T-Rex had a huge jaw gape, study shows


The ferocious and dangerous Tyrannosaurus rex had a nasty bite, researchers suggests through a new study where they analysed jaw gapes of meat- and plant-eating dinosaurs.

University of Bristol researchers used digital models to analyse the muscle strain during jaw opening of three different theropod dinosaurs with different dietary habits – Tyrannosaurus rex, Allosaurus, and Erlikosaurus. Using computer simulations, researchers compared their findings with those of dinosaurs’ living relatives, crocodiles and birds, for which muscle strain and maximal jaw gape are known.

Through the study, researchers try to establish a relation between musculature, feeding style and the maximal possible jaw gape of these dinosaurs. Dr Stephan Lautenschlager from Bristol’s School of Earth Sciences says “All muscles, including those used for closing and opening the jaw, can only stretch a certain amount before they tear. This considerably limits how wide an animal can open its jaws and therefore how and on what it can feed.”

Researchers created detailed computer models to fully understand the relation between muscle strain and jaw gape. Using these models, they simulated jaw opening and closing, while measuring the length changes in the digital muscles.


According to the team, Tyrannosaurus and Allosaurus were capable of a wide gape (up to 90 degrees), while the herbivorous Erlikosaurus was limited to small gape (around 45 degrees). Between the two carnivores, results show that Tyrannosaurus could produce a sustained muscle (and, therefore, bite) force for a wide range of jaw angles, which would be necessary for biting through meat and skin and crushing bone.

Dr Lautenschlager said: “We know from living animals that carnivores are usually capable of larger jaw gapes than herbivores, and it is interesting to see that this also appears to be the case in theropod dinosaurs.”