18th October 2008 on Channel 5
The documentary series examining freak occurrences in the natural world continues. This instalment uncovers the mystery of a group of hideously disfigured Tasmanian devils discovered by scientists in the late 1990s.
The devil is a carnivorous marsupial unique to the Australian island of Tasmania. It is the size of a small, sturdily built dog, and the name ‘devil’ comes from its loud and fiendish shriek. Due to its status as the largest carnivorous marsupial in the world, the animal is of great interest to conservationists and wildlife enthusiasts alike.
One night in 1996, a wildlife photographer set out to capture these fascinating nocturnal creatures on celluloid. The resulting pictures sent shock waves through the scientific community. “What we saw was both disgusting and spectacular,” says Nick Mooney, a biologist who has studied the Tasmanian devil in its natural habitat for 30 years. The pictures showed the devils emerging from the forest with grotesque disfigurements in the form of monstrous facial growths.
It was not until five years later that zoologist Dr Menna Jones came across another group of devils with the same affliction. “They were horrific,” she says. “Teeth falling out, jaws breaking off, tumours protruding into eye sockets.” The growths had all the hallmarks of cancer. But cancer is not contagious, so why were so many devils suffering the same symptoms? “You cannot catch cancer from someone else,” confirms immunologist Professor Greg Woods, “so something unusual was happening with these Tasmanian devils.”
Experts looked to the past for answers. Devils have been extinct on the Australian mainland for over 600 years because they were easy prey for dingoes. Yet the devils were not safe in Tasmania either. For over a century, they were hunted and poisoned by local farmers. It was not until 1941 that a new law was introduced banning anyone from harming the creatures. As a result of inbreeding within the dwindling population, the devils’ immune systems had weakened. This meant their bodies had no defences against foreign cells, and diseases such as cancer became transmissible.
The mystery of the ghastly tumours was eventually solved once and for all when scientists diagnosed the growths as a new type of cancer exclusive to the species – devil facial tumour disease (DFTD). Only two other strains of transmissible cancer have been recorded in the world, making it incredibly rare.
On learning about DFTD, conservationists feared the worst for the future of the devils. “An island is a very finite place, and extinctions have a very nasty habit of occurring on islands,” says Nick. Indeed, DFTD is a particularly aggressive form of cancer, with death almost certainly resulting within three to eight months of contracting the disease. In an attempt to halt the advance of DFTD, authorities launched the Save the Devil Campaign in 2003. Donations made to the cause help fund research into and management of this devastating disease.