Friday, September 07, 2007

Did the Tasmanian Tiger loose to the Dingos?

Via a comment to one of PZ's posts over at Pharyngula, I came across this piece of news. Unfortunately I can't find the comment where the link was posted, so I can't give proper credit to the orginal poster.

Tasmanian tiger's weaker bite gave dingoes the edge

The Tasmanian tiger probably died out because of competition from the dingo, whose stronger head and neck could better handle the stresses of tackling bigger prey, according to research on the animals’ skulls. The new study challenges the theory that humans were mainly to blame.

First of all, I dislike the mis-use of the word "theory" here. It was at best a hypothesis, which was considered as one possible explanaition (the other hypothesis was that the extinction was caused by the Dingos). So the findings are not quite as revolutionary as the lead paragraph makes it sound.

What I find quite interesting about this study, is that it's based upon some computer models, where the scientists modelled the skulls of Dingos and Tasmanian Tigers.

Using a series of CT scans of the skulls, they created sophisticated computer models of the animals' heads. They then studied the stresses on the skull, jaw, teeth, and muscles around the skulls while they simulated the biting, tearing and shaking of prey.

They found that as the size of a struggling prey animal got bigger, so too did stresses at the back of both the skulls. But differences in skull geometry, and the amount of muscle that would have been attached to the back, meant that these stresses were relatively much higher in the thylacine.

So, in other words, Dingos could hunt larger animals than Tasmanian Tigers. Combined with the later's larger size (according to the article, they were 70% heavier than dingos), and there is a distinct evolutionary advantage to the Dingos.

The study can be found behind a pay-wall at the Proceedings of the Royal Society, though a abstract can be read here

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