Researchers say deadly tumour that has wiped out 80% of the marsupials will evolve to ensure its survival – and devils will do the same

This article is more than 5 years old

This article is more than 5 years old

The deadly facial tumour disease that has killed large numbers of Tasmanian devils is evolving to increase infection rates but is unlikely to wipe out the species completely, according to new research.

A study of devils in north-western Tasmania by Australian and British scientists found that the facial tumour disease has been evolving to allow the devils to live for longer, thereby increasing the spread of the infection.

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The facial tumours are spread by contact between devils, which often fight and clash heads when competing over food. The disease, first identified in 1996, is estimated to have wiped out 80% of the of the feisty marsupial’s population, based on sightings of the animal in Tasmania.

However, the findings of a 10-year project by the University of Tasmania, University of Cambridge and the Tasmanian government found that this evolution in the tumours meant that the threat of extinction was dwindling.

“The tumour is subject to changes – for its own benefit rather than the devil’s benefit,” said Dr Rodrigo Hamede, of the University of Tasmania’s school of biological sciences. “The tumour is a living organism and wants to do whatever is best for it.

“The tumour used to allow devils to survive longer and the population to sustain itself. Then the diploid strain arrived and out-competed the more benign tumour strain, and has caused a severe population decline.

“The diploid tumour at this site is the older and most common tumour type which is spread over most of Tasmania.”

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This sharp population decline followed six years of stable devil numbers in the area studied by the scientists. The competition between the tumour strains provides hope that the devils will evolve to coexist with it, and the tumour will further change to ensure its host is not completely wiped out.

Hamede said it would be “unrealistic” to expect the disease to be eradicated but that it was possible for the devils to avoid extinction.

Several devil “insurance” populations have been set up on the Australian mainland as well as islands off Tasmania, such as Maria Island.

The species is considered a key part of Tasmania’s ecology. Some researchers are plotting the devil’s return to Victoria and New South Wales in order to combat the harmful spread of foxes and feral cats.