Australian researchers investigating the extinction of the country's Tasmanian Tiger put the fault solely with humans Thursday, saying they had debunked a long-held theory that disease was to blame.
The last known tiger, or thylacine, died in Hobart Zoo in September 1936 and though there have been numerous unconfirmed sightings in the wild over the years since, it was officially declared extinct in 1986.
When European settlers arrived in the southern island state of Tasmania in 1803 the thylacine—a shy, carnivorous marsupial which resembled a long, large dog with a striped coat and wolflike head—was widespread.
Their final extinction has long been linked to a distemper-like disease that tore through the last remaining tigers, but a University of Adelaide team said it had proven that disease was not a central cause.
"Many people believe that bounty hunting alone could not have driven the thylacine extinct and therefore claim that an unknown disease epidemic must have been responsible," said Thomas Prowse, lead researcher of the study published in the latest edition of the Journal of Animal Ecology.
"We found we could simulate the thylacine extinction, including the observed rapid population crash after 1905, without the need to invoke a mystery disease."
Prowse's team used new species interaction modelling to study how the arrival of European sheep farmers had impacted on the thylacine in a range of ways including bounty hunting between 1830-1909.
"Importantly, we 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," Prowse said.
"We showed that the negative impacts of European settlement were powerful enough that, even without any disease epidemic, the species couldn't escape extinction."
The thylacine was once widely distributed across Australia and New Guinea, and the native dingo, or wild dog, is thought to have contributed to its demise outside of Tasmania.
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More information: Paper: onlinelibrary.wiley.com/doi/10.1111/1365-2656.12029/abstract