Wednesday, August 31, 2011

Tasmanian tiger's jaws were too weak to kill sheep

Closer examination of the animal's jaws showed they were too weak to trap a struggling adult sheep.

Related Stories

At the end of the 19th Century, the thylacine had a price on its head.
The strange marsupial carnivore, which became extinct in 1936, was thought to kill sheep. Sheep farming was the backbone of the Australian economy, and the government duly set up a bounty scheme to exterminate the species.
But a new study has now revealed that the marsupial carnivore's jaws were too weak to snare a struggling adult sheep.
The findings are reported in the Journal of Zoology.
As well as revealing the injustice of its being hunted, the study also suggests that the animal's diet contributed significantly to its demise.

Start Quote

The species puzzled settlers and people would hunt them out of fear and hate”
Marie Attard University of New South Wales
"They would need to hunt a lot of small animals to survive," explained lead researcher Marie Attard from the University of New South Wales (UNSW) in Sydney.
"So just small disturbances to the ecosystem - such as those resulting from the way European settlers altered the land - would have reduced their odds of survival."
Thursday marks the 75th anniversary of the death of what is believed to have been the last remaining thylacine, named Ben. The animal was kept at Hobart Zoo in Tasmania.
Thylacines, also known as Tasmanian tigers because of their striped back, used to roam throughout Australia and New Guinea. By the end of the 19th Century, Tasmania was the last refuge for a few remaining animals.
"It was given a really poor reputation in its day - accused of being a vicious, wasteful sheep killer," said Ms Attard.
'Digital crash test' She and her colleagues, including Stephen Wroe - also from UNSW - examined the animal's skull.
"We scanned the skull and then used the same software on it that you would use in engineering, to investigate the stresses on man-made structures, such as bridges and aircraft wings," explained Dr Wroe.
This digital "crash test" revealed that thylacine's jaws were simply too weak to have brought down an adult sheep.
"If a large carnivore - like a big cat for example - wants to take down a big prey item, it has to clamp down on its throat and suffocate it," said Dr Wroe.
"A thylacine wouldn't have been capable of this."
Digital reconstruction of a thylacine skull The digital "crash test" revealed the weak points in thylacine's jaws
Dr Wroe also explained that thylacine's teeth were "built for slicing" rather than for crushing bone.
Comparing its skull performance with closely related, living species with known diets, the scientists were able to predict the likely body size of its prey.
"It probably fed on small animals, such as possums," said Dr Wroe. "And its limited diet would have made it more vulnerable to extinction."
But, at the time, people were afraid of the strange, long-snouted tiger.
Ms Attard told BBC Nature: "After only a century of European settlement the thylacine was pushed to the brink of extinction.
"The species puzzled settlers and people would hunt them out of fear and hate."
Eventually, when the imminent extinction of the species became apparent, the thylacine received official protection from the Tasmanian government. But by then it was far too late.
"That was just two months before the last known individual died at Hobart Zoo," said Ms Attard.
"The terrible loss of the thylacine signifies unjustified, negligent destruction of our native flora and fauna. It is a cautionary reminder of what we have lost, and that without urgent intervention other species will suffer the same fate."
The Australian team use hi-tech scanning and "biomechanics" to examine the feeding patterns of extinct and living endangered animals.
Their recent studies have also revealed some surprising insights into the bite force of great white sharks.
Ms Attard concluded: "An understanding of risk factors - such as habitat and diet specialisation - in species that have already become extinct may help guard against future biodiversity loss by anticipating and preventing species declines before they begin."
Post a Comment