Tasmanian Devils Could Be Gone in 20 Years

Robin Lloyd, LiveScience.com Yahoo News 3 Nov 08;

An Australian zoologist is leading a national project to help save the endangered Tasmanian devil from extinction, a situation that could arise within the next 20 years, experts predict.

Jeremy Austin will lead the project, which has received $168,000 Australian (Australian dollars currently are about two-thirds the value of U.S. dollars) from that nation's government. The research will rely on genetic procedures to examine the impact of an infectious cancer, devil facial tumor disease, on Tasmanian devils.

Tasmanian devils became extinct on the Australian mainland about 400 years ago and are now found only on the Australian island state of Tasmania. Unlike Tasmanian tigers, devils survived initial human impacts following European colonization but in the past decade their numbers have fallen drastically.

"We have lost over half our devils in the past 10 years, with an estimated population of 20,000 to 50,000 mature devils left. Extinction within the next 20 years is a real possibility unless we find a vaccine, eradicate the disease and establish captive colonies," Austin said.

Breeding program

There are 500 disease-free devils in zoos and wildlife parks on the Australian mainland, so scientists recently suggested a breeding program as an "insurance policy" in case a vaccine is not found in time, the British Telegraph newspaper reported.

Some forecasts for the extinction of devils are as low as 10 years, Guy Cooper, conservation society director of Taronga Zoo in Sydney, told the newspaper. The disease is spreading faster than expected.

Austin and colleagues will spend the next three years establishing a conservation program and working to suppress the disease, which is ravaging Australia's largest living marsupial carnivore.

Symptoms of the disease, including cancerous lesions around the mouth, face and neck, were first reported in 1996 at one spot on Tasmania. By 2007, the disease had spread over more than half of the devils' home range there. Some populations have lost up to 89 percent of their members as a result of the facial tumors.

Sex sooner

One way devil populations are coping is by having sex at an earlier age, a study found earlier this year. The fatal disease strikes when devils reach the age of 2, which is about when they become sexually mature enough to breed. So earlier breeding is critical for the survival of the species. Devils only breed two or three times in their lifetime.

The Tasmanian devil is not only a key tourism icon for Australia's most southern State, but also ecologically critical to Tasmania's native ecosystem.

Because Tasmanian devils have extremely low levels of genetic diversity and a chromosomal mutation unique among carnivorous mammals, they are more prone to the infectious cancer. Austin's team will analyze genetic material from devil populations to understand the origin, spread and impact of the disease and try to find a vaccine.

"We need to establish whether the low levels of genetic diversity are due to recent human impacts or a long-term historical pattern," Austin said. "We also need to look at how the cancer is affecting surviving populations and identify individuals that may be resistant to the disease."

Devil facial tumor disease is one of only two known clonally transmissible cancers and appears to have originated from a genetic change of mutation in a single individual. It is spread through biting during fights over food and during mating.