Christine Ellis doesn’t like feral cats. As an Aboriginal Warlpiri ranger at Newhaven Wildlife Sanctuary in central Australia’s Great Sandy Desert, she knows what they can do to Australia’s native animals: In just over 230 years since their introduction to the continent, feral cats have wiped out more than a dozen species that lived alongside Ellis’s people for millennia and pushed others to the brink of extinction. As she puts it, out there, “There are no stories without cats”.

Cats arrived in Australia with the first European settlers in 1788. Within 70 years, cats had spread throughout the country ; cats now inhabit 99.9 percent of Australia’s total land area . On a yearly average, an estimated 2.8 million feral cats roam the continent, but according to John Woinarski, a conservation biologist at Charles Darwin University and co-author of the book Cats in Australia: Companion & Killer , this number can balloon to 5.6 million in years of heavy rainfall.

With its 23 ecosystems, Newhaven—an area in northwest Australia about one-third the size of the U.S.’ Yellowstone National Park—encompasses 1,023 square miles of sand dunes, salt lakes and red-rock escarpments. At the sanctuary’s heart is a fenced, 36-square-mile reserve from where Ellis and her colleagues from the Australian Wildlife Conservancy removed feral cats—escaped pet cats or the descendants of cats that came to Australia aboard the convict transportation ships—to create an area where native species could recover.

“Australia's biodiversity is special and distinctive, forged over millions of years of isolation,” says Woinarski. “Many mammal species that survived have been reduced to a minute fragment of their former range and population size, are now threatened and continue to decline. Left unmanaged, cats would continue to eat their way through much of the rest of the Australian fauna.”

The fence at Newhaven was completed in March 2018 and the exclosure—an area built to keep unwanted animals out—was declared feral-predator-free the following year. Inside the fence, threatened and reintroduced native species such as the red-tailed phascogale and western quoll are making a comeback.

Newhaven is on the front line in Australia’s fight to protect its native animals from cats. With time running out for many species, this February, Australia’s federal parliament released a report that confirmed that cats were the primary drivers of mammal extinctions in the country. The report asserted that Australia leads the world with 34 such species wiped out and a further 74 land mammal species under threat. Faced with this crisis, the report launched “Project Noah,” a plan to increase the number of exclosures like Newhaven. The report also recommended greater cooperation between all levels of government in dealing with Australia’s feral and pet cats.

Set up in June 2020, the committee conducted hearings and received more than 200 submissions from scientists, conservation organizations and animal welfare groups throughout the second half of 2020. The final report found that every year, each individual feral cat in Australia kills 390 mammals, 225 reptiles and 130 birds. That adds up. Every year, feral cats kill 1.4 billion native Australian animals—around the same number that died in the catastrophic 2019-20 bushfires when more than 73,000 square miles burned.

Feral cats are not the only problem: The parliamentary report also found that Australia’s almost 3.8 million pet cats kill up to 390 million animals every year.

To reduce the impact pet cats have on native animals, the report recommended three major steps. First, pet owners should be required to register their cats, a measure designed to encourage responsible pet ownership and ensure revenue reaches local councils who enforce cat-control regulations. Second, cat owners should be required to spay and neuter their cats to reduce the number of unwanted litters and the dumping of stray cats. Most controversially, the report also urged governments to mandate night-time curfews to prevent domestic cats leaving their homes after dark.

Some conservationists hoped the report would go further. Night-time curfews “would benefit native nocturnal mammals, but won’t save birds and reptiles, which are primarily active during the day,” wrote Woinarski and others in response to the report. “Pet cats kill 83 million native reptiles and 80 million native birds in Australia each year. From a wildlife perspective, keeping pet cats contained 24/7 is the only responsible option.”

Cat containment measures even have the support of the Royal Society for the Prevention of Cruelty to Animals (RSPCA), Australia’s peak animal welfare organization. RSPCA animal shelters take in 65,000 cats every year, and around 40 percent of these are euthanized. In a 2018 policy document that was cited favorably in the 2021 parliamentary report, the RSPCA agreed that “Cat containment regulations need to mandate 24-hour containment, rather than night-time curfews, if they are to significantly reduce wildlife predation, breeding of unwanted cats and cat nuisance.”

This support from the RSPCA stands in contrast to the political situation in the United States. A 2019 study published in Conservation Letters found that while Australia and the U.S. have a similar number of threatened species, government spending to protect them is more than 15 times higher in the U.S.. Even so, when it comes to cats, animal welfare and cat advocacy groups in the U.S. strongly resist proposals by scientists and conservationists to reduce cat populations and governments at all levels have been reluctant to take on the issue. And it’s as serious a matter in the U.S. as it is in Australia. More than 58 million pet cats and anywhere between 30 million and 100 million self-sufficient feral cats and strays partially cared for by humans live in the U.S. A 2013 study in Nature found that cats kill as many as 22.3 billion mostly native mammals in the U.S. annually.

Conservation scientist Pete Marra, the author of Cat Wars: The Devastating Consequences of a Cuddly Killer and a leading advocate for cat control measures, says that in the United States, animal welfare organizations such as Alley Cat Allies and Best Friends Animal Society, aggressively oppose any attempts to control cat numbers. In 2019, Becky Robinson, president and founder of Alley Cat Allies, described plans by the Australian government to kill feral cats as “barbaric, reprehensible, and a morally flawed choice”.

For Marra, the contrast between the U.S. and Australia when it comes to cats couldn’t be clearer: While Australia’s federal parliament commissioned a report that recognized the seriousness of the country’s cat problem and demanded action, he says those who identify cats as a major conservation issue in the U.S. are shouted down. “You have in Australia this entire country taking on cats because they understand they’re on the razor’s edge of this conservation issue,” says Marra.

The chances of the U.S. government conducting an inquiry into the problems caused by unowned and pet cats are slim, according to wildlife biologist Christopher Lepczyk of Auburn University, partly because he sees the conservation lobby as focused on other pressing issues, such as addressing climate change and moving to greener energy policies. “I worry now, as I have essentially the entirety of my career, that cats just aren’t a large enough issue to rise to the top of concern,” Lepczyk says. “Adding to this problem is the cat lobby. The various organizations that make up this lobby are exceptionally well-funded, have large support amongst celebrities and the public (all of whom may not fully understand the science regarding cat impacts), and are able to lobby in ways that government agency scientists cannot.”

The result, Lepczyk says, is a political hot potato that no-one wants to handle.

One area of commonality between animal welfare groups in the two nations is support for a program called Trap-Neuter-Release, also known as Trap-Neuter-Return, which involves trapping and spaying feral cats, then returning them to the wild.

Arian Wallach, a lecturer at the Centre for Compassionate Conservation in the University of Technology Sydney and who describes herself as “an abolitionist when it comes to using violence for conservation purposes,” says Trap-Neuter-Release is only part of the solution. Wallach, who has in the past received funding from Alley Cat Allies—which is based in the U.S.—argues that feral cats should be redesignated as ‘Australian wildcats’, and that “cats are an intrinsic part of urban human ecology”.

Such views, however, remain in the minority within Australia’s scientific community and the parliamentary report rejected Trap-Neuter-Release as a measure for controlling cats. Proponents of the practice, the report concluded, “fail to consider the ongoing impacts to native wildlife when cats are released after having been desexed.”

The report went on to consider further measures for controlling feral cats.

One of these, gene-drive technology, would allow scientists to genetically engineer cats and make them, for example, less fertile or more susceptible to toxins. But the technology has only been tested successfully in yeast and other single-cell organisms. “It’s at least 20 years away,” says Woinarski, “and there’s no guarantee that it will work either.”

“The ethics of it start to get tricky,” says Sarah Legge, a wildlife ecologist at Australian National University. “Think of the public’s reaction to genetically modified food. Then you’re talking about super-charging a cat. It just gets a lot harder.”

Indigenous hunting of cats is a more immediate tool for reducing feral cat numbers. Aboriginal communities have hunted feral cats for food since at least the 1890s, and feral cats became an increasingly important part of the local diet throughout the 20th century as cats replaced native mammals in Australia’s Western Deserts. In the last two decades, cat hunting has also become a conservation tool.

As part of what was at the time the world’s largest feral cat eradication project, Ellis, the Newhaven ranger, would track cats on foot in the reserve as her ancestors once tracked kangaroos. She examined footprints in the sand to determine how recently the cats had passed, followed the tracks and then killed the cats with a single blow to the head, usually with a heavy iron bar. She still hunts feral cats in the unfenced areas of Newhaven, and from finding footprints to catching each cat rarely takes Ellis longer than an hour. The practice is, however, dying out as more Indigenous hunters abandon traditional hunting techniques in favor of vehicle-based hunting with guns, and younger generations of Indigenous populations move to the cities.

Although Wallach is careful not to criticize Indigenous hunters, she opposes such hunting if used as a cat control measure, “My rule of thumb is that if you’re going to kill something, then you eat that something,” she says. “If it’s just another method to increase the body count, then I do not consider that an ethical approach to cats.”

Apart from Ellis and her mother, Alice, at Newhaven, traditional cat hunters operate only at Kiwirrkurra, an unfenced Indigenous community area covering 17,700 square miles in the Gibson Desert west of Newhaven. These hunts have helped to save local populations of two threatened species—the greater bilby, a small, large-eared native marsupial, and the great desert skink.

But Indigenous hunting can’t operate on the scale required to counter the impact of feral cats. And the parliamentary report recognized that only the Newhaven model—using cat hunters to remove feral cats, building fences and then reintroducing threatened species into the exclosures—can protect many species from cats in the short to medium term.

So the report proposed Project Noah to continue the trend of building fenced exclosures in sensitive habitats around Australia. The recently fenced area at Mallee Cliffs National Park in New South Wales is similar in size to Newhaven. Also in the state, Yathong Nature Reserve will soon enclose nearly 155 square miles of critical habitat. And the Australian Wildlife Conservancy plans to expand the Newhaven exclosure, one of eight such protected zones in its portfolio, to 386 square miles.

In 2019, the Australian Wildlife Conservancy notched a major conservation milestone at Newhaven when it reintroduced the mala, a miniature kangaroo-like marsupial that became extinct in the wild in the 1980s, to the exclosure.

Free to roam without human interference and safe from feral cats, the mala and other reintroduced species are making a remarkable comeback, establishing territories and breeding successfully. Stepping inside the fenced area is like stepping back centuries. “You’ve got to watch where you step,” says John Kanowski, an ecologist and the Australian Wildlife Conservancy’s chief scientific officer. “A lot of these animals are burrowing or at least dig holes.”

“In the desert landscape, those holes trap water when it rains, they trap the leaf litter, they create these rich microsites for plant regeneration,” says Kanowski. “It’s how the ecosystem works.”

Or as Woinarski puts it, at Newhaven, “you might just catch a glimpse of Australian nature as it was and should be.”