Tassie Devils are amazing creatures, but their situation is dire. Australia’s largest marsupial carnivore is one of the few species on Earth whose major plight isn’t caused by humans. Rather, it is caused by something much more insidious – evolution.
Evolution, in combination with low genetic diversity caused by a series of historical population crashes, has conjured up a horrible illness called the Devil Facial Tumour Disease or DFTD. Originating from the mutated cell of a single devil, DFTD causes large, cancerous growths to form in the animal’s mouth, preventing feeding and often causing death due to starvation. It’s a horrible way to go.
However, what is most frightening about this tumour is that it is contagious - among devils, not people. Devils often feed together on the same carcass, or even fight over it. This causes the cancer cells to move from devil to devil through saliva in their food as they argue over the last scraps. It’s this aggressive, transmissible quality that has seen the cancer spread like wildfire from one single individual to nearly the entire Tasmanian population, from east to west. The result is a species teetering on the brink of extinction.
Despite a lot of work being done on creating vaccines for DFTD, maintaining captive breeding populations and, recently, establishing a wild population on Maria Island free of DFTD, this may not be enough. A new, potentially game changing proposal has also been gaining momentum: to re-establish or rewild disease-free populations of the Tassie Devil to mainland Australia. This kind of innovative thinking could be the saviour of the species.
So, what is the case for rewilding the Tasmanian Devil?
1. Devils used to be here, anyway
Fossils show that the devil coexisted with other native mammals on the mainland up until fairly recently (5000 to 400 years ago, depending on the accuracy of the dating). In fact, Devils once lived far up into the north of the country. Why did they disappear? No one knows for sure, but hunting by Indigenous Australians and the introduction of the dingo may have had something to do with it.
Because of this, we can be fairly sure that devils, if brought back to mainland Australia, wouldn’t be another cane toad or European carp disaster, eating everything in its path. Also, Devils have lived with an enormous range of bite-sized marsupials in Tasmania, much more than mainland Australia. This suggests that Devils are capable of coexisting with smaller prey species without hunting them to extinction.
Recent research using species distribution models has shown that the prevailing climate is just right for devils across south eastern Australia. According to this modelling, places like Wilson's Promontory and Barrington Tops might be perfect homes for Devils.
2. Devils need More insurance populations
The species needs insurance populations that are disease-free, simply so that the devil’s survival is ensured. Captive breeding programs have been the saviours of species many times over, but they can sometimes struggle to emulate the experiences of living in the wild. As the saying goes; ‘there’s no place like home.’ A wild, disease-free population will maintain the instincts and behaviours required for survival, as well as providing another source of genetic diversity for the species. These two things will be vital when the time comes to help build the Tasmanian population back up to historical levels.
Indeed, there’s evidence that Devil introductions or reintroductions can occur successfully. A couple of years ago, a population of devils was established on Maria Island on the east coast of Tasmania. This is the first time devils have existed on the island and there’s every indication that individuals cope with moving houses, with little harm on existing native wildlife.
3. Devils may help balance our ecosystems
Where they persist, Tasmanian devils are apex predators. They are typically quite timid and prefer carrion, but their mere presence in the environment can scare smaller species away, creating a ‘landscape of fear.’ Not dissimilar to the neighbours cat being terrified of your
otherwise lovely Jack Russell. They are capable of keeping grazing animals like rabbits down, allowing vegetation to do well.
Perhaps more importantly, recent research has suggested that devils can also disrupt feral cat behaviour. This may mean that the devil could shield endangered prey species from predation, which has immense conservation benefit. Some recent computer modeling also supports this suggestion, even predicting that devils may scare foxes away, too.
4. There's scientific and public support for a trial
A recent public survey by Rewilding Australia found that, of over 400 respondents, 85% supported a trial reintroduction of Tasmanian devils to the mainland, whilst another 13% suggested they could be persuaded if presented with enough evidence. There's also strong scientific backing for a trial to occur in Victoria, with scientists from Deakin University, University of NSW and the University of Tasmania in support.
Any proposed reintroduction will need to be a well thought out and planned exercise. Returning the Tasmanian devil to its original home, such as Wilson's Promontory, has real potential to not only help secure a species, but also provide greater benefits on an ecosystem scale. There will be tensions that need to be addressed, but ultimately the pros outweigh the cons to the point where reintroducing the Devil needs to be considered, such as the proposal outlined by Zoos Victoria in their Conservation Master Plan. With a dying population due to DFTD, proactive and innovative solutions are required. So, perhaps it’s time to welcome the devil back to its ancient home and recreate a thriving ecosystem.
Cover image supplied by Catherine Cavallo
Billy is the Science & Conservation Editor at Wild Melbourne. He is a wildlife ecologist interested in predator-prey interactions and invasive species management.
You can find him on Twitter: @billy_geary