They're cute, they're distinctive - and they're endangered. The 60 per cent decline in Tasmanian devils over the past decade is one of the oddest stories in science.

The critters - the world's largest carnivorous marsupials, which, according to early settlers, "taste like veal" - are under threat from a highly contagious form of cancer, devil facial tumour disease, first identified in 1996. The cancer, spread by biting, leads to tumours that grow over their mouths and prevent them feeding, killing them in as little as nine weeks.

Elizabeth Murchison, a research fellow at King's College, Cambridge, who grew up in Tasmania, says that the species could be extinct in the wild within 20 to 30 years.

There are several quirks about the Tazzie tale that make it particularly interesting to scientists. One is that an infectious cancer is an intriguing medical proposition (cervical cancer in human beings, associated with the human papilloma virus, works similarly; a sexually transmitted cancer has also been discovered in dogs). Another is that all the cancers found in Tasmanian devils are genetically identical, and different from the host's DNA- devils implant cancer cells from their saliva into their victims. In effect, they all have the same cancer.

To watch a clip of Dr Murchison talking about her research, visit the ted.com website.