Feb. 3, 2006 — Australian scientists believe they have gained vital insight into the drastic decline of the Tasmanian devil, a marsupial whose numbers have been decimated by a facial tumor disease.

Malignant facial cancers, which kill the devils by preventing them from eating, now affect more than half of the animals on Tasmania, their sole home in the wild.

Devils normally have a life expectancy of about five years, but it is now rare to see an animal in the wild that is older than three.

Reporting on Thursday in the British science journal Nature, a Tasmanian duo propose that the horrific, disfiguring disease is transmitted by biting when the animals fight or engage in courtship rituals.

Cancerous cells are dislodged from an infected devil and are passed on to another animal if it gets bitten around the mouth, according to their study, which is based on an ID scan of the cancer's genes.

The spread of the disease is compounded by the small gene pool of remaining Tasmanian devils. Lack of genetic diversity diminishes the capacity of their immune systems to fight the infection, the researchers believe.

The study was led by Anne-Maree Pearse of Tasmania's Department of Primary Industries, Water and Environment.

In a related news report, Nature said a pilot study conducted in two peninsulas on Tasmania's southeastern coast showed progress in combating the spread of the disease.

All infected animals were removed from a 120-square-kilometer (46.3-square-mile) area of the peninsulas. As a result the population of devils in this area remained intact and no new cases of the facial cancer were reported.

Despite this, it may be impossible to introduce such a scheme across all of Tasmania, which places the onus on a vaccine or therapy to combat the disease, Nature said.