Return of the devil

When seven Tasmanian devils were born north of Sydney in May, they were the first born on the Australian mainland in 3000 years. Fossil records show that Sarcophilus harrisii were once found across much of south-east and central Australia, and as far west as the Kimberley, where they are depicted in rock paintings. Until sea levels rose between 8000 and 11,000 years ago, a land bridge connected what we now know as Tasmania with the mainland, and devils moved freely between the two. Even for thousands of years after Bass Strait formed, devils survived on the northern landmass that would later become mainland Australia.

But all of a sudden, 3000 years ago, devils disappeared from the mainland. No one knows exactly why. Scientists think that a changing climate may have played a part. Also, Australia’s human population was becoming larger, hunting techniques were improving, and some communities began to live more sedentary lives. And then there was the dingo, which arrived in Australia around 3500 years ago. Devils may be the largest carnivorous marsupials left on the planet, but they were no match for dingoes and soon disappeared from the mainland.

A few hundred devils hung on in dingo-free

Tasmania.

Over the centuries, devil numbers grew on the isolated island, until Europeans arrived in the 19th and early 20th centuries, and bounty hunters and livestock farmers nearly wiped them out. But the devils survived, and, by the 1990s, there were around 53,000 in Tasmania. Then their world fell apart. In 1995, unsettling reports of dead and strangely disfigured devils began to emerge. The following year, the first case of devil facial tumour disease (DFTD) was described. Soon it was sweeping across the island, killing the marsupials everywhere it went.

Tasmanian devils can be aggressive when fighting over territory, food and mating partners, and this was crucial to their demise: the rare example of a transferable cancer spread quickly and easily when the animals bit each other in the face during combat. In 1996, the International Union for Conservation of Nature classified the Tasmanian devil as “least concern”. By 2009, it was listed as “endangered”. Scientific modelling suggested that the devil would become extinct within a decade.

Fighting against time and the animals’ limited geographic range, scientists scrambled to create an insurance population of devils in zoos and wildlife sanctuaries. Some were on the mainland, including at Healesville Sanctuary, 60 kilometres east of Melbourne, and at Aussie Ark, a private sanctuary 300 kilometres north of Newcastle. But these were captive populations.

In 2012, one of the more interesting experiments took place on Maria Island, off Tasmania’s east coast, where scientists introduced around 30 disease-free wild devils. The population has since grown to nearly 100, and devils from Maria Island are frequently relocated to areas in Tasmania where they are otherwise scarce.

As if part of some Herzogian drama where cruel nature plays to the laws of unintended consequences, the Tasmanian devils soon wiped out Maria Island’s population of little penguins and shearwaters. Even so, this gave scientists a glimpse of how devils might one day play an important role in regulating ecosystems elsewhere. Proposals were made for establishing a mainland population at Victoria’s Wilsons Promontory National Park, which is the remnant of the land bridge connecting Tasmania

and the mainland. But such plans foundered due to Tasmanian government resistance.

“The focus is securing the future of the devil where it belongs in the wild in Tasmania,” a government spokesperson told The Sydney Morning Herald in 2016. “The Tasmanian government does not support any proposal for an introduction of devils to the mainland. Such an introduction is not required to secure the future of the Tasmanian devil.”

And then a remarkable thing happened: Tasmanian devils with the tumour began to recover, as did devil numbers in some populations.

Normally, the evolution of a species takes many generations, sometimes thousands of years, to adapt in response to a threat or change in conditions. There are exceptions. The rabbit, for example, adapted swiftly in response to the myxoma virus. But unlike the devil, the rabbit belonged to a massive population with great depth and variety in its gene pool.

By any normal measure, faced with a threat as fast-moving as DFTD, Tasmanian devils should have fallen extinct. Instead, the decline in their numbers began to slow. By 2021, the wild devil population in Tasmania stood at an estimated 16,900. Models project a low point of around 12,000 by around 2030, whereafter they predict that devil numbers will stabilise. According to Chris Johnson, professor of wildlife conservation at the University of Tasmania, it is “one of the great stories in science”.

Job done? Well, sadly not.

As the devil’s bad luck would have it, a second, wholly unrelated new facial tumour cancer – named, with no great imagination, DFTD2 – has emerged in devil populations south of Hobart in recent years. While less virulent than its predecessor, DFTD2 is a reminder of the complex dangers faced by these marsupials.

“Twelve thousand is a good number of devils,” says Johnson. “But it’s probably not enough. As we’ve already seen, bad things can happen when you’ve just got one population to go with. With one disease, and now two diseases, it’s just a little bit scary.”

With that in mind, Johnson says that the reintroduction of Tasmanian devils on the mainland should still be a priority. “We don’t need to do it right now to save the devil from extinction. But to secure its long-term future and viability, we probably do need to do it.”

Without the urgency of saving a species to cloud the debate, other potential impacts of reintroducing devils have become part of the discussion. Despite their impact upon little penguins and other seabirds on Maria Island, Tasmanian devils bring a range of benefits to most ecosystems they inhabit. As master scavengers, these marsupials are one of the natural world’s great recyclers: relative to size, they have the strongest bite of any mammalian predator, and can crunch through bones with their jaws. They’re also predators and they help to keep herbivore numbers at sustainable levels, with flow-on effects for the survival of many different kinds of vegetation in an ecosystem.

There are fears about the devil’s impact upon smaller mammals, from bettongs and bandicoots to pademelons and potoroos, but these may be overstated. “Many of the species that we’d like devils to help us save on the mainland are already in Tasmania coexisting with devils,” says Johnson. “They’re managing perfectly well with the devil.”

And the devil has one more trick up its sleeve, one that could make it the darling of the conservation movement. At a time when feral cats are eating their way through Australia’s native wildlife, devils may provide part of a solution. A recent field study from Tasmania found that putting devils back into an ecosystem reduced the number of feral cats by 58 per cent. As devil numbers rose, feral cat numbers fell, and the population of southern brown bandicoots recovered. Devils may, Johnson says, provide a unique opportunity to “reset the system so that it becomes a system with native carnivores and native prey, rather than overwhelmingly introduced predators”.

And for all the tangible benefits that could flow from having devils in mainland ecosystems, their biggest impact could be psychological. “It’s telling people that we can actually get accustomed to the idea of devils on the mainland,” says Johnson. “We just don’t think of devils in that way. We think of them just being a Tasmanian thing.”

In 2020, Aussie Ark reintroduced 26 devils into a 500-hectare fenced sanctuary alongside Barrington Tops National Park, in central NSW. It was here, in May, that the seven devil joeys were born.

For Tim Faulkner, executive director of Aussie Ark, such a release was long overdue, and as much about saving the local environment as it was about saving Tasmanian devils. “We’ve got cats and foxes annihilating our native species and basically have ecological ghost towns within our forests.”

The devil is, says Faulkner, particularly suited to reintroductions. “Imagine if we were trying to reintroduce a wolf or a tiger or a bear! Devils don’t eat people, and they generally don’t pose a threat to livestock, other than perhaps lambing. But they get along with people and agriculture. That’s a massive opportunity.”

If this first, soft introduction of 26 Tasmanian devils works – if the devils and their offspring survive, and if they don’t wipe out the other native mammals within the fence – then Faulkner and others hope that carefully controlled reintroductions could begin beyond the fence.

Were that to happen, the devil might finally be back where it belongs.

Then a remarkable thing happened: Tasmanian devils with the tumour began to recover, as did devil numbers in some populations.