Humans killed off Tasmanian Tigers single-handed

Posted by Kate Taylor

It really is all our fault: the Tasmanian Tiger, or thylacine, was wiped out entirely by human actions; disease didn't play a part, as was previously thought.

Between 1886 and 1909, the Tasmanian government encouraged people to hunt thylacines, a unique marsupial carnivore found throughout most of Tasmania before European settlement in 1803.

By the time the bounty was lifted, the government had paid bounties on over 2000 thylacine carcasses, and only a handful of animals were ever found afterwards. The last known thylacine was captured from the wild in 1933.

"Many people, however, believe that bounty hunting alone could not have driven the thylacine extinct and therefore claim that an unknown disease epidemic must have been responsible," says  research associate Dr Thomas Prowse of the University of Adelaide.

"We tested this claim by developing a 'metamodel' - a network of linked species models - that evaluated whether the combined impacts of Europeans could have exterminated the thylacine, without any disease."

The team says their model improves on the competition by including species interactions.

"The new model simulated the directs effects of bounty hunting and habitat loss and, importantly, also considered the indirect effects of a reduction in the thylacine's prey (kangaroos and wallabies) due to human harvesting and competition from millions of introduced sheep," says Prowse.

"We found we could simulate the thylacine extinction, including the observed rapid population crash after 1905, without the need to invoke a mystery disease. We showed that the negative impacts of European settlement were powerful enough that, even without any disease epidemic, the species couldn't escape extinction."