Elongated eyes may be what allowed Tyrannosaurus rex to chomp down on prey

The Tyrannosaurus rex is known for its ability to easily and fiercely attack and eat its hunted prey. A new study by a paleontologist from the University of Birmingham, UK, Stephan Lautenschlager has discovered that the dinosaurs’ eye socket shapes were crucial to their ability to chomp down on their feasts, according to an article by Physics published on Thursday.

Over 400 skulls evaluated

The research evaluated the shapes of the eye sockets of over 400 skulls from dinosaurs and related species and found that carnivorous dinosaurs, such as the T. rex, had eye sockets in the shape of elliptical holes. These elongated shapes would have allowed a T. rex’s skull to withstand the powerful forces that these large creatures produced when they chomped down on their food.

Lautenschlager made use of a technique from facial recognition technologies to characterize the shapes of the outlines of each eye socket and then analyzed them with a finite-element-analysis tool to see how they deformed when subjected to the various stresses emanating from a bite.

He discovered that most of the species in his study had eyes shaped like circular openings and that the T. rex and the Skorpiovenator boasted socket outlines with shapes, ranging from simple ellipsoids to lobed patterns. “The Skorpiovenator eye socket is essentially separated into two, giving it an hourglass-like outline,” Lautenschlager told Physics.

Lautenschlager further found that the dinosaurs with these types of eye sockets were all meat eaters with big skulls compared to their body size. During a bite, the jaws of these animals could come down with a force of around 50,000 newtons which would most likely deform an eye socket with a circular outline.

To withstand this pressure, the animals would have developed thicker bones in the most deformed areas. “That would have made the skull a lot heavier, or impacted on the space for other tissues,” Lautenschlager said. As such, concluded the researcher, carnivores evolved sockets that could withstand these powerful forces.

Incomplete previous studies

Although researchers have long noticed the peculiar eye socket shapes in archosaurs, previous studies have looked primarily at eyeball diameter or studied only one subset of archosaurs, added Thomas Holtz, a paleontologist at the University of Maryland, College Park. “This [new study] is a vastly more comprehensive look at the evolution of archosaur eye size and shape than has ever been done before,” Holtz said.

He further complimented Lautenschlager for incorporating different lines of evidence in the study. “It is nice to find reasonable—and mathematically supported—explanations for the particular shapes we find in anatomical structures,” he concluded.

The new research sheds light on a period of the planet’s history we have much to learn about. It might seem like a small development, but it is a critical one in understanding the anatomy and function of carnivorous dinosaurs.

More studies will be needed to evaluate how eye sockets developed from a dinosaur’s birth to its adult age. Still, the study does provide a strong foundation to build upon.