A new study found that eating patterns and food preferences of dinosaurs are significantly influenced by how wide they can open their jaws.
University of Bristol researcher Stephan Lautenschlager utilized computer models to analyze the amount of jaw muscle strain among theropod dinosaurs having diverse types of dietary habits.
Theropods were a disparate type of two-legged dinosaurs and included the largest carnivores ever. Lautenschlager, who is part of the university's School of Earth Sciences, said that theropods like the Tyrannosaurus rex (T. rex) are usually portrayed to have jaws that can open to a great extent. Such claim may be due to the emphasis put on the species' carnivorous state. However, Lautenschlager said that there have been no studies targeting the relationship between jaw muscles, feeding techniques and maximal jaw gape.
The new study focused on three types of theropods: a large meat-eating T. rex, a medium-built carnivorous Allosaurus fragilis (A. fragilis) and a herbivorous Erlikosaurus andrewsi (E. andrewsi).
Lautenschlager created detailed digital models that imitate the opening and closing of the jaws of the three theropods. He then measured the length modifications in the digital musculature. Aside from that, the study also compared the dinosaurs to their living relatives such as birds and crocodiles, which are recognized to have a wide jaw gape and muscle strain as well.
The findings of the study found that the T. rex and the A. fragilis, which were both carnivorous, had a wide gape, reaching to about 90 degrees. The T. rex was found to have a sustained muscle force for an extensive range of jaw angles, which was important in penetrating the skin and crushing the bones of its prey. The plant-eating E. andrewsi exhibited a smaller jaw gape of approximately 45 degrees.
"All muscles, including those used for closing and opening the jaw, can only stretch a certain amount before they tear," said Lautenschlager. He added that this then restricts how wide the animals could open their jaws and hence affects the type of food they ate.
Lautenschlager also said that based on observations of living animals, it is well recognized that carnivores have wider jaw gapes than herbivores. Finding out that the same setup also transpired among theropod dinosaurs is something interesting to know.
The study was published in the Royal Society Open Science journal on Nov. 3.
