The world's largest marsupial carnivore is facing extinction from a mystery facial cancer.

But scientists say Cedric appears to be naturally resistant to the contagious tumours which have killed half the devil population in Tasmania.

Cedric is the first Tasmanian Devil to have shown any immunity from the disfiguring disease.

Infected animals become so consumed by the cancer they can no longer eat or see and eventually die of starvation.

Cedric was captured in western Tasmania last year, along with his half-brother, Clinky.

Both were injected by scientists with dead tumours. Clinky produced no antibodies, but Cedric did and appears to have built-in defences against the mystery illness.

The experiments have now moved up a gear.

Researcher Alex Kriess says the pair have had live cancer cells inserted into their faces.