Humans are to blame.
Guilty as charged. That is the verdict reached by scientists studying the extinction of the Tasmanian tiger (Thylacinus cynocephalus).
According to new research, human activity led to the extinction of the meat-eating marsupial, not disease as some scientists have previously claimed.
The study, relying on a newly devised population modelling approach, found The Tasmanian tiger, also known as thylacine, could have gone extinct as the result of human hunting and habitat destruction. Previous modelling approaches had reached the conclusion that the extinction of such a large group of animals required at least two or three factors. While the scientists conceded that more than one factor contributed to the marsupial’s extinction, all three factors were directly the result of human activity.
“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,” said Research Associate Dr. Thomas Prowse, who led the study. “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.”
According to Prowse, the new model simulated the effects of bounty hunting and habitat loss and also considered the impact of the reduction in the thylacine’s prey, kangaroos, and wallabies, due to human harvesting. The scientists noted the introduction of sheep grazing was especially devastating to the thylacine’s survival rate, as the marsupial was often cited as the culprit of attacks by farmers.
The thylacine was a unique marsupial carnivore found throughout most of Tasmania before European settlement in 1803. The thylacine was once widely distributed across Australia, Tasmania, and New Guinea. According to scientists, the native dingo is thought to have contributed to its demise outside of Tasmania.
Between 1886 and 1909, the Tasmanian government encouraged people to hunt the animal, evening going to so far as to pay bounties to individuals able to collect more than 2,000 carcasses. Only a handful of animals were located following the lifting of the bounty. The last known thylacine died in Hobart Zoo in September 1936 and it was officially declared extinct in 1986. The last known thylacine was captured from the wild in 1933, according to researchers.
The results of the study are likely to spark debate. Finding released last year attributed the thylacine’s extinction to low genetic diversity. Writing at the time, scientists say individual thylacine samples were 99.5 percent similar over a portion of the genome that normally has lots of differences.
The study is published in the Journal of Animal Ecology.