Tasmanian Devil - Conservation Status

Conservation Status

Widespread across Australia in the Pleistocene, the Tasmanian devil had declined and become restricted to three relict populations during the mid-Holocene period around 3,000 years ago. Rock art and a single fossil near Darwin point to a northern population, and remains in the southeast signify a southeastern population ranging from the mouth of the Murray River eastwards to the vicinity of Port Phillip in Victoria. This population had contracted from northern Victoria and New South Wales. The rising sea levels in the Holocene also cut it off from Tasmanian populations. The third population was from southwest Western Australia. Fossil evidence from this last location has proven controversial. As with many native animals, ancient devils were larger than their contemporary descendants. In 1972, Mike Archer and Alex Baynes found a devil tooth at the foot of a cliff near Augusta in Western Australia and dated it to 430±160 years of age, a figure widely circulated and cited. Australian archaeologist Oliver Brown has disputed this, stating that the authors' uncertainty about the origins of the tooth casts doubts on its age, especially as other remains all date to around 3,000 years ago.

The cause of their disappearance from the mainland is unclear, but their decline seems to coincide with the expansion across the mainland of indigenous Australians and dingoes. However, whether it was direct hunting by people, competition with dingoes, changes brought about by the increasing human population, who by 3000 years ago were using all habitat types across the continent, or a combination of all three, is unknown; devils had coexisted with dingoes on the mainland for around 3000 years. Brown has also proposed that the El Niño-Southern Oscillation (ENSO) grew stronger during the Holocene, and that the devil, as a scavenger with a short life span, was highly sensitive to this. In dingo-free Tasmania, carnivorous marsupials were still active when Europeans arrived. The extermination of the thylacine after the arrival of the Europeans is well known, but the Tasmanian devil was threatened as well.

Thylacines preyed on devils, and devils attacked thylacine young; devils may have hastened the thylacine's extinction. While the thylacine was extant, apart from hunting devils, it may also have put pressure on the devil for survival, by competing for scarce food and dens; both animals sought caves and burrows. It has been speculated that devils may have become more predacious and presided over larger home ranges to fill in the vacancy left by the thylacine.

Habitat disruption can expose dens where mothers raise their young. This increases mortality, as the mother leaves the disturbed den with her pups clinging to her back, making them more vulnerable.

Cancer in general is a common cause of death in devils. In 2008, high levels of potentially carcinogenic flame retardant chemicals were found in Tasmanian devils. Preliminary results of tests ordered by the Tasmanian government on chemicals found in fat tissue from 16 devils have revealed high levels of hexabromobiphenyl (BB153) and "reasonably high" levels of decabromodiphenyl ether (BDE209).

Since 1999, all devils caught in the field have had ear biopsies taken, providing samples of DNA. As of September 2010, there are 5,642 samples in this collection.