Doctor's trek for elusive platypus

After more than a decade of researching Australia's most unusual native animal, the platypus (Ornithorhynchus anatinus), David Goldney admits he still becomes excited when he manages to track one of them down in the field.

"I think they're probably the most unique mammal in the world and I still get a real buzz when I see them. It's a great privilege to study them, and I find it enormously rewarding," Dr Goldney says, his white beard bobbing with excitement as he talks.

Featuring no external ears, a jaw that resembles a duck's bill, and small eyes, the platypus is a warm-blooded, egg-laying, semi-aquatic mammal that lives in long burrows along the banks of rivers in Tasmania and eastern Australia.

Dr Goldney is one of a handful of researchers trying to find out more about the elusive animal the English believed was a taxidermist's trick when they received their first specimens from early settlers.

Despite its unique features, relatively little is known about the platypus, largely a result of the difficulty researchers face in tracking them down. The animal not only swims in waterholes, but walks across land - a feature which may explain the apparent disappearance of many young platypuses each year, as they leave their waterholes and wander through paddocks and across busy roads.

"We know less about the platypus than we do about rabbits, even though it's a flagship animal for Australia," Dr Goldney said.

Most Australians are unaware that the male platypus is capable of partially paralysing a human being through spurs on its back legs, which release a dangerous venom. People are usually poisoned on the lower arms or legs, and the result is an extreme pain that travels along the limbs, and is accompanied by swelling, partial paralysis and respiratory problems that can last up to several months.

Also not well known is the fact that the platypus uses electroperception with its bill - the ability to pick up small electric discharges from living organisms - to detect prey underwater. Dr Goldney's research has concentrated on the platypus's population, ecology, how they respond to different environments, and diving patterns.

He has trapped and tagged almost 400 specimens, mainly from the Duck Maloi River near Oberon in the NSW central west, in an effort to monitor their living and dispersion patterns. His conclusion is that the average platypus enjoys an extremely active and dynamic existence, and rarely stays in the same place for long.

One intriguing mystery of the platypus is the dispersion of juveniles every year. Dr Goldney's tagging and monitoring has revealed that around 80 per cent of young platypuses move away from their birth area, but what happens to them is unknown.

"It could well be the case that they are forced out of their pool, and they go walkabout, which in reality is a death sentence," Dr Goldney said. Platypuses live up to ten years and at full maturity reach a length of around two feet. What is known of the platypus ecologically and physically will be the focus of a symposium at Charles Sturt University (where Dr Goldney lectures in environmental studies unit) this October.