Tasmanian tiger was no sheep killer
Wrongly accused New research has revealed the Tasmanian tiger may not have deserved its sheep-killing reputation.
September marks the 75th anniversary of the death of the last known tiger, or thylacine (Thylacinus cynocephalus), at a Hobart zoo.
When it was alive it had a bad reputation as a sheep killer.
From 1830 till 1909 there was a bounty on the species because it was considered a pest.
PhD candidate Marie Attard, from the University of New South Wales, says people thought each thylacine could be eating up to 100 sheep each year.
While it has been more recently acknowledged that that was an exaggeration, she says thylacines may not have even been capable of killing and eating sheep.
"We actually found that thylacines have really weak jaws," says Attard.
"Even though it had quite a large body and a large head it actually wasn't really very good at eating big animals.
"If you think about a sheep, it weighs about 90 kilos and thylacines were about 30 kilograms and their jaws were just too weak to be able to take on something that big."
Instead, Attard believes thylacines ate small animals such as bandicoots and possums.
"Animals that weigh over 22 kilograms should be taking down animals that weigh about their body size or even a bit more," she says.
"So the fact that this animal is eating very small animals, probably around five kilos, is quite an interesting find and it would also mean that they have to eat a lot of small animals to be able to survive."
The researchers used CAT scans of a thylacine skull to build digital 3-D engineering models.
"What we do is we can digitally crash test that skull to test its mechanical strength," says Attard.
"It's actually quite similar to the software that engineers use to look for weak points in materials used to build man-made objects such as bridges and aircraft wings."
The researchers simulated thylacine behaviours including biting, tearing and pulling to see how they responded to struggling prey in their mouths.
In the images produced, different colours showed how much stress each part of the skull was under.
"In the end the skull basically, for the thylacine's case, ended up lighting up like a Christmas tree because it had so much stress in it," says Attard.
Study co-author Dr Stephen Wroe, also from the University of New South Wales, says the findings were surprising.
"I had expected that we would find that the thylacine would have been better adapted to take large prey," he says.
"That would have meant there would have been less competition between the thylacine and its close relatives, the Tasmanian devil and the spotted tail quoll."
It is believed this competition for food, the bounty and settlers altering the land all contributed to the species' demise.
The findings appear in the latest edition of the Journal of Zoology.