With a huge body, sharp claws and dagger-like teeth, Tyrannosaurus Rex Will not rely on appearance to kill. But research suggests that her eyes may have contributed to the bone fracture bite.
A study suggested that the keyhole-shaped eye cavities of the T rex may have helped deflect stress across the fearsome predator’s skull as it chomped on its prey.
“They had specialized shapes in the eye sockets, which helped them deal with high biting forces,” said Dr. Stefan Lautenschlager, a vertebrate paleontologist at the University of Birmingham and author of the study.
But he added that the benefit of skull stabilization may come at a cost, noting that T-Rex’s eyes are relatively small relative to the size of their skull.
While Luttenschlager said that didn’t mean the T-Rex had bad eyesight, he did say that big eyes are associated with clearer vision.
“There is little trade-off between better vision and larger eyes, but greater pressures in the skull due to [a circular eye socket],” He said.
Writing in the magazine Communication biologyLautenschlager analyzed the shape of the eye sockets, or orbits, of 410 species that lived between 252 and 66 million years ago, including dinosaurs, pterosaurs, and ancestors of crocodiles.
His results reveal that while most species had circular eye sockets, some had keyhole-like or octagon-shaped orbits.
“It has two-thirds or three-fourths of the typical circular orbit, and then the rest veer off that and do something more extreme or more luxurious,” Luttenschlager said.
Lautenschlager notes that a keyhole or eight-orbit shape is generally found among large-skull carnivores, particularly large, legged meat-eating dinosaurs such as Tyrannosaurus rex.
There are a few groups within theropods that have changed their diet and adapted to one that eats plants or eats herbs. “These again have circular orbits,” Lautschlager said. “So [orbit shape is] It is closely related to diet and size.”
Lautenschlager used a series of computer models to explore the implications of different eye socket shapes, and found that a circular orbit was associated with greater deformation of the bones around the eye socket during biting, and that a keyhole or shape of eight helped the orbits distribute stresses across the skull so that they were not concentrated at one point.
The study also suggests that circular orbits may limit the area of the jaw muscles, and therefore their size, with Lautenschlager noting that this may affect overall bite force.
It’s possible that non-circular eye cavities and high bite forces may have evolved in parallel, Luttenschlager said.
“Interestingly, you see, in juvenile T-Rex, they still had perfectly circular or nearly circular orbits, because they probably didn’t produce that high biting force, or they had a slightly different diet, or different prey repertoire,” Luttenschlager added. .
Professor Steve Brusatte, a paleontologist and T rex expert at the University of Edinburgh, who was not involved in the work, welcomed the study.
“When you look into the eyes of a T-Rex skull, the eye socket looks a bit funny, like a keyhole. It seems small for an animal with a head the size of a bathtub.”
“This innovative new study shows that T-Rex eyes are shaped not only by the need for intense vision, but also by the need to bite hard,” Brusatte said.
“As strange as it may sound, the eyes of a T-Rex have helped make him one of the most powerful speculators in Earth’s history.”