Tasmanian Devil (Sarcophilus harrisii)
In 1996, the Tasmanian Devil was placed in the category of animals at 'Least Risk' of extinction. In that same year, a few devils were observed and photographed with growths and tumors on their faces. Today, 10 years later, it is estimated that 40% of the Devil population has been wiped out by what has come to be known as Devil Facial Tumour Disease (DFTD). The disease causes large tumours to grow on the faces of the Devils, and once the tumours appear, there is no recovery--at least not yet. Researchers are actively pursuing research to combat DFTD and preserve the threatened population of Devils.
DFTD is transmitted by allograft, which is fairly rare. Allograft occurs when diseased cells are passed physically from one individual to another. In the case of DFTD, it is thought that the cells are passed between individuals during their frequent scuffles, or mating which often involves biting the necks of their partners.
Currently, captive breeding populations have been established to ensure that the species will survive in the event that DFTD causes them to disappear from the wild. There is also concern that competition with introduced species such as foxes will hinder the Devil's ability to recover.
Tasmanian Devils are confined to the island of, well, Tasmania, and are named for their eerie calls (my friends will tell you that at times, I can be convinced to attempt an imitation).
Here's a site with info on how you can get involved, donate, or volunteer.