen inches below the + surface of the ground. These burrows have two or three outlets, and + are usually divided into twelve or fifteen branches; usually one + of these outlets is placed beneath, or at the level of, the water, + to facilitate retreat in case of danger. Although these burrows, + which are dug in clayey banks, have a great number of passages, + they ordinarily include but a single nest, placed right at the end + farthest from the water, and in an enlarged space; this space seems + able to hold three or four of the animals. The nest is composed of + débris of reeds and other aquatic plants, and forms a bed thick + enough to protect the _Ornithorhynchus_ from the damp produced by the + constantly percolating water.... It is ... an excellent digger; and I + have watched one, in very gravelly and very hard ground, successfully + dig a hole more than two feet deep in less than ten minutes. For + the purpose of this operation, the webs of the fore-feet, which are + so highly developed for swimming, undergo a curious transformation, + disappear, and leave visible only the powerful claws, which are + equally useful for climbing when it is a question of surmounting an + obstacle. In the attitude which it assumes when burrowing, one might + take this animal for a mole rather than a swimmer. I have witnessed + the quickness with which they can dig in the muddy places which they + prefer. The beak is first used to dig the earth, then the claws are + brought into play. + + “One observation worthy of note, which shows a resemblance between + _Ornithorhynchus_ and the beaver, is that, as it digs, it uses its + tail to beat and consolidate the earth. During this work the animal, + twisted in the shape of an auger, turns upon itself. The tail, moved + by powerful muscles, follows the movement. I have observed this fact + with several live individuals, which I placed in a box filled with + moist earth, and have been able to study at all times.” + +The account of _Ornithorhynchus_ in Gould’s beautiful folio _Mammals +of Australia_ (1863) is based very largely upon the observations of +Bennett and Verreaux, supplemented by those of the author himself. +He writes, on p. 1, of the burrow as--“a retreat to which it resorts +during the day or on the approach of danger.” No distinction is made +between resting- and nesting-burrows; nor does Gould add anything from +personal observation to the sum of knowledge of the burrowing habits. + +The first precise description, with measurements, of nesting-burrows +is that of Mr. G. F. Bennett (1877, pp. 161-166), son of Dr. George +Bennett, who examined three burrows on Lockyer Creek, a tributary of +the Bremer River, near Helidon in southern Queensland. The first one +opened was twenty feet in total length, with cross-section four inches +by three. The entrance is shown as just under water; five feet from +it a chamber measuring twelve by eight by six inches opened off the +burrow on the right side. Five feet farther on, and also on the right +side, a second chamber occurred; ten feet beyond that, the nest. The +nesting-chamber measured eighteen inches by ten, with a height of eight +inches; in the nest, which was composed of dried grass, reeds, and +gum-leaves--all, from their blackened appearance, evidently collected +under water--were two young ones, estimated to be a month old. This +nest was opened on 27 October, 1876. + +Almost a month later a second burrow was found, eleven feet in length, +with two offset chambers, one on each side, and with a nesting-chamber +excavated but containing no nest. A third contained three offset +chambers, and two young in a nest, which was four feet underground--a +very unusual depth--and twenty-two feet above the level of the entrance. + +Caldwell has nothing to say about the burrows. His only reference +(1887, p. 466) is as follows:-- + + “In September my friend Bloxsome superintended the transfer of the + camp to the colder river Mole, further south, where we hoped to + dig out the later stages of _Ornithorhynchus_ from their nests. I + employed some white navvies, who opened up a large number of burrows, + but the renewed exposure in Queensland had brought on my fever + again, and this seriously interfered with the completion of the + _Ornithorhynchus_ series. + + “The later stages of Monotreme development have, therefore, to be + worked out, mainly with _Echidna_ material.” + +The last sentence might imply that some later platypus material was +obtained; but, if this were the case, it is remarkable that Caldwell +has made no mention of it. His remarks are so non-committal as to +justify a suspicion that he got neither eggs nor young from the burrow. + +Semon (1899, p. 42) describes the burrows thus:-- + + “These burrows have one entrance above and one below the water, + uniting in a tube of 20 to 50 feet, which leads slantingly upwards + from the river-surface and ends in a little cave. I have never found + burrows with a greater number of tubes labyrinthically entwined, and + believe that their existence may be regarded as exceptional.” + +Semon here repeats the popular belief that there are two entrances, +one below, and one above the level of the water. This does happen +occasionally, and the reason will be explained later; but it is the +exception rather than the rule. + +Lucas and Le Souef (1909, p. 145) allow the burrow one paragraph:-- + + “The home of the Platypus is a long narrow tunnel-like burrow, which + begins with an entrance under the surface of the water, and then + runs obliquely upwards in the bank for a distance of 20-50 feet. It + eventually terminates in a rounded chamber or living apartment, lined + with grass and leaves, and situated not very far below the surface + of the ground. Very often the main burrow gives off at intervals + lateral branches also terminating in chambers. Sometimes the burrow + is provided with an additional opening above the level of the water, + though this is certainly not always present.” + +Despite its brevity, this paragraph contains some minor errors. +The burrow does not begin with an entrance below water-level; the +nesting-burrow is not a ‘home;’ and the lateral chambers (pug-pits) are +excavated in the side walls of the main tunnel, and are not connected +with it by branches. + +[Illustration: A NEWLY-OPENED NESTING-CAVITY. + +1. Asleep; 2. Awake; 3. Away. + +_Plate 17_] + +To Kershaw (1912, pp. 102-105) must be given the credit of the first +adequate account of the nesting-burrow, several examples of which he +carefully examined in the banks of the Hopkins River near Mortlake in +Victoria. He writes:-- + + “The river, at the spot visited, is a fairly broad, quiet stream, + winding about through an extensive grassy flat, margined and shaded + with large old red-gum trees. The banks in places are steep; in + others they slope rapidly to the water’s edge. At the time of my + visit the river was low, but when in flood it rises fully ten or + twelve feet. + + “After a careful search along the banks several burrows were located, + places where the soil is easily worked being usually selected. The + entrances to the burrows, when once seen, may always be easily + recognised. In every instance these were situated some feet above the + level of the water, varying from four to fully twelve feet above the + present level. In no case did the burrows open out below the water, + though during heavy floods several of those seen would certainly be + covered. In nearly every instance there was an opening to the surface + higher up the bank, and in one case a double opening was found in + the same burrow--one immediately beyond the other--the narrow ridge + of earth separating the two holes being worn smooth, as though the + animal, when passing up, came out of one and immediately entered the + other. These surface-holes are probably for use during flood times, + when the entrance is under water. + + “Along the steep, muddy bank, close to the water’s edge, the tracks + made by the animals when passing to and from the water through the + grass tussocks were easily recognised, being worn flat and smooth + by the animal’s wet bodies. Claw marks could also be seen here and + there. Such places where the projecting roots of the gum-trees run + into the water are, apparently, most favoured for landing. + + “The entrances to the burrows varied from four to five inches wide + and three inches high. They are always arched above and quite flat + below, following the shape of the animal’s body. This form is + followed throughout the whole length of the burrow, though the latter + may be enlarged here and there. The entrance is occasionally blocked + up with earth.[13] + + “The burrows do not follow a direct line, but wind about, at times + very considerably. They always follow up the slope of the bank, + parallel to and rarely more than a foot below the surface. In no + instance was one found deeper than fifteen inches, while here and + there they approach within a few inches of the surface. A short + branch, from one to three feet long, is frequently made on either + side of the main burrow; in one instance four were seen--two on + either side. These end abruptly, without any apparent cause. Although + in the same class of soil, the length of the burrows varies, the + shortest examined being ten feet, and the longest, carefully + measured, thirty-five feet. While usually terminating in the + nest-chamber, the burrow is occasionally continued beyond the nest + for a foot or two. + + “A peculiarity which, I believe, has not been noted before is that + when the burrow is occupied it is completely blocked with earth for + about a foot. This occurred in three places in one burrow, and is + apt to lead one to conclude that the end has been reached. From this + it is also assumed that the female does not leave the nest for some + time after the eggs are laid or the helpless young are hatched, and + during the time the latter are attached to the mother. The object + in so securely blocking the burrow is, probably, for protection + against flood water in the event of a sudden rise of the river, or + from possible enemies. Unless the block is removed from time to + time, however, it is difficult to conceive how the animal obtains + sufficient air during her lengthened seclusion. + + “The nest-chamber is rounded in form, the bottom always being much + lower than the floor of the burrow, which enters about its centre. + All those examined were of about the same dimensions, the two + carefully measured being each twelve inches deep, thirteen inches + wide, and eleven inches from the entrance. + + “The nest itself is composed of fine grass and gum-leaves, and + completely fills the cavity. The bottom of the chamber is first + covered with a thin layer of grass, followed by a thick layer of + gum-leaves about four inches deep, which is continued up the sides, + and--at least in one case--completely encircles the cavity, forming + a compact circular nest, with the entrance in the side opposite + the tunnel. It was noticeable that many of the leaves were green, + and appeared to be quite fresh. The bottom of the chamber in every + instance was wet, owing to surface soakage, and it is apparently + with the object of avoiding this that the bottom of the chamber is + excavated below the level of the burrow and so thickly lined with + leaves. + + “The first burrow examined had been opened up by Mr. Hood on the + 17th October (nine days prior to my visit), and from the nest two + fresh eggs were taken. These, when found, were attached to one + another, and had been kept in a small box; but in two or three days + they collapsed. When I received them on the 26th October they were + flattened and dry. Several other burrows close by, though having the + appearance of recent occupation, were untenanted, but each contained + a nest, more or less complete. From one of these the shrivelled + remains of two eggs were obtained. + + “Later in the day a burrow was discovered which had every appearance + of being occupied. It was situated on the sloping side of the bank, + fully twenty-five feet from the water, and was the only one I saw + with recently scratched earth at the entrance. The burrow followed + up the slope of the bank for about twenty-five feet, terminating + in a nest-chamber, some ten or twelve feet above the level of the + river. This one was blocked up in three separate places, the last + within three feet of the nest. When about a foot from the nest a + peculiar grating growl was heard, and the next shovelful of earth + exposed the side of the very compact structure, through which the + old one hurriedly forced her way. She was permitted to traverse + the excavation for a couple of feet to a depression, where she was + covered with clods of earth, while a careful examination of the nest + was made. This proved to be the most complete of all those examined, + the whole cavity being completely filled with leaves. No opening + into the interior of the nest could be seen, the entrance being + evidently closed by the animal during occupation. As was the case + in all those examined, it was composed of gum-leaves, with a small + layer of grass at the bottom of the chamber. The lower portion was + tightly compressed from the weight of the animal, while those forming + the sides and top were loosely interwoven. The interior measured six + inches across and four and a half inches deep. The shrunken remains + of one egg were found in the nest.” + +With the exception of the blocking of entrances, and two or three +other minor matters, I can confirm Kershaw’s statements after a long +term of practical experience in the field. What this has involved in +labour alone may best be judged from the remarks of Professors Wilson +and Hill (1908), who, like myself, spent a number of years getting +together material for embryological study. They write:-- + + “The records of Australian biology bear sufficient witness to the + fact that it is extremely difficult, even for residents in Australia, + to procure the material necessary for an investigation into the + development of the eggs of _Ornithorhynchus_. It is only through the + organisation of special expeditions, with ample resources both of + time and money, that any large measure of success in this direction + can be hoped for. + + “The animal itself, though pretty widely distributed, and probably + still far from becoming extinct, is to be found, in any one locality, + only in comparatively small numbers. It is now much less plentiful + than formerly, owing to the demand for its fur--a demand which is + still satisfied in spite of the measure of legal protection which + the animal has obtained in the various Australian states. The + depredations of the fur-hunter are not easily repaired, since the + animal breeds only once in the year and produces but two eggs at a + time. + + “The eggs, when laid, are deposited in a burrow which it is far from + easy to locate, and whose opening up involves a considerable amount + of labour, since, apart from its great length, the river-bank in + which it is situated is commonly enough permeated by tree-roots. And + when at length the actual dwelling chamber or nest is successfully + opened up, no reward at all may be forthcoming, or the material which + is obtained may be unsuitable for the immediate purpose in view.... + + [Illustration: (1) NEST COMPOSED OF GUM-LEAVES AND GRASS STEMS. + + The earth has been removed, leaving cavity and nest undisturbed. + + _Plate 18_] + + “We have only to a very limited extent been able to superintend + personally the work of collection, and have found it necessary + to rely largely upon the efforts of the scientifically untrained + collector in the accumulation of the material for our investigations. + Unfortunately, the material result of the work of such a collector + during an entire season is so meagre that he requires considerable + inducement to carry on the work at all; whilst the product to + the investigator may be practically nil. The genuineness of the + difficulty in procuring this kind of material is sufficiently + indicated by the fact that whilst Semon, in his expedition, was + successful in obtaining a very considerable number of eggs and + foetal specimens of Echidna, his collection of _Ornithorhynchus_ and + embryos would appear to have been limited to a small number of early + intra-uterine eggs. + + “Our own collection is very far indeed from being complete, though + the work of collection has been going on for quite a number of years.” + +[Illustration: (2) BROODING FEMALE PLATYPUS, SHOWING SEPARATION OF FUR +AND SLIGHT INDENTATION OF ABDOMEN IN LIEU OF POUCH. + +_Plate 18_] + +Semon (1894, p. 13) tells a similar story:-- + + “Concerning the development of the eggs after being laid and + concerning the young after hatching I can unfortunately make no + statements. I had not the good fortune even to find eggs or young + in the numerous burrows which I and my white companions opened. My + blacks showed the greatest dislike for this work, and were averse + to troubling about _Ornithorhynchus_ at all: we ourselves were too + absorbed with the several other works in hand ... to be able to + give our whole time and zeal to the wearisome and for the most part + disappointing work of digging out _Ornithorhynchus_ nests.” + +The two great expeditions of Caldwell and Semon failed to secure eggs +and young of the platypus from the nest. Wilson and Hill, after many +years of endeavour, obtained only a very limited number, most of which +have not yet been described. Since the eggs and young, which cannot +escape from the nest, are so difficult to get, it may well be imagined +that the doings of the elusive female, hidden in the darkness of her +burrow, are infinitely more difficult to observe. + +The interest attaching to precise observations of the actual burrowing +method is great, the chief point being to determine the relative extent +to which the highly sensitive muzzle and the powerful claws of the +fore-paws are used in the process. I therefore experimented with a +single female platypus which I had in captivity at my home. + +The creature was placed in a specially contrived enclosure, of which +the essential features were a plate-glass front and a wooden back, +four inches apart at the bottom, widening to six inches at the top. +This enclosure was filled with sifted soil, which was put in a +bucketful at a time, each bucket of soil being followed by a bucket +of water, until the frame was full, when the whole was tamped and +thoroughly flooded with water. The object of the taper was to cause +the soil to wedge, and so prevent it from collapsing on the burrowing +animal. Water was used to consolidate the soil to something like the +consistency of the banks in which the platypus burrows naturally in the +wild state. + +The enclosure thus prepared was allowed to stand for twenty-four hours, +and the animal was then introduced at one side, where a portion of the +earth was removed to make room for it, at 2 p.m. No attempt was made to +burrow until about 5.30 p.m.; but I am not certain whether this time +bears any relation to what normally happens. The observations which +follow were made during a period of about an hour, by means of the +plate-glass front, and during this time I kept myself concealed as far +as possible from the animal. + +The platypus, in order to obtain the greatest purchase before beginning +to burrow, tucked the tapering end of its pliable tail between its +hind legs and simultaneously hooked its out-turned hind-claws into the +earth at each side. While in this crouching attitude, with stiffened +top lip and splayed fore-claws it proceeded smartly to break away +the earth. After burrowing for several inches it rested awhile; +then it energetically contorted its neck and body so as to tamp the +freshly-loosened earth tightly into the hollow surrounding it. + +While stationary, the creature occasionally beat the walls with its +trowel-like tail; but whether this action was deliberately intended +as part of the tamping process, or was due to muscular reaction as +the result of the strenuous exertion, or both, I do not profess to +know. Nevertheless, it certainly did not distort or tend to break +away the true design of the burrow by its spasmodic action. In fact, +the structure and shape of the tail suggest that it is designed as an +actual modelling-tool. + +After a few minutes’ rest, during which the breathing was laboured +and was accompanied by an apparently involuntary gulping, the animal +again deliberately shovelled the earth over its head with the end of +its snout. In this way it created a crude cavity in which to loll its +head to one side, while, with neck shortened, it reached to the utmost +with one web-palmed paw, and scratched a hemispherical hollow to one +side of the tunnel, contorting its shoulders the while. The energetic +digger then placed its head in the recess so made, and, without any +hesitation, performed a similar operation on the opposite side with the +other splayed paw. Then, to dislodge the partition separating the two +recesses, it probed its muzzle vigorously into it, and then proceeded +as far as the out-stretched neck permitted, to form another “loll-hole” +to one side with its muzzle, in readiness for its head in burrowing a +further section. Meanwhile, the well-worked earth trickled round the +wriggling creature’s body, principally about the powerful shoulders, +whence a portion eventually filtered down as far as the hips. + +While the fore-paws and rooting muzzle were working at high tension, +the hind legs were alternately keeping the specialized fore-parts +well up to their work by clinging tenaciously to the solid earth. In +their struggle to do this, the hind-claws actually aided the process +of excavation by cutting the lateral angles which complete the arched +design of the burrow. + +A remarkable feature of the burrow is that no soil is ejected, but +the whole of it is reduced to a consistency suitable for packing into +the sides of the burrow, and even the soil dislodged when commencing +a burrow is consolidated into the river-bank. When the platypus has +burrowed about six inches, it packs the loose soil by contorting its +body and pressing against the sides, at the same time beating the floor +with its tail. The width of the excavation is about double that of the +finished burrow, that is to say, the earth excavated is tamped into +about half its original bulk. The whole of the earth taken from each +section is not always beaten in before a new section is commenced; but +the animal appears to work very systematically, and, according to +the consistency of the soil, it moves backward from time to time and +adds the finishing touches. In the experiment the captive repeated the +burrowing and tamping alternately, until it eventually broke through +the surface. + +The powerful claws of the fore-paws do practically all the burrowing, +the only help they receive being a probing or lateral shearing movement +of the muzzle (when the earth is not too hard) and the pressure exerted +by the hind feet. Although apparently preferring to burrow in the +normal position, the platypus will readily lie on its back, or on +either side, and at times will work in a spiral fashion, either while +excavating or while tamping the tunnel, even in the absence of any +serious obstacle; but eventually it reverts to the normal position +for the purpose of finally shaping the burrow. The position in which +it works does not affect the rate of its progress in the least. When +confronted with temporary obstacles, such as impoverished or caked +earth between the roots of trees, etc., the platypus will, miner-like, +in order to avoid retracing its steps or branching off in another +direction, throw itself into the required position and follow, not the +line of least resistance, but of favourable soil. + +The thickness of the pug or pugs tamped into position with the tail by +the female prior to retiring to the nest for the purpose of laying and +incubating the eggs, is about six inches, and it is packed so closely +as to be indistinguishable from the surrounding soil. + +[Illustration: MODEL OF NESTING-BURROW. + +Note rocky obstruction above nesting cavities. The cavity nearer to the +entrance has been abandoned. + +_Plate 19_] + +During the process of dragging back and packing into the sides of +the burrow the soil scratched out by the fore-paws and muzzle, the +platypus exhibits its remarkable ability to reverse the action of its +hind legs, and actually “advances” backwards. Students of anatomy +will have observed, no doubt, that the hind feet of a platypus have +a tendency to turn outwards from the flanks, and that the grooved, +curved claws continue in that trend towards the tail. This is as it +should be for the purpose of gripping and scratching back surplus soil +while tunnelling ahead. It is also as it should be when reversing. +Especially is this so when burdened with a packing of adhesive pug, and +when, incidentally, the fore-paws are practically out of action. The +muscular contortions of the body at that time certainly afford great +assistance. Nevertheless the hind quarters and cumbersome tail would +during one of its essential functions become useless, if not a burden, +to the platypus, but for the natural provision of a “two-way” action of +the hind limbs. Preparatory to pulling backwards, the trend of the hind +feet continues until the sets of claws are facing one another beneath +the tail. This contortion enables the animal to take a firm grip of +the flattened earth-floor; it then pulls the body backwards step by +step, while the fore-paws, when freed, do the shoving. The alternate +action of the fore-legs in walking forward is imitated exactly by the +hind legs in the reverse direction, and the platypus can thus, at will, +reverse the direction of its movements. It is rather amusing to witness +this act, for, at the outset, the fore-parts are usually obliterated +with earth, and the tail, which in contour and elevation somewhat +resembles the head, sometimes puts one at a loss to guess whether the +creature is really coming or going. + +In addition to the uses of the hind-claws and to the reversible nature +of the entire limb, the hind foot of the platypus, especially of the +male, is just as versatile in its actions as that of a chimpanzee, +even to the power of deliberately gripping. During a backward march +it resembles, in action and general appearance, the fore-limb of a +grizzly bear, or, more nearly still, that of a long-clawed sloth. +Is it possible that this versatility is reptilian in origin? What +other mammal in the world is able thus to interchange the functions +of its hind- and fore-legs to such advantage? Such ability may be +characteristic of moles, etc., but it is certainly a remarkable +adaptation. + +I have already mentioned the stiffening of the top lip, and, when one +realizes its extreme limpness when not employed in burrowing, it will +be obvious that stiffening is necessary in order that a groove may be +made in earth by lateral oscillation (“lipped-in,” so to speak). While +this groove is being formed, and until it is sufficiently deep for the +bony prong of the upper jaw to be used for shovelling the earth away, +the direction of the stiffened lip is maintained by the earth above and +below it. + +Given favourable conditions, a platypus can excavate a cavity of +approximately 6 × 5 × 5 inches in five minutes. It can tamp loosened +earth completely into a six-inch section of a tunnel in fifteen +minutes. This makes twenty minutes in all to a shift. Therefore, if the +tunneller continued unceasingly in this manner, in sixteen hours it +would have completed a tunnel twenty-four feet in length. This is the +average length of a breeding-burrow. + +Quite possibly the spasmodic gulping observed in the throat of a +burrowing platypus is due to involuntary exhalations of spent air, +corresponding to the periodical bubbling when the creature blows +beneath water. Under open conditions, normal breathing may be +reasonably governed at will, but this exhaust spasm appears to be +quite beyond control. This is probably so that it may collect its food +unhampered beneath water, and that it may also delve freely while +tunnelling, without having to relinquish such immediate business for +the purpose of replenishing spent air. The breathing observed while +the platypus was tunnelling was at the rate of thirty respirations +per minute, and the gulps in the throat approximately at intervals of +twenty-five seconds. The normal breathing of a sleeping platypus I have +found to be fifteen respirations per minute. + +During the experiment the animal apparently kept the facial furrows, +embracing the orifices of the eyes and ears, tightly closed, as when +swimming under water. + +Accounts of the bionomics of the platypus in current works on natural +history invariably assume that the nesting-burrow is the home of the +animal, in the same sense in which a rabbit-warren is the home of +the colony that it contains. As has already been stated, this is not +so, each burrow being inhabited by a single female, and that only +during the nursing period. The usual statement that the burrow has two +entrances, one under water and one above, is also erroneous. It is true +that such a condition often exists; but this merely indicates that +a rise in the river has covered the original entrance, which is always +put in above water-level, and that a new entrance has been broken out, +or that the secondary under-water “getaway” has been formed later by a +washaway at the root of an adjacent tree. + +[Illustration: Bird’s-eye view of river-bank, showing platypus burrow +winding 40 feet from entrance to nesting-cavity. (Scale about ¾-inch to +1 foot.) + +From model by H. Burrell. + +_Plate 20_] + +The female excavates her burrow unaided. She selects a suitable site, +preferably in a high sloping bank, well held together by the roots +of trees; it is all the better if a fringe of reeds adorns its edge, +so that she may come and go as safe from observation as possible. +The entrance is made above water, at a height varying from nearly +water-level to as much as twelve feet. When fresh, it has a definite +shape--low-arched above and flat below--and measures from four to six +inches in width, and from three to four inches in height, corresponding +pretty accurately to the cross-section of the occupant. On account of +this definite shape, it is easily distinguishable from the burrows +of water-rats (_Hydromys_) and rabbits found in similar localities. +But after a time this entrance may become adventitiously enlarged and +altered in shape, so that the distinction is not always completely +maintained. Bennett suggests that the entrance is usually concealed +among the vegetation of the bank; but, though this may happen where +banks are covered with a lush vegetation, my observations agree with +those of Kershaw that there is no attempt actually to ‘camouflage’ the +entrance, even though ample vegetation may be found growing close by. +The entrance is usually quite obvious, and, in any case, attention +directed to it by the runs of the animal, worn smooth and hard by the +dragging of its wet body over them. Upon these runs the impress of the +tail is usually to be seen, and the pricked tracks made by the claws of +the hind feet are unmistakable. + +[Illustration: Nesting-burrow with two openings. Nest marked N.] + +The burrows exhibit an infinite variety of form and length, but all +show the arched roof and flat floor adapted to the size of the female +which has constructed them. This size may therefore be gauged with +reasonable accuracy during the process of digging the creature out. +Here and there, however, there may be, in the calibre of the tunnel, +some irregularity apparently due to the adoption of an unusual position +during digging in order to deal with some particular obstruction. +The tunnel usually follows a sinuous course, but invariably keeps at +about the same distance (from 12 to 18 inches) below the surface. +This power of the platypus to judge how far it is below the surface +is as remarkable as that sense which warns it when it is approaching +another burrow, whether of its own kind, or of some other animal. +In constructing its tunnel, it sometimes circles round, so that, if +it continued on its course, it would break into an earlier section +of its own burrow. This, however, never happens. In one case it was +observed that the platypus stopped a foot from this earlier section, +and forthwith constructed its nesting-chamber. In a number of others, +it avoided breaking into its own burrow by passing under it at a +distance of a foot, coming up on the other side to the usual distance +below the ground-level (see page 127 and Plate 20). In the same way +it avoids the burrows of water-rats and rabbits by tunnelling clear +of them. I have known it go down to the very unusual depth of four +feet to avoid a rabbit-burrow. In some cases, instead of going under +an obstructing burrow, it turns aside, and continues its tunnel in a +different direction. One more example of this uncanny sense may be +quoted. Plate 19 illustrates a model of a burrow made to scale. In +this the nesting-cavity is shown at a vertical depth of about three +feet. The animal burrowed in at the usual level below the bank +where it sloped, until it came to a place where the bank suddenly rose +steeply. Here two alternatives were open to it. Either it must go +straight upwards through rocky soil for more than two feet, or it could +construct its nest where it found itself, three feet below the level of +the upper bank, but still the normal distance from the lower face. It +chose the latter alternative. + +[Illustration: VARIETY IN NESTS. + +1. Couch grass stems, and a few gum-leaves; 2. Willow “swishes,” willow +rootlets, and reed flags; 3. River reed roots, entirely; 4. Couch grass +stems, and gum-leaves; 5. Fuzzed reed stalks, and reed flags. + +_Plate 21_] + +A great amount of discrimination is necessarily displayed in selecting +a suitable soil in which to burrow. Burrows commenced in soil that +ultimately proves unsuitable because of its friable nature, are--as +often--promptly deserted. Although a preference for soft soil is +indicated, I noticed that in one burrow which I investigated the animal +had removed three inches of compacted river-gravel from the face of the +bank before reaching the ideal earth behind, which she evidently knew +was to be found by perseverance. Sandy banks, unless reinforced with +lengthy lucerne or similar roots, are left severely alone, since the +burrows tend so easily to collapse. + +No general statement can be made as to the length and direction of +the nesting-burrows, since both are infinitely variable. The length +varies from five feet to upwards of sixty in one season’s burrowing; +but all the short lengths recorded are probably abnormal, and due to +exigencies brought about by flood-conditions. From fifteen to twenty +feet would appear to be a fairly adequate length, though that is under +the average, which is raised by a number of extraordinary length. + +What it is that impels the animal sometimes to go on burrowing up +to the amazing distance of 100 feet, I will here explain. These +abnormalities occur only in ground that has been occupied undisturbed +by platypus for many years. Indirectly, floods are responsible for the +trouble that compels platypus to enlarge and renovate. These shy and +timid creatures naturally do not wish to make their ideal breeding-bank +more conspicuous to their enemies than is necessary; they therefore +prefer to use the same entrance (when convenient) year after year, +rather than perforate the face of the bank with tell-tale porches for +which there is no necessity. Leave well alone, is their motto. Now +suppose that a platypus puts in a burrow in any one season, and that it +is, at some later time, covered by flood waters. Being in soft soil, +it soon becomes silted up--at least, here and there. The following +year, the same or even another female enters the porch and traverses +the tunnel, as far as it is habitable, to investigate. If she approves +of it up to a certain distance, she will cut a pit in the side wall +there and then, and plug up the section which is not to her liking; +then she will tunnel anew in another direction to the average distance, +as if commencing from the original porch. This may go on year after +year, with flood after flood, until the enormous length of 100 feet is +recorded by the collector as the longest breeding-burrow discovered. +Peter Yates, my able assistant, can vouch for that fact. + +The nesting-chamber is generally placed at the extreme end of the +burrow, though sometimes a blind branch is carried on beyond it. It +varies somewhat in size, but is usually more wide than high, and +measures on an average about twelve inches by eleven. In this chamber +a nest is constructed, a variety of materials being used, the nature +of which depends upon the locality. In the New England district the +commonest type of nest is composed almost entirely of eucalyptus +leaves and the rhizomes of couch grass, but I have also found willow +“swishes,” roots, branchlets, and leaves; roots and stems of the reed +_Arundo phragmites_; and the leafless branches of she-oaks (_Casuarina +spp._). These materials are arranged as a lining of the cavity, except +for the opening where the burrow enters, and are of even thickness, +except on the floor, where the lining is distinctly thicker. I have +been informed by an aboriginal that he has seen a male carrying +nesting-material by means of his spurs, but am not disposed to believe +it, although I am quite sure he could do so. All my own observations +suggest that the female alone digs the burrow and makes the nest. They +also show that the amount of nesting-material never more than half +fills the cavity until the babies begin to grow and toss the litter +about. For instance, where triplets are concerned one is apt to find +the nest-cavity crammed to the dome with such material. + +In all the years during which I have been making observations I +have never once actually seen the female in the act of carrying in +nesting-material. It seems likely, therefore, that nest-building is +done at night. The materials used are those closest to hand. As the +foundation of one nest I found a willow “swish” more than five feet in +length. It would surely be awkward to drag such a thing to the end of +a long burrow. It seems likely that the animal collects a great deal +of material that is lying loose upon the ground, or even in the water. +But there is no doubt that it is also able to cut off reeds and grass +rhizomes by means of the elongate horny ridges in the anterior part +of the mouth. These ridges are also used to shred the stems of reeds, +reducing them to a mass of soft fibres (see Plate 3). + +As soon as the nest is completed, and before the eggs are laid, the +most remarkable habit of all comes into evidence--that of plugging +the burrow. G. F. Bennett (1877) was the first to observe the lateral +pits from which the earth to form these plugs is drawn; but he did not +observe the plugs, and therefore missed the import of the pits. Kershaw +(1912, p. 103) saw the plugs, but did not connect them with the lateral +pits. He writes:-- + + “A peculiarity which, I believe, has not been noted before is that + when the burrow is occupied it is completely blocked with earth for + about a foot. This occurred in three places in one burrow, and is + apt to lead one to conclude that the end has been reached. From this + it is also assumed that the female does not leave the nest for some + time after the eggs are laid or the helpless young are hatched, and + during the time the latter are attached to the mother. The object + in so securely blocking the burrow is, probably, for protection + against flood water in the event of a sudden rise of the river, or + from possible enemies. Unless the block is removed from time to + time, however, it is difficult to conceive how the animal obtains + sufficient air during her lengthened seclusion.” + +The mining term “pug” seems appropriate to the earth composing these +plugs, and “pug-pits” to the cavities from which it is derived. I +therefore propose to use these terms. What apparently happens is +this. When the female has completed the nest to her satisfaction, she +goes to the entrance of the burrow, and, turning, re-enters it. At a +varying distance from the entrance she excavates a chamber opening +off the side of the tunnel and compacts the earth so obtained into a +pug, which is always placed close to the first pug-pit, and between +it and the entrance. Proceeding towards the nest, she excavates a +second pug-pit in the same way, compacting the pug behind her, and so +on, without having to turn once from beginning to end. I have found +from two to nine of these pugs in different burrows, the usual number +being three. The pits would seem to occur indifferently on either side +of the burrow, but I have noticed that the latter usually changes +direction immediately after a pug. This device has nothing to do with +preventing the entry of ordinary flood waters. The nest is almost +always placed at a sufficient height above water-level to escape these, +and the platypus can easily break out a new entrance anywhere it +pleases. It is obviously a cunning device, partly for protection from +enemies, but principally for securing ideal brooding conditions. It has +doubtless baffled many investigators, human and otherwise. With all my +experience, it has frequently taken me some time, after having arrived +at a pug, to pick up the further course of a burrow. Consequently it +is easy to imagine that a less experienced observer would be entirely +misled, believing he had come to the end of an untenanted burrow, and +thus retiring in disgust. This probably accounts for the long time it +has taken to ascertain fully the animal’s nesting habits. A final pug +is always placed near the entrance to the nesting-chamber. + +[Illustration: MALE PLATYPUS. + +Note bare tip of tail, due to pugging off unnecessary openings in +camping burrow. + +_Plate 22_] + +[Illustration: (2) MALE PLATYPUS. + +Note position of paw when bearing weight. + +_Plate 22_] + +Now to explain how the labyrinths mentioned by Verreaux are made. +Very much the same thing happens as that described above, except that +more breeders make use of the bank at the same time, and, in their +endeavours not to clash with one another, they take most erratic +courses to avoid neighbouring burrows. Admittedly they do not see +these obstacles, any more than Verreaux did. Nevertheless they are +quite aware of their proximity, and act accordingly. Hence the maze as +seen and wondered at by man. + +Another point is that, where an objectionable section of a burrow has +been pugged off in the past, the pug, through soakage during floods, +becomes solidified like the surrounding earth. When the burrow is +followed by man later to that particular partition, this is generally +looked upon as a blind or dead end; yet possibly, a foot or two farther +on (not necessarily in a direct line), a so-called “beginningless” +subway may be found further to bewilder the weary mattock-wielder. +Again, every time a flood occurs, fresh strata of silt and débris are +left lying on the surface of the bank after the water recedes, and +thereon grass and herbage readily take root, thus increasing the depth +of earth above the ancient tunnels. These, when hit upon, appear to the +student as extraordinarily deep for platypus to work, in comparison to +the depths previously described by the more fortunate collector who +accidentally happened upon a positively new burrow, which, throughout +its entire length, did not lie more than fifteen inches below the +surface. + +My experience goes to show that the female does not leave the nest +between the times when the eggs are laid and the young are able to +suck, and that she digs through and replaces the pugs whenever she +leaves the nest or returns to it. The constant removal and working of +the soil of which the pugs are built makes it so soft and fine that it +sometimes becomes quite velvety to the touch, and clings like flour if +squeezed in the hand. It is always slightly damp after being worked by +the platypus; but on one occasion when I took a nest containing large +triplets without their mother, the pug near the nest had dried and +shrunk away from the sides of the tunnel so much that I was able to +remove it in a mass, though it fell to powder in my hands when slightly +squeezed. Possibly, that absent female had met her death in some way, +for I am positive that it would require some days for the pug to dry +and shrink to such an extent. However, the young, which I presented +later to the Australian Museum, appeared none the worse for their term +of imprisonment without food. + +How does the animal make and replace the pug? Wood Jones states (p. +48):--“... the form of the tail resembles that seen in the Beaver ... +It has nothing whatever to do (either in the Platypus or the Beaver) +with any supposed habit of puddling clay....” After much experience of +observing the habits of platypus in their wild state, I succeeded in +1925 in proving the accuracy of my own notions on this subject. While +collecting on the Namoi River for the proposed National Museum which is +to be erected at Canberra, I unearthed a female platypus on her nest, +which contained twin young. While I was registering the temperature of +the nesting-cavity, the mother made off from the nest along an offset +tunnel. Knowing that I could secure her later, I leisurely finished +my duties with the young and carefully extracted the nest (whole). +About fifteen minutes later my assistant started in pursuit of the +mother. To our surprise, the offset, which usually measures only a +few feet in length, on this occasion measured about seven. After +following along for about three feet we discovered a pug sealing the +runway. I carefully examined the hurriedly-constructed barrier, and +then followed closely along the workings as my assistant tactfully +broke the earth away. Presently another pile of pug met my gaze, and +beyond it the platypus could be clearly seen up against solid earth +scratching for her life, and at the same time deliberately shoving +the refined earth behind her with the dorsal end of her tail to pug +herself in. Of course, this tunnel was there prior to her leaving the +nest, but was evidently pugged off at the first section from the nest +before she retired to perform her maternal duties. This pug, then, she +had burrowed through and built again behind her, and she had almost +succeeded in excavating sufficient solid earth at the end of the runway +to pug herself in with the idea of outwitting us. + +During an exceptionally wet season the earth, in certain situations, +becomes sodden, like clay. At such times the pugging in the tunnels +is found to be a conglomerate mass of marble-sized mud balls, more +closely compacted than shot in a gun-shell. This confirms my statement +that the nesting-cavity is sealed up before incubation begins, and that +in building the pug, the tail is used for rolling the earth along the +runway into position. Hence the baldness of that trowel-like member. +It proves also that, wet or dry, pugging is worked methodically into +position a portion at a time. + +The hair on the dorsal surface of the tail of the female becomes +increasingly abraded during the nursing period, so that by the time the +young are in fur she usually exhibits a bald patch of some size. So +much is this the case that I have several times accurately guessed the +size of the young from the degree of baldness of the mother’s tail. Now +this particular hair is exceedingly coarse and harsh, and could only be +worn away by some such drastic use as in the tamping of the pugs, which +must be removed and replaced so many times during the nursing period. +Wood Jones’ suggestion that the flat tail is used to warn neighbours +by continuous smacking of the surface of the water is certainly not +supported by my observations of the living animal. + +The thickness of the pugs varies from three inches to a foot; +ordinarily it is from six to eight inches. I have found pug-material +beneath the nest itself to a depth of several inches; the animal must +therefore dig up and work the earth on the floor of the cavity before +she begins to build the actual nest. This is probably a provision for +the more rapid carrying away of any water that may reach the nest by +seepage; but, on the other hand, it may serve to hold moisture, and +thus maintain the damp atmosphere which seems to be necessary for +successful incubation. + +[Illustration: Burrow with four nests. Crossing under burrow marked X.] + +The platypus would appear to dig a new burrow for each breeding-season, +and it certainly does so after being disturbed. Occasionally an old +burrow may be refurnished and remodelled, and one main entrance used +for several seasons. On two occasions only have I found more than one +nest in a burrow; and a diagram of one of these burrows is given here. +It contained, in different positions, no fewer than four nests, three +of which were in various stages of dilapidation; the fourth, though +scanty in material, contained twins. Mr. Hoy examined these four nests +with me, and agreed that they bore the appearance of having been built +at different times, probably at yearly intervals. The bank in which +this burrow was placed was unusually faulty for the purpose, having a +sandy subsoil. It was on a beautiful stretch of water about three miles +below the New England waterfalls, where the river is in places actually +bridged by rocks, so that when it is at a low level, as in periods +of drought, the river becomes a chain of ponds, and the platypus +is prevented from travelling far. Possibly, therefore, the animal +or animals which inhabited the four nests successively had become +river-locked, so to speak, and compelled to make shift in the only +available quarters. We dug out three other unoccupied burrows in the +same bank, each of which had evidently been abandoned on account of the +surface sand collapsing while the nesting-chamber was being excavated. +The platypus was probably compelled to shift along the bank until, in +the only part which could be used for its purpose, it found the old +burrow, and so contented itself with burrowing on past the vacant nests. + +A second example was opened up on the Macdonald River on September +28, 1920. After a rainy spring the river was eighteen inches above +its normal level. The original entrance to the burrow was then twelve +inches below water, but a new entrance had been broken out seven +inches above. The main tunnel wound gradually up the sloping bank for +36 feet, and then divided into two, one arm, ten feet long, going to +the first nest--which contained a female and twin eggs--the second +branching off to the left to another nest, which, at fifteen feet from +the junction, contained a female and a single egg. The two nests were +eleven feet apart in a direct line. The season of 1920 was abnormal in +rainfall; but, even so, it was remarkable to find two females occupying +self-contained flats in one and the same burrow. The accident that the +females and their eggs were duly preserved in the interests of science +probably saved them from considerable complications, which might have +ensued if they had been allowed to bring out their young. + +[Illustration: PLATYPUS EGGS AND YOUNG. + +1 and 3. Eggs, new-laid; 2. Week-old young and egg capsules; 4. Relaxed +egg capsules (triplets and twins), showing adhesion, also rents made +by young in hatching; 5. Young, about fourteen days old; 6. (above) +Dried-up egg, (below) single, twin, and triplet collapsed capsules; +7 and 9. Eggs, partly incubated; 8. Day-old young, and capsules from +which hatched. + +(_About two-thirds natural size_) + +_Plate 23_] + +It is of some interest to note in passing that on the previous day I +had suffered a defeat only fifty feet away from this burrow. Opening +up a burrow, I came to a pug. When this was opened it broke into +a rabbit-burrow, and was discarded as a ‘duffer.’ The following +morning, on examining the excavation again, I found a freshly-dug +platypus-shaped hole in the side of the trench, and, following up this +clue, came upon a finished but empty nest, its tenant having deserted +it during the night. Such a congestion of tenanted burrows is, however, +quite unusual, and in this case was due primarily to the fact that +the ordinary conditions of the season had been considerably upset by +freshes in the river. I have since found several platypus breeding +in the same bank side by side, but not from choice nor because of a +neighbourly disposition. Scarcity of suitable soil is the main reason +for overcrowding, but rabbits and even the European rat are invading +these ideal water frontages and are ousting _Ornithorhynchus_ from his +birthright. Otherwise, as I have explained before, breeding platypus +prefer “solitary confinement.” + +To describe a number of burrows in detail would not serve any good +purpose, for they are too variable to be sorted into types, and each +seems to be constructed according to the vagaries of its builder. One +burrow which I examined at Manilla on 22 September 1920 had an entrance +four feet above water-level in an almost perpendicular bank. It was +opened up and followed for a distance of twenty feet. and came to an +end just as it was tending back towards the river. The nesting-chamber +was found five feet from the end, but was placed in a very unusual +situation, twelve inches above, and just to one side of, the tunnel, +so that it was approached by a short lead from below. As this passage +was securely pugged, the nest was extremely difficult to locate and +might easily have been overlooked. However, since then. I have found a +similar burrow in New England, thus proving that the first find was not +unique. + +The platypus invariably begins its burrow above water-level, and the +presence of other entrances, whether above or below water, is due +to variations of that level. I at first thought that some of these +additional entrances might be of the nature of air-shafts, but found +that the pugging of the burrow would prevent their being of any use +for such a purpose. Kershaw, too, wonders how the animal and its young +obtain sufficient air-supply, plugged in as they are in an almost +air-tight chamber. The resting-burrows are often provided with two or +more adventitious entrances, which may perhaps serve as apertures for +ventilation; but additional entrances to the breeding-burrow could not +serve this purpose. + +Occasionally the entrance to a breeding-burrow is at a considerable +distance from the water; I have found one as much as forty feet from +the river, and fifteen feet above its surface--the river being at the +time two feet above normal level. + +I have also found burrows coming to the surface on the river side of +a sheep-track, and disappearing into the ground on the other side of +it. Kershaw (1912, p. 103) noted one such, in which the narrow ridge +of ground separating the two holes was worn smooth, as if the animal +passed up, came out of one, and immediately entered the other. I think +the reason is that stock using an accustomed track may annoy the +platypus by bringing down her roof, until in exasperation, she abandons +the section of burrow underneath. + +My opinion is that the vagaries observed in breeding-burrows are due +to the nature of the ground. Obstacles such as roots, stones, and +rabbit-burrows--or, more important still, patches of friable soil +which tends to cave in--force the female to continue her efforts until +she finds a suitable position for her nesting-cavity. As I have said +before, the faulty nature of the bank often leads to the abandonment of +a burrow. + +As to the question of a sufficient air-supply, I find that in the +case of the very young little air is required up to the age when they +begin to take milk. Seeing that the mother is, up to that time and +until disturbed, always found in the pugged-up cavity with her eggs or +her young clamped to her abdomen,[14] it is evident that the only air +obtained is that which percolates through the several pugs arranged +here and there throughout the tunnel. From tests made with very young +platypus thus taken direct from the mother, I find that, the younger +the nestling, the longer it can remain under water. + +At Manilla, on 3 September, 1925, I unearthed a female platypus +nursing twins. The temperature of the outer air was 70 deg.; of the +nesting-cavity (containing young) 68 deg.; the river water 62 deg.; +of the mother (cloacal) 82 deg. The young were apparently about three +days old and measured 28 mm. from tip to tip. The mother’s cloacal +temperature would, I think, correspond approximately with her body heat +when coiled up around the young. Immediately after being taken from +the nest, the twins were put into a bottle containing river water; yet +one of them lived for three hours; the other survived for three and a +half hours before drowning; and both would probably have survived much +longer but for the shock caused by the sudden change of temperature +from 82 to 62 deg. In other cases, when drowning young platypus taken +for scientific purposes, I have always tried to be sure that they were +dead before preparing them for pickling; but on several occasions, when +they have been placed in wadding for the removal of moisture and while +I have been engaged on other work, they have been found crawling about +and have had to be “redrowned.” This is on all fours with the fact +that flies, apparently drowned and then placed in the sunshine, recover +their vitality. + +On an earlier occasion (3.35 p.m. on 2 October 1920) in bitterly cold +weather I took twin young ones measuring 40 mm. from a nest at the +Macdonald River and put them into a bottle of about 6 2½ inches, into +the bottom half of which I pressed a handkerchief tightly, so that they +might not crawl within its folds. The bottle was then securely corked +and carried to camp in a billy-can--four miles over a rough bush track +on the floor of a stiffly-sprung van. On arrival I was surprised to +find them alive, but they were apparently asleep, snugly coiled. On my +flicking the bottle with my finger, both uncoiled and pawed the air, +only to subside again. This performance was repeated half-hourly for +5½ hours, until, being tired after a hard day in the field, I decided +to chance results, wrapped the bottle in a chaff-bag, and retired +to my canvas sleeping-bag until morning. At 6.40 a.m. I found them +asleep, and when the bottle was uncorked they were as lively as when +collected. Three hours later they were “snap-shotted” with the shells +of their eggs (see Plate 23, fig. 8), and, as I had another busy day +ahead, I concluded the observation by dropping them into a bottle of +fixative. During the day I unearthed a set of triplets of the same +age as the twins. These, with a portion of the nest, were placed in a +loosely-woven calico collecting-bag. After being several times exposed +to light and air, they were found dead at the end of six hours. + +Tests made with young at various ages prove that, from the time when +they begin to consume milk, the time required for drowning is gradually +lessened. I have observed that, during the period when the mother +has to replenish her food and milk supply, the pugs, through being +continually removed, are less compactly re-arranged. Fresh air is, +therefore, introduced into the nesting-cavity in graduated supplies, +and this would indicate that the young require more air in proportion +to their growth. + +[Illustration: (1) MACDONALD RIVER, N.S.W. + +The banks here are ideal for burrowing, in the shade of the river-oaks. +The granite boulders in centre are favourite sun-baking places of the +long-necked river tortoise. + +_Plate 24_] + +[Illustration: (2) “BLUE HOLE,” NAMOI RIVER, N.S.W. + +The banks, being rocky, are unsuited for burrowing, but the river at +this “bend” is an ideal feeding-place. + +_Plate 24_] + + + + +CHAPTER IX + +DISTRIBUTION AND HAUNTS + + +The platypus is confined to that part of Australia which lies east of +138° E. long., and to Tasmania. It has not so far been recorded from +the Cape York Peninsula north of 15° S. lat.; but this country is +little known, and it is not improbable that the animal will be found +there when the rivers are examined. The most northerly rivers from +which we have definite records are the Mitchell and its tributaries +on the western side, and the Barron on the east. A number of rivers +farther to the north--such as the Coleman, Archer, and Batavia, running +into the Gulf of Carpentaria, and the Normanby and Kennedy rivers +entering Princess Charlotte Bay--are probably suitable as habitats, and +may in time be found to contain _Ornithorhynchus_. + +The first record of the platypus in the Gulf rivers is given by +Armit (1878, p. 413). He observed one swimming in a large water-hole +150 miles west of Georgetown on the road to Normanton. It is not +clear whether this water-hole was part of a river bed; but it could +not, in any case, have been far away from the Gilbert River, along +which the road runs. He also stated that platypus occurred in the +Leichhardt River, which is the most westerly record. Waite (1896) +published records from the Norman River at Normanton on the Gulf +side, and from the Barron, Herbert, and Burdekin rivers on the east +coast. Through the kindness of Mr. H. A. Longman, of the Queensland +Museum, Mr. A. H. Chisholm, and a number of other correspondents, +I have gathered a considerable series of records for Queensland +waters. The platypus is exceedingly plentiful in the upper waters of +the Mitchell and its tributaries, in the Barron, and the Herbert, +especially on the tableland. It is also common enough in the small +creeks draining into the Herbert below the range. It would seem to +be almost equally plentiful in all the chief coastal river systems to +the south--Burdekin, Fitzroy, Burnett, and Mary--although it is not +so frequently seen in the more closely settled portions of the river +valleys. No platypus has ever been seen (so far as I can ascertain) +in the Diamantina and Cooper’s Creek, which drain into the interior; +nor can I find any records for the Paroo and Warrego. They are found, +however, in the Condamine, Macintyre, and Dumaresq rivers, and a +tributary of the last is named the Mole River from the occurrence of +the duck-mole in it. It was, indeed, on this stream that Caldwell +collected some of his material. Mr. Longman mentions that his Museum +has records of platypus from the Brisbane district in the early days, +but none of recent date. + +In New South Wales _Ornithorhynchus_ is found in the upper waters of +all the rivers draining to the east coast, and even in small creeks +such as Ourimbah Creek, north of Gosford. It is especially numerous in +the trout streams of the southern Alps, both those draining into the +Murray system, and those running southwards into the Snowy. Inland, +the records cover the upper waters of the Gwydir, Namoi, Castlereagh, +and Macquarie in the north, but not the Bogan. In the south, the upper +waters of the Lachlan, Murrumbidgee, and Murray still hold a goodly +store. It will be remembered that the first platypus was discovered in +a lagoon off the Hawkesbury. Two correspondents of the Sydney _Daily +Telegraph_ mention the occurrence of the animal in swamps and ponds +not directly connected with streams. Mr. C. R. Stranger, writing from +Curlewis, states that, when the great drought broke in June and July of +1920, the Curlewis swamp, which had been dry for several years, filled. +Soon afterwards a platypus was seen in the swamp, and was there for a +considerable time, always about the one spot. The swamp was four or +five miles from the nearest stream, the Mooki River, though the two +waters may have been connected by a backwater during the flood. Mr. +George Boyd has often seen platypus in swamp lagoons of a permanent +nature, situated in the neighbourhood of Wyong Creek but not connected +with it except in times of flood. A third correspondent describes the +finding of a platypus, after a thunderstorm, in a small water-hole in +the rocks near the top of Black Mountain, a few miles from Dundee, and +three or four miles from the nearest permanent water. + +Krefft in his _Catalogue of Mammals in the Australian Museum_ (1864) +records three females in spirits from the Botanic Gardens; but these, +if taken from the ponds, must have been previously released in them. +He also records an adult male from North Shore, Sydney, and a female +from George’s River, from both of which places they have long since +disappeared.[15] The upper reaches of the Nepean and its tributaries +are, however, still tenanted, so that the platypus still occurs fairly +close to Sydney. + +The Victorian records include most of the southern tributaries of the +Murray system, such as the Campaspe, Loddon, and Avoca rivers. The +Snowy River, to the east, has already been mentioned. Kershaw made his +observations upon the Hopkins in the west, and there are records from +the Glenelg, close to the South Australian border. Mr. Noel Learmonth, +writing to the _Australasian_ (30 June, 1923), comments on the fact +that the platypus is absent from the Eumeralla, Darlots, and Fitzroy +rivers, though inhabiting the Wannon on one side and the Hopkins on the +other. Mr. E. R. Waite, Director of the Adelaide Museum, has kindly +supplied the known South Australian records--the Murray River at Murray +Bridge and Tailem Bend, the Onkaparinga River, and the Glenelg, which +just crosses into South Australia close to its mouth. + +For information as to the distribution in Tasmania, I am indebted to +Mr. Clive Lord, Director of the Tasmanian Museum and Art Gallery. He +writes:-- + + “This species is generally distributed throughout Tasmania. From + personal observation I can state that it can be found in most of the + inland lakes that are not close to the settled areas. In certain + of the National Park lakes (Mt. Field--20 miles NW. of Hobart) the + platypus is numerous, and, as the area is an absolute sanctuary + for our native fauna, it has a chance of living there in peace; + but, despite the fact that the platypus is totally protected by + law, they are very largely taken in other parts. At the Great Lake + large numbers were captured for their skins, but we could not get a + conviction. During the recent Christmas holidays I saw numbers in the + lakes in the Cradle Mountain and Barn Bluffs district (NW. Tasmania). + Along some of the rivers of the NW. coast the platypus is still to + be found; but, generally speaking, the advance of settlement is + reducing the number in the rivers, and the mountain lakes will be its + stronghold in the future. There are numbers in Lake St. Clair, and, + as previously noted, they frequent even the highest alpine lakes, + over 3000 ft. above sea level.” + +This sketch of its distribution shows that _Ornithorhynchus_ is still +widely spread throughout the eastern portion of the mainland and +Tasmania, and is in no immediate danger of becoming extinct provided +present laws are enforced. It is very probable that closer observation +would discover its presence in many streams where its existence is +wholly unsuspected, and it is remarkable that it has not been recorded +from main rivers such as the Darling and Murray and the main channels +of their larger tributaries, such as the Lachlan and Murrumbidgee. +Although the creature seems partial to high places, it cannot be +influenced altogether by altitude, for it occurs commonly throughout +the low creeks and rivers of the coastal plain. Nor is rapidly running +water essential, since the Tasmanian lakes are so well stocked. +Certainly the platypus prefers clean, clear water, but it manages to +survive quite comfortably in rivers like the Mary and the Burnett, +which are far from being limpid streams. This, however, may be a matter +of necessity, not of preference. It is probable that it finds a greater +abundance of the food that most delights it in the more rapid waters of +the upper stream. It may be, too, that the occurrence of large Murray +cod (_Oligorus macquariensis_) in the larger rivers of the plains +has something to do with the matter. The platypus, foraging blindly +under water, or floating idly at the surface, would have no protection +against these voracious creatures. + +[Illustration: PLATYPUS MANOEUVRING ALONG A SANDY BOTTOM. + +The hind legs are kept stationary to balance the buoyant body (or, to +use a nautical phrase, to maintain an even keel). The one on the right +is touching the sand with its muzzle, its right paw is fully extended, +and the left is being brought forward for the next stroke. The finished +stroke is shown by the position of the fore-paw (close to the body) of +the one swimming on the left. + +_Plate 25_] + +The antiquity of the platypus, and the changes in river systems during +the ages, render it probable that the animal inhabited at one time or +another all the waters of Tasmania and of eastern Australia. Closer +settlement is very likely responsible for its disappearance from +certain rivers of the (Australian) coastal plain, and, as that area is +not now subject to general flooding, it is hardly to be expected that +the denuded rivers will ever be replenished with platypus by natural +means. + +That the platypus does travel over land is quite satisfactorily +determined. But how far it can travel is not known. During floods +it has to move about in search of food, and usually works towards +the top of billabongs and backwaters, where supplies are more easily +obtainable. As the waters recede, it is often left isolated in some +deep water-hole, where it may continue to live happily for a time. +Ultimately, however, it makes back to the main water, either by +following the channel, or, if the river be nearer by another way, +by cutting directly across country. I have observed this happening +on many occasions, and have no doubt that the platypus possesses +a highly-developed sense of direction, by means of which it makes +straight for water. Animals released close to, but out of sight of, +water, never hesitate; they make straight off towards the water closest +at hand. In corroboration I quote the following paragraph from the +_Northern Daily Leader_ (Tamworth, N.S.W.) of 6 April, 1922:-- + + “The duck-billed platypus at times shows a remarkable knowledge of + locality. I carried one in a bag from its native river, where it + was caught on a night-line set for eels, to a shallow lake about a + mile away. It was then gently slid into the water, but promptly swam + ashore and started on the long crawl, straight for the home river. + The duck-bill was recaptured and returned to the lake, which, it may + be remarked, had no banks suitable for a platypus burrow. But again + the animal swam out and made tracks for the old address. Eventually + the beast was put far out in the lake and left to its own devices. + A few days afterwards it was found dead in a patch of scrub about + half-a-mile from the river in a direct line with the pool from which + it was taken.” + +The observations of correspondents indicate that the animal can cover +a land distance of four or five miles, and may cross intervening high +land. Since it has considerable powers of endurance, and, despite +its voracious appetite, can survive without food for comparatively +long periods, it is possible that it has managed to contrive its own +distribution by direct means. + +Platypus have often been observed working in a general direction either +up or down stream. These movements are almost certainly influenced by +food conditions. A migration of platypus was observed by the late Mr. +William Hill in 1859, when he was manager of the Pallamallawa cattle +station (now a township) on the Gwydir River. About fifty aborigines, +under ‘King’ Binamoore, were camped on the river-bank not far from the +homestead. One evening Mr. and Mrs. Hill strolled down to the camp +for a yarn with Binamoore, who was an old friend, but the chat was +interrupted by a sound from up river, similar to that made by a mob of +cattle fording a stream. Always on the alert for movements of his herd, +Mr. Hill, accompanied by his wife, walked down to the water’s edge to +investigate. The river at the time was low, but still flowing, with +occasional deep holes, connected by rapidly running shallows. Presently +the noise was heard again, this time closer at hand, in fact so close +that Binamoore and his tribe, and the tribal dogs, took fright, and +bolted off to the next station, deserting their gunyahs. Mr. and Mrs. +Hill then clearly observed a mob of platypus all swimming together at +top speed with the current, and estimated that there were at least a +hundred of them. There could be no doubt about the identification, as +the animals were frequently obliged to expose themselves in climbing +over obstructions in the shallows. On the following morning only an +occasional platypus was to be seen, floating at the surface or swimming +about in a leisurely way. I have every confidence in my informants, +each of whom has repeated the story to me several times. I know of +no other record of any mass movement of platypus, and my explanation +is that the mob had gradually congregated from streams in which food +supplies had been affected by flood, and were following the main +channel in search of further supplies. + +To anyone knowing the rivers and lakes mentioned in the records of +distribution it will be obvious that the platypus inhabits a varied +range of waters, from clear, icy, rapid alpine streams of the southern +Alps to warm, turbid waters of the Queensland coastal plain, and from +large lakes to small waterholes. Despite this apparent catholicity of +taste there are certain conditions which determine the parts of these +various waters chosen by the animal. The chief is that of abundant food +supply. + +Semon (1894, p. 10), who made careful observations on the Burnett, +writes:-- + + “_Ornithorhynchus anatinus_ inhabits the banks of running water + within the area of distribution. It follows these from their source + of origin down to the plains. The main condition for its occurrence + is the scooping out of comparatively expansive depressions in the + bed of the river, in which the water flows slowly, so that fine + silt collects on the bottom and a vegetation of aquatic plants can + develop, which serves as a resort for innumerable aquatic creatures, + worms, crustaceans, larvae of insects, and molluscs. Here the + Duckbill seeks its food, and hides from its hunter by diving. Here + it can remain in periods of extended drought, which dry up the rest + of the river bed, in a small amount of water. At such times those + Duckbills which live in the smaller waterholes, so soon as the level + of the water sinks too low, wander out into larger holes which are + less likely to dry up. Then one notices an increase in the latter, + and a coming together of the platypus folk.” + +My own observations in the Manilla and New England districts confirm +this statement. There the streams are partially blocked at frequent +intervals by granite boulders, and a succession of quiet pools is +formed between stretches of rapidly running water. In these pools the +platypus finds its food. When freshes come down the river, however, +coarse sand and gravel are deposited on the silt bottoms, and for a +time the feeding-grounds are spoiled. At such times the animal is +forced to seek for food where it may be found, and generally works its +way upstream. After prolonged floods the animals are often found in +considerable numbers dead upon the banks. This would seem to indicate +that they had starved to death, but it must also be borne in mind that +they dislike turbid water, and a continuance of disturbed conditions +may have some physical effect upon them. + +Heat and cold appear to have little effect, since the platypus seems +equally at home in the warm streams of tropical northern Queensland and +at a height of 6000 feet on the Kosciusko tableland--which, though not +continuously snow-clad, nevertheless experiences falls of snow during +the summer. + +[Illustration: (1) MALE PLATYPUS RUNNING AT TOP SPEED. + +Note elevation of all except tail, which sometimes is hoisted also. + +_Plate 26_] + +[Illustration: (2) ANOTHER VIEW OF MALE PLATYPUS RUNNING AT TOP SPEED. + +Note powerful thrust of hind foot. + +_Plate 26_] + + + + +CHAPTER X + +HABITS + + +The early records contain little in the way of precise information as +to the general habits of the platypus. Bennett (1860, p. 95) complains +that, as long ago as 1829, “notwithstanding all the inquiries I +made of persons long resident in the colony, I could get no correct +information; I found then, as I have found during an extended residence +in the colony, that the majority preferred forming theories of their +own, and arguing upon their plausibility, to devoting their time to the +collection of facts.” It is the same to-day. + +Bennett went out to seek his first platypus at sunset, “knowing, as +I did, the crepuscular nature of the animals,” and it was not long +before his companion directed his attention to one on the surface of +the water, not far from the bank on which they were standing. He writes +(_loc. cit._, p. 104):-- + + “In such circumstances they may be readily recognized by their dark + bodies just seen level with the surface, above which the head is + slightly raised, and by the circles made in the water around them + by their paddling action. On seeing them, the spectator must remain + perfectly stationary, as the slightest noise or movement will cause + the timid creature instantly to disappear, so acute are they in + sight or hearing, or perhaps in both; and they seldom reappear when + once frightened. By remaining perfectly quiet, however, when the + animal is paddling about, it is possible to obtain an excellent + view of its movements on the water; it seldom remains longer than + one or two minutes playing on the surface, but dives, and reappears + a short distance above or below the place at which it was observed + to descend. Although the animal may ‘come up’ close to the place + where the sportsman is standing, it would be useless to attempt to + level the gun, for that action alone would cause its instantaneous + disappearance; but, after waiting patiently until the animal dives, + and watching the direction in which it sinks, preparation must be + made to receive it with the discharge of the piece instantly on its + reappearance at the surface, which (when it descends unfrightened) is + almost certain to take place in a short time.” + +And again on p. 108:-- + + “These creatures are seen in the Australian rivers at all seasons of + the year, but are most abundant during the spring and summer months, + and I think a question may arise whether they do not hibernate. The + best time for seeing them is early in the morning, or late in the + evening. During floods and freshes, they are frequently perceived + travelling up and down the rivers: when going down, they appear + to allow themselves to be carried by the force of the stream, + without making any exertion; but when swimming against the current, + their muscular power is exerted to the utmost to stem its force, + and generally with success. I recollect, however, seeing two make + repeated and ineffectual attempts to pass a small waterfall in a + rapid part of the river, and, after many persevering efforts, they + were unable to attain their object. The opinion that so generally + prevails that these animals must be shot dead instantly, or otherwise + they would sink and not reappear, I did not find from my own + observations to be correct.” + +These observations are of special interest, since they were made as +long ago as 1829 in a district which had but recently been settled, +so that the platypus could not have had time to alter its ways on +coming into contact with Europeans. More than sixty years later +the distinguished German zoologist Richard Semon spent some time +on the Burnett River, where he reports that the platypus was very +plentiful and was not molested by the white colonists or hunted by +the aborigines. His account of its habits agrees in all essential +particulars with that of Bennett. In the English translation of his +popular account of his journey (Semon, 1899) will be found a summary of +his observations; I prefer to give a translation from his paper in the +_Forschungsreise_, which is somewhat fuller. He writes (p. 10):-- + + “On the Upper and Middle Burnett, where alone I observed the + animal, it was plentiful everywhere in suitable localities along + the river. In _Ornithorhynchus_ a considerable preponderance of + males over females was observed, so that for each female captured + there were two or three males. As in Echidna, the fully grown male + is larger than the female. Like Echidna, too, _Ornithorhynchus_ + does not lead an exclusively nocturnal life. More than once I saw + the animals swimming in the river in daylight, searching for food; + yet this could be termed exceptional. It is during the twilight of + morning and evening that the animal leaves its home and passes to + the water. Generally they turn to the river shortly before sunrise, + and remain there till the sun has completely risen. In the evening + it is the same--from a short time before sunset to a little while + afterwards, a period of twenty to thirty minutes. This holds good + for the winter months, from June to the beginning of September, when + the nights are cold and the thermometer in the mountainous regions + of the Burnett is almost at freezing point. One is then sure to meet + with plenty of _Ornithorhynchus_ at suitable places both morning + and evening; and now and again to see them in broad daylight. This + is changed, however, when the Australian summer begins. The days + become hot, and the nights warm. In the middle of September, during + 1891 and 1892, I very seldom found an _Ornithorhynchus_ in the river + during the morning and evening hours, and still less frequently by + day. Doubtless they then use the nights for these excursions, for + they must enter the water to obtain their food. I took great pains + actually to observe the animal in the river by night. I did not + succeed, however, nor even in bright moonlight. Since, however, + _Ornithorhynchus_ lies flat like a plank in the water, scarcely + projects beyond the surface, and is absolutely noiseless in diving + and reappearing, one would need an exceptionally favourable occasion + to perceive and observe the animal by night. + + “In the cool part of the year, on the other hand, I could observe + the behaviour of the animal in the river during dawn and during + daylight as long as the sun was low. As has been already mentioned, + _Ornithorhynchus_ lies quite flat in the water, with only the flat + head projecting, and that very inconspicuously. Usually the animal + lies motionless at the surface. After a few minutes it dives suddenly + and noiselessly, stays under water two or three minutes, and comes up + again just as suddenly, and just as noiselessly. During its dive it + has collected by means of its flat bill, after the manner of a duck, + all sorts of aquatic life, and richly filled its cheek-pouches. The + reappearance takes place in order that it may get air, and chew and + swallow the contents of these pouches.... + + “If an animal is frightened while in the water, it dives immediately, + and does not reappear. Although it is a good diver, it can only spend + a certain amount of time under water. Those which become accidentally + caught in fishing-nets at night, and are held fast for a long time + under water, are always found drowned next morning. + + “The pursuit of the animal is not difficult if one knows its habits. + Small as is its eye, and deeply buried in the fur as is the opening + of the ear, yet sight and hearing are distinctly sharp; it is + therefore useless to begin matters by trying to creep up while the + animal is at the surface. The position of the eyes enables it to + observe exactly what is going on on the rising banks above it. It + does not recognise danger, however, unless the observer moves. But + the mere lifting of a gun is sufficient to scare the animal away. + Every dubious noise causes it to disappear.... Once scared off, the + animals nearly always seek their homes, and do not reappear during + that same morning or evening. And yet, it is easily taken if one + approaches while it is under water, and at once stops motionless when + it appears.” + +These accounts of two very competent observers, both made in districts +where the animal had not yet been disturbed or harassed, show that +the platypus has not developed its alertness and timidity since the +advent of man. The same remark applies to its predominantly crepuscular +habits. It has sometimes been erroneously claimed that these have been +adopted to escape from man and his gun. It must also be remarked that +the months during which Semon noted occasional animals in the water by +day are those of the breeding-season. At that season, when opening up +burrows containing suckers, I have frequently found that the mothers +were absent. It seems certain that they are forced to feed at irregular +times during the nursing period, and that this is the principal reason +for their being found in the river in broad daylight. + +As to the preponderance of males noted by Semon, here again we must +consider the time at which the observations were made. Wilson and +Hill (1908, pp. 33-4) state:--“During the breeding-season, however, +the pregnant female appears to keep much more closely to the burrow, +so that one may then commonly enough shoot five or six males to one +female.” As far as my observations go, the sexes seem to be numerically +about equal. + +A few other earlier observations are of interest. It is worth +remembering that Charles Darwin (1845) saw the platypus with his own +eyes. On January 19, 1836, while staying a day at “a farm called +Walerawang,” he had the following experience. + + “In the dusk of the evening I took a stroll along a chain of ponds, + which in this dry country represented the course of a river, and + had the good fortune to see several of the famous _Ornithorhynchus + paradoxus_. They were diving and playing about the surface of the + water, but showed so little of their bodies that they might easily + have been mistaken for water-rats. Mr. Brown shot one: certainly it + is a most extraordinary animal; a stuffed specimen does not at all + give a good idea of the appearance of the head and beak when fresh, + the latter becoming hard and contracted.” + +Crowther (1879, p. 97) gives the only detailed description of its +swimming motions known to me:-- + + “When swimming, the fore-paws are widely expanded, being convex + forwards, propelling themselves by an antero-lateral movement. The + hind paws and tail take but little share; the former have a slight + lateral horizontal movement, the tail lazily moving with the body. + When diving, the head is rapidly thrown beneath the body, front + paws quickly moving until the bottom is arrived at, when they are + seen turning rapidly over with their bills the sand, and even large + stones.... A train of small bubbles proceeding from the nose marks + the exact course the animal is taking.” + +Crowther also states that the tail is the first part to reach the +surface of the water. + +Allport (1878, pp. 30-31) also watched ‘a large specimen, and one +of that variety which has very red fur on the sides’ feeding over a +gravelled bottom in the clear waters of the Mount River (a tributary +of the Huon) in Tasmania; “his method of proceeding was to burrow his +head and more than half the body amongst the stones, causing a cloud of +sediment to rise at each dive.... He never remained under water longer +than a trifle over half a minute, and stayed on the surface between +the dives rather less than half a minute.” Allport also records that +a large number of small bubbles were continuously emitted, and that +the animal fed for three-quarters of an hour, and then went off to +his burrow. I also have observed platypus feeding in clear water, and +have seen them tear stones aside with their claws, or lever them up +with their powerful bills and shoulders, to get at food underneath; +but bubbles are certainly not emitted continuously while the animal +is under water, as all platypus-hunters know. When it dives in alarm, +the breath is apparently held, and no tell-tale bubbles issue. The +first bubbles that come to the surface, after the animal dives, are +not emitted by the platypus at all, but are formed by the imprisonment +of air when the bill is suddenly submerged, and, as the body turns +downwards, the bubbles traverse the contour of the back and break away +at the rump to ascend rapidly to the air. This was formerly believed +to be escaping breath; but as the animal, before sounding, undoubtedly +fills its lungs to the utmost capacity so that it may remain under +water, if need be, for several minutes in search of food, it is not +likely to exhale until compelled to do so, and then only in brief +spasmodic puffs. + +From the sum of these observations, and without drawing further upon my +own, we may safely conclude that the platypus is normally crepuscular, +and was so before the advent of European man; that it resorts to the +water twice daily to feed, and remains there for a period of from +twenty minutes to three-quarters of an hour, perhaps longer when food +is scarce; that the sum total of its aquatic life amounts to less than +two hours out of each twenty-four; that it is so wary as to disappear +for the day at the first sight of some unaccustomed movement on the +river-bank, or the hearing of some unaccustomed noise close at hand; +that while feeding undisturbed it remains at the surface for a period +variously estimated at from rather less than half a minute to one +minute, for the purpose of chewing and swallowing its catch, and then +dives to collect more food, remaining under water for a similarly +varied time; that in feeding it burrows with its sensitive, tactile +muzzle among mud and stones, sometimes burying more than half its body, +and thrusting fairly large stones aside with its powerful shoulders; +that the greatly webbed fore-paws are the chief swimming-organs; and +that, when floating at the surface, it lies flat, with the body just +submerged except for the upper part of the flattened head and the +middle of its back and tail, though occasionally it will be seen as in +Plate 5, fig. 2. + +Most of those which have occasionally been observed during the daytime +(especially during the breeding-season) are undoubtedly females; but +in well-shaded pools it is not uncommon to see individuals of both +sexes abroad during the day. The time spent in feeding is bound to vary +according to the supply of the invertebrate fauna and other commodities +which constitute its food at that particular period of the year. Where +food is plentiful, an adequate meal can be collected quickly, and the +time required may be no more than Semon’s minimum of twenty minutes. +The gravel bank referred to by Allport would not be so productive as +a silt-bottomed water-hole, full of aquatic plants, in the Burnett, +and it might easily take three-quarters of an hour to obtain a full +meal. The nature of the food itself has been variously reported. For +the Burnett, Semon (1894, p. 11) reports that the main food consisted +of molluscs, and that the cheek-pouches were usually found to be full +of immature individuals of a bivalve, _Corbicula nepeanensis_, 10 to +15 mm. in length. He mentions in addition, however, worms and insect +larvae. Bennett (1860, p. 113) writes:-- + + “On examining the cheek-pouches or the stomachs of these animals, + I always observed the food to consist of _débris_ of insects of + the family _Nauceridae_, very small shell-fish, etc., which were + constantly found comminuted and mingled with mud or gravel. This + latter might be required to aid digestion, as I never observed the + food unmingled with it. The natives say that they also feed on + river-weeds; but as I have never seen that kind of food in their + pouches, I cannot confirm the correctness of the statement.” + +Allport (_loc. cit._) states that the food found in the cheek-pouches +consisted of larvae of caddis-flies; Crowther found freshwater shrimps, +water-fleas, and hard black beetles. + +Wood Jones (1923, p. 55) notes that Bennett recorded the feeding of +captive animals on freshwater mussels; but the mussels were broken up +before they were given. From the nature of the masticatory apparatus +he argues against shell-fish as a diet, and he concludes that common +river-shrimps may be regarded as the staple article of diet. Since such +thoroughly competent observers as Semon and Bennett have both actually +found molluscs in the cheek-pouches, these cannot be put out of +consideration as food. There is, moreover, a great deal of difference +between the ‘very small shell-fish’ which Bennett mentions, and the +large swan-mussels which were probably (though it is not specifically +stated) the kind given in broken form to the captives. All observers +agree that the platypus finds its food by nuzzling in the mud or gravel +of the river-bottom after the manner of a duck. When it is remembered +that its eyes are kept closed while beneath the water, it becomes +extremely unlikely that the animal should catch such active creatures +as freshwater shrimps except very occasionally. Crowther certainly +mentions shrimps; but he probably refers to crustacea like the curious +and archaic _Anaspides_, which is found in Tasmania among stones on the +river-bottom, and which runs rather than swims. + +The food of the platypus must necessarily vary in different places and +at different times of the year, limited as it is to the invertebrate +fauna present in the water at any given spot. It consists of +immature molluscs, aquatic worms, the aquatic larvae of many insects +such as dragon-flies, caddis-flies, may-flies, and the like, the +larvae and perfect insects of groups such as the water-beetles and +water-fleas--which are wholly aquatic--bottom-feeding water-bugs, and +such crustacea as inhabit the bottoms of streams. This food is taken in +with a certain quantity of mud or sand, which, as Bennett has noted, +appears to be absolutely essential for the purpose of mastication. The +living prey is killed while held in the long horny ridges situated in +the anterior part of the mouth-cavity, and is passed rapidly backwards, +being prevented from reaching the gullet by the bulbous hinder end +of the tongue, and directed to one side or other by the tooth-like +projections at the base of the bulb. + +I cannot agree with Crowther’s observation that the tail is the first +part of the animal to reach the surface. Apart from the inherent +improbability that so cautious an animal should expose its blind end +first, my observations, both in the open and in a tank in captivity, +show that the tip of the muzzle is always the first part to appear, +followed by the top of the head. The eyes immediately open, and, if +there be no suspicious sight or sound, the rest of the body is allowed +to float towards the surface, beneath which, however, it usually +remains almost submerged. The animal floats in a spread-eagled fashion, +with its webbed hands moving slowly, palms upward, to maintain its +position, and causing the rings of ripples to which Bennett refers. +Semon’s comparison to a plank is not very happy, nor do I concur in +his statement that the animal usually lies motionless at the surface. +Bennett (1860, p. 106) puts it thus:-- + + “When the fur of the _Ornithorhynchus_ is wet, it has a sordid and + far from attractive appearance, resembling rather a lump of dirty + weeds than any production of the animal kingdom; indeed, were it not + for their paddling motion on the water, these creatures would often + escape observation; for their suppleness and colour, when wet, would + cause them to be regarded only as masses of weeds, which are so often + seen floating about the rivers.” + +At the surface the animal chews the results of its catch in a leisurely +manner, its jaws working laterally like those of a cow when chewing +its cud; having swallowed the contents, it dives in search of more. In +diving, the head is first immersed by bending the anterior half of the +body downwards and almost simultaneously humping the back. The head +is then flexed violently against the chest, giving a very powerful +downward thrust comparable with that produced by a crayfish through +the sudden flexure of its abdomen. This carries the body below the +surface, a process which is aided by an upward thrust of the muscular +tail. The webbed fore-paws are used alternately, the web being arched +in the manner described by Crowther; the feet and tail trail behind. +The animal swims in a determined fashion, at a steady but not fast +pace, to the bottom, which is first touched by the tip of the muzzle. +The fore-limbs are now laid back beside the trunk, and the webs are +kept beating upwards, to hold the animal at the bottom. The body is +strongly arched, the sides of the tail curve inwards so as to produce a +concavity of its lower surface, and the end of this concave surface is +applied to the bottom as if helping to keep the platypus down. In this +somewhat constrained position it ‘bobs’ along the bottom of the river, +testing every part with its tactile muzzle. It has every appearance of +having to work hard against a natural tendency of the body to float to +the surface. After two or three minutes it raises its head, relaxes the +tense attitude of its body, immediately begins to float upwards, and +hauls itself to the surface hand over hand by means of the webs of the +fore-paws. If suspicious or frightened, it may merely show enough of +the tip of the muzzle to expose the nostrils, take in a new supply of +air, and dive again immediately. When the animal is undisturbed, the +dive is practically noiseless; but when it is alarmed, there is often a +distinct double splash made by the almost simultaneous strokes of head +and tail, one downward, the other upward. + +The swimming motions described above are those employed during +feeding-time. When the platypus is definitely on the move, it swims +fairly rapidly at the surface, and frequently raises its head out of +and parallel with the water, so that it looks rather like a duck. Both +myself and the late Charles M. Hoy have on several occasions noticed +another kind of progression in the water. The naturalist’s way of +collecting platypus is not to shoot it, but to place a bullet from a +heavy rifle beneath it when the animal is floating. The concussion from +the impact is usually sufficient to kill it out-right; but sometimes +it is only temporarily stunned, and, on coming to, makes for the bank, +where it can be easily secured. When a platypus has been temporarily +stunned by concussion, and then recovers, it can almost be declared +that when forging for the bank, it actually crawls along the surface +of the water, for the fore-paws can sometimes be seen clearly above +the surface, which the tail frequently lashes. On such occasions, +two of which I have witnessed, the pace is decidedly fast and noisy, +while the water is beaten and churned considerably by the action. Hoy, +writing to me from Ravenshoe in northern Queensland on September 3, +1920, describes an uninjured male doing much the same thing:--“Saw +male and female evidently copulating, and secured female--left ovary +very much enlarged. Although usually very shy, the male came to the +surface and swam up to within three feet of me, while I was taking +the female from the river. He elevated his head from the surface of +the water, splashing vigorously with his limbs and tail and taking +on a very pugnacious attitude.” It is worth noting here that this +particular male persisted in his charge until he was within three feet +of Hoy, although the latter tried hard to frighten him back by throwing +up his hands. Hoy admitted to me later that he was afraid of being +spurred by the “hissing” ferocious creature. On the strength of this +authentic observation, made in broad daylight, and of others that I +have made at dusk, I am quite convinced that this method of swimming is +also indulged in during nocturnal frolics. Apart from the actions of +the infuriated male encountered by Hoy, platypus cautiously submerge +themselves to the extreme during the daytime; but this is not the case +when darkness sets in, principally because their vision then becomes +acute. The late Geoffrey Smith (1909, p. 124) has observed this mode of +swimming, and writes:--“I was surprised at the extraordinary tameness +of the Platypus, several of which swam quite near the boat with the +whole of their body exposed above the water and shining with a curious +grey appearance in the sunlight.” This occurred at Mount Read, in +north-western Tasmania. + +Semon has observed that a platypus which has been shot and killed +invariably floats high out of water. I can substantiate his statement, +and have observed also that the submerged animal has to work +continuously to keep itself down. Just how it manages to float with the +body submerged in the way described above I am not certain, but the +slight motions of the hind limbs and tail probably aid in this act. The +swimming stroke of the fore-paw is outwards, backwards, and upwards, +and ends with the hands palm-upwards against the sides of the body. +When performed slowly and gently, this stroke would serve to pull the +fore-part of the body down in the water. As the limb is thrust forward +again, the resistance of the water keeps the web folded on the palm, +until it is voluntarily extended to begin a new stroke (see Plate 25). + +[Illustration: VENTRAL VIEW OF MALE PLATYPUS. + +Note upturned palms, also stain on breast, probably due to secretion +from scent-glands. + +_Plate 27_] + +On land the progress of the platypus is not nearly so happy. The web of +the fore-paw is folded under the palm, and the two limbs of one side +are rotated outwards and forwards together. The nails of the fore-paw +take a grip, and the creature pulls itself forward, going over on its +knuckles as it does so. Meantime the backwardly directed claws of the +foot have taken purchase, and the body is levered forward on the right +limb. Then the limbs of the other side come into play. The result is +a shuffling, sinuous motion, resembling, as I have said before, that of +a heavy-bodied lizard, such as the Blue-tongue (_Tiliqua scincoides_). +Both the trunk and tail drag upon the ground. Considering how clumsy +its method of locomotion is, it is surprising how fast the platypus +can move when it has need of haste. When going at top speed, it can +raise its body almost completely from the ground, as the photograph +reproduced in Plate 26 shows, and can travel on level ground at the +rate of 200 feet per minute (by stop-watch). + +The platypus cannot remain for any great length of time in water +without some means of resting, otherwise it will become exhausted and +drown, for it must be remembered that the platypus is a mammal and +resorts to water mainly for its food, after which it must dry its +coat and retire to its burrow for warmth. A freshly-trapped robust +male was placed in an open tank while I leaned over so that it could +clearly see me. The animal immediately dived and, by maintaining upward +pressure with its fore-paws reversed, remained at the bottom for +several periods of six minutes each, with intervals of one minute at +the surface, during which it exposed the tip of its bill as far as the +nostrils. While collecting two specimens of brooding females for the +University of Sydney, and as they had to be killed in the process, I +took the opportunity to ascertain that they survived 5½ and 6 minutes +respectively before drowning in small wire cages. These observations do +not prove that the male can stay under water longer than the female, +as, during a test made midway between breeding seasons, a female +survived for 10 minutes. This is by far the longest period which I have +observed. + +The aquatic life of the platypus occupies but a small portion of its +time. Besides feeding and tunnelling, its only other duty would seem +to be that of making its toilet--the rest of its time being spent in +sleep. It performs its toilet, as a rule, while resting on the bank, or +at all events rids itself of most of the moisture from its fur before +going off to continue toilet operations in its resting-burrow. Bennett +(1860, p. 119) gives an account of the operations performed by a +captive which was tethered by means of a cord attached to one leg:-- + + “After it had wandered some distance up the chain of ponds, feeding + about the shallow water and mud near the margin, it crawled up the + bank, and, lying down on the grass, enjoyed the luxury of scratching + itself and rolling about. In this process of cleaning its skin, the + hind-claws were brought into use--first the claws of one hind leg, + then those of the other; but finding that it could not use the one + to which the string was attached so well as the other, which was + disengaged, after repeated trials it gave up the attempt. The body, + being so capable of contraction, was readily brought within reach of + the hind feet, the head also coming in for its share of the process. + The animal remained for more than an hour cleaning itself, after + which it had a more sleek and glossy appearance than before. Placing + my hand on a part which it was scratching at the time, the claws + passed over it instead of the animal’s body, when I found that it + performed the combing in a remarkably gentle manner. On my attempting + to scratch the place gently, it started away, but not far, and soon + resumed the method of cleaning itself, which I had interrupted.” + +From personal experience with platypus in captivity, I am convinced +that Bennett’s tethered specimen was actually dying of shock and +starvation the while he imagined it was enjoying the pleasure of +scratching itself and rolling about. + +Bennett also describes the animal as preening its fur with its muzzle, +like a duck. Semon (1894, p. 11) records that on two occasions he saw +duckbills lying in the grass on the river-bank, stretching themselves +and cleaning their fur. + +My observations show that the hind-claws play the principal part in +toilet operations, but that the fore-paws are used as well. The animal +squats on its haunches, and by its gymnastic ability is able to bring +almost every part of the body within reach of one or other of the hind +feet. It aids this process in a rather ludicrous way by pulling the +loose skin round into the desired position with the paws, the webs +being extended but not expanded in the action. It also cleans itself +with bill and fore-paws, just as a seal rubs itself with the hairy palm +of its flippers while lolling in calm water. I have seen a wet platypus +sit up and pull its exceptionally loose skin about with its fore-paws, +as if actually massaging itself. The pressure of the broadened claws +against the intervening thin webbing is evidently quite sufficient for +that particular phase of its toilet. In that case the webbing serves +for a rub-down in the same way as a moistened chamois pelt, if nothing +more. Seeing, however, that the fore-claws are used principally for +scratching into solid soil, and that the versatile and oscillating +hands are adapted for grasping, the platypus may readily transform them +into excellent combs by merely palming the webbing, as when burrowing, +walking, running, or climbing, and may use them for combing the parts +which cannot be reached with the hind-claws. + +In respect of thorough cleanliness the platypus easily holds its own +among mammals. In person and in dwelling-quarters, even when brooding, +it always exhibits conditions exceptionally tidy. How different is +this monotreme from its only known living relative, the echidna. To +my mind, as regards toilet at least, the contrast is extreme. Every +time I have examined a freshly-caught platypus--wet or dry, young or +old--it was particularly clean in skin, pelage, and external orifices, +such as facial furrows, nostrils, etc. Of course, this may be partly +due to its semi-aquatic nature. Its water-dreading cousin, meanwhile, +is about the dirtiest wanderer afoot. Quite apart from its perpetually +begrimed muzzle and snuffling nostrils, the eyelids of an adult echidna +of either sex are frequently found to be caked with a mixture of earth +and secretions from the eyes, while the skin of the abdomen and the +hair thereon are seldom found to be clean. Again, the temporary pouch +of the female echidna, prior to weaning the occupant, is filthy, and +this condition is certainly not entirely due to milk stains. Obviously, +then, it is a blessing for both that the pouch is not a permanent +feature, otherwise the mother would have to evolve something better +than awkwardly-turned toe-nails and, possibly, a tacky tongue to +complete her so-called toilet. Incidentally, it is fortunate for the +young one that it is transferred, in a lethargic state, to sweeter +quarters before attaining sufficient sense to observe its surroundings. + +Though I have often disturbed platypus on river-banks, I have never +seen them engaged in performing their toilet in the open. They resort, +as a rule, to flat ledges under projecting roots, or to similar cover; +these places, judging from the tracks leading to them, and from the way +in which they are flattened down as if through long usage, would seem +to serve as toilet tables of a comparatively permanent nature--that is +to say, regular resorts of a given animal while it is in any particular +locality. In such a place the platypus, secure from observation, and +able to slip quietly into the water at the slightest alarm, removes +the water from its fur, and reduces the latter to that condition of +sleekness which is so essential to its well-being. As with most wild +animals, the first sign of ill-health is the neglect of toilet, and +this neglect in the case of _Ornithorhynchus_ is rapidly followed by +death. I have frequently noticed that sickly and enfeebled animals +will attempt to perform the toilet motions, but are so little able to +correlate their activities that the claws pass helplessly up and down +without touching the body at all. In this condition they take no heed +of man’s presence, being practically unconscious. It should also be +noted that the feet are used for scratching the body while the platypus +is floating at the surface; but this is probably due to the irritation +caused by parasites. _Ornithorhynchus_, although flealess, shares with +a very few animals the rather doubtful distinction of having a tick, +_Ixodes ornithorhynchi_, all to itself. + +[Illustration: FEMALE PLATYPUS, TAKEN DIRECTLY FROM NEST AND PERSUADED +TO ADOPT SLEEPING POSITION. + +This same position is used in the nest during incubation and nursing of +the very young. + +_Plate 28_] + +Its toilet completed, the animal retires to its resting-burrow +to sleep. Between this burrow and the nesting-burrow of the +breeding-season a sharp distinction must be drawn. Existing accounts +of the habits of the animal assume that the nesting-burrow of the +breeding-season is the home of the platypus all the year round. Nothing +could be farther from the truth. The complicated nesting-burrow is +constructed by a single female for the purpose of laying her eggs and +rearing her young, and is not resorted to by any other individual. +Resting-burrows are, however, made by both males and females at all +times of year. They are usually semicircular excavations under the +roots of large red-gum trees and the entrance at each end is concealed +by overhanging ledges, generally in the neighbourhood of the ‘toilet +tables.’ The diameter of these tunnels is irregular, but always much +greater than that of the nesting-burrows; the sleeping-chambers, +from one to three in number, are simply enlargements of the burrow, +containing no sign whatever of nesting-material or bedding. These +burrows appear to be either purely male quarters or purely female +quarters, the sexes not being found together in them. At most I have +found two males occupying a single burrow. + +When the animals are on satisfactory feeding-grounds, such burrows +appear to be used regularly by the same individuals. But when they are +forced by flood or freshes to move elsewhere, it becomes necessary to +find new quarters. During these times platypus are sometimes captured +in hollow logs or, in districts where alluvial mining is carried on, in +sluice-boxes. Under stress the animal appears to make use of any kind +of cover available. The males evidently make their own camping-burrows, +as they are frequently found with the bald patch near the end of +the tail. This is caused, as in the case of the female, by plugging +off undesirable subways, etc. Burrows used by males may also be +distinguished from breeding-burrows by a foxy odour which is compared +by Mackenzie and Owen (1919, p. 12) to that of an onion. The odour is +caused by the secretion of the scent-glands, which are situated at the +base of the neck, just in front of the shoulder (see Plate 27). + +Although, except during the breeding-season, platypus may be considered +solitary animals, they are occasionally found in company for short +periods, when forced by seasonal conditions to migrate. The greatest +number that I have observed at the same time was four, and they did +not appear to be consorting with one another, but simply feeding +about quite independently. On one occasion I unearthed two adult males +which were camping contentedly together in the one burrow. On another +occasion I secured two males in a “turret trap” which had been set in +the early morning for only an hour and a half. On a third occasion +three males were trapped in one night, either while leaving or entering +a camping-bank beneath a giant red-gum--a “buck barracks,” as I have +since named the haunt. + +Although Bennett has made the suggestion that _Ornithorhynchus_ +hibernates, my investigations do not bear him out. In the New England +district of New South Wales the pairing season commences in July, which +is the midwinter month on those cold highlands. The platypus lives an +active life the whole year through, and eats prodigious quantities of +food. + +The thing one first notices in a living platypus is its extraordinarily +restless activity. It is far more difficult to hold than any other +animal of its size with which I am familiar, not so much on account of +the actual strength and violence of its struggles, but because of its +persistence in them. Bennett frequently remarks on the way in which +the “looseness of its integuments” renders it difficult to hold. He +refers to the skin and its underlying muscle-layer (the _panniculus +carnosus_), which, in most mammals a very thin sheet, is in the +platypus a thick muscular jacket, with slits through which the limbs +and tail project and with numerous strong slips attaching it to various +parts (see Plate 10). The animal seems to be able to slip its body +through this loose overlying sheet in an uncanny invertebrate fashion, +struggling forward for a time, and then, when it finds its progress +prevented, suddenly changing its direction and slipping backwards out +of one’s hands. At the same time all four powerful limbs are brought +into play, and the head, flexed downwards by strong depressor muscles, +also helps in the struggle. The only way in which the animal can be +held safely is by grasping the scruff of the neck with the left hand +and the tail with the right. While most animals after a time resign +themselves to the inevitable, the platypus continues to struggle until +exhausted, unless one is fully acquainted with its ways and coaxes it +(see Plate 28). + +Many observers have borne witness to the nervous temperament and +restless activity of the animal in captivity. Three individuals which +were forwarded by me at various times to the Department of Zoology at +the University of Sydney, in order that some observations might be +made, were all very impatient of the excitement and fuss of constant +inspection and handling, and none lived longer than seventy-two hours. +As the animals are easily capable of standing fasts for much longer +periods, death would appear to have been due to nervous exhaustion, and +certainly not to inanition--although, it is true, they took very little +of the food that was provided for them. + +It does not seem that the platypus displays anything of that affection +for its mate which is so characteristic of the behaviour of birds and +higher mammals. The period during which the mated pair are together +is short, and I have no evidence that the male takes any further +interest in the female and its young when once impregnation has been +accomplished. The solitary observation of Hoy, quoted earlier--which +might be taken to mean that the male charged in defence of his +mate--is equally open to another, and, it seems to me, a more natural +interpretation. Anger at the actual deprivation may have played a +greater part than affection, for the actions were those of an angry +beast. Moreover, since the occurrence took place in broad daylight, +it is possible that the animal had only a very incomplete conception +of what was going on. Nevertheless it remains to the credit of this +particular male, that he did not dive and disappear after the report of +the rifle, and the impact of the bullet close to him in the water. + +Nor would the female platypus seem to show any actual affection for +her offspring. She uses great cunning to keep them safe, and sees to +their physical well-being with meticulous care, reducing herself to +a state of emaciation and exhaustion in the process. But she makes +no attempt to stay by and defend them when a burrow is opened up, +her chief anxiety being to escape. I have never known a female in the +burrow to show fight, or attempt resistance of any kind. Yet, even so, +she shows signs of agitation, which is more than some marsupials do. +When one tears the young from the back of a koala (_Phascolaretos_) for +instance, the mother, after one vacant look in the direction of her +puling infant, goes on calmly chewing gum-leaves. + +The male platypus sometimes proves both pugnacious and aggressive. One +which I was using for photographic purposes showed a great dislike +of the process and deliberately charged and bit me on the arm and +fingers. I compare the bite--which was made with the anterior pairs of +horny ridges--with that of a gander, and it was sufficiently severe +to cause me to take precautions against further attacks. Since then I +have experienced bites from both male and female platypus which were +deliberately roused for the purpose. + +How far it is permissible to attribute to intelligence habits of +wariness and cunning which have become what we are pleased to call +instinctive is a moot point. The wary ways of the platypus have been +described more than once, and there is no need to repeat them here. We +may, however, assume that these ways, though they are proving useful +against the onslaughts of European man, were used before his arrival. + + + + +CHAPTER XI + +BREEDING HABITS AND LIFE HISTORY + + +MATING + +Since the platypus is such a shy and secretive creature, rarely seen +at all except by those who take the trouble of investigation, it is +not surprising to find that, in the past, very little was gathered as +to its mating and nest-building habits. One platypus-hunter quoted by +Anderson Stuart makes the statement that the males fight furiously +for possession of the females. Although I have never seen such combat +between platypus at large, from what I have seen in this direction with +specimens in captivity I feel justified in agreeing fully with that +statement. + +Early in the breeding-season there is in the male a correlated rapid +growth and enlargement of three sets of glands--the testes, the crural +glands, and the scent-glands. The enlarging of the testes (which +from quite a small size become as big as pigeon’s eggs) needs no +explanation. The scent-glands are more prominent in the male than in +the female, and the fact that they become so remarkably enlarged at +mating-time implies that the female seeks the male. This is rendered +more probable by the fact that, when once impregnation has been +effected, the female (so far as I have been able to ascertain) carries +out the remaining duties of reproduction entirely unaided--quite a +mammalian trait. + +At breeding-time platypus usually leave their accustomed +feeding-grounds and select a stretch of bank suitable for nesting. +Under normal conditions nesting-burrows are not found close together. +For the upper Namoi, the Macdonald, and the Manilla rivers, upon which +most of my observations have been made, the average is one tenanted +burrow to six miles of bank--that is, to three miles of river. Under +abnormal conditions (in times of flood, etc.,) a different state +of affairs often occurs, as will be evident from what follows, but +normally the female does not seem to care about neighbours at this +season. She requires a stretch of undisturbed water to herself while +hatching her eggs and nursing her young, so that she may be assured of +a near and easily accessible food supply. + +Verreaux claims to have witnessed the actual act of copulation. +According to his own account he spent whole days and nights hidden in +a specially constructed hut, and was completely successful. I give his +account for what it is worth (1848, p. 130):-- + + “The male, after chasing the female for nearly an hour, ended always + by taking her into the middle of the rushes. There, clinging tightly + to her with the help of his bill, he clutched the skin of her neck, + while his hind-spurs grabbed her hinder end. The female, struggling + violently against him, swam along uttering plaintive cries that were + rather like the squeaks of a young porker and grew louder as they + went on. The act took five or six minutes, and afterwards the two + animals played together for more than an hour.” + +If Verreaux meant that the male grasped the skin on the female’s +neck, as a drake does, he manifestly did not understand that the +extent to which the upper mandible overhangs the lower would render +that impossible, quite apart from the pliable nature of the lips and +the fact that both jawbones are divided at their extremities and are +pliable as far back as the secateuring ridges. With regard to the +squeak, I have never heard any sound from a platypus which might be +so described, and I am convinced that either the whole account is +imaginary or Verreaux was misled by a sound from some other source, +possibly overhead. + +Two observations which I was fortunate enough to make were widely +separated. The first was made at 7.30 a.m. on August 27, 1909, in the +Namoi River at Manilla. A platypus appeared on the surface, and was +immediately followed by a second. As neither exhibited any surprise +or alarm, it is probable that they had been together for some time. +After a short interval one animal began to swim in a circle round the +other, which, however, soon followed, so that the two were swimming in +a circle one behind the other. They were about equal in size--probably +an old female and an adult, but young, male--and it was on this +account difficult to distinguish which had been the one to start the +proceedings. After about a minute of this circling, one of the animals +(which proved to be the female) submerged its body and tail, and +floated perfectly still with its head alone above water. The male then +came slowly up, and mounted in a leisurely fashion. The whole process +offered a very close resemblance to the early stages in copulation of +a drake and duck, with the exception that the male platypus did _not_ +take a grip with his ‘bill.’ The male then threw himself back into a +sitting posture, partly out of water, but at this moment there was a +great splash, and both animals disappeared. + +The second observation was made twelve years later, on September 23, +1921, in the same river at a spot three miles from the first, and at 7 +o’clock in the morning. There I saw what looked at first like a large +male platypus floundering on the surface of the river as if sick or +hurt; this, after a moment or so, dived. Immediately another object +followed in its wake, partly-submerged and upside down. In a couple +of minutes a second platypus (this time apparently of smaller size) +rose to the surface; more floundering, or wallowing, took place at the +surface, and I could now perceive quite distinctly that what I had seen +was a pair of platypus coupled in an extraordinary position. The tail +of each was laid flat along the belly of the other, completely hiding +the bright gold and silver of the ventral fur. The precise position +of the hind limbs could not be made out, as no movement thereabouts +was discernible; but it must have been the grip of these that kept the +animals together. So closely were they apposed that they appeared at +times like a single giant platypus. The processes of diving, blowing, +and floundering at the surface were repeated several times at short +intervals. On each occasion the first to rise for a blow would be +the only one visible above water, the second being clearly visible +only as it trailed upside down in the wake of the first on diving. +During the floundering and rolling which took place at the surface +the under animal could be seen dimly. The animals rose alternately, +apparently for breathing purposes, and on each occasion the second +animal seemed to follow, helpless and rudder-like, upon the movements +of the first. The whole of the manoeuvring was carried out in a calm, +slow, deliberate manner, and almost noiselessly. How long they had +been coupled together before I observed them I do not know; but my +observation lasted fully three minutes; then the couple separated +beneath water, and simultaneously appeared again on the surface, +finally diving and disappearing. + +I made an attempt to follow the actual process of copulation, making +use of a recently killed male and female which, though dead, were still +limp and pliable. I found that, when the male rises into the sitting +position which I have already described, the tips of his spurs may +easily be inserted into the sockets which occupy the corresponding +position on the hind legs of the female. If the male then throws +himself right back, and at the same time the female draws her pliable +tail between his legs, the position observed in the final stages is +reached, and in this position the cloacal apertures may easily be +opposed. This use of the spur would supply the reason for its being +movable, a matter for discussion later. + +To insert the spur into the socket to its full extent, as stated by +Home, would certainly involve gymnastic ability. My firm belief as +to what really happens, is this: When in the sitting position, the +male straddles the hips, keeping his feet at right angles with his +legs. In this attitude the spur can be erected to its fullest extent +(in a manner similar to the action of one’s thumb when the clenched +hand is opened suddenly). In an adult male the space between the foot +and the tip of the spur, at that time, measures over an inch. This, +then, is more than sufficient to embrace the female ankle comfortably. +Presumably the female does not resist the application of the grip, +and, when it is securely taken, she flicks her pliable tail into +position. It is with such simplicity then that the grip is secured and +steadfastly retained to the end, though, possibly, aided with two pairs +of clutching feet. + +Now if we take into consideration the shape and length of the curved +spur, which follow befittingly the depth and ovalness of the female +ankle, it will not be difficult to ascertain the reason why it is +impossible for the male to insert more than the tip of the spur into +the socket, even were he desirous of doing so. + +As regards Home’s statement that the male ejects the secretion of the +spur into the female socket to bring about release, to me this also +appears wide of the mark. On examining the spur, which averages ¾ in. +long and is shaped somewhat like that of a cock, it will be found that +the aperture is not at the tip, but back from it, and, furthermore, is +situated on the convex surface farthest away from the socket during the +embracing position. I therefore fail to see how a fluid ejected beneath +water could enter the socket. As a matter of fact, the poison cannot +be ejected unless the spur is pressed against the male’s own leg. +How, considering the shape of the weapon, can this possibly be done +while the thickness of the female’s ankle, or lower leg, intervenes? +The purpose of the aperture’s being set back from the ripping tip of +the spur is obviously to prevent clogging while fleshing prior to +administering the poison. This strengthens my belief that the secretion +is intended to irritate a wound. + + +BREEDING-SEASON + +The breeding-season of the platypus in northern New South Wales may +be estimated with fair accuracy from my long series of observations +and records. I have observed copulation, as I have already stated, on +two dates only, 27 August 1909, and 23 September 1921; but I had a +report from a competent observer, Mr. J. Maclean, that platypus were +“courting” in the Macdonald River in the middle of July, 1920. The +earliest date on which I have actually taken eggs from the nest is +24 August (1925). On the same day I unearthed twin young ones which +I estimated to be three days old. This would carry back the date of +laying to, perhaps, the first week of August. I have no guide as to +the time which elapses between the laying of the egg and the hatching +of the young, but I think it must be less than that necessary for the +incubation of birds’ eggs, owing to the partial development of the +foetus before the egg is laid. + +The latest date upon which I have taken eggs is 22 October (in 1918); +Kershaw (1912) has recorded the taking of eggs upon the same day of +October in 1912 in Victoria. Consequently the period during which +oviposition has actually been observed ranges from about the middle +of August to a little after the middle of October. There are certain +conditions, however, which affect the breeding-season, and I do not +believe that normally it has so great a length. In the first place +there is, as one would expect, a general tendency towards earlier +breeding in the north; as one proceeds south littering becomes +progressively later. In central Queensland July and August are the most +active months; in New South Wales, August and September; in Victoria, +September and October. I have no information as to the breeding-season +in Tasmania. But the normality of the breeding-season may be seriously +interfered with by conditions of weather, and particularly rainfall. +Heavy rains occurring in August and September flood the burrows, which +are consequently deserted. This flooding is brought about chiefly by +seepage through the soil, as the upper parts of the burrow are almost +always above ordinary flood-level of the river. It is thus clear that +the pugging of the tunnel is not a precaution against the entrance of +water from the river, as has sometimes been suggested, but is for the +purpose of providing conditions necessary for incubation. The effect +of floods upon the breeding-season in the New England district was +observed during September and early October of 1920. In July, the +rivers were in flood. Platypus were reported plentiful after the waters +had receded in the early part of August. A second flush occurred late +in August, when the waters rose to six feet above their normal level; +and sporadic rain continued until September 18. Under these conditions +a number of burrows which I opened up were found to be deserted and +the contained nests sodden with water. More remarkable still, several +tenanted burrows were found in close proximity to one another, which +is unusual; and in one case two females were found occupying nests in +burrows which had a common entrance, an occurrence without parallel in +my observations. Furthermore, several tenanted burrows showed signs of +extremely hasty construction, being only a few feet in length, and with +fewer pug-pits than usual. Again, in 1923 an eight-foot rise in the +river had washed out all the breeding females, and no tenanted burrows +at all were found on the plateau. A female killed on October 9, when +examined, was found to have in her left uterus eggs in the early stages +of segmentation. In a normal season eggs are laid during the later part +of August and early September, and from late September on to the end of +October large young are found in the nests. + + +THE INTRA-UTERINE EGG + +The ovum of _Ornithorhynchus_ (that portion of the egg which +corresponds to the yolk of a fowl’s egg) is, at the time of +fertilization, a small yellow sphere about 3 millimetres in diameter. +After fertilization it becomes surrounded by an exceedingly thin layer +of albumen, and, outside this, by a thin, transparent, horny shell. +In birds there is a thick layer of albumen (the white of the egg) +deposited in several distinct layers, the innermost having spirally +twisted prolongations which serve to hold the yolk suspended in +the middle of the egg. Outside this thick albumen are two delicate +membranes, closely adherent everywhere except at the larger end of the +egg, where they separate to enclose an air-chamber; these membranes are +closely applied to the rigid, calcareous shell. The most remarkable +difference between the egg of a bird and that of a monotreme is that +in the former the shell is deposited round the fully-formed egg, and +there is no increase in its size during the growth of the embryo, +whereas in the monotreme the eggshell increases in size and alters in +structure during the intra-uterine development of the embryo. The thin +shell, which is at first only 4 millimetres in diameter and spherical +in shape, stretches and thickens until a diameter of 10 millimetres has +been attained. At this stage the egg is still practically spherical, +but the shell has become thicker, and has been rendered opaque by the +deposition of lime-salts. As it goes on growing, it becomes ellipsoidal +in shape, the longer axis corresponding to that of the contained embryo +(Wilson and Hill, 1908), and finally attains its maximum size (16 to +18 millimetres long by 14 to 15 wide) just prior to being laid. There +can be no doubt that this curious growth of the egg, which has no +parallel in nature outside the monotremes, is due to the imbibition of +fluid from the uterus. There is not sufficient nutrient material in the +yolk-mass of the fertilized ovum to produce the young platypus which +hatches from the egg; consequently the intra-oval foetus is nourished +in a considerable measure by secretions from the maternal uterine wall. +Since secretions can pass into the egg through the mesh-work of horny +fibres of which the shell is at first composed, it is also possible +that foetal secretions may pass out; there is at present, however, no +evidence that such a process takes place. The point is of interest, +for, in the higher mammals, a secretion from the foetus--of the nature +of a hormone, or chemical messenger--which passes into the maternal +blood-stream, is conveyed to the mammary glands, and stimulates them +to the active secretion of milk; but, in the platypus, neither at the +time of oviposition, nor later, when the young actually hatch out, +are the milk glands of the mother in active condition. The stimulus +to lactation would seem to be derived in some external and mechanical +way from the presence of the young. This question will be further +considered below. + +It is thus obvious that, though the monotreme egg is usually looked +upon as similar to those of birds and reptiles, it is in reality very +remarkably different. The nourishment of the embryo within the egg by +secretions from the uterine wall is distinctly a mammalian feature. +Such a process does not occur among birds and reptiles;[16] in +these, when once the egg-shell is formed, the embryo has to depend +altogether upon the nutrient material packed within the egg. It must be +admitted, however, that what occurs in the monotremes appears to afford +very little clue as to the evolution of the placental habit in the +higher mammals. + +[Illustration: (1) TWIN EGGS IN NEST COMPOSED ENTIRELY OF REED ROOTS. + +_Plate 29_] + +[Illustration: (2) TRIPLET NESTLINGS, ABOUT FOUR DAYS OLD. NEST +COMPOSED OF GUM-LEAVES AND GRASS. + +_Plate 29_] + + +EGG-LAYING + +The platypus lays one, two, or three eggs, two being the usual number. +There is no record of four eggs, or four young, ever having been +discovered, and the statements of Bennett and by Lucas and Le Souef +that the number of eggs is one to four are probably based on Geoffroy +St. Hilaire’s unfortunate experience (see p. 36). When two eggs are +laid, these are invariably found joined together side by side. So +closely do the apposed walls adhere that considerable force, comparable +to that required to pull apart two fairly dry ‘tangle-foot’ fly-papers, +must be exerted to separate them. The only records of triplet eggs are +of two sets taken after hatching and one intra-uterine set. Each of the +former sets of shells was in the form of a cluster, with the length +of all three eggs lying practically parallel, but the ends free for +emergence of the young. In one of the sets the three were all joined to +each other; in the second set there was a small space separating two of +the shells, but both of these were joined to the third. This difference +is evidently unimportant, and occurs when the eggs are being clamped +together immediately after they are laid. + +There is no longer any mystery as to the way in which the eggs are laid +and afterwards fastened together. When the eggs are ready to be laid, +they are well apart from one another in the uterus, with their longer +axes in the direction of the length of that organ. The capsule of each +separate egg is at that time completely covered with a sticky fluid. +When about to lay, the female squats on her rump in the nest, with her +tail between her legs, and her fore-paws in readiness at each side +of the aperture of the protruding cloaca. Presumably, the eggs are +deposited singly into her soft rubber-like hands and held there firmly +until each egg capsule, where in immediate contact with its fellow, +becomes affixed thereto; then, with the help of the under surface of +her fat, pliable tail, they are clamped to her warm abdomen. Meanwhile +the solution still covering the remaining portions of the capsules soon +loses its stickiness through either evaporation or absorption. It is +improbable that the eggs are held for long in the fore-paws, or that +their adhesion and the drying of the exterior portion of the capsules +is a lengthy process. + +It may interest my readers to know how I have come to these +conclusions, seeing that the eggs are laid in a pugged cavity beneath +the solid earth. While collecting embryological material for the +Canberra National Museum on September 2, 1925, at Manilla, I took a +female platypus with mature triplet eggs in her left uterus, and on +extracting these I found that their capsules were conspicuously glossed +with a thick coating of sticky liquid. I immersed them separately in +a powerful drying fixative called “Bles;” but notwithstanding the +bleaching and hardening properties of this mixture of formalin, spirit, +and acetic acid, the eggs not only stuck firmly together on coming into +contact with each other, but also adhered to the glass and to a paper +label attached to another specimen in the bottle. This, I think, proves +that the eggs adhere to each other only after being laid, and not even +in the cloaca, as has been hitherto supposed. Drying off after adhesion +and exposure to the atmosphere would appear to be quite natural; this +could not occur prior to deposition. But one may ask why, if the eggs +will stick to paper and glass, they do not stick to the hands of the +mother during the act of manipulation. The probable explanation is +that the rubber-like membrane of the fore-paws of a platypus is always +cold and moist, however dry and warm the rest of the animal’s body may +be. This is as it should be, because of the various functions that the +versatile fore-paws are called upon to perform at a moment’s notice, +such as walking and swimming, involving rapid action similar to the +alternate opening and closing of an umbrella. It will be obvious +that the very existence of the platypus depends on the versatile +manipulation of this membrane. Nature would not permit any temporary +clogging of this intricate member. In 1924, while Mr. Ramsay and I were +making a moving picture of the natural habits of monotremes, I tried +with strong fish glue to fix the staff of an Australian flag in the +closed palm of a living platypus, but found that it was impossible. + +My observations of intra-uterine eggs apply to two pairs in the early +stages of segmentation. Each pair was found in the gravid left uterus, +which alone is functional; in each case the eggs, one behind the other, +were separated by an appreciable interval. Wilson and Hill obtained +a number of intra-uterine eggs, some in a fairly advanced state of +development; but they give no information as to how the eggs were +situated in the uterus. They do, however, figure (1908, Pl. 4, fig. 6) +a section of a uterus containing a fairly advanced single egg, which +shows that the egg lies in the position one would expect, namely, with +its longer axis in the direction of the length of the uterus. Caldwell +(1887, p. 464) states that he shot a platypus which had laid her first +egg, while the second lay in the mouth of the uterus. He does not, +however, state that he actually found the first egg, and it may be that +he went on the assumption that the animal invariably laid two eggs, +which we know not to be the case. Gold-receiver Rumby’s platypus is +reported to have laid two separate eggs in a gin-case (see pp. 41-43); +but there is so much that is dubious about this particular story that +it cannot be accepted as definite proof. If the evidence could be +relied upon, it would show that the eggs are laid separately, and the +fact that they were not found cemented together might be attributed +to the unnatural circumstances in which the mother found herself. As, +however, the two eggs follow each other down the uterus lengthwise, it +is obvious that they cannot in the process become joined together side +by side. Moreover, when there are three eggs it would not be possible +for them to be laid if they became cemented together within the body of +the mother. It is therefore certain that this cementing takes place +after they are laid. + +My observations, together with those of Wilson and Hill, show that any +pair of eggs contains embryos in an identical state of development, +even in the earliest stages of segmentation. This would imply uniform +conditions for both eggs, and from this it may be presumed that the ova +are extruded from the ovary and are fertilized simultaneously, that +they pass down the oviduct (including its uterine portion) close to +one another, but end to end, and that they are laid practically at the +same moment. At the moment of extrusion they are coated with a sticky +secretion from the oviduct walls, and it is a simple enough matter for +them to become adherent. But the fact that their long axes are always +parallel after laying would seem to necessitate definite action by the +platypus. There might be one other suggestion--that the eggs, having +passed through the pelvis separately, are retained in the cloaca long +enough to become attached to one another before their final extrusion; +but this I consider impossible. A further curious feature is that the +embryo lies along the long axis of the egg, parallel to that portion +of the shell which is cemented to its fellow, and, after the egg is +bleached, may be seen through the shell with the naked eye. + +My observations of the right ovary and oviduct go to show that, +though not functioning in the true sense, they appear to be affected +in a certain proportion to the activities of those on the left. For +instance, while the left is maturing triplet eggs, the right becomes +enlarged to about the size that the organs on the left would have +when carrying a single egg. In cases of twin and single eggs, the +enlargement is proportionately less. + +Of seventy tenanted nests examined by me, eleven contained either one +egg or one young one; fifty-four contained two; only five contained +three. Of six nests recorded by Kershaw, one contained a single egg +and five either twin eggs or twin young. Hill’s record of stages of +eggs taken from nests comprises one single egg and four twins. Wilson +and Hill’s paper (1907) on the intra-uterine stages does not state +clearly what was the exact proportion of singles to twins in the +material examined. There are a number of older records by Maule, the +Bennetts (father and son), and others, but the figures given above are +sufficient to indicate the approximate frequency of each egg-number. +Triplets are rare, the only record apart from my five (four times of +young in nest, and once of intra-uterine eggs) being a single record +of young by Dr. George Bennett. Ignoring triplets altogether, singles +are in a proportion of roughly twenty per cent, and twins of eighty per +cent. + +[Illustration: FEMALE PLATYPUS IN NEST OF GUM-LEAVES AND GRASS. + +The position is same as shown on Plate 28. The earth has been removed +to render photography possible. + +_Plate 30_] + + +THE LAID EGG + +Kershaw (1912, p. 106) gives the measurements of a pair of +eggs as 18 × 15 mm. and 16 × 14 mm., and of a single egg as 18 +× 15 mm. My observations give the following measurements (in +millimetres):--Shrivelled egg (unhatched), 16 × 10; single egg, 18 × +14; twin intra-uterine eggs, 3 × 3; twin eggs, 16 × 12; twin eggs, 17 × +14, 16 × 14; single egg, 17 × 13; twin eggs, 15 × 26 and 17 × 26; twin +eggs, 15 × 25 and 16 × 25; twin intra-uterine eggs, 5 × 5; twin eggs, +18 × 14, 15 × 14; twin eggs, 18 × 25 and 16 × 25; single egg, 15 × 13; +twin intra-uterine eggs, 6 × 6; triplet intra-uterine eggs 17 × 15, 18 +× 15, third smashed (abortion). No triplet eggs have yet been taken +from a nest. It would appear from the measurements given above that the +average of the single egg is usually larger than that of either of twin +eggs, the measurements being 17.25 × 14 mm. against 17.5 × 13.8 mm. It +will also be noticed that in only one of five pairs of twin eggs are +the eggs of equal size. In the others one is usually distinctly smaller +than the other. + +Of the intra-uterine specimens listed above, the 1920 pair measured +3 mm. in diameter; they were spherical in shape, yellow in colour, +and were situated in the oviduct close to the left ovary. The 1923 +intra-uterine pair were 5 mm. in diameter, spherical in shape, yellow +in colour, and were situated in left uterus. The 1925 pair measured +6 mm. in diameter, were spherical in shape, “orange” in colour, and +surrounded by albumen. + +The 1925 triplets measured (1) 17 × 15, (2) 18 × 15, the third being +smashed through abortion while in the uterus but uniform in size with +the others. They were ellipsoidal in shape, glossy white in colour, +and were situated in an abnormally enlarged left uterus, two adjoining +nearest to the oviduct, the other in a separate compartment close to +the cloaca. All three were lying lengthwise with the trend of the +uterus, while the ovary connected therewith was partly covered with +a crystal jelly encased in a thin transparent film. This jelly, or +“hydatid-like” sac, was almost as large as the swollen ovary, and, +except where it was attached, somewhat similar in shape to its host +ovary. Whether it was for the purpose of supplying the compound which +envelops the eggs when capsuled in the uterus, I cannot say; but it was +preserved intact for later investigation. + +When first deposited, the eggs have a full outline, but as incubation +proceeds they frequently become dented, as well as discoloured. Kershaw +(1912, p. 106) notes that mere exposure to dry air produces denting in +a few minutes. I think, however, that the denting is due to the age of +the egg, because on two occasions I have exposed apparently new-laid +eggs for thirty minutes in the open while photographing them, and they +retained their full outline perfectly throughout, although handled +considerably. It may be that the necessity for a moist atmosphere is +part of the reason for the pugging of the burrow. + +The shell is thin, and easily compressible. It is composed of a +mesh-work of keratin fibres, impregnated with calcareous salts; +except in shape, it resembles that of a lizard. The shape is broadly +ellipsoidal, the ends being shortly and evenly rounded. The colour +of the newly laid egg is a glossy white, which, when the egg is dry, +turns to a flat chalky white, and later becomes stained brownish. The +shells from which the young have been hatched have a more polished and +translucent brownish-white appearance, which may best be compared with +that of the celluloid balls used in “ping-pong,” when they have become +crushed (see Plate 23). + + +INCUBATION + +Incubation is carried out by the female alone. During many years of +observation no male has been found in a breeding-burrow, and Joseph’s +account of platypus in captivity (p. 205) indicates that females resent +the intrusion of the male even into their resting-places. On one +occasion I was fortunate enough to catch a mother-platypus napping, +and she did not wake until an attempt was made to insert a thermometer +into the middle of her curled-up form. Her tail was turned up over +her abdomen, holding against it two 65 mm. young. I am convinced that +the eggs are held during incubation in a somewhat similar manner, and +that their cohesion supports this view (see Plate 30). Kershaw (1912, +p. 105) records the finding of newly hatched young, one of which was +attached firmly to the skin of the mother. At this stage the young +have not begun to suck, but they are very helpless and might become +entangled in the fur of the mother’s abdomen, where they invariably +nestle. Kershaw has also expressed this view, and he mentions, +incidentally, that the other young one fell off as the mother left the +nesting-chamber. Of two observations by Kershaw (_loc. cit._), and six +by myself, of nests in which eggs were found, in no instance was the +mother absent from the burrow. This would surely indicate that the +female incubates her eggs in the way described. + +The point is of importance, because there is a considerable difference +between the temperature of the nest and the body temperature of +the mother. I have found that the average temperature of the +nesting-chamber (taken by thrusting in a thermometer the moment it was +opened up, and blocking the hole with a sack) was 64.5° Fahrenheit +(19.2° centigrade), whereas the average cloacal temperature of seven +brooding females was 90° Fahrenheit (32.2° centigrade). Such a +difference in temperature would have a considerable influence upon the +duration of incubation. The length of the incubation period is unlikely +to be ascertained by observation in the field, but I think it should +be possible to discover it artificially. At present it can only be +conjectured from comparison with other oviparous animals. Passerine +birds which lay eggs of the same size as those of the platypus have +an incubation period of from twelve to fourteen days; they also have +a higher blood-temperature. But, as against this, Caldwell has made +the observation (1887, p. 464) that the egg of _Ornithorhynchus_, when +ready to be laid, contains an embryo already in approximately the same +stage of development as a thirty-six-hour chick. It may not be very +wide of the mark to suggest that the incubation period of the platypus +is about fourteen days, though possibly less. + +I am convinced that, during the three weeks or more which elapse +between the laying of the eggs and the onset of lactation, the female +not only does not leave the nest, but also passes into a condition +of partial aestivation. I think the eggs are laid in the fore-paws +and placed, in the manner described above, between the upturned tail +and the abdomen, and that they remain there throughout the incubation +period and possibly beyond, until mammary secretion is excited by the +mechanical stimulus of the movements of the young. These convictions +pass beyond the observed facts, but are, nevertheless, consistent with +them. + +[Illustration: MILK GLAND FROM LEFT SIDE. + +The protrusion near centre of upper edge shows where the gland was +connected with perforation in abdominal skin. + +(_From fresh carcass_) + +_Plate 31_] + + +HATCHING + +The hatching process has not been observed completely. The shells +from which the young have hatched are always found in the nest in a +flattened condition. On relaxing them in warm water, months later, I +have found that they can be made to resume their original shape. It is +worth noting here that the warm water has no effect upon the substance +which caused the eggs to stick together when laid. The young are seen +to have emerged through ragged rents, and seldom is any portion of the +shell missing. The twin eggs examined all show that both young emerged +at adjoining ends. In the only two sets of three shells recorded, a +somewhat different state of affairs was found (see Plate 23, fig. 4). +In two of the eggs the rents were at opposite ends; in the third the +rent opened at right angles to the plane of the other two; the result +being three openings as far removed from one another as the surfaces +of the eggs would allow. It is impossible to credit the mother with an +instinct enabling her to arrange the eggs with regard to the planes +of embryos which are only very little formed at the time of laying. +It is likewise difficult to conceive that the embryos themselves can +possess any instinct which leads them to break their way out in a given +direction in which their passage is assured. The probability is that +the eggs are invariably attached to each other by their sides, and that +the young always break out at the ends, and so no complication can +arise. + +When young from the nest were first described by Owen, it was thought +that the caruncle on the muzzle, which is hard and sharp a couple of +weeks after hatching, corresponded to the ‘egg-tooth’ found in many +birds and some reptiles, and was the means by which the young one cut +its way out of the egg. The discovery of earlier mammary foetus stages +has shown, however, that at the time of hatching the caruncle is merely +a fleshy knob, which could not possibly serve as a cutting instrument. +Professor J. T. Wilson states that in the newly hatched young there is +a small egg-tooth anterior to the caruncle; but this must be a very +evanescent structure, for no sign of it can be seen in young ones 18 +mm. long, the earliest mammary foetus (a term to be explained later) +collected by me. These, from the soft, moist condition of the shells, +and the umbilical protrusions exhibited by the young, I considered +to be newly hatched, but Professor Wilson’s specimens are smaller. +Whether helped by an egg-tooth or not, it is probably an easy matter +for a restless, muscular creature like the platypus embryo to break out +through the thin shell, using the caruncle as a point of resistance +against the pull of the fore-paws, with an action similar to that +adopted by the young when pummelling the mother’s abdomen and nuzzling +for milk. I have observed a similar action on the part of overturned +naked young regaining their feet. + + +NURSING HABITS + +The young, when first hatched, show few of the characteristic features +of the adult platypus. There is no sign of the curious muzzle, which +Geoffroy St.-Hilaire protested would be such a stumbling-block to the +imbibing of milk from mammary glands. Indeed, except for the flattening +of the rudimentary tail, and the shortness of the limbs, with their +even fingers and toes, the young platypus has little to distinguish it +upon casual examination from any early mammalian foetus. It grows into +characteristic platypus form at a later stage. + +The most remarkable and mysterious feature about the baby platypus +is that it is not suckled at all by the mother for some days after +hatching, for the very good reason that the maternal mammary glands +are not yet actively functional. Investigations of this extraordinary +phenomenon have advanced far enough to place the matter beyond doubt. +On October 9, 1923, I took three female platypus, two with the mammary +glands almost dry, the third with them quite so. I noted the inflamed +condition of the uterus of the third individual, and it proved on +examination to contain two eggs in the early stages of segmentation. +On September 27, 1921, I took a female with a young one 45 mm. long. +Here the mammary glands had begun to enlarge, but had not reached half +the maximum size, and would seem not to have been actively functional, +though four or five days must have elapsed since the time when the +young one was hatched. Against this it must be recorded that Kershaw +(1912, p. 105) took a 30-mm. young one, “so securely attached to the +skin as to require a little force to detach it.” Kershaw does not +state the method of attachment; but, as the limbs are very feebly +developed at this stage, it is certain that the little creature must +have been sticking to the fur accidentally. In all my experience I have +never found the young ‘attached’ to the fur. Whether the individual +which Kershaw observed was really obtaining nourishment cannot now +be determined. Had he dissected the mother, he would have discovered +that at that stage the milk glands were dry. I have made a careful +examination of the glands of a mother with 20-mm. young, and could not +induce milk to flow by external pressure--a process which can easily be +carried out when the young are older--nor, on dissection, could I find +any trace of milk, the glands appearing quite dry. An examination of a +considerable series of mammary glands from nursing mothers which have +been collected with their young has convinced me that during the first +week, at least, after hatching there cannot be more than a very slight +milk-secretion, if any at all, and I think this characteristic applies +to the echidna also. + +I have made the experiment of placing young apparently two weeks old +upon the abdominal fur of the mother, who was laid upon her back and +held in that position. The young ones crawled aimlessly about, and +passed and repassed over the mammary area without appearing to be +aware of its presence. They made no attempt whatever to cling to the +fur with either mouth or feet. Older ones, however, clung tightly with +their fore-paws, using their hind limbs as additional supports when the +mother was held up vertically (see Plate 10). While observing these +latter young, I noticed a peculiar action which appears to lend some +support to a rather speculative conclusion previously reached as to the +function of the caruncle. The young were observed to bend their heads +under their bodies, and to withdraw them in such a way that the dorsal +surface of the muzzle, towards the end of which the caruncle is borne, +was dragged forward over the mammary area so that the sharp point of +the caruncle scored its surface. It had occurred to me previously +that, since the caruncle could not, for reasons given above, have the +function of an egg-tooth, it might well serve the purpose of exciting +mammary secretion. It is at least a significant coincidence that the +onset of obvious lactation occurs simultaneously with the completed +growth of the caruncle. It may be that the stimulus afforded by this +‘milk-spur’ is necessary to induce the very primitive milk glands +of _Ornithorhynchus_ to act; and the delayed lactation which I have +observed may be due to the incomplete development of the necessary +stimulus in the early young. How the young platypus is nourished in +the meantime I do not know. + +On one occasion only have I found the mother to be absent from a nest +containing young less than two weeks old. It must be remembered, +however, that burrows are always opened up by daylight, and, as the +female is certain to be more than usually wary during the nursing +period, it is safe to assume that she would generally feed under cover +of darkness. When the young are older, they are frequently found by +themselves, presumably because the mother has to feed long and often in +order to maintain her milk supply. When the female leaves the burrow, +all the pugs are closed behind her, which means that she digs her way +through each of them, passing the earth under her body and compacting +it with her tail as she goes. Since the same process has to be repeated +on her return, and since as many as nine pugs have been observed in a +burrow, feeding excursions must be a laborious business and are not +likely to be indulged in more often than is necessary. + +During the early nursing period, then, the mother spends most of her +time curled up about her babies, holding them snugly against her +abdomen by means of her tail. The young at this stage are generally +referred to by the term ‘mammary foetus,’ which is the name given +to the pouch-young of marsupials during the time they remain on the +teat. There is, however, no close correspondence between the two. The +marsupial, coming to active life for a brief space after birth--long +enough, it is said, to reach the pouch of the mother by its own +voluntary effort--relapses into a foetal condition in which it is +apparently incapable of voluntary movement. It cannot even suck, +the milk being pumped into it by the mother. This act is obviously +impossible for the teatless monotremes, hence their fasting. The +young platypus, although its bodily form undergoes a fair degree of +modification during the first fortnight, and though it is not hatched +entirely after the image of its parents, is continuously capable of +voluntary movement from the time it leaves the egg. In the newly +hatched young the movements are comparatively feeble; but after the +first week the young are in a state of perpetual motion, at least +when exposed to daylight, which they appear to dislike. In the darkness +of the nest, however, they probably spend most of their time in sleep. + +In the echidna the mammary areas open into the pouch, which is formed +as a temporary structure during the breeding-season, and the young one +laps its nourishment with its slender projecting tongue. The platypus +has no pouch, and the milk oozes out through numerous fine apertures +upon two mammary areas of the abdomen, each about half an inch in +diameter. These areas are covered with fur, and are not in any way +distinguishable from their surroundings, so that they are difficult +to locate by external examination. Pressure upon the mammary glands, +however, causes the milk to flow gently out, and their precise position +can then be seen. The hair covering the areas serves, apparently, in +place of a teat, and the young pluck at this and suck the milk from +it, much as a little aboriginal eats his honey by sucking it from a +piece of shredded bark. The “lips” of the young, owing to the shortness +and undeveloped form of the bill at this early stage, are adapted for +sucking in conjunction with the tongue (see plate 33). + +An unsuccessful attempt was made to keep alive two young ones (about +a fortnight old), which had been sent to the Department of Zoology at +the University of Sydney, by inducing them to suck cow’s milk from pads +of cotton wool. Even when the milk was squeezed out upon their tiny +muzzles, they did not appear to take the slightest interest in it. I +had much the same experience in the field with a pair of well-grown +young, which were in fur and had their eyes open. I placed drops of +milk upon the hairy portion of my forearm, but they merely brushed it +aside. After crawling inside my sleeve (evidently to avoid daylight), +they did, however, pluck at the skin of my arm with their jaws, with +a sucking action sufficiently strong to bring a flush of blood to the +spot. The opening of the jaws was accompanied by a feeble kiss-like +explosive sound, resembling that made by a man releasing smoke from the +side of his mouth when lighting a pipe. + +The naked young range from bright red to rose-pink in colour when +alive, and their delicate skin has a silken sheen, and is minutely +wrinkled. In preserved specimens these wrinkles become much +exaggerated, owing to the contraction of the underlying muscle-layer. +When the hair-follicles begin to develop, the skin of the back assumes +a bluish appearance, like that of a shaven chin, but the under surface +of the body still keeps its pink colour (see Plate 33). Finally, with +the growth of the hair, which is at first fine and silky, the adult +appearance is reached. + +A feature of interest in connection with the nursing habits is that +the nest never shows any sign of having been fouled with excreta. +Young which I have had in temporary confinement defaecate freely; the +faeces take the form of an odourless, greenish, oily slime, which may +be compared with the contents of the gall-bladder of an ox. (Adults, +in captivity or at large, always defaecate in water.) As the nest is +always clean, this inoffensive matter would readily filter through the +nesting-material without causing more discomfort than that endured by +nestling Owlet Nightjars--in fact, not so much, since it would not form +hard masses like the bird droppings. But it is reasonable to suppose +that very little faecal matter passes from either the mother or the +young during the period of incubation and the nursing of little ones. +While suckling, the mother leaves the nest occasionally to feed, and, +presumably, to defaecate also. The nest is then probably relined from +time to time, as is the custom of the Owlet Nightjar. + +It is for these reasons that I maintain that platypus, when brooding, +fall into a lethargic state and, thus requiring little food, do not +evacuate in the nest unless abruptly disturbed. + +[Illustration: BROODING FEMALE STEALTHILY GROVELLING HER WAY FROM HER +NEST WHICH HAS BEEN EXPOSED + +Note cautious attitude and rubber-like muzzle. + +_Plate 32_] + + +ADOLESCENCE + +About six weeks after hatching, the young will have reached a length of +twelve inches. By this time their eyes are open, their fur is a quarter +of an inch in length, and they are able to crawl freely about the +burrow. (See Plate 12, fig. 2). This may seem a rapid rate of growth, +but such rapidity is explained by the fact that when once the young +commence to suck, their appetites increase rapidly. The quantities of +food found in their stomachs on dissection are surprising. (Because +of this, the stomachs must be tapped and the contents drained before +fixing in “Bles,” otherwise the milk putrefies and is apt to spoil the +entrails.) + +Just prior to the appearance of pelage on a large nestling, the +intestines and stomach are found actually bloated with milk. When +fully extended, the skin of the abdominal area becomes remarkably +tight-fitting; but elsewhere the trunk does not nearly fill out the +skin. By holding such a specimen, back down, on one’s palm, and +slightly tilting the hand from side to side, the entire contents of +this out-size skin slop about as a quantity of mercury would if placed +in a pliable bladder. + +The largest young that I have found in the nesting-burrow measured +thirteen inches in length. The smallest known by me to have been found +at large were fourteen inches long, captured in shallow water among +weeds. My own youngest capture at large measured fifteen inches. +It would thus appear that the young are generally from thirteen to +fourteen inches long when they leave the burrow. For some time prior +to this, however, they would seem to run about the burrow, and, +possibly, to enter the water in company with their mother. When once +their eyes are open, the young are able to swim. The mother then no +longer replaces the pugs in her tunnel, and one which contains large +furred young may be recognized during excavation by the fact that +nesting-material is strewn along its course. This is mentioned casually +by Bennett (1860, p. 130), and it seems probable that this material is +scattered about by the young in running to and fro. At this stage the +breeding-burrow is about to be deserted. + +Bennett (_l.c._, p. 131) records the capturing of twin young, ten +inches in length, which had a most beautiful, sleek, and delicate +appearance, and seemed never to have left the burrow. These were kept +alive for some little time, and enjoyed playing in a dish of shallow +water, in which, however, they never remained longer than fifteen +minutes at a time. It would thus seem likely that platypus of that age +have already begun to make short excursions into the water. Bennett +captured a female which he assumed to be the mother of these, and found +her to be in a very poor condition, with the mammary glands practically +dry. Two healthy young, ten inches in length, would certainly need +more nourishment than could be supplied by glands in this condition; +but possibly they had just previously sucked the mother dry. But we +may assume that the young are by this time learning to eat the food +of the adults, and that, as this is always eaten in the water (unless +taken from the mother’s mouth, pigeon-fashion), they go to the water +to be fed. Verreaux’s observations are certainly interesting, but +I cannot entirely agree with him. He records (1848. p. 131, Owen’s +translation):-- + + “I redoubled my attention and care, and by dint of perseverance, + having at my disposal (always on the banks of the New Norfolk) a + pretty considerable number of adults and young, I saw the latter + accompany their mothers, with which they played, especially when they + were too far from the bank to take their nourishment. I distinguished + very well that when they wished to procure it they profited by + the moment when the mother was among the aquatic plants, near the + land, and where there was no current. The female having her back + exposed, one can easily conceive that on the exercise of a strong + pressure, the milk would float to a little distance, and that the + young might suck it up with facility; this it does, turning about + so as to lose as little as possible. The manoeuvre is the more easy + to be distinguished, since one can see the beak move with rapidity. + I cannot better compare the greasy liquid of the female than to the + iridescent colours produced by the solar rays upon stagnant water. + I have witnessed the same fact repeated daily and nightly. I have + also remarked that the young, when it was fatigued, climbed upon the + mother’s back, who brought it to land, where it caressed her.” + +It is improbable that the female discharges milk into the water. Most +likely she catches and crunches food for her young, and releases it +into the water where they can pick it up; this would be good schooling +for both swimming and diving. It is possible that Verreaux witnessed +some such process, though he mistook its nature. + +I have observed a young captive platypus feeding upon an aquatic +plant, stripping the leaves one after another from the stem with its +mouth, and using its fore-paws to assist in the process. The adult may +disdain a vegetable diet; but, if any significance can be attached to +this single observation, it may be that the young devour a certain +amount of vegetable food, for which they can forage for themselves in +the shallows. Bennett’s aborigines, who were not altogether reliable +concerning what took place in the burrows, informed him that the +animals ate water-weeds, and that the mother fed the young first with +milk, and then with comminuted insects and molluscs (1860, p. 131). + +The furred young are more vocal than the adults, and, when disturbed or +hungry, indulge in a puppy-like growling, accompanied by a kiss-like +popping sound. Bennett records a squeaking call, which was answered; +this I have never heard. In a passage quoted on p. 160 he describes +the careful toilet which they make. They habitually sleep in a curious +position, sitting up upon their hind quarters, with the muzzle laid +flat against the chest, and the tail drawn up over it (see Plate 28). + + +SEXUAL MATURITY + +Little is known of the age at which the platypus reaches sexual +maturity. Judging from the size which it attains in a couple of months, +one would imagine that it could breed by the following season. Against +this, however, is Semon’s opinion that only those two years old, or +older, take part in breeding. Semon’s observations are based upon the +examination of a long series of individuals; but I collected a female +in “full milk,” on October 27, 1922, measuring 407 mm. (16 inches), +only four inches longer than a 12-inch nestling of my collecting. To me +this is rather perplexing, seeing that the nestling would grow another +inch or two more before deserting the nest. And who can say that that +was her first breeding-season? Therefore I cannot agree altogether with +Semon’s statement. + +All that can be said at present is that the female begins to breed +when sixteen inches in length, and finally reaches a maximum size of +eighteen inches; but there is no precise information as to the length +of time involved. + + +LONGEVITY + +The length of life of the platypus is not known. It is my intention to +ring-mark some fully-furred young as opportunity offers, and it may be +that we shall gain some information on this point at a later date, if +these marked individuals are captured. + + + + +CHAPTER XII + +PRESERVATION AND ECONOMICS + + +1--PRESERVATION + +So long ago as 1819, Barron Field published the despondent couplet-- + + “When sooty swans are once more rare, + And duck-moles the Museum’s care.” + +Since his day Cassandras have not been wanting. Spicer (1876, p. 166) +writes from Tasmania:-- + + “This is all I have been able to bring together anent Platypus and + his spur, and little enough it is. I dare say when Australia is more + settled, and Ornithorhynchus has been improved off the face of the + earth, biologists will have leisure and thought to bestir themselves + to enquire into the matter. Just as now we are searching for Dodo’s + bones, and writing books about them, and doing work which ought to + have been done two centuries ago.” + +Wilson and Hill (1908, p. 33) express their views as follows:-- + + “The animal itself, though pretty widely distributed, and probably + still far from becoming extinct, is to be found, in any one locality, + only in comparatively small numbers. It is now much less plentiful + than formerly, owing to the demand for its fur--a demand which is + still satisfied in spite of the measure of legal protection which + the animal has obtained in the various Australian States. The + depredations of the fur-hunter are not easily repaired, since the + animal breeds only once in the year and produces but two eggs at a + time.” + +Lucas and Le Souef (1909, p. 144) comment on the protection extended to +the animal by the States of New South Wales and Victoria, and add--“so +we may hope that his tenure of existence may at least be considerably +prolonged.” + +The platypus is probably in no present danger of extinction; given a +reasonable measure of effective protection, it is likely to last as +long as the waters in which it lives. Quite apart from the measure of +safety resulting from its secretive ways, it dwells in mountain streams +running through many hundreds of miles of almost entirely uninhabited +ranges, much of which never will be inhabited owing to the inhospitable +nature of the country. Its aquatic habit saves it from the action of +what has been the chief means of bringing about a diminution of the +marsupial fauna--the opening up to pastoral and agricultural settlement +of a great part of the country. Australia is not guiltless as concerns +the destruction of marsupials, but it is not generally recognized +how much of this destruction was inevitable. For that which was not +inevitable--the wholesale destruction of grass-eating marsupials simply +because they ate grass intended for sheep and cattle--the pastoral +industry is already being called to account. The dingo, deprived of its +natural marsupial food, is attacking flocks in an unprecedented manner, +and greed and stupidity have defeated their own ends. The destruction +of forests has brought with it the extermination of their tree-living +inhabitants, as well as of the smaller terrestrial forms which +sheltered beneath the trees. But the platypus has not been affected by +these things. + +One thing, and one thing only, can bring about the extinction of +_Ornithorhynchus_, and that is the permitting of open traffic in +its skin. The skin is small; but, in the present world-shortage of +fur-skins, the beauty of the fur is sufficient to create a keen demand +for it, if it once be made available. The Australian bushman is well +able to follow the animal to its ultimate fastnesses if it be worth +his while; but he is patriotic enough to refrain from slaughtering +Australian fauna when his reason is appealed to. + +At the present time the platypus is, and for some years has been, +completely protected in all the Australian States in which it occurs. +The laws of the different States vary in detail; but, after years of +effort on the part of individuals and societies interested in animal +preservation, they have been brought closely into line and all except +certain scheduled native animals are protected--the eaters of grass and +similar heinous offenders. Even these may be granted the protection of +a close season, or of a period of absolute protection, in a district +in which they are becoming depleted, at the discretion of the minister +administering the Act. On paper, then, the future of the Australian +fauna appears to be a rosy one. + +Legislative enactment does not, however, entirely prevent traffic in +platypus skins, and there is no doubt that large numbers are smuggled +out of Australia under wrong descriptions, mixed in with parcels of +rabbit and other small skins. The extent of this traffic cannot be +ascertained, owing to the perfectly natural reticence of the people who +engage in it. + +Fortunately it is only in comparatively recent times that the skin of +the platypus has become commercially desirable, and the growth of a +national sentiment, together with the increasing difficulties placed +in the path of the poacher, have combined to keep destruction down to +a minimum. A certain amount of thoughtless and wanton destruction is +almost inevitable, since youths in the country districts of eastern +Australia grow up in an atmosphere of callous indifference to the lives +of individual animals. This indifference is simply the natural outcome +of large-scale pastoral operations in a country subject to sudden +meteorological vicissitudes. Men who have grown accustomed to seeing +hundreds of animals dying, which they are powerless to aid, cannot be +expected to become sentimental about a platypus. In 1863 Gould (p. 1) +wrote:-- + + “the diminution in its members is solely due to the wholesale + destruction dealt out to it by the settlers, which, if not + restrained, will ere long lead to the utter extirpation of this + harmless and inoffensive animal, a circumstance which would be much + to be regretted; it is in fact often killed from mere wantonness, or + at most for no more useful purpose than to make slippers of its skin.” + +According to Semon (1894, p. 12):-- + + “The fur is beautiful and thick, yet its qualities are not so good + as to warrant the wearisome and deluding pursuit. Consequently the + Duckbill is little pursued either by whites or blacks, and the early + extinction of this paradoxical creature need not be feared.” + +At present there is little danger of an export trade being developed; +the Federal minister for customs can prevent the export of animals and +animal products by the simple process of issuing an order-in-council. +There is no doubt that the measure of protection enforced by the +States during the last decade has had a valuable effect in increasing +the numbers of platypus. A healthy popular sentiment in favour of +Australian birds and mammals has also had a most gratifying growth +during the same period. Books on Australian natural history are +numerous, and additions are constantly being made to their number, +whereas twenty years ago there were none of a popular character. The +next generation of Australians will look upon its fauna with different +eyes, and it is not likely that the platypus will be deprived of the +protection it now enjoys. + +In one respect, however, enthusiasm for animal protection is beginning +to prove embarrassing, since accredited representatives of scientific +institutions are finding it increasingly difficult to obtain permits +to collect specimens for scientific purposes. The platypus is, from +a scientific point of view, perhaps the most important mammal that +exists, and a great deal of anatomical investigation remains to be +done. The number of individuals required for scientific investigation +is negligible when compared with the ordinary annual wastage. Moreover, +zoologists are more interested than any other class of men in the +continued existence of the animal, and are therefore least likely to +threaten that existence. The rights of science should be safeguarded in +any scheme of animal protection; but the enthusiastic people who raise +their voices loudest for the preservation of native fauna have not, as +a rule, a sufficient knowledge of science and its aims to appreciate +those rights. They desire that no wild innocuous animal whatever shall +be killed--which is in some respects a very laudable desire; but such +an attitude betrays the want of a sense of proportion, and of knowledge +of the balance of nature. It has been alleged quite seriously that +collectors for overseas museums, though operating under jealously +restricted permits, were bringing rare species within danger of +extinction; and there was some outcry against the expedition on behalf +of the British Museum being allowed to collect at all. Such allegations +are ludicrously far from the truth, but they seem, when made loud and +often, to carry a certain amount of weight with authorities who do not +ask for responsible advice. + +Natural enemies of the platypus appear to be few in number. The +carpet-snake (_Python variegatus_) occasionally catches one, as has +been found on opening up a gorged snake; but the toll it collects must +be quite negligible, as a constricting snake could not take its prey in +the burrows, and must depend upon their approaching its lurking-place +on the open bank. It is probable that the omnivorous monitor lizard +(_Varanus varius_) takes platypus on land, and possibly the Whistling +Eagle and the Murray cod, in the water; but of this I have no definite +evidence. + +Its principal enemy at the present day, apart from man, is without +doubt the introduced rabbit, which by a process of peaceful penetration +has riddled banks where once the platypus enjoyed a quiet seclusion. I +hold the opinion that the presence of rabbits tends in time to drive +platypus from their accustomed haunts, and without suitable soil for +brooding burrows they cannot multiply. I attribute their disappearance +from settled regions almost entirely to this cause. The water-rat +(_Hydromys chrysogaster_), which also burrows in the banks of streams, +is in a less degree a disturbing factor. + +The rabbit is followed by the trapper, and rabbit-traps set on +river-banks and elsewhere are responsible for destruction of both the +platypus and the echidna. The latter, being useless from a commercial +point of view, is usually released, and frequently heals its wounds +with reptilian indifference. The trapped platypus is, however, knocked +on the head and relieved of its skin--for which proceeding there is at +least this justification, that it would not be likely to survive its +injuries, and, worse still, even the skin is destroyed when the whole +carcass is thrown into the river to rot. + +The greatest menace to the animal is, however, the fish-trap. Despite +the fact that in most waters the use of traps is illegal, most +homesteads on a river-frontage make use of traps to catch food for home +consumption. These are heavy wire cages. They have a conical entrance, +through which fish pass in, but are unable to escape. Platypus, in +their blind nosings about the bottom, enter these traps simply by +chance; as they cannot reach the surface to breathe, they are drowned. +Naturally, since the animals are dead when the trap is examined in the +morning, their skins are taken. It would be a simple enough matter to +save the lives of the animals thus accidentally caught, if the users of +fish-traps would take the trouble. An elongated funnel-shaped outlet +of wire-netting, fixed vertically to the upper part of the trap, with +the top portion open above water, would allow platypus, water-rats, and +tortoise to escape by climbing up the spout, and still retain the fish. +The device is quite simple to construct, and is also inexpensive. + +Closer settlement will bring about the disappearance of snakes, +lizards, rabbits, and rabbit-trappers. It may bring about an adequate +regulation of fish-traps. The more important question is--Will it bring +about the disappearance of the platypus? I do not see any reason why +it should, if settlers will but refrain from the grosser methods of +disturbing the creature. If shot at and hunted, either in wantonness +or for their fur, the survivors will undoubtedly desert the waters in +which they have been harried. But if a favourable public sentiment +can be aroused, and some interest taken in the preservation of an +interesting animal in the midst of closely settled communities, there +is little doubt that the platypus will contrive to flourish, despite +settlement. At Belltrees on the Hunter River in New South Wales, Mr. +H. L. White--to whom Australian natural history owes a great debt--has +made the homestead area a sanctuary, and the animal flourishes in those +pleasant reaches of the river which meander through the lucerne flats +of the home farm. Belltrees is quite a village, but the mere presence +of many men, engaged in activities about the river-banks, has not +frightened the platypus away. + + +2--ECONOMICS + +Economically there is little to be said either for or against the +platypus. It does no positive good; neither does it do any positive +harm. It has a valuable fur, but neither exists in sufficient numbers, +nor breeds sufficiently rapidly, nor lends itself to any scheme of +cultivation in such a way as to hold out hope of its becoming an +important national asset. It is not good to eat, and apparently serves +no purpose useful to man. + +The value of its fur is difficult to arrive at, since there is no +open trade in it. During the Pan-Pacific Conference in 1923 a Sydney +naturalist’s shop had a window-display of skins, priced ‘from thirty +shillings each.’ Platypus rugs--the staple form of use of the fur in +Australia in the past--rarely appear in auction-rooms now, but good +ones, containing from fifty to sixty skins, are usually sold at about +a guinea a skin. Should platypus fur ever be allowed to come into the +open market, there is little doubt that prices much higher than those +quoted would be obtained--and no doubt that the animal would be in +danger of early extinction. + +Mr. Clifford Coles has kindly supplied me with the following notes on +the skin from a furrier’s point of view:-- + + “The fur of the platypus is without exception the best-wearing of + all Australian furs. It is short, dense, glossy, and hard to the + touch; in colour, dark brown down the back, graduating to a silvery + whiteness on the flanks. Being somewhat even in length over the + whole of the body, the utmost use can be made of the skin. The + surface-hairs are very much coarser than the under-fur, which is + dense, soft, and practically impervious to water. The skin is not + in much request, primarily because of the thickness of its pelt + rendering the finished article somewhat stiff. Modern methods have + made this difficulty easy to overcome, but the reputation which the + skin of the platypus obtained in the years when it was an article of + commerce still holds with it, and the later generation, who only + know the platypus of old, always think of it as a heavy-pelted fur + and consequently do not seek it. + + “One of the principal drawbacks to its use as a fur is the difficulty + of manipulating the skin without leaving the furrier’s ‘cut’ marks in + ‘dropping’ conspicuous to the view. The art of the furrier is to-day + a great feature in fashionable furs. The skins, instead of being + split and divided into sections end on end, are now, by a series of + ‘V’ cuts, called ‘drops,’ altered to any shape desired. This is a + matter of great difficulty in a fur having a short texture, as the + knife-marks are conspicuous; and it is this fact which renders the + platypus so unattractive to the furrier. + + “The average woman of to-day, if shown a fur made of rabbit-skin + properly dressed and dyed to a fashionable colour, and another of + similar size made of platypus, would choose the rabbit-skin--not + because she would be protecting one of the rarest animals in the + world by the choice, but because the rabbit looks better and is very + much softer to the touch. + + “Platypus skins can be plucked so that the outer coarse hairs are + entirely removed. When this is done, a soft and most delightful + fur is obtained, closely resembling otter. In this form it is most + durable. The writer has known platypus skins used in this way which + have not been worn out after twenty years of service. + + “Because of the restrictions which have been placed upon the capture + of the animals, generally speaking, the skins are not on the market. + One can go for a whole season through all the wholesale stores of + Sydney and not see nor have offered him a single platypus pelt. + + “Tasmania produces the finest quality of these skins. The fur + there is longer, and the skins very much larger, than those from + the mainland. Reports from fur-trappers all along the eastern + watershed of Australia and Tasmania indicate that the animals are + increasing[17] in numbers.” + +The flesh of the platypus must be extremely distasteful, since neither +aborigines nor dogs will eat it. Bennett certainly states that the eyes +of his aborigines glistened at the sight of fat young ones in fur, +taken from the burrow, and that they said the animals were very good +to eat; but he does not record any definite instance of their eating +platypus flesh, and it may be that the sight of plump young animals +called forth the remarks, and not any previous gastronomic experience. +Semon (1894, p. 12) writes:--“The blacks on the Burnett do not hunt the +animal, since they scorn its flesh entirely; as a matter of fact it +gives forth an objectionable smell when skinned.”[18] A correspondent +of the Sydney _Daily Telegraph_ (10 February, 1923) records that some +miners ate one, and found it a somewhat oily dish, with a taste between +those of red herring and wild duck. The objectionable smell is due to +scent-glands situated at the base of the neck; but it is unlikely that, +even after these have been removed, the platypus will ever be a popular +item on a bill of fare. + +On the negative side, the only accusation brought against the animal +is that by Jamison (1818), that he found ova and fry of fish in the +platypus he examined. No one has repeated that observation. From +the discussion of the animal’s feeding habits given earlier, it +will be obvious that it is not likely to catch much in the way of +actively-swimming fry; and its habits in captivity show that it does +not care about fish as food. It may eat a certain amount of demersal +spawn (though there is no satisfactory evidence that it does), but such +a diet would be more or less accidental. Consequently its presence in +streams which have been stocked with introduced trout cannot be said to +be a danger to the fish. Large numbers of both platypus and trout are +said to co-exist in the Tasmanian lakes. + + + + +CHAPTER XIII + +THE PLATYPUS IN CAPTIVITY + + +Australian mammals have so far proved disappointing. The dingo will +certainly parade his enclosure by day, but he is just a dog, after all. +The kangaroos and wallabies show well enough, but one is very much +like another. The long series of interesting and beautiful marsupials, +which one would much like to see in our Zoological Gardens--pouched +mice, flying ‘squirrels,’ ‘opossums,’ bandicoots, and others--are +not only nocturnal, but so cryptozoic that they are rarely seen, +even in the bush. In the ‘Zoo’ they are represented merely by labels +on apparently untenanted cages, though occasionally one may catch a +glimpse of something furry rolled up in a ball in the heavy shadow of +the sleeping-hutch. Perhaps some day we shall have a special Marsupial +House, lit by powerful electric lamps all night, to simulate daylight +and drive our fauna to slumber, and darkened down by day to the +intensity of bright moonlight, in which we may come to know the grace +and beauty of the smaller arboreal forms. + +In September 1921 I sent two living adult and three nestling platypus +to the Zoology Department at the University of Sydney. The limited +number of people who on that occasion were privileged to see the +platypus swimming and diving in a large glass-fronted tank were all +agreed as to the interest and beauty of the exhibition. The loveliness +of the fur on the ventral surface, with its gold and silver lights as +seen under water, was certainly something to remember. This same fur, +by the way, is described in the British Museum Catalogue of Mammalia as +‘dirty-white’--an indication of the difference between the stuffed and +the living animal. + +The platypus can be kept alive in captivity; and it is very probable +that, with sufficient pains and interest, it can be satisfactorily +exhibited. As it is probably the most interesting animal in the whole +world, it would certainly be worth while to make the attempt. + +Until quite recently, although the animal has been kept alive for +fairly long periods in Australia, no living platypus had ever been +exported from the country. Chenu (1879, p. 351) certainly writes:--“Ces +animaux longtemps rares dans nos collections européennes y sont +actuellement plus fréquemment apportés, _et l’on en a même de vivants_, +surtout en Angleterre;” but there is no truth in the statement. It is +probably founded on lying reports of rascally dealers. Bennett relates +one such case, in which it was reported that a loud quacking noise, +like that of a duck, was heard coming from an East London pond; that a +gentleman struck with his stick at the spot from which the noise was +proceeding; and that some hours later a fine male _Ornithorhynchus_ was +found dying on the bank. It was now stuffed, and might be seen in Mr. +So-and-so’s shop. + +Maule (P.Z.S., 1832, p. 146) says:-- + + “in one of the nests he was fortunate enough to secure an old female + and two young. The female lived for about two weeks on worms and + bread and milk, being abundantly supplied with water, and supported + her young, as it was supposed, by similar means. She was killed by + accident on the fourteenth day after her capture.” + +Verreaux (1848, p. 133) had, of course, no difficulty whatever in +keeping them in captivity. During all the time that he was making his +important and painstaking series of observations, he had platypus of +all sorts and sizes in his possession. He fed them on broken rice +mixed with yolk of egg--which, after a time, they preferred to their +natural food. They fed at night, and growled and got angry if no food +was provided. Seeing how easy it all was, and how glad the French +zoologists would have been to welcome them, it is remarkable that +Verreaux did not take his pets back to France, or even send them by a +reliable hand. But there is no record of his making the attempt. + +Dr. George Bennett was very anxious to send the living animal to +Europe and made an ill-planned effort to accustom the platypus to +captivity; but, as he evidently had not studied its feeding habits, he +was not successful. He gives an extended account of his attempts in +his _Gatherings of a Naturalist_, from which these few paragraphs are +quoted:-- + + “I arrived with my little family of _Ornithorhynchi_ safe at Sydney, + and as they survived for some time, an opportunity was afforded me + of observing their habits. The little animals appeared often to + dream of swimming, for I have frequently seen their fore-paws in + movement as if in the act. If I placed them on the ground during + the day, they ran about, seeking some dark corner for repose; and + when put in a dark place, or in a box, they huddled themselves up + as soon as they became a little reconciled to the locality, and + went to sleep. I found that they would sleep on a table, sofa, or + indeed anywhere; but, if permitted, would always resort to that spot + in which they had previously been accustomed to repose. Although + for days together they would sleep in the bed made up for them, + yet on a sudden, from some unaccountable caprice, they would shift + their resting-place and seek repose behind a box, or in some dark + retirement, in preference to their former habitation. They usually + reposed side by side, looking like a pair of furred balls, and + surly little growls issued from them when disturbed; nevertheless, + when very sound asleep, they might be handled and examined without + evincing any signs of annoyance. One evening both the little pets + came out about dusk, went as usual and ate food from the saucer, + and then commenced playing, like two puppies, attacking each other + with their mandibles, raising their fore-paws, and tumbling one over + the other.... In the struggle one would get thrust down; and at the + moment when the spectator would expect it to rise again and renew the + combat, it would commence scratching itself, its antagonist looking + on and waiting for the sport to be renewed. When running, they were + exceedingly animated, their little eyes glistened, and the orifices + of their ears contracted and dilated with rapidity; if taken into + the hands at this time for examination, they struggled violently to + escape, and their loose integuments rendered it difficult to retain + them. Their eyes being placed so high on the head, they do not see + objects well in a straight line, and consequently run against every + thing in the room during their perambulations, spreading confusion + among all the light and easily overturnable articles ... besides + combing their fur to clean it when wet, I have seen them preen it + with their beak (if the term may be allowed) as a duck would clean + its feathers. It is, indeed, interesting to watch them engaged in the + operations of the toilet, by which their coats acquire an increased + bright and glossy appearance. When I placed them in a pan of deep + water, they were eager to get out after being there only a short + time; but when the water was shallow, with a turf of grass placed in + one corner, they enjoyed it exceedingly. They would sport together, + attacking one another with their mandibles, and rolling over in the + water in the midst of their gambols; and afterwards, when tired, get + on to the turf, where they would lie combing themselves, until the + fur was quite smooth and shining. It was most ludicrous to observe + these uncouth-looking little creatures, running about, overturning + and seizing one another with their mandibles, and then, in the midst + of their fun and frolic, coolly inclining to one side and scratching + themselves in the gentlest manner imaginable. After the cleaning + operation was concluded, they would perambulate the room for a short + time, and then seek repose. They seldom remained longer than ten or + fifteen minutes in the water at a time. As they were not confined + during the night, I sometimes heard them growling; they seemed as + if they were fighting or playing, and as if the saucer containing + their food had been upset in the scuffle; but, on the following + morning, they were quietly rolled up, fast asleep, side by side, + in the temporary nest I had formed for them.... One evening, when + both were running about, the female uttered a squeaking noise, as if + calling to her companion, which was in some part of the room behind + the furniture, and was invisible; he immediately answered her in a + similar note; and marking the direction from which the answer to + her signal came, she ran at once to the place where he had secreted + himself. + + “It was very ludicrous to see the uncouth little creatures open + their mandible-like lips and yawn, stretching out the fore-paws + and extending the webs of the fore-feet to their utmost expansion. + Although this was natural, yet, not being in the habit of seeing + a duck yawn, it had the semblance of being perfectly ridiculous. + It often surprised me how they contrived to reach the summit of a + book-case, or any other elevated piece of furniture. This was at last + discovered to be effected by the animal supporting its back against + the wall, placing its feet against the book-case, and thus, by means + of the strong cutaneous muscles of the back and the claws of the + feet, contriving to reach the top very expeditiously. They often + performed this mode of climbing, so that I had frequent opportunities + of witnessing the manner in which it was done. The food I gave them + was bread soaked in water, chopped egg, and meat, minced very small. + Although at first I presented them with milk, they did not seem to + prefer it to water. + + “Some time after my arrival at Sydney, to my great regret, the little + creatures became meagre, and their coats lost the sleek and beautiful + appearance which had before called forth so much admiration; they ate + little; yet they ran about the room as before, and appeared lively. + But these external symptoms argued strongly against their being in a + state of health. When wet, their fur became matted, never appearing + to dry so readily as before; and the mandibles, and indeed every + part of the animal, indicated anything but a satisfactory condition. + How different was their appearance now, from the time when I removed + them from the burrow! then their plump and sleek appearance roused + even the apathetic blacks; now the poor creatures could only excite + commiseration. The young female died on the 29th of January, and the + male on the 2nd of February, having been kept alive only during the + space of nearly five weeks; and thus my expectations of conveying + them to Europe in a living state were frustrated, and the ladies of + England lost an opportunity of beholding these really ‘darling little + ducks’ of quadrupeds.” + +[Illustration: (1) TWIN NESTLINGS, ABOUT FOUR WEEKS OLD, DIRECT FROM +BURROW. + +The nest is composed of willow “swishes,” willow rootlets, and flag of +reeds. + +(_About one-fourth natural size_) + +_Plate 33_] + +From my experience with platypus in captivity, I think the so-called +engaging antics of Bennett’s captives were really the desperate +struggles of slowly starving nestlings, while the food supplied and +general treatment were quite the reverse of their requirements. + +[Illustration: (2) NESTLING PLATYPUS, ABOUT THREE WEEKS OLD, SHOWING +“MILK-LIPS.” + +Note that both upper and lower lips in this undeveloped state are +adapted for sucking. + +_Plate 33_] + +I settled at Manilla, on the Namoi River, in northern New South Wales, +in 1901, and soon established a small zoological garden, in which +I kept a variety of marsupials and birds. While engaged in getting +water-weeds for my wild ducks, I met my first platypus, and confess +to having fallen in love at first sight. From this first meeting, the +idea of establishing a platypus amongst my pets never left my mind. +I wrote to the zoological authorities in Sydney, asking for advice +how to proceed with my plan, but received the discouraging reply that +the animal would not live in confinement, and that if I felt disposed +to experiment for myself, I should give a milk diet. Far from being +discouraged, I became the more determined to attempt this apparent +impossibility. Local people could give me no precise information as +to the food on which the platypus normally subsisted, until one day I +learned that one of the creatures had been caught upon a fishing-line +baited with a worm. Here was a ray of light on the food-question, and +I at once set about devising a suitable vivarium, in which to keep a +supply of worms. A kerosene-tin with small perforations in the bottom, +filled with alternate layers of grass-roots and earth, and topped off +with a layer of grass (which was renewed daily), served admirably. This +was hung in a shady place, and kept moist, and the worms throve in it. + +The first enclosure used (Plate 34, top figure) consisted of a +brick structure, roofed over, and floored with a thick layer of +river-earth--to represent the burrow--which was connected by a +submerged tunnel with a cemented pond, also fitted with a cover, the +top being made of wire-netting. The experiment was begun on 14 January, +1910, with a female which had been trapped in the river. Within a +short space of time two more females and two males were added. Here I +recorded the interesting fact that, when the males (which were caught +together in the same trap) were placed in the tank, they circled +round a few times, then entered the submerged tunnel and made their +way to the ‘burrow,’ where they were received with growls and muffled +snorts by the females, who evidently resented the intrusion. This was +the first occasion upon which I had heard an adult platypus utter a +vocal sound. To find a sufficient supply of food for five animals--two +more specimens were added later--was a difficult problem. I worked six +hours daily, with mattock and shrimping-net, and served my captives +with a mixed diet of earth-worms, freshwater shrimps, larvae of +scarab beetles, and pond-snails, supplemented by a certain amount of +water-weed, and fresh water daily. But my utmost endeavours succeeded +in producing only about two pounds of animal food a day; and this, +apparently, was not enough. One by one the animals died, until there +was left only the original female, ‘Biddy,’ with whom the experiment +had begun. This powerful animal escaped by tearing her way through the +wire-netting covering the tank, after having been in captivity for nine +weeks and five days. + +So ended the first attempt, but it pointed the way to success. The +most important discovery arising out of it was made during the period +of Biddy’s sole survivorship, when it was found that she could eat +quite comfortably the amount of food that had been thought sufficient +for herself and her four companions. It had not previously been +suspected that a platypus could eat half its own body-weight of food +in the course of a single night. The natural food, and the order of +its preference, had also been ascertained--shrimps, earth-worms, and +insect larvae, in that order; tadpoles in default of something better; +molluscs and water-weeds only very sparingly, even when the creature +was hungry. River fish she would not touch, even though shrimp-size and +served alive. + +Consideration was now given to the question of improving the enclosure. +In the first primitive structure the water was contained in a cemented +tank. Food had to be given alive in this tank; as the animal invariably +defaecates in the water, it rapidly became foul, and had to be changed +each morning. Running water being out of the question where the sole +supply consisted of rain-water caught in tanks, some better system +of pond had to be devised, which would allow of easier emptying and +renewal. + +The sleeping-compartment had not been opened during the time of the +first experiment. It was, as has been said, built with brick walls and +a cemented floor, and was filled with river-earth. When the cover was +removed, the interior was found to be in a foul and dank condition, +the water brought in by the animals on their bodies having converted +it into a bog, with a few mounds of damp soil projecting above the +general level. Obviously such a retreat could not have been healthy +for the captives. The next fault lay in the use of brick and cement, +which caused sores upon their knuckles. Finally it was noted that, as +long as the animals were able to see anything of their terrestrial +surroundings, they spent all their time trying to escape; and it was +resolved that wire-netting should be used only as top cover, in such a +way that clear sky alone could be seen through it. + +Coupled with a wish to improve the enclosure in these different +directions, I next considered the question of portability. The outcome +of my deliberations was the designing and construction of a portable +artificial habitat, which I called a Platypusary, and which Dr. W. +T. Hornaday, Director of the New York Zoological Park, subsequently +described as “the most amazing contraption that we have ever seen in +use in animal transportation.” + +The nature of the invention may be gathered from Plates 34 and 35. It +was planned, as in the first attempt, in two distinct parts--a tank +to represent a river, and a labyrinth to simulate the burrow in the +bank, the two being connected by a sheet-metal tunnel. The general +arrangement is best seen from above (the view shown in Plate 35). The +tank was to the left, the labyrinth to the right. Taking the latter +first, it will be seen that an animal coming from the tank through the +tunnel would enter the small chamber at the upper left-hand corner. +Here it would rid itself of some of the water from its body, and +possibly rest awhile and chew some of the food in peace and comfort. +It would then pass on through a series of holes cut in the partitions, +first passing through an aperture in the short longitudinal partition, +then through one at the right-hand end of the upper transverse +partition, and so on, the holes in the remaining partitions being +alternately left and right, until it reached the sleeping-chamber shown +at the lower right-hand corner. It will be seen that, altogether, it +must pass through six of these holes, each of which was guarded by +a soft rubber gasket with an aperture smaller than the body of the +animal, so that the wet fur was effectively ‘squeezed’ and the animal +arrived at its sleeping-quarters with fur almost dry. Not only was this +essential to its comfort, but it was necessary also to prevent, to some +extent, the observation glass above the burrows from becoming so moist +as to obscure the view when exhibiting the sleeping occupants. + +A second feature of the labyrinth was that the apertures through the +transverse partitions were placed progressively higher up, and the +floors of the runways sloped up accordingly, so that the platypus +had to climb a kind of zig-zag ramp on its way to bed. This was a +simulation of the natural rising course of its burrow in a river-bank; +and, though some critics suggested that it was over-elaborate, my +experience of the platypus in captivity is that no precaution can +be too elaborate (especially during a test case) for the successful +treatment of a creature so delicately organized. + +[Illustration: THE AUTHOR EXHIBITING A PLATYPUS IN AN EXPERIMENTAL +“PLATYPUSARY,” CONSTRUCTED IN 1910. + +_Plate 34_] + +The labyrinth was further improved by using curved mouldings in all the +corners, so that no right angles might remain, and by fastening sheet +rubber on the floors of the runways, to minimize injury to the animal’s +knuckles and feet. It was covered with a wooden lid, beneath which was +a framed sheet of plate-glass, permitting inspection of the burrow. + +The tank portion was of much larger size, and was constructed of +galvanized iron, set in a wooden crate, the sides of which were carried +up to such a height that animals in the water could see nothing but the +sky above them. To the right is the exercising and feeding-tank. This, +at the bottom, contained sand and shell-grit. Of course, mud would +have been preferable, but it would have tended to discolour the water, +and, without a continuous supply of fresh water, the animal would have +died. The metal drum in the middle, the flat top of which projects +three inches above the water, forms an island upon which the captive +may rest, but its special purpose is to give the animal an endless +swim. To the left is a smaller tank in which aquatic plants are grown +in mud. The space at each side of it was filled with clean sand to form +two banks, on which the animal could exercise by digging, or take a +rest, at will. A continuous stream of water could be run from the main +tank into the mud tank, which was kept at a constant though lower level +(to prevent pollution of the feeding-tank) by means of an overflow +pipe. The platypus is intolerant of water which is not clean--hence +the necessity for clean sand and flowing water, where these can be +provided. The doors covering the tank were made with wooden frames, +upon which wire-netting was stretched, so that the water was open to +the sky, day and night, in all weathers. + +[Illustration: PORTABLE “PLATYPUSARY” DESIGNED FOR TRAVELLING. + +Over-alls are occasionally very necessary during the trials of a +Platypus providore. + +_Plate 34_] + +By means of this enclosure I succeeded during 1910 in achieving my +aim of placing the platypus on exhibition in the Sydney Zoological +Gardens, then at Moore Park. One animal lived for three months in good +condition; but on the approach of winter it became difficult to secure +for it a supply of natural food, and it was released in one of the +ponds of the Centennial Park. Discouraged by what I considered to be a +lack of interest in my endeavours, I took no further measures for some +time, and my contraption was scrapped. + +In 1913, however, I interviewed Ellis Stanley Joseph, a well-known +animal-dealer, who became keenly interested in a scheme for taking a +live platypus to America. I at once recovered my discarded artificial +burrows, etc., from the scrap-heap, and set them up again for Joseph at +his Moore Park vivarium. Here I instructed him in the art of feeding +and caring generally for the appetites and other requirements of +captive platypus. Owing to his occasional absence, however, matters +proceeded but slowly. Later, at Granville, two more of these enclosures +were built for Joseph under my supervision. Subsequently a number of +animals were obtained and kept for various periods. Joseph, in the +New York Zoological Society _Bulletin_ for September 1922, gives the +following account of his experiences:-- + + “My first attempt to bring one to New York was in 1916, and I must + say that it was not a fair trial, either to the animal or to myself. + Mr. Burrell had secured one for me from the Namoi River, and it + arrived in Sydney one day before I sailed on the S.S. _Niagara_, one + of the Canadian-Australian liners. I kept it for exactly one week, + and then unfortunately it died. + + “On my return to Australia from the United States in February, 1917, + I was unable to give the matter much attention, as I was too busy + getting a collection together, and so deferred action until I had + made another trip to America. When I returned to Sydney on October + 27, 1917, I put all my energy into the keeping of the platypus alive + in captivity. I secured two, and kept one for 96 days and the other + for 125 days. Then I got several others from time to time and kept + them for varying periods, from one week to over one year. On August + 27, 1918, I secured one and kept him until April 26, 1919, on which + date the animal died. I honestly believe that the animal would have + lived longer had it been possible for me to give it my personal + attention, because for three weeks before its death I saw very little + of it. I was ill with the pneumonic influenza--raging at the time all + over the world--and had to depend on others to see to his keeping. + + “As soon as I was up, I secured several more specimens, and on one + occasion I had three females and one male quartered together. To + my sorrow I found that the male fought them and just worried them, + and in one instance there were several scratches on the bill of the + female which I am sure could not have been made except by the claws, + or possibly by the spur, of the male. The females ultimately were + afraid to go in their sleeping-box; for I put them in myself on + several occasions in the course of a day, and they would struggle + hard to get out. It seems to me that it was actual fear of the male. + + “On August 22, 1919, I secured a fine male measuring 23½ inches, and + during a period of nine months he was responsible for the death of + no less than two females and one male. In August, 1920, I approached + the authorities in Sydney for a permit to take this specimen to the + New York Zoological Society, but was refused. Keenly disappointed, I + left Sydney on September 3, 1920, on the S.S. _Bellbuckle_, bound for + New York, without my platypus. On October 15, 1920, while I was still + on the sea, the animal escaped from his tank because the lid had not + been properly secured. I certainly would have liked to have kept him + till he died, as it would have been very interesting to learn how + long he could have lived in captivity. + + “When I decided to go to the United States again, I felt that I + should bring a platypus along, as I knew the great desire of the + Zoological Park authorities in New York to obtain a specimen. At + first things looked black for securing a permit from the Federal + Government for the exportation.” + +Here follows an account of his difficulties, which were finally solved +through the good offices of the Federal member for Parramatta, Mr. E. +K. Bowden, and Sir Baldwin Spencer. Joseph continues:-- + + “Having secured the Federal permits, I made arrangements to get the + animals. I secured six, five of which were males. Unfortunately the + female died sixteen days after I received it. + + “I left Sydney with five male platypus on May 12, 1922, on the U.S.S. + _West Henshaw_ (Shipping Board Steamer), bound for San Francisco via + Newcastle, N.S.W., and Honolulu. On May 19, while we were still in + Newcastle, one of the medium-sized ones died. The remaining four were + absolutely in the best of health as far as I could make out, because + they were eating well; that being about the only sign by which I + could determine their condition. We left Newcastle on May 20, and + for six days it blew a regular gale. The seas were mountain-high, + and unfortunately the ship was more under water than over it, and + certainly that did the animals no good. On the night of May 25 a + huge sea came aboard, and rushing along the deck smashed into one of + the platypus-tanks, bent the metal neck and jammed it so effectively + that the animals were imprisoned in the sleeping-quarters for that + night. From then on that pair ate less and less, but they lived till + the 5th and 6th of June respectively, on which dates they died in a + comparatively poor condition. + + “Of the remaining two, one was fine and healthy but the second was + just about medium, and I am sorry to state that on the 14th of June + while the ship was at Honolulu, it also died. My feelings can readily + be imagined. I would rather have lost all of my shipment of a very + valuable cargo of birds, animals, and reptiles. This was not because + the platypus was worth more (far from it), but because it was my + ambition to bring one alive to America. I am glad to say that good + fortune eventually favoured me, since on June 30, 1922, I landed in + San Francisco with the first living platypus ever brought to America. + + “I had to stay five days in San Francisco in order to procure a + new supply of fresh worms, and this I can assure the reader was + not an easy matter. From Honolulu I had sent two wireless messages + to different parties to try and get some for me, but to my great + disappointment I found on my arrival in San Francisco that neither + of them had been able to get any. After a lot of work, worry, and + expense I managed to secure sufficient for the trip across the + continent to New York. That trip was the hardest part of the long + journey, for the shaking and the jolting of the train was a very + great strain on the animal. When two days out from San Francisco, the + platypus began to get hungry, for he used to get out whenever the + train stopped and look for food, and so I was up day and night, and + whenever the train stopped for any length of time I put water in the + tank and also food, and that gave the animal a chance to eat a little. + + “I was glad when we arrived in Chicago, where I rested for two + nights, and that gave the animal a fresh start. I started on the last + lap on Tuesday night and on Thursday, July 14, arrived in New York, + both man and animal completely tired out.” + +What Dr. Hornaday thought about the matter finds expression in his +article in the same number of the Society’s _Bulletin_, some paragraphs +from which are here quoted:-- + + “The spell of ten thousand years has been broken. + + “The most wonderful of all living mammals has been carried alive + from the insular confines of its far-too-distant native land, and + introduced abroad. Through a combination of favoring circumstances + it has been the good fortune of New York to give hospitality and + appreciation to the first platypus that ever left Australia and + landed alive on a foreign shore.... + + “No matter what evil fate may hereafter overtake the platypus + species, nothing can rob us of the fact that New York has looked + upon a living _Ornithorhynchus paradoxus_, and found it mighty + interesting. It cost us $1400, but it was worth it. + + “When our first platypus arrived at the Zoological Park on July 14, + 1922, after a journey (of 10,000 miles) that had consumed the lives + of four companions, we felt reasonably certain that when fairly out + from under the excitement of foreign travel the queer little beast + would die in a very few days. We hoped that it might live for one + week, but we resigned ourselves to the impending loss. It lived at + the Park forty-nine days, and was on exhibition daily for one hour. + + “At the outset we observed that the platypus is an animal of nervous + temperament, and easily excited by too many observing eyes. It + was evident that one hour of daily exhibition was all that the + little animal could endure, and subsequent observations proved the + correctness of this estimate. We are sure that a longer exhibition + period would speedily have proven fatal to the distinguished + stranger.... + + “The exhibition of the platypus was accomplished by removing the + wire-netting tops of the contraption, admitting visitors in a line, + in single file, and permitting them to pass entirely around the + man-made habitat of the animal. As the stream of visitors marched and + countermarched, the platypus briskly swam and emerged, scrambled, and + climbed up the wire-netting walls of its main salon in efforts to get + out.... + + “The two features of a living platypus that make the daily life + of its keeper a nightmare and a burden are its food habits and its + water habits. In this vale of tears there seem to be just about five + kinds of food that it will consider and consume. Named in the order + of their acceptability these are: angle worms, very small shrimps, + wood-grubs (of the kind most difficult to find!), oysters, and water + insects. Of any one of the three leading kinds the animal soon tires, + and requires a change. The cost of digging angleworms, even if it is + possible to preserve them, is quite serious; and wood-grubs cost us + ten cents each, with few purveyors. + + “While it lived, our little platypus--about half grown--cost us + between $4 and $5 per day to feed. Even in summer the food problem + kept us moving, but we looked forward with apprehension to the + horrors of winter. + + “One trouble lies in the voracious appetite of a healthy platypus.... + One day’s ration of our specimen was as follows: + + “August 6; ½ lb. earthworms, 40 shrimps, and 40 grubs. + + “One week’s food supply for the platypus consisted of the following: + + “Each day, between three and four o’clock, the animal was given + one-quarter of a pound of earthworms. On Tuesday nights and Friday + nights one-quarter of a pound of shrimps and one-half pound of grubs + were given. On the evenings of Monday, Wednesday, Thursday, Saturday + and Sunday he received one-half pound of shrimps each day.... + + “Really, it seems incredible that an animal so small could chamber + a food supply so large. I know of nothing equal to it among other + mammals.” + +During an experiment which I made in September 1910 to test the +appetite of an adult platypus, I found that in the space of 72 hours +it ate 70 ten-inch red worms (resembling an ordinary lead pencil in +both length and girth), 10 ground-grubs, and 600 salt-water prawns (of +the size usually bought in packets as bait). The record for one night +was:--red worms, 30; prawns, 300. + +Hornaday remarks on the fact that the creature showed itself, in +captivity, to be of nervous and active temperament, a fact that must +strike any observer who has had to do with it. That is why I would not +allow my captives to observe any surroundings other than those within +their enclosure. Because of this, I claim to have practically solved +the problem of keeping platypus in captivity. By comparison the echidna +is a dull animal, unless taken young and trained systematically for +exhibition purposes. It does not pretend to be a gourmet, and thrives +quite well on raw egg-and-milk, a diet utterly different from that to +which it is accustomed when at large. True, it uses its very remarkable +bodily strength to explore all possible ways of escape; but, once +having found the task hopeless, it becomes resigned. It does seem to +show an intermediate mentality, as much reptilian as mammalian, despite +the fact that its brain has a convoluted surface, while that of the +platypus is smooth. The natural food of the platypus resembles that of +a bird, rather than that of a mammal. It demands a varied diet, and +will starve to death in the presence of food which no longer pleases +it. It must have clean, clear water, and sweet, dry sleeping-quarters. +It is impatient of observation, and resents being handled. It is +easily killed by too much excitement. These things bear witness to an +organization of a higher grade than that of many of the lower Didelphia +and Monodelphia, despite its Ornithodelphian plan. + +This being so, is it possible to exhibit the animal satisfactorily in +a Zoological Garden? I believe so, provided that the lessons to be +learned from experience up to the present are fully realized. Young +animals (not necessarily nestlings) which have never tasted the true +delights of wild life, will pretty certainly take more kindly to +confinement than adults. The questions of food and transport may be +looked upon as solved. The method of exhibition, however, could be +greatly improved. It is remarkable that the New York animal should have +lived for so long as seven weeks, when for an hour each day it was +surrounded by a continuous stream of curious visitors, and underwent +constant handling by the keeper. Think of it! + +What I suggest, apart from improved burrows, is a raised tank, with +a plate-glass front. The eyes of the platypus are kept closed under +water, and it would never see people standing below the water-level +of its tank. It would thus be saved the greater part of the fret and +excitement of the exhibition period. The animal would soon become +accustomed to a regular feeding-time in the afternoon, and would not +need the intervention of a keeper to turn it out into the exhibition +tank. Given these conditions, there seems to be no reason whatever why +the platypus should not live in Zoological Gardens at least so long on +the average as other animals which are commonly kept in such places. +Unfortunately, many of these do not survive so long as one might expect. + +[Illustration: INTERIOR OF PORTABLE “PLATYPUSARY” TURNED ON ITS SIDE IN +ORDER TO PRESENT A BIRD’S-EYE VIEW. + +(_This negative is owned by the New York Zoological Society_) + +_Plate 35_] + + + + +BIBLIOGRAPHY + + + ALLPORT, MORTON. Notes on the Platypus (_Ornithorhynchus anatinus_): + _Report of the Royal Society of Tasmania_, 1878, pp. 30-31. + + _Annales des Sciences Naturelles_, ii, 1824, pp. 74-77--Quelques + Observations nouvelles sur l’Ornithorhynque; x, 1827, pp. + 193-195--Sur les Habitudes de l’Ornithorhynque. See also references + to articles by Lesson, 1825, and Etienne Geoffroy, 1826 and 1829. + + _Antologia di Firenze_, xxiv, p. 305, quoted in _Annales des Sciences + Naturelles_, x, 1827, p. 194. + + ARMIT, WM. E. Notes on the Presence of _Tachyglossus_ and + _Ornithorhynchus_ in Northern and North-eastern Queensland: _Journal + of the Linnean Society of London_ (Zoology), xiv, 1878, pp. 411-413. + + AXFORD, T. Notice regarding the _Ornithorhynchus_: _Edinburgh New + Philosophical Journal_, vi, 1829, pp. 399-400; _id._ Oken, _Isis_, + viii, 1832, col. 806. + + BADEN-POWELL, G. S. _New Homes for the Old Country_, 1872, pp. + 296-314, 3 figures. + + BENNETT, GEORGE. _Gatherings of a Naturalist in Australasia_, 1860, + pp. 94-146, 1 plate; Notes on the Natural History and Habits of the + _Ornithorhynchus paradoxus_ Blum.: _Transactions of the Zoological + Society of London_, i, 1835, pp. 229-258, plate 34. + + BENNETT, GEORGE FREDERICK. 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OWEN. _The Glandular System in Monotremes + and Marsupials_, 1919, pp. 11-35, 12 figures. + + MARTIN, C. J., and F. TIDSWELL. Observations on the Femoral Gland + of Ornithorhynchus and its Secretion; together with an experimental + enquiry concerning its supposed toxic action: _Proceedings of the + Linnean Society of New South Wales_, (2), ix, 1894, pp. 471-500, 4 + plates. + + MAULE, LAUDERDALE. [Habits and Economy of the _Ornithorhynchus_]: + _Proceedings of the Zoological Society of London_, 1832, pp. 145-6; + id., _Philosophical Transactions of the Royal Society_, 1832, pp. + 533-4. + + MECKEL, J. F. Ueber den Stachel und das Giftorgan des + Ornithorhynchus: _Deutsches Archiv für die Physiologie_, viii, 1823, + pp. 592-595; _Ornithorhynchi paradoxi descriptio anatomica_, Lipsiae, + 1826. + + OWEN, RICHARD. On the Mammary Glands of the _Ornithorhynchus + paradoxus_: _Philosophical Transactions of the Royal Society + of London_, 1832, pp. 517-534; On the Ova of _Ornithorhynchus + paradoxus_: _Philosophical Transactions of the Royal Society + of London_, 1834, pp. 555-566, 1 plate; On the Young of the + _Ornithorhynchus paradoxus_ Blum.: _Proceedings of the Zoological + Society of London_, 1834, pp. 43-44; id., _Transactions of the + Zoological Society of London_, i, 1835, pp. 221-228, 2 plates; + Monotremata: _Todd’s Cyclopaedia of Anatomy and Physiology_, iii, + 1839-47, pp. 366-407, 6 figures; Remarks on the ‘Observations sur + l’Ornithorhynque’ par M. Jules Verreaux: _Annals and Magazine of + Natural History_. (2), ii, 1848, pp 317-322; On the Marsupial + Pouches. Mammary Glands, and Mammary Foetus in the _Echidna hystrix_: + _Philosophical Transactions of the Royal Society of London_, clv, + 1865, pp. 671-686, 3 plates and 1 figure. + + PARKER, W. K. _On Mammalian Descent_: the Hunterian Lectures for 1884. + + PERON, F., and L. FREYCINET. _Voyage de Découvertes aux Terres + Australes_, Atlas, Paris, 1807, plate xxxiv. + + POULTON, EDWARD B. The Tongue of _Ornithorhynchus paradoxus_: the + Origin of Taste Bulbs and the parts upon which they occur. _Quarterly + Journal of Microscopical Science_, new series, xxiii, 1883, pp. + 453-472, 1 plate. + + SEMON, R. _Zoologische Forschungsreisen in Australien und dem + Malayischen Archipel_, ii-iii, 1894-1908; _In the Australian Bush_, + 1899, p. 164. + + SHAW, GEORGE. The Duck-Billed Platypus: _The Naturalists’ + Miscellany_, x, 1799, plate 385; _General Zoology_, i, 1800, pp. + 228-232. + + SMITH, GEOFFREY. _A Naturalist in Tasmania_, 1909, pp. 124-126. + + SPICER, W. W. On the Effects of Wounds on the Human Subject inflicted + by the Spurs of the Platypus (_Ornithorhynchus anatinus_): _Papers + and Proceedings and Report of the Royal Society of Tasmania_, 1876, + pp. 162-167. + + STUART, T. P. ANDERSON. Poison of the Platypus: _Journal of the Royal + Society of New South Wales_, xxviii, 1894, pp. 5-9. + + SUTHERLAND, ALEXANDER. Temperatures of Reptiles, Monotremes and + Marsupials: _Proceedings of the Royal Society of Victoria_, new + series, ix, 1897, pp. 57-67, 1 plate. + + _Sydney Gazette_, December 4, 1823. + + THOMAS, OLDFIELD. _Catalogue of the Marsupialia and Monotremata in + the Collection of the British Museum_ (_Natural History_), 1888, pp. + 373-391. + + TIEDEMANN, F., _Zoologie_, i, Landshut und Heidelberg, 1808, p. 589. + + TRAILL, T. S. On the Spurs of the Ornithorhynchus: _Edinburgh + Philosophical Journal_, vi, 1821-2, p. 184. + + VERREAUX, JULES. Observations sur l’Ornithorhynque: _Revue + Zoologique_, xi, 1848, pp. 127-134. + + WAITE, EDGAR R. The Range of the Platypus: _Proceedings of the + Linnean Society of New South Wales_, xxi, 1896, pp. 500-502. + + WATERHOUSE, G. R. _A Natural History of the Mammalia_, i, 1846, pp. + 24-39, 1 plate and 4 figures. + + WIEDEMANN, C. R. W. Nachricht von einem äusserst sonderbaren, + neuentdeckten Säugethiere, _Platypus anatinus_: _Wiedemann, Archiv + für Zoologie und Zootomie_, i, 1800, pp. 175-180. + + WILSON, J. T., and J. P. HILL. Observations on the Development of + _Ornithorhynchus_: _Philosophical Transactions of the Royal Society + of London_, Series B, vol. 199, 1908, pp. 31-168, 17 plates, 15 + text-figures. + + +FOOTNOTES: + +[1] In this book the words muzzle, snout, bill, and beak are used +synonymously, when the upper and lower mandibles combined are referred +to. The pliable tissue extending beyond the jawbones is always referred +to as the lips. + +[2] That is, segmenting eggs from the uterus. + +[3] For details, see page 208. + +[4] The spurs are not for laying hold of the body, but, if at all, of +the hind legs, ankles, or feet, of the female. + +[5] With this statement I agree. See page 96. + +[6] I have never succeeded in passing a fine horse-hair through, even +after extracting the inner tube (see Plate 14). + +[7] The Australian Philosophical Society. + +[8] I have found both males and females in this state. The denudation +is the result of moulting, and has nothing to do with the use of the +spur. + +[9] Platypus are frequently seen during daylight, and can easily be +taken by hand beneath water, even though it may be necessary to jump +into the water to do so. + +[10] I find that the scent-gland enlarges and diminishes in unison with +the other glands described here. This strengthens the statement that +the poison gland is subject to seasonal variations. + +[11] See page 157. + +[12] With the theory that the discharge is for the purpose of dilating +the socket I entirely disagree. + +[13] I have never known an entrance to be blocked up, and I have +examined over 150 breeding-burrows, all of which were glaringly open to +view. + +[14] See description of breeding habits in chapter xi. + +[15] Since this was written Mr. H. R. Carne reports the capture of a +platypus in George’s River at Glenfield. + +[16] In a few species of viviparous lizards, e.g., _Tiliqua_, a +primitive placental apparatus is found. + +[17] Trappers are not likely to report otherwise. + +[18] During the breeding-season, to which my experience is limited, the +smell is only occasionally noticeable on living specimens; but it is +always found in the process of skinning. + + + + +INDEX + + + Activity, 164 + + Adolescence, 188 + + Affection of pairs, 165 + + Air in burrows, 137 + + Albino, 48 + + Allport, Morton, 152, 153, 154 + + America, living platypus landed, 214 + + Amphibia, 26, 28 + + Anteater. _See_ ECHIDNA + + Aquatic adaptations, 9 + + Armit, W. E., 139 + + Aves, 28 + + Axford, Thomas, 80, 90 + + + Baden-Powell, G. S., 90 + + Banks, Sir Joseph, 1, 5, 6, 20, 22, 23, 26 + + Barrington’s _History of New South Wales_, 25 + + Beak. _See_ MUZZLE + + Beaver, comparison with, 54, 112, 132 + + Bennett, George, 4, 5, 32, 39, 54, 56, 65, 66, 67, 68, 81, 98, 100, + 106, 111, 112, 125, 147, 154, 155, 160, 179, 189, 191, 200, 204 + + Bennett, G. F., 4, 113, 129, 179 + + Bill. _See_ MUZZLE + + Birds, organs of reproduction, 28 + + Birds, resemblance to, 28 + + Blainville, Henri D. de, 3, 30, 32, 33, 77 + + Blood, 56 + + Blumenbach, J. F., 1, 6, 7, 22, 26, 33 + + Body. _See_ TRUNK + + Boyd, G., 140 + + Brain, 15, 63, 217 + + Breathing, 124 + + Breeding habits, 167 + + Breeding-season, 171 + + Brisbane, Sir Thomas, 79 + + Broderip, W. J., 5, 39 + + Bruta, 26 + + Buffon, Comte de, 26 + + Burrow, blocking with earth, 116, 117, 122, 129 + + Burrow, descriptions of, 105 + + Burrow, entrance, 107, 111, 114, 115, 117, 124, 134, 135 + + Burrow, length of, 106, 108, 110, 113, 114, 116, 117, 124, 127, 134, + 135 + + Burrow, smell of, 163 + + Burrow, ventilation of, 137 + + Burrowing, method of, 112, 120 + + + Caldwell. W. H., 3, 5, 45, 113, 119, 177, 182 + + Captivity, 202 + + Carpenter, W. B., 41 + + Caruncle, 183, 185 + + Casy, Dr., 111 + + Characters described, 46 + + Cheek-pouches, 13, 73, 150, 154 + + Chenu, J. C., 6, 7, 203 + + Chisholm, A. H., 139 + + Claws, 12, 52, 120, 122 + + Cleanliness, 161 + + Cloaca, 2, 28, 29, 58 + + Cold, effect on distribution, 146 + + Collins, David, description of platypus, 17 + + Colour, 47, 187 + + Contorting ability, 61 + + Cookoogong (aboriginal), 78, 105, 106 + + Copulation, 61, 76, 91, 99, 104, 168 + + Crowther, A. B., 44, 151, 154, 155, 156 + + Crural gland, 76, 167 + + Crustacea as food, 155 + + Cuvier, G., 30, 32, 33 + + + Darwin, C., 28, 151 + + Daytime habits, 149 + + _Dermipus_, 7, 22 + + Didelphia, 2 + + Digging, 12 + + Digits, 12, 52 + + Distribution, 139 + + Diving, 147, 150, 152, 156, 157 + + Dobson, Mr., 17, 20 + + Drowning, 137, 150, 159 + + “Duck-bill” first used, 23 + + Duck-like bill. _See_ MUZZLE + + + Ears, 10, 12, 50, 124 + + Echidna, 6, 15, 27, 29, 30, 45, 57, 58, 59, 99, 133, 149, 161, 187 + + Economic value of platypus, 199 + + Edentata, 26 + + Edwards, Milne, 35 + + Eggs, controversy _re_, 2, 29, 32, 33 + + Eggs, description of, 173 + + Eggs found by Caldwell, 3, 45; + Kershaw, 117; + Semon, 119 + + Eggs, laid, 179 + + Egg-laying, 175 + + Egg-tooth, 183, 185 + + Enemies, 197 + + Evolution, pre-Darwinian ideas, 28 + + External features, 9 + + Eyes, 10, 46, 50, 65, 124 + + + Facial furrow, 10 + + Faeces, 188 + + Feeding habits, 10, 149, 151, 152, 153 + + Feet (hind), 12 + + Female affection for offspring, 165 + + Female, excavation of nesting-burrow, 125, 128, 163 + + Fish-trap, effect of, 198 + + Flap at base of muzzle, 14, 49, 68 + + Fleming, J., 34 + + Flesh, 200 + + Fletcher, J. J., 5 + + Floating, 155, 158 + + Floods, effect on distribution, 143, 145 + + Food, 13, 14, 73, 154, 208, 216 + + Food supply, effect on distribution, 145 + + Fore-paws, 12, 52, 120, 122, 151, 156, 157, 158, 160 + + French scientific expeditions, 25 + + Fur. _See_ HAIR + + Furrier’s point of view, 199 + + + Generation; ovi-viviparous, 27, 33, 38, 40, 41 + + Geoffroy St.-Hilaire, Etienne, 3, 4, 29, 30, 32, 34, 35, 36, 38, 184 + + Geoffroy St.-Hilaire, Isidore, 30, 31, 79 + + Gould, John, 112, 195 + + Graafian follicle, 34 + + Grant, Robert E., 36 + + Growling. _See_ VOICE + + + Haacke, W., 45 + + Habitat, first described, 24 + + Habitats, 139 + + Habits, 5, 147 + + Hair, 9, 47, 49, 155 + + Hatching of eggs, 182 + + Head, 46 + + Hearing, 67, 72, 150 + + Heat, effect on distribution, 146 + + Hibernation, 148, 164 + + Hill, Patrick, 3, 4, 34, 35, 78, 105 + + Hill, William, 144 + + Hind feet, 53, 122, 123, 160 + + Holmes, Mr., 37 + + Home, Sir Everard, 1, 2, 3, 6, 22, 23, 25, 26, 27, 28, 29, 33, 36, + 37, 76, 78, 97, 98, 100, 170 + + Hornaday, W. T., 70, 209, 215 + + Hoy, C. M., 74, 93, 134, 157, 165 + + Hunter, Governor, 1, 17, 20, 21, 24 + + + Illiger, C., 30 + + Incubation, 181 + + Insect larvae as food, 155 + + _Ixodes ornithorhynchi_, 162 + + + Jamison, Sir John, 2, 3, 34, 35, 77, 79, 91, 103, 105, 201 + + Jawbones, 10 + + Jaws, 13 + + Jones, F. Wood, 52, 54, 55, 63, 65, 102, 132, 133, 154 + + Joseph, E. S., 211 + + + Kershaw, J. A., 4, 114, 125, 129, 136, 141, 172, 179, 181, 184 + + King, Governor, 22, 23, 26 + + Knox, R., 1, 3, 78, 79, 91, 98 + + Krefft, G., 81, 141 + + + Lalor, Dr., 85 + + Lamarck, J. B., 30 + + Latreille, P. A., 30 + + Leadbeater, Mr., 36, 37 + + Learmonth, N., 141 + + Lendenfeld, R. von, 57 + + Lesson, P., 3, 36, 106 + + Life history, 5, 167 + + Limbs, 12, 52 + + Lips, 9, 10, 68, 120, 123 + + Longevity, 192 + + Longman, H. A., 139, 140 + + Lord, C., 141 + + Lucas and Le Souef, 114, 193 + + + McCoy, Professor F., 44 + + Mackenzie, W. C., and W. J. Owen, 99, 163 + + Maclean, J., 171 + + Male, pugnacity of, 92, 93, 95, 96, 157, 165, 166 + + Mammalia, 27, 28, 30, 31 + + Mammalian relationship, 2, 32 + + Mammals, early forms of, 7 + + Mammary glands, 4, 29, 30, 31, 184, 187 + + Man, 7, 8 + + Mandibles, 9, 16, 18, 68 + + Marsupials, 29, 30 + + Martin, C. J., 57 + + Martin, C. J., and F. Tidswell, 4, 84, 91, 98, 103 + + Mastication, 13 + + Maturity, 191 + + Maule, Lauderdale, 4, 32, 39, 106, 179, 203 + + Measurements, 55 + + Meckel, J. F., 3, 29, 30, 31, 32, 34, 79 + + Mesozoic mammals, 7, 8 + + Miklouho-Maklay, N. N., 57 + + Milk, 29, 32, 190 + + Molluscs as food, 154 + + Monodelphia, 2, 57, 63 + + Monotremata, 8, 29 + + Mouth, 12 + + Mud as food, 10, 73, 155 + + Mueller, Dr. F. von, 42 + + Murray cod, 142 + + Muzzle, 9, 10, 21, 27, 46, 49, 68 + + _Myrmecophaga aculeata_, 27 + + + Neck, 52 + + Nervous organization, 63 + + Nervous temperament, 165 + + Nest, 108, 111, 112, 113, 116, 117, 127, 128, 131, 134, 136, 181, 188 + + Nesting-burrow, 105 + + Nesting habits, 4 + + Nestlings, 110 + + Newcastle Literary and Philosophical Society, 21 + + New South Wales habitats, 140 + + New York Zoological Gardens, exhibition of platypus, 215 + + Nicholson, Dr. John, letter to Sir R. Owen, 41 + + Nicols, A., 85, 90 + + Nipples, absence of, 2, 27, 30 + + Nostrils, 49 + + Nursing habits, 183 + + Nursing period, 151, 186 + + + Odour of burrows, 163 + + Oken, L., 33 + + _Oligorus macquariensis_ (Murray cod), 142 + + Opossum, 27 + + Ornithodelphia, 2, 30 + + _Ornithorhynchus_, generic characters described by Home, 27 + + _Ornithorhynchus anatinus_ Shaw, 1 + + _Ornithorhynchus hystrix_, 27 + + _Ornithorhynchus paradoxus_, 1, 6, 7, 22 + + Ovaries of birds, reptiles and mammals compared, 28-9 + + Oviducts, 2, 28, 29 + + Ovi-viviparous mode of generation, 27, 33, 38, 40, 41 + + Ovum. _See_ EGGS + + Owen, Sir R., 3, 5, 38, 39, 41, 44, 98, 99, 183 + + + _Panniculus carnosus_, 31, 164 + + Parasites, 62, 162 + + Parker, W. K., 5, 8, 75 + + Parmeter, Dr. T., 79 + + Penis, 27 + + Placenta, 29 + + _Platypus anatinus_, 1, 6, 7, 17, 20 + + Platypus described by David Collins, 16; + by George Shaw, 17; + by Bewick, 21; + by Hunter, 23; + by Home, 27 + + Poison, effects of, 82, 83, 85, 94, 96 + + Poulton, E. B., 5, 69 + + Preservation, 193 + + Protection, 193 + + Prototheria, 30 + + Psychological characteristics, 14 + + “Pugs” and “pug-pits,” 129, 130, 133 + + + Queensland habitats, 139 + + + Rabbits, effect on platypus, 197 + + Ramsay, J. S. P., 177 + + Rawley, Mr., 4, 105, 106 + + Rectum, 27 + + Reproduction, method of, 3 + + Reproduction, organs of, 26, 28 + + Reptantia, 30 + + Reptiles, organs of reproduction, 28 + + Reptile relationship, 6, 59, 63 + + Reptilia, 26 + + Resting-burrow, 162 + + Rumby, G. J., letter to Dr. Mueller, 42, 177 + + Running, 159 + + + Scent-gland, 30, 67, 90, 163, 167 + + Scott, Mr., 34 + + Selkirk, H., 24 + + Semon. R., 57, 66, 67, 99, 100, 114, 119, 145, 148, 151, 153, 155, + 158, 160, 191, 195, 201 + + Senses. _See_ HEARING, SIGHT, SMELL, TASTE, TOUCH; + also “SIXTH SENSE” + + Sensory perceptions, 63 + + Septum, 29 + + Sexes, external differences, 55 + + Shaw, George, 1, 3, 6, 17, 26, 76 + + Shell-fish as food, 154 + + Shrew, 30 + + Shrimps as food, 154, 155 + + Sight, 65, 72, 150 + + Simson, A., 81 + + “Sixth sense,” 10, 70, 72 + + Sizes of specimens, 55 + + Skeleton, 11 + + Skin, 46, 160, 164, 195 + + Sleep, 162 + + Smell of burrows, 163 + + Smell, sense of, 67, 72 + + Smith, Geoffrey, 66, 158 + + Smith, Southwood, 35 + + Snout. _See_ MUZZLE + + Socket (female) in place of spur, 54 + + Solitary nature, 55, 163 + + South Australian habitats, 141 + + Spicer, W. W., 81, 90, 91, 193 + + Spiny anteater. _See_ ECHIDNA + + Spur, 3, 27, 54, 76, 170 + + Stomach contents, 154 + + Stranger, C. R., 140 + + Strength, 59 + + Stuart, Sir Anderson, 82 + + Sutherland, Alexander, 57 + + Swan, E. D., 44 + + Sweat-glands, 31 + + Swimming, 9, 66, 151, 156, 157, 158 + + + Tail, 9, 46, 54, 112, 120, 132 + + Tasmanian habitats, 141 + + Taste, sense of, 69, 74 + + Teat, mammalian, 29 + + Teats, absence of, 27, 30, 31 + + Teeth, 12, 27 + + Temperature, 56 + + Testes, 89, 167 + + Thomas, Oldfield, 20, 47, 69 + + Tiedemann, F., 30 + + Timidity, 147 + + Toilet habits, 159, 162 + + Tongue, 12, 27, 69, 155 + + Toothless mammals, 26 + + Touch, sense of, 10, 50, 68, 74 + + Traill, T. S., 3, 77 + + Trapping, effect of, 197 + + Trunk, 46, 52 + + Turtle, green, 61 + + Type skin, 20 + + + Urine, 27 + + Uterus, 2, 27, 29 + + + Van der Hoeven, J., 30, 79 + + Verreaux, J., 6, 32, 41, 68, 81, 91, 111, 112, 130, 168, 190, 203 + + Victorian habitats, 141 + + Vitality of young platypus, 137, 138 + + Voice, 75, 110 + + + Waite, E. R., 139, 141 + + Walking, 158 + + Wardlaw, Dr., 57, 58 + + Water, instinct for finding, 143 + + “Water-mole” first used, 23 + + Water-rat, effect on platypus, 197 + + Weatherhead, Dr., 39 + + Webbing of feet, 9, 12, 52, 53, 151, 156, 157, 158, 161 + + White, H. L., 198 + + Wiedemann, C. R. W., 7, 22 + + Wilson, J. T., 5, 183 + + Wilson, J. T., and J. P. Hill, 5, 118, 119, 174, 177, 193 + + Womb. _See_ UTERUS + + Worms as food, 155 + + + Yarrell, W., 37 + + + Zoological position, 26 + + +Eagle Press Ltd., Allen St., Waterloo + + +Transcriber’s Notes. + +Italic text is indicated with _underscores_, bold text with =equals=. +Small/mixed capitals have been replaced with ALL CAPITALS. + +Evident typographical and punctuation errors have been corrected +silently. Inconsistent spelling/hyphenation has been normalised. + +Half-titles and reiterations of chapter titles have been discarded. + +End of page footnotes have been sequentially numbered and relocated to +the end of the text. + +Chapter numbers have been added to the Table of Contents. + +On page 179, a reference to “Mawle” has been changed to “Maule” + +On page 220, the entry for “Learmouth” has been change to “Learmonth” + +The text in the list of illustrations for page 186 has been changed +from “Female Platypus” to “Brooding Female” to match the caption. + +Illustrations have been moved between paragraphs/chapters to improve +text flow. + +The List of Illustrations has been expanded where necessary to allow +links to images with the same page number. + +New original cover art included with this eBook is granted to the +public domain. + + +*** END OF THE PROJECT GUTENBERG EBOOK 78386 *** |