Skull injuries reveal Tyrannosaurs’ violent and cannibalistic past

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Researchers have found evidence skull of a genus of tyrannosaur called Daspletosaurus that suggest that these dinosaurs have had a violent and cannibalistic past and out of the numerous injuries suffered during their life at least were likely inflicted by another Daspletosaurus.

Daspletosaurus was a large carnivore that lived in Canada and was only a little smaller than its more famous cousin Tyrannosaurus. Like other tyrannosaurs it was most likely both an active predator and scavenger.

The dinosaur in question, from Alberta Canada, was not fully grown and would be considered a “sub-adult” in dinosaur terms. It would have been just under 6 m long and around 500 kg when it died.

Researchers found numerous injuries on the skull that occurred during life. Although not all of them can be attributed to bites, several are close in shape to the teeth of tyrannosaurs. In particular one bite to the back of the head had broken off part of the skull and left a circular tooth-shaped puncture though the bone.

The fact that alterations to the bone’s surface indicate healing means that these injuries were not fatal and the animal lived for some time after they were inflicted.

Lead author David Hone said that this animal clearly had a tough life suffering numerous injuries across the head including some that must have been quite nasty. The most likely candidate to have done this is another member of the same species, suggesting some serious fights between these animals during their lives.

There is no evidence that the animal died at the hands (or mouth) of another tyrannosaur, but the preservation of the skull and other bones, and damage to the jaw bones show that after the specimen began to decay, a large tyrannosaur, possibly of the same species, bit into the animal and presumably ate at least part of it.

Combat between large carnivorous dinosaurs is already known and there is already evidence for cannibalism in various groups, including tyrannosaurs. This is however an apparently unique record with evidence of both pre- and post-mortem injuries to a single individual.

The study appears in Journal PeerJ.