They disappeared from mainland Australia 3,000 years ago; now Tasmanian devils are breeding again, with conservationists hoping their return will reshape ecosystems and suppress predators

For thousands of years, Tasmanian devils belonged to mainland Australia’s ecological story. Then they disappeared. The species had once occupied much of the continent, but fossil evidence indicates that Tasmanian devils vanished from mainland Australia roughly 3,000 years ago. Scientists have linked their disappearance to major ecological changes, including competition and predation from dingoes. The devils survived only in Tasmania.

In 2020, conservationists put Tasmanian devils back on the mainland. The first release involved 26 devils at Barrington Wildlife Sanctuary in New South Wales, a predator-proof conservation site in the Barrington Tops. The project was designed not simply to rescue an endangered animal, but to restore a predator that once performed an important ecological role.

A predator facing a predator of its own

The timing of the reintroduction is significant because Tasmanian devils themselves are fighting for survival. Since Devil Facial Tumour Disease (DFTD) was first identified in Tasmania in 1996, the contagious cancer has devastated wild populations. National Geographic reported in 2020 that the disease had reduced the species' numbers dramatically, while conservation organisations continue to maintain disease-free mainland populations as an insurance against extinction.

Aussie Ark's mainland breeding programme began in 2011 with 44 disease-free devils. By 2023, the organisation had celebrated the birth of its 500th joey, demonstrating that a sizable mainland population could be maintained outside the disease's stronghold in Tasmania. The programme has continued to produce offspring.

Barrington Wildlife Sanctuary covers about 400 hectares and is surrounded by predator-proof fencing. Aussie Ark says foxes and cats were removed before the sanctuary began its rewilding programme, creating an environment in which threatened native animals can forage, breed and develop natural behaviours without constant pressure from introduced predators.

Could devils become Australia's natural pest controllers?

This is where the reintroduction becomes an experiment in ecosystem restoration. A 2015 study published in Biological Conservation, “Reintroduction of Tasmanian devils to mainland Australia can restore top-down control in ecosystems where dingoes have been extirpated,” by Menna Jones and colleagues, modelled what could happen if devils returned to parts of southeastern Australia.

The researchers found that devils could produce ecological effects similar to, although weaker than, those associated with dingoes. Their models predicted reductions in invasive mesopredators such as foxes and cats, along with changes in herbivore populations and increases in the abundance of some small and medium-sized mammals and vegetation complexity.

But there is an important qualification: the research largely concerns ecological potential and modelling, not proof that mainland devils have already controlled fox and cat populations at a continent-wide scale.