In the middle of the Australian outback’s arid deserts, many of the country’s distinctive small marsupials – the bilbies, bandicoots and quolls – have been missing for a century or more, wiped out by land clearing and the hunting prowess of feral cats. Felis catus – introduced by European invaders and settlers – was too fast and too agile for the native mammals that had not evolved with this voracious and adaptable new predator.

While efforts to rid the landscape of cats have so far failed, a group of scientists have entered into a bold project to see if small marsupials can train themselves to survive alongside the cats that drove their species almost to extinction.

The ‘training zone’ in the Sturt national park, where quolls, bilbies and bandicoots have been released into an area where feral cat numbers are being controlled. Photograph: Richard Freeman/UNSWA young bilby is released by ecologist Bec West. Photograph: Richard Freeman/UNSW

“It’s a grand experiment. So far, we’re getting success with animals breeding in there. Numbers are building up,” says Prof Richard Kingsford, the director of the University of New South Wales Centre for Ecosystem Science and project leader of Wild Deserts.

The experiment is centred on a 100 sq km “training zone” created inside the sprawling 3,200 sq km Sturt national park in north-west New South Wales.

Nearby are two fenced areas where the feral cats cannot reach and where conservationists have reintroduced six small marsupials – from crest-tailed mulgaras to bilbies and quolls.

A feral cat spotted by one of the project’s 50 motion-activated cameras. Photograph: Wild Deserts project

“They were there 100 years ago and were all killed by cats and foxes. All these bite-sized marsupials were decimated,” Kingsford says.

“But how do we get these native species to smarten up to a new predator in the landscape that they didn’t evolve with?”

The “training zone” is bordered on two sides by dingo fences that also keep out some, but not all, cats.

Sign up to get climate and environment editor Adam Morton’s Clear Air column as a free newsletter

Inside, cat numbers are kept low by shooting and by devices that can tell the difference between a native animal and a cat, before firing a lethal toxin on to their fur which the cats lick off.

Now there are only about three cats in every square kilometre of the training zone.

“Outside, there are 10 times that number,” Kingsford says.

Estimates suggest feral cats kill more than 2 billion Australian animals each year.

‘They are taking back the desert’

Dr Bec West is the principal ecologist at the Wild Deserts project. She has lived in an old homestead in the national park for eight years with her husband and three young kids.

Since 2024, 51 western quolls, 305 bilbies and 234 golden bandicoots – all nationally threatened species – have been released into the training zone. Coming soon will be burrowing bettongs.

“Some will be eaten. But predation is natural,” West says.

A mulgara is released into the Wild Deserts precinct. Photograph: Richard Freeman/UNSW

Last month, the Wild Deserts team caught 57 quolls, bilbies and bandicoots inside the training zone. The bilbies and quolls had been there at least a year and the bandicoots had survived three months.

skip past newsletter promotion

Sign up to Clear Air Australia

Adam Morton brings you incisive analysis about the politics and impact of the climate crisis

Privacy Notice: Newsletters may contain information about charities, online ads, and content funded by outside parties. If you do not have an account, we will create a guest account for you on theguardian.com to send you this newsletter. You can complete full registration at any time. For more information about how we use your data see our Privacy Policy. We use Google reCaptcha to protect our website and the Google Privacy Policy and Terms of Service apply.

Every month, West’s team review images from 50 motion-activated cameras around the training zone.

“In the last few months, we have been seeing more bilbies and quolls than cats. That is such a win. They are taking back the desert,” she says.

Evolving to survive

But how might the marsupials learn to live with cats? Some might simply watch and learn, picking up new strategies to be more wary.

Experiments in another desert area in South Australia have shown bettongs become more alert and more vigilant if cats are around.

Another experiment has monitored a group of bilbies exposed to cats and a group that was not. After five years, the generations of bilbies living alongside cats had larger feet and would flee an approach by humans much earlier than before, suggesting they had become warier of a potential predator.

“Those larger feet might mean they’re better at escaping,” says West, who has been part of some of the studies.

The reintroduced species have already spread out across the whole training zone.

One of the two cat-free fenced zones. Photograph: Richard Freeman/UNSWA bettong is carried in a bag before being released into the wild. Photograph: Richard Freeman/UNSW

“They have been able to breed and the progeny have grown up in that environment,” she says.

“They’re spreading out and we hope in the future we can use these predator-smart animals to establish them further afield.”

Small marsupials like bilbies, bandicoots and bettongs are known as ecosystem engineers. They dig and overturn soils that create pools for water and help seeds to germinate, encouraging native plants to grow.

Near the training zone are the two cat-free fenced zones. West says the animals have transformed the ground cover, seeing native plants flourish in the dry.

“It is unrecognisable now,” she says. “They’re turning over the environment and you can see the seeds collecting in those pools. You have a really high risk of turning your ankle!”