According to an assessment made in 2008, when the Tasmanian devil was put on the red list of endangered species, there are about 10,000 to 25,000 mature Tasmanian devils left in the wild. All Tasmanian devils not in captivity live on the island of Tasmania off the coast of Australia.
In the 1990s, the total Tasmanian devil population was estimated at 130,000 to 150,000. However, the population has been in continual rapid decline since then. The main cause has been an outbreak of devil facial tumor disease. It is a contagious cancer that causes tumors to form around the face and mouth. Because the afflicted animal cannot eat, it starves to death. In some areas where the disease is widespread, Tasmanian devil populations have diminished as much as 90 percent. Additionally, thousands of Tasmanian devils are victims of roadkill annually. A number of Tasmanian devils are also killed by poorly controlled dogs every year. In the 1980s and 1990s, large amounts of Tasmanian devils were poisoned by ranchers, and extermination on ranch lands continues on a lesser scale despite the Tasmanian devil's endangered status.
Efforts to eradicate DFTD include euthanasia of affected individuals and research into treatments and vaccines. Additionally, healthy populations of Tasmanian devils have been isolated in captivity to protect them from the disease, so that if wild populations become extinct, the species can be reintroduced.