September 1, 2011
Tasmanian Tiger Not To Blame For Killing Sheep
Hunted to extinction in the early twentieth century for allegedly being a killer of sheep, Australia´s iconic Thylacine, also known as the Tasmanian tiger because of its striped back, has been found not guilty in a new study published in the Zoological Society of London´s Journal of Zoology.
“Our research has shown that its rather feeble jaw restricted it to catching smaller, more agile prey,” said lead author Marie Attard, of the University of New South Wales Computational Biomechanics Research Group.
“That´s an unusual trait for a large predator like that, considering its substantial 30 kg body mass and carnivorous diet. As for its supposed ability to take prey as large as sheep, our findings suggest that its reputation was at best overblown.”
The study also suggests that the animal´s diet was significant to its demise. “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,” BBC News is reporting.
This week marks the 75th anniversary of the death of Ben, believed to have been the last remaining thylacine, kept at Hobart Zoo in Tasmania.
“It was given a really poor reputation in its day - accused of being a vicious, wasteful sheep killer,” said Attard.
The UNSW research team, using advanced computer modeling techniques, were able to simulate various predatory behaviors, including biting, tearing and pulling, to predict patterns of stress in the skull of a thylacine.
“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 Stephen Wroe, director of the Computational Biomechanics Research Group at UNSW.
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. A thylacine wouldn´t have been capable of this.”
“We can be pretty sure that thylacines were competing with other marsupial carnivores to prey on smaller mammals, such as bandicoots, wallabies and possums.
“Especially among large predators, the more specialized a species becomes the more vulnerable is it to extinction. Just a small disturbance to the ecosystem, such as those resulting from the way European settlers altered the land, may have been enough to tip this delicately poised species over the edge.”
Image 1: Thylacines in Washington D.C., c. 1906. Credit: Smithsonian Institution
Image 2: This is a frontal view of thylacine. Credit: Marie Attard
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