| Issue 59 Contents |
International Scientific Controversy: THE TAXONOMY OF THE PLATYPUS
The curious creature that baffled the world
From the moment the first preserved specimen of a platypus reached England in 1799 it was a 9- day wonder. Was this a colonial hoax? A creature with webbed feet and the bill of a duck attached to the body of a quadruped? Astonished naturalists pondered an animal that confounded all their views of taxonomic classification. Warm-blooded, furred, but with bird-like and reptilian features and structures, it was clearly unique. The single chamber for its reproductive and excretionary function (dubbed a ‘one-holer’ Down Under) challenged all established taxonomic boundaries.
Early expeditions of
scientific survey and discovery to Australia in the first 3 years of the new
century the French under Baudin and the British under Matthew Flinders
brought back elegant and delicately accurate depictions of the platypus drawn
by Charles Lesueur and Ferdinand Bauer, although these were not sighted by
scientists or the public for more than 150 years. Dried specimens arriving in
England were dissected and analysed. Joseph Banks, with his large networks,
got into the act. Dissent broke out between leading zoologists and comparative
anatomists in Britain and Europe. Ever since the ingenious Aristotle made the
first scientific classification of animals in 334 BC, their reproductive
organs were regarded by systematists as increasingly important in arranging
animals into related groups, classes and genera. Mammals in general gave birth
to live young, and were viviparous; reptiles and sharks hatched their young
from eggs inside their body and were ovoviviparous; while creatures that laid
eggs, like birds, were oviparous. Where, with its bizarre configuration, did
this extraordinary new arrival from the Antipodes fit?
From 1800 until the mid-1830s, scientists wrangled across the Channel. Was the platypus a mammal? Did it suckle its young? Where were its mammary glands? What implications did it have for their ideas of a Universe of Design and the Chain of Being? Nationally competitive, the great biologists tried to shoehorn the little creature into their differing systems of classification and scientific and theological belief. In 1836 Charles Darwin, visiting Australia aboard the Beagle, became the first key British scientist to sight the live platypus in the Cox¹s River near Bathurst. ‘A Disbeliever in everything beyond his reason might exclaim,’ he noted in his Diary, ‘surely two Creators must have been at work’. But shaping his theory of evolution and natural selection later, that ‘wonderful creature’, as he called it, seen in an Australian river on a summer’s evening, drifted in his consciousness and became a persistent player in his maturing ideas on biogeography and the survival of special species in isolation.
The platypus question was not a
question in isolation. As exploration ranged out and returned a vast weight
of new specimens from remote regions of the world, the 19th century became the
great century of classification involving such key scientific figures as
Lamarck, Cuvier and Geoffroy St Hilaire in France, leading German zoologists,
and Sir Everard Home and Sir
Richard Owen at the Royal College of Surgeons in Britain. The extreme oddity of the animal and of other Australian fauna fuelled the general British perception that Australia with its convicts was also a ‘zoological penal colony’ a faunal Gulag where everything was ‘queer and opposite’. These patronising attitudes were to delay the solving of the problem.
In Australia, Sydney naturalist and
physician Dr George Bennett spent 50 years pursuing the platypus puzzle,
hunting it in the field and in its labyrinthine underground burrows and
wreaking considerable carnage. But the influence and conviction of his
colleague and monotreme authority, the great Sir Richard Owen, that the
platypus produced its young from eggs hatched inside the body, confused and
skewed the investigation. Significantly, the Aborigines and their long
knowledge of the platypus form an important part of the story. But, in the
climate of the period, their evidence was dismissed or ignored.
In the event, the mystery was solved not by the long-involved major protagonists but by a visiting Scottish postgraduate student, William Caldwell, who camped on the Burnet River in northern Queensland in 1884, rounded up a horde of platypuses with the help of Aborigines and discovered a female who had just laid one egg and had a second egg dilated in her uterus. Staggering to a small telegraph station nearby, he communicated the news to the scientific world. ‘Without the services of these people,’ Caldwell acknowledged later, ‘I should have had little chance of success’.
The 20th century offered further
fascinating strands. From its beginning, platypus research and knowledge
shifted to Australia among scientists like J. T. Wilson and his team at Sydney
University, and to practical men like the knowledgeable Henry Burrell and the
remarkable David Fleay, who bred the first platypus in captivity at
Healesville in 1944. Winston Churchill got into the act. And in the late 1980s
the opalised jaw of a Cretaceous fossil platypus ancestor from some 100
million years ago was found in the dry opal fields of Lightning Ridge.
Darwin was right: here was a great survivor.
Most importantly, in the 1990s researchers at Monash University and the Australian National University discovered that the platypus has an ‘electric’ beak, a dense set of nerve endings across the shield on its bill that enables it to find its food. Platypuses shut their ears and eyes when diving for food and from considerable distances retrieve their meal of shrimps and insects from the riverbed by a process of electrolocation. From this striking evidence researchers concluded that the platypus left the mainstream and evolved a completely new and distinct sensory system that differed from any other animal. Hence, far from being a primitive animal, as 19th century scientists believed and insisted, the platypus has emerged as the most highly evolved animal in the animal kingdom. Monotreme expert Mervyn Griffith calls it ‘the animal of all time’.
Secretive, highly elusive, drifting down the rivers of eastern Australia, it remains a magical creature and a great story.
Ann Moyal is the author of A
Bright & Savage Land, Scientists in Colonial
Australia and Clear Across Australia, a history of telecommunications.
Platypus is published by Allen & Unwin (RRP $29.95). An American edition is to be published by The Smithsonian Institute in 2002.
Reproduced with permission from Australasian Science