“Often times, large carnivorous dinosaurs, such as the allosaurus or tyrannosaurus, are depicted with their jaws wide open, probably to emphasize their predatory nature,” says Stephan Lautenschlager, from the Faculty of Earth Sciences at the University of Bristol. in the United Kingdom. “However, to date there have been no studies relating the musculature of the jaws of these animals, their maximum capacity for mouth opening and their eating habits, ” emphasizes this paleontologist.
Now, in a new essay published in the Royal Society’s journal Open Science , Lautenschlager points out that, in general, and as is the case with most carnivores today, dinos that were carnivores were able to display more their jaws than herbivores. To determine this, Lautenschlager has analyzed using digital models the maximum effort that the jaw muscles of some of them could undertake and has compared them with that of their living relatives, birds and crocodiles.
Thus, he has focused his research on three types of theropods, dinosaurs that moved bipedally, whose diet and way of feeding differed: the tyrannosaurus, about 12 meters long and 7 tons, which lived 66 million years ago; the allosaurus, which was around 8 meters and a ton in weight, and lived 150 million years ago; and the Erlikosaurus , about 6 meters and about 90 million years old , which, unlike the previous ones and the vast majority of theropods, consumed plants.
“All muscles, including those that allow you to open and close your mouth, can only be stretched to a certain extent; beyond that limit, they tear. This considerably marks the opening capacity of the jaws and, therefore , defines how an animal eats and what it can swallow, ”says Lautenschlager.
The study has shown that in allosaurs and tyrannosaurs, the optimal mandibular opening angle was 28º, while in Erlikosaurus it was 20.5º. The maximum, for its part, reaches 43.5º in this last dinosaur, but in tyrannosaurs it was much higher, 63.5º. The palm was taken by the aforementioned allosaurs, whose jaws opened up to 79º. Of course, the Tyrannosaurus rex were able to maintain a sustained force with their jaw muscles at different angles, allowing them to penetrate through the meat of their prey and break bones more easily.
