The paradoxical platypus

Abstract

The paradoxical platypus T he story of the discovery of the platypus (Figure 1) teaches us much that is relevant to the nature of scientific evidence, ortho-doxy, entrenched authority, the role of personalities in science, the slow overthrow of old mores, national rivalries, prejudices and priorities, the strictures of animal classification , what it takes to be described as a mammal, conservation, and extinction. A rivalry that pitted nation against nation, naturalist against naturalist, and professional against amateur endured for 85 years before the true nature of the platypus was revealed. Long after the evidence was wrested from Nature half a world away from where the debate raged, professional biologists continued to argue about this paradoxical creature. How did such a situation arise? Discovery and description Platypuses-duckbills, watermoles, or duckmoles, as the European settlers of New South Wales called them-are found only in Australian freshwater lakes and streams. David Collins, who arrived with the First Fleet as Deputy Judge-Advocate, provided an early description in the second edition of An Account of the English Colony in New South Wales: The Kangaroo, the Dog, the Opos-sum, the Flying Squirrel, 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 has 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-by Brian K. Hall 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 [mammal], 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 have been frequently noticed rising to the surface of the water, and blowing like the turtle. (Collins 1802, p. 62) Captain John Hunter, the second governor of the new colony, watched an Aborigine spear a platypus in Yarramundi Lagoon near the Hawkesbury River just north of Sydney in 1797. The Aborigine sat patiently at water's edge for more than an hour, observing the animal as it came to the surface to breathe, before he attempted to spear it with his short wooden spear. Hunter's fine drawing of this animal accompanied Collins's description of this "amphibious animal, of the mole spe-cies" (Figure 2). A keen naturalist and fellow of the Royal Society, Hunter supplied many animals and plants to naturalists in England. Many saw his sketch and read Collins' description before specimens became available. The incomparable English wood engraver, Thomas Bewick, published another early representation in 1800 in his justly renowned A General History of Quadrupeds (Bewick 1800; Figure 3). The platypus was given its scientific name, Platypus anatinus (flat-foot duck), in 1799 by George Shaw, a parson turned Keeper of the Department of Natural History of the Modern Curiosities of the British Museum. His description of the platy-pus was based on a single skin and accompanying sketch sent by Hunter to the Literary and Philosophical Society in Newcastle-upon-Tyne in 1798. The skin of this original (type) specimen is still preserved in the British Museum. Shaw's description (Shaw 1799) was published in the tenth volume of an important natural history journal of the time, Naturalist's Miscellany or , to give it its full, descriptive title: The Naturalist's Miscellany: or Coloured Figures of Natural Objects Drawn and Described Immediately from Nature-produced by Shaw and the illustra-tor Frederick P. Nodder as an outlet for all manner of discoveries from the natural world. Over 1000 different animals were illustrated in its pages between 1798 and 1882, including the kangaroo, black swan, and echidna from the Great South Land, now known as Australia. Shaw's description was remarkably accurate, based as it was on a dried skin with a desiccated and hardened "bill" so unlike the soft, flexible bill of the living animal. Although he thought it was a mammal, its exotic, even bizarre appearance mystified Shaw: 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 de-March 1999 211 University of California Press is collaborating with JSTOR to digitize, preserve, and extend access to BioScience