A contagious devils cancer is threatening Tasmanian devils with extinction, but these unique carnivores - and their human helpers are adapting to breakneck speed, giving new hope for their survival.

Evolutionary change is usually measured over millennia, but in the craggy northern Tasmania mountains of Tasmania, it can be seen in real time.

Three decades after the first cases of fatal transmissible cancer scythed through Tasmanian devil populations, experts are seeing dramatic changes in the 15 percent of creatures that have survived.

The cancer spreads via the bite of an infected individual, usually during mating or when they challenge each other in jaw to jaw.

But scientists have reported that famously feisty devils - now numbering 15,000 to 18,000 - are fighting back, with the first signs of an immune response reported.

The disease is till almost always fatal, and a second strain is being investigated, but anti-bodies have been detected in infected animals for the first time and more than two two dozens have contracted the cancer and survived.

''We have seen animals that are not contracting the disease. We have seen animals that even if they contract the disease, they survive for much longer,'' said Rodrigo Hameda at the University of Tasmania.

''We are also seeing a small number of animals that have manged to regress tumours in other words to cure themselves of the cancer.''

Experts working with the marsupials every day also report significant behavioral changes taking place that have helped steady population numbers.

Chris Coupland is the senior keeper at ''Devils @: Cradle'', a refuge that allows tourists to see the elusive animals up close, but which also keeps an insurance population   -a kind of Ark, safe from the  rising tide of disease.

''The rate of decline was serious and the risk of extinction was there,'' he says while playing with two young relatively tame devils he hand-raised. ''Its still there.''

Coupland reports a number of promising trends, particularly devils mating at  a younger age and females being on heat more than once a year.

''For the first time we had multiple oesttruses, and that's becoming more common,'' said Coupland, adding that it was probably due to a lower population density.

Coupland says they are also seeing the survivors become sexually active at an earlier age.

With fewer devils, food is more abundant and competition is reduced, allowing  the animals to reach mating weight more quickly.

''These days they seem to be breeding at one [year old], whereas historically it was two.'' Together these trends are helping population numbers stabilise. [Agencies]


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