Captive-bred eastern quolls breed in

Endangered eastern quolls, functionally extinct on the Australian mainland, have successfully bred in a Tasmanian rewilding project. According to a report by Mongabay, captive-bred animals released in 2025 at The Quoin, a private conservation property, have reproduced and contributed to the next generation.

The eastern quoll is a nocturnal carnivorous marsupial. It resembles a ferret and comes in two color variants: light fawn and blackish-brown, both with white spots. Once abundant on the mainland, the species was lost there by the 1960s due to disease, habitat loss, car strikes, and predation by cats, dogs, and invasive foxes. A wild population persists only in Tasmania, which is free of foxes.

Population decline in Tasmania

While the exact number is unknown, the IUCN Red List estimated the Tasmanian population at between 10,000 and 12,000 mature individuals in a 2014 assessment. A 2023 study using historical data revealed a dramatic drop in their numbers across Tasmania since 1985, with sharp declines in 2000 and 2009.

David Hamilton, a conservation ecologist with the Tasmanian Land Conservancy, described a concerning downward trajectory. "There was a steep decline around the start of this century, and that’s continued unabated in some areas," Hamilton told Mongabay. While initial declines were linked to climate, the reasons for failed recovery in some populations remain unclear.

The threat from cats

Predation by cats is now considered a likely driver of the ongoing decline in Tasmania. Rob Brewster, rewilding manager for the Invasive Species Council, stated that cats have directly killed some of the quolls released in Tasmania. "We can directly implicate cats in the decline of eastern quoll populations in Tasmania," Brewster said. He expressed concern over the state's cat management plans, which he described as "dithering."

Rewilding trials and success

Conservationists are using rewilding to boost populations. An early attempt in November 2020 saw 20 captive-bred adult quolls released at the Silver Plains conservation property. Genetic testing later showed none of those released adults contributed to the local population's next generation. Researchers believe this was partly because the released animals lacked reproductive experience in the wild.

Subsequent releases used a different strategy. At The Quoin in 2025, a mix of adult and juvenile quolls was released. This approach proved successful. "These animals have gone out and reproduced successfully and contributed towards the next generation in their new environment," Hamilton confirmed.

Mainland reintroduction challenges

Rewilding on the mainland has been far more challenging. Liz Gerber, conservation manager at Sydney Zoo, explained that the quoll's "flight or freeze" survival tactic works against ground predators like foxes. A 2018 pilot program in unfenced Booderee National Park lost 14 of 20 released quolls to fox predation within three months.

Current mainland efforts focus on fox-free fenced sanctuaries. Sydney Zoo began a breeding program in 2024 for this purpose. By January 2026, it had released nine eastern quolls, including four joeys, into the fenced Bannockburn Rewilding Sanctuary south of Sydney. The long-term goal is to secure more fox-free land for releases.

Gerber emphasized the species' ecological role. With a diet of insects and small mammals, they act as important scavengers. "We have lost that key role in our bushland, the little recycler, the little scavenger that stops the spread of disease," she said. The question remains whether bringing such a species back would visibly change the environment.