One of the World's Biggest Extinction Crises Is Being Caused by Cats

Officials in Australia are combatting the nation's unraveling biodiversity by targeting an unexpected source of mammal extinctions: the hordes of feral cats that number in the millions across the continent. While it's become clear that it will be impossible to eliminate the national menace, a summit of experts and policy makers has been called this month to explore how to kill as many of them as possible.

Over the past 200 years, Australia has seen the extinction of more mammals than any other nation, losing at least 29 indigenous mammal species since 1788 — which is 10 percent of the warm-blooded creatures that inhabited the continent when it was colonized by Europeans. Among the creatures lost for good are the desert bandicoot and the Tasmanian tiger. Currently, 21 percent of Australia's land-dwelling native animals are threatened or endangered, including the hairy-nosed wombat and the northern quoll, according to a survey in the journal Proceedings of the National Academy of Sciences.

The Australian government says there are approximately 20 million feral cats in Australia. Dr. Jim Radford, a conservationist with Bush Heritage Australia, told VICE News that feral cats are the "single biggest threat" to protecting many of Australia's threatened species.

"There's hardly a part of the continent that hasn't been touched by them," he said.

And according to Threatened Species Commissioner Gregory Andrews, over 100 species are currently under threat from feral cats.

"Each feral cat eats between three and 20 native animals a day. That adds up to a conservative 80 million native animals a day," he told the Australian Broadcasting Corporation on Monday.

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Greg Hunt, Australia's environment minister, has even gone as far as declaring "war" on feral cats, in an effort to end "the loss of mammal species by 2020." And according to the government's Action Plan for Australian Mammals, feral cats are the "most severe threat to terrestrial mammals in all threat categories."

"We're kidding ourselves if we think we can eradicate them," Radford explained. "It's difficult to bait and trap them, because they're very shy, and culling through shooting is very difficult; you can't shoot that many cats."

"Australia is more vulnerable to introduced pests, because it's been an island for so many millions of years," he added. "The evolutionary history has been one of long isolation, and species here don't have the wherewithal to survive these invasive pests."

A draft of the government's own Threat Abatement Plan For Predation By Feral Cats, released last week, said that, "it is not feasible with current or foreseeable resources and techniques" to eradicate them.

Devising a strategy for this new war on the national menace is on the agenda for the summit, set for later this month. John Woinarski from Charles Darwin University, author of the mammal action plan, plans to attend.

"This was essentially a hidden problem, people didn't know cats were this detrimental," Woinarski told VICE News.

There has never even been an attempt to eradicate cats on mainland Australia — only three islands have been cleared completely. On the mainland, there have only ever been population control programs, which have been operated across the country by a hodge-podge of NGOs, local councils, and government agencies.

Asked if there was hope of ever hope of fully eradicating the pests, Woinarski said, "It won't be possible in the next decade. There's some hope it's possible over the next several decades."

Cats simply reproduce at such a rate that current technology and manpower can't do the job.

Woinarski explained it would take a "biological agent," which is to say an engineered virus, to eradicate cats from the country and described the development of such a weapon as the "great white hope" of conservationists.

For now, poisoned baits are the weapon of choice for population control. The largest programs for this method use aircraft to scatter baits across Australia's vast outback. The aircraft can drop upwards of 60,000 baits across areas of over 1,000 square kilometers.

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Until a stronger solution is found, endangered animals will have to be kept alive by isolating them from the vast swathes of the country where the cats roam unabated.

"The only place many mammal species are secure are inside cat proof fences," Woinraski said. "It's an expensive operation to build those fences, so the areas that can be protected aren't vast, but it's currently the only effective mechanism."

The ongoing feeding frenzy on Australia's native wildlife may finally be getting the attention of policy makers, but Woinarski said the battle can only be fought with public support, and that the numbers showed Australians generally have other priorities.

"Australia spends $8 billion on pets annually," he said. "We definitely don't spend that on conservation."

House pets are a major source for the enormous feral population, with runaways and abandoned pets joining the flocks of wild felines. The amount Australia spends on conservation, according to the most complete figures available, was around $520 million annually between 2001-2008. The gap between pet spending and conservation indicates what animals Australians are willing to care for, according to Woinraski.

"We're still not living comfortably with this land and its wildlife," said Woinarski. "We're still aliens here."

Follow Scott Mitchell on Twitter: @s_mitchell

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