2. Tasmanian devil (Sarcophilus harrisii)
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Between 1996 and 2008, the population of Tasmanian devils dropped some 60% due a contagious cancer known as Devil Facial Tumour Disease. It continues to decimate populations of the species, which only occurs on the Australian island of Tasmania. There may only be 10,000 wild individuals remaining. Captive breeding of uninfected individuals has been instituted and efforts have been made to develop a vaccine for the cancer, which is thought to have stemmed from mutated cells from a single specimen.
