Saturday, 5 November 2011

The Strongest Terrestrial Mammal Bite Ever

An Agriotherium africanum skull
There have been many mammals throughout prehistory that could have delivered a bone shattering bite. One of the most infamous was Thylacoleo carnifex. It had the strongest bite, pound per square inch, than any other land predator. Now a team led by Dr Stephen Wroe from the University of Newcastle have found an even more powerful predator. Agriotherium africanum was a giant, short-faced bear that became extinct around 5 million years ago.

The bite stress comparison between (A) Agriotherium, (B) Asian bear,
(C) black bear, (D) brown bear, (E) giant panda and (E,F) polar bear. The
areas in pink mark the areas of highest stress, while green shows relatively
 mild strain. Agriotherium (A) demonstrates the least strain out of all seven
specimens, giving the greatest potential bite strength out of all terrestrial
mammals both alive and extinct
While not the largest of bears, it was the dominant predator on the African grasslands; a hyper-carnivorous apex predator that would have fed upon all other creatures in its hunting ground. Using CT scans, Wroe and the team created 3D computer models of Agriotherium's skull and several other closely related predators, including polar and black bears and a giant, extinct panda. Then they applied simple physics to investigate the strains that bites would place upon the jaws.

The scans showed that most of the force would have been exerted by the canine teeth, and that there was very little grinding area at the back. This creature would have sliced chunks of meat from its prey, swallowing them whole. The models also showed that the jaw bones of Agriotherium were incredibly strong in comparison to the other specimens; and while the others exhibited high stress points on the joints, Agriotherium was far more resilient and could potentially produce far stronger bites than any other terrestrial mammal today or in prehistory.

Wroe suggests that Agriotherium had a far stronger skull and bite force, as it fed upon a wider variety of prey to get at the nutritious red meat. In contrast, the polar bear possessed the weakest bite force and skull strength out of all of the specimens. Wroe believes that this contrast is because Agriotherium was adapted to feed upon meat, whereas the polar bear has a diet of soft blubbery seals, eating the energy-rich fat as opposed to the tough muscle.