August 19, 2009

Tasmanian devils’ social network studied

University of Tasmania scientists in Australia say they are using radio collars to study the social networking of Tasmanian devils to prevent their extinction.

The researchers, led by Rodrigo Hamede, said the Tasmanian devil -- the largest marsupial carnivore in existence -- is being threatened with extinction from a unique infectious cancer known as devil facial tumor disease. Devils are usually solitary animals, and the disease is thought to spread through biting when devils interact aggressively around prey carcasses and during mating season.

Hamede's team used radio collars to discover the structure of the devil's contact network.

Measuring individual contact patterns in wild animals is difficult, particularly for nocturnal forest-dwelling species, Hamede said. However this information is critical for understanding animal sociality, disease dynamics and for building epidemiological models.

The team attached proximity sensing radio collars to adult devils in Narawntapu National park, a 15-mile area containing a disease-free devil population. The collars were fitted to 46 sexually matured devils -- 23 males and 23 females.

The resulting data revealed that despite devils being solitary animals, all individuals were connected to a single social network meaning all of the collared devils were connected to all other individuals. That revealed how the disease is able to spread easily across the entire population.

The study is reported in the journal Ecology Letters.