With an enormous physique, sharp claws, and dagger-like tooth, Tyrannosaurus rex wouldn’t have relied on appears to be like to kill. However analysis suggests its eyes might have contributed to its bone-crushing chunk.
A research has proposed the keyhole-shaped eye sockets of T rex might have helped to disperse stress throughout the cranium of the fearsome predator because it chomped on its prey.
“They actually had specialised eye socket shapes, which helped them take care of excessive chunk forces,” mentioned Dr Stephan Lautenschlager, a vertebrate palaeontologist on the College of Birmingham and writer of the research.
However, he added, the profit to cranium stability might have come at a price, noting the T rex had comparatively small eyes for the dimensions of its cranium.
Whereas Lautenschlager mentioned that didn’t imply the T rex had dangerous eyesight, he mentioned massive eyes have been related to sharper sight.
“There’s a little bit of a trade-off between higher imaginative and prescient, bigger eyes, however greater stresses within the cranium due to [a circular eye socket],” he mentioned.
Writing within the journal Communications Biology, Lautenschlager analysed the form of the attention socket, or orbit, of 410 species that lived between 252m and 66m years in the past, together with dinosaurs, pterosaurs and the ancestors of crocodiles.
His outcomes reveal that whereas many of the species had round eye sockets, some had orbits that resembled a keyhole or a figure-of-eight.
“About two-thirds or three-quarters have the standard round orbit after which the remaining are deviating from that and doing one thing extra excessive or extra fancy,” mentioned Lautenschlager.
Lautenschlager notes the keyhole or figure-of-eight orbits have been usually discovered amongst meat-eaters with massive skulls, specifically massive carnivorous theropod dinosaurs resembling Tyrannosaurus rex.
“There are just a few teams throughout the theropods which have switched weight loss program and tailored to a plant-eating or herbivorous weight loss program. And people once more have round orbits,” mentioned Lautenschlager. “So [orbit shape is] very carefully linked to weight loss program and measurement.”
Lautenschlager used a sequence of laptop fashions to discover the ramifications of the completely different eye socket shapes, discovering {that a} round orbit is related to higher deformation of the bones across the eye socket throughout biting, and that key-hole or figure-of-eight formed orbits helped to distribute stresses throughout the cranium so that they weren’t concentrated at one level.
The research additionally proposes that round orbits may restrict the house for jaw muscle tissue, and therefore their quantity, with Lautenschlager noting that might have an effect on general chunk power.
Lautenschlager mentioned it was seemingly the non-circular eye sockets and excessive chunk forces developed in parallel.
“Apparently, you see that in juvenile T rex, they nonetheless have the superbly round or almost round orbits, as a result of they didn’t produce that top chunk forces presumably, or had barely completely different weight loss program, or completely different prey repertoire,” Lautenschlager added.
Prof Steve Brusatte, a palaeontologist and T rex knowledgeable on the College of Edinburgh, who was not concerned within the work, welcomed the research.
“While you peer into the eyes of a T rex cranium, the attention socket appears to be like a bit of bit humorous, sort of like a keyhole. And it appears small for an animal with a head the dimensions of a tub,” he mentioned.
“This progressive new research reveals that the eyes of T rex have been formed not solely by the necessity for eager imaginative and prescient, but in addition by the necessity to chunk strongly,” mentioned Brusatte.
“As bizarre because it appears, the eyes of T rex really helped make it one of many strongest biters in Earth historical past.”