Why Did T-rex Have the Strongest Bite Ever in a Land Animal?

The fused nasal bones

By on May 21st, 2007 07:06 GMT
Tyrannosaurus rex was the terror of the dinosaur world.

Now researchers not only have calculated the power of its terrible bite, but also the secret behind it: its hardened snout.

"Fused, archlike nasal bones are a unique feature of tyrannosaurids. This adaptation, for instance, was keeping the T. rexes from breaking their own skull while breaking the bones of their prey." said lead researcher Eric Snively of the University of Alberta.

Tyrannosaurids (T-rex and its relatives) had big, strong teeth and skulls but also large gaps on the skull for attachment and development of jaw muscles, suggesting a powerful bite able to crush the flesh and bones of large dinosaurs.

Now, the biomechanics and the latest scan technology have explained how the fused nasal bone contributed to the beast's powerful bite to make it the strongest of any land animal ever.

Snively's team compared the skulls and teeth between tyrannosaurids and non-tyrannosaurids carnivorous dinosaurs. The researchers focused on teeth-bending, nose and skull strength. The nasal bones are located over the tooth-bearing upper jaw and each bite induced a hit on them. The fused tyrannosaurid nasals proved significantly stronger than unfused nasal bones of the non-tyrannosaurid.

"When T. rex bit down, the forces from the upper teeth would be channeled right to the [fused] nasal bones," Snively said.

This way the bite would break the bones of the prey.

In the case of a non-tyrannosaurid carnivorous dinosaur with unfused nasal bones connected just through elastic ligaments, some of the bite force would be wasted on the slide of the nasal bones against each other.

"Because the nasals [of T. rex] were fused, all of the bite force was transmitted to the food instead of some of the force being distorting the skull. The T. rex especially had a very strong skull and jaw muscles that would turn it into a zoological superweapon." Snively said.

It was calculated that a medium-sized T. rex had a more powerful bite than larger carnivorous dinosaurs, like Carcharadontosaurus saharicus, with a head about 1.5 times longer than that of T. rex and this results even from conservative estimates.

"We kept the muscle numbers down because we thought they couldn't possibly be that powerful," Snively said.

A team at the Tyrrell museum has calculated T. rex's bite power at 200,000 newtons, enough for lifting a tractor-trailer.

T. rex's powerful neck helped the dinosaur ear: when it had its teeth embedded in the prey, the dino could swing its head and rip apart large pieces of meat from it.

"The tossing showed us how easily T. rex could feed; it would toss food back in the throat," Snively said.

"All of the T. rex's features came together to give it the strongest bite of any land animal," he further explained.

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