Can a fence save Tasmanian devils?

Scientists want to build a double fence more than 3 feet tall in some locations to stop the relentless spread of a contagious facial cancer that threatens the Tasmanian devil with extinction.

Devils in the rugged northwest of Australia’s island state of Tasmania are free of the disease, but the ferocious fox-size marsupials spread the cancer when they bite each other during mating or squabble over food.

For any chance of success, the fences would have to be completed within two years, said Hamish McCallum, the senior scientist in the rescue program. He predicts the devil will go extinct in the wild within 20 years.

Tasmania is the only natural home for the world’s largest marsupial carnivore, made notorious by its Looney Tunes cartoon namesake. Its Latin name is Sarcophilus harrisii, or “Harris’ meat lover,” after the scientist who first studied the devils.

Scientists had hoped to find a genetic solution to the disease through Cedric, a young devil who showed signs of natural immunity. But last month Cedric contracted a mutated strain of the cancer.

Warner Bros., which owns the rights to the cartoon character, and CNN founder Ted Turner, who started the Cartoon Network, are helping the Australian and Tasmanian governments bankroll the fight against the disease.

In the last three years, Australian zoos have bred 170 devils as “insurance populations.” Plans to establish a wild colony on uninhabited Maria Island off Tasmania are controversial because of fears that devils could endanger rare birds and beetles.

The Tasmanian government says it is considering offshore islands as well as fenced areas up to 12 miles long, but its first priority is the populations in mainland zoos.

McCallum, professor of wildlife research at the University of Tasmania, said the only fence precedent he knew of was in South Africa, where Kruger National Park was fenced on its southern and western borders in 1961 to prevent foot-and-mouth disease from spreading from wildlife to cattle. The Tasmanian fence would be built in selective areas, such as corners or peninsulas.

“This isn’t going to be a huge barrier like the Berlin Wall across all of Tasmania,” McCallum said.

Government wildlife biologist Nick Moonie noted that fences would also trap other animals, such as wallabies and echidnas, some of which may need to move or migrate. Moonie suspects cancer won’t wipe out devils, but European foxes just might.

Scientists say it is no coincidence that devil numbers have dropped by half in the same decade that foxes have gained a foothold in Tasmania, with potentially disastrous consequences for the island’s unique wildlife. For example, penguins and the kangaroo-like bettongs have lived with the devil for thousands of years but are easy prey for foxes.

Devils and foxes are the top predators in Tasmania. But previously, foxes have faced tens of thousands of devils competing for food and devouring their litters.

Foxes and rabbits were first brought to Australia about 200 years ago by British settlers. Unimpressed by Australian wildlife that hopped on hind legs and carried their young in pouches, the newcomers hoped to re-create an English landscape Down Under. Since then, 25 mammal species have become extinct, giving Australia the world’s worst extinction record, according to the Tasmanian government.

Only one of these extinctions occurred in Tasmania. The devil’s larger cousin, the dog-like Tasmanian tiger, was wiped out by farmers determined to protect their lambs and encouraged by a hefty government bounty.

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About the devil

Their ferociousness starts at birth. Females give birth to about 50 young, or joeys, at a time. These race to the mother’s rear pouch to attach themselves to one of four teats. Only one joey in a dozen will survive.

They’re described as the vacuum cleaners of the forest because they eat animals that have already died.

They grow to only a foot high at the shoulder and to 25 pounds, but their powerful jaws enable them to consume entire cattle carcasses, including bones and fur.

They release a foul odor under stress and make eerie growls as they search for food. When they feed together, they screech and scream.

Numbers in the wild have dropped by 64% from an estimated 140,000 since the devil facial tumor disease was discovered in 1996.

Once almost shot and trapped to extinction, devils thrived, scientists believe, on reduced competition for food as their larger cousin, the Tasmanian tiger, died out during the early 20th century.

Long the target of bounties, devils became a protected species in 1941 and were listed as endangered in 2008.

Sources: Tasmanian Parks and Wildlife Service, San Diego Zoo