The Devil is in the details: the decline of an Australian icon
If I asked you what comes to mind when you think of Tasmania, you’d likely be thinking about the Tassie devil. But you might not know that this species may be headed for the same fate as the Tasmanian tiger – extinction.
The Tasmanian devil is famed as the world’s largest marsupial carnivore – which sounds good in writing, but in real life the size of these bumbling balls of playfulness is a little underwhelming.
Males only reach a body length of 65cm, and females are even smaller at 57cm. But after hearing their screeches it’s easy to understand how they got their name. If I’d lived during colonial era Tasmania, hearing their high pitched, yet throaty growls in the dark of the night would have sent me running for the hills too.
A difficult history
These fearsome creatures developed such a bad reputation from their devilish sound that they almost met the same fate as the Tasmanian tiger. Trapped and killed by early European settlers, their numbers declined until they became protected under the law in 1941.
Since then, the devil’s population has dealt with threats such as food availability, competition, habitat loss and road kills.
Then, in 1996, cancerous growths appeared around the heads and mouths of the devils. This fatal disease is known as Devil Facial Tumour Disease, or DFTD.
DFTD – the final blow for the Tasmanian Devil?
Now known to be transmissible, the cancer spreads from one individual to another when the devils fight. In 2008, they were upgraded to ‘endangered’ status and are now considered a protected species. There has been an 85% decline in their population, with some areas facing reductions of greater than 95%.
Today, cancer-free reserve populations may be their only hope, as the cancer spreads through the wild populations. The mortality rate is 100%, with no chance of survival – the tumours on their faces will eventually restrict their eating, and they will starve to death.
So why are these misunderstood creatures so important? Are they worth saving?
The answer to that is: yes! Here’s why.
Top of the food chain
These little guys play a fundamental role in the circle of life of the Tasmanian wilderness. You see, the devils are an apex predator, sitting at the top of the Tasmanian food chain. If you take an apex predator out of an ecosystem it throws the natural order out of balance.
The devil’s decline will have carry on effects for predators lower in the food chain (known as ‘mesopredators’) and prey. It’s a phenomenon known as ‘trophic cascade’, and its impacts have already been observed.
The cats take over
It turns out that as the devil population decreased, the feral cat population went up. The cats are larger than native eastern quolls, who already face competition with the larger spotted-tailed quolls as well.
So now eastern quolls are under threat too: their population declined by 50% in the 10 years leading up to 2009. Declines in their population have occurred in DFTD-affected areas.
The cats also prey on small mammals, so a larger cat population will put pressure on the survival of smaller species. Examples of this already occur in mainland habitats with species such as little penguins. To make matters worse, the recent introduction of the red fox has the potential to further escalate the problem.
Too much of a good thing
As apex predators, devil’s play a key role in controlling the population of their prey. These include the pademelon, the Bennett’s wallaby and the brushtail possum. While it might sound cute to have hundreds of these furry little friends running around, it can put a lot of pressure on the environment and food sources.
So far, no population changes have been observed for these species. But some animals have already changed their behaviour. The brushtail possum now forages for longer and further from shelter where devils are rare. It’s proof that without the devils, Tasmanian ecosystems are changing.
So, saving the Tasmanian Devil is important both for ethical and environmental reasons. And while humans have been responsible for the extinction of many species, we also have the resources to prevent such tragedies. Programs such as Save The Tasmanian Devil are working to both minimise the impact of the disease and maintain a captive insurance population to save this iconic Australian species from extinction.