Tasmanian devils are carnivorous marsupials native to the Australian island state of Tasmania. They are known for their extremely loud and disturbing nocturnal screech, which has also earned them their name. However, Tasmanian devils have been making news headlines more frequently in the recent years as a fatal disease is causing the species to face extinction in the wild.
An aggressive and contagious cancer called Devil Facial Tumour Disease (DFTD), first diagnosed in 1996, is decimating the species and causing a rapid decline in wild populations, with as little as 10% of the original population left in the wild today. The initial signs of the disease include lesions and lumps in and around the mouth which progressively develop into cancerous tumours that grossly distort the face and neck, sometimes spreading to other parts of the body. These large tumours interfere with eating and drinking, and eventually the animal dies of starvation and dehydration within three months of the initial appearance of tumours.
One of three recorded transmissible cancers, DFTD is spread from one devil to another through biting during feeding (individuals often fight over food) or mating. In 2006, Pearse and Swift discovered that the DFTD tumour cells are all clonal descendants of one ancestral tumour from an individual devil that was spread to others. One year later, researchers at the University of Sydney found that once transferred into a new host, the live tumour cells are not recognised as ‘foreign’ by the animal’s immune system because the genetic diversity among Tasmanian devils is so low; therefore the devil’s immune system does not try to fight it off and the cancer takes over rapidly.
Currently, there are virtually no Tasmanian devils left in southern and eastern Tasmania. Attempts to eradicate the disease through culling and selectively removing diseased individuals from the wild have proven unsuccessful, and with no signs of a cure in sight their survival now rests on the research and conservation efforts led by the Save the Tasmanian Devil Program. One of the Program’s vital components is the establishment of healthy and genetically diverse captive populations (an insurance population) of Tasmanian devils; these animals are being bred and carefully managed in order to ensure that they retain their wild traits and their descendants are able to be successfully released into the wild once the disease is gone.