Tyrannosaurus Rex Had Weird Holes in Its Skull That Acted As an 'Air Conditioner' for Its Head, Scientists Discover

Tyrannosaurus Rex had holes in its skull that acted like an air conditioner for its head, according to research.

For decades, scientists thought that the two holes in the roof of the dinosaur's skull—known as the dorsotemporal fenestra—were involved in the movements of the fearsome predator's jaws, because they were believed to be filled with muscles.

However, a team of researchers led, by anatomist Casey Holliday from the University of Missouri (MU,) has now suggested this may not be the case, according to a study published in The Anatomical Record.

"It's really weird for a muscle to come up from the jaw, make a 90-degree turn, and go along the roof of the skull," Holliday said in a statement. "Yet, we now have a lot of compelling evidence for blood vessels in this area, based on our work with alligators and other reptiles."

For their research, the team used thermal imaging equipment to examine alligators—animals that also feature similar holes in the roofs of their skulls—at the St. Augustine Alligator Farm Zoological Park in Florida. These investigations revealed that the holes were part of the alligators' thermoregulatory systems.

"An alligator's body heat depends on its environment," Kent Vliet, another author of the study from the University of Florida's Department of Biology, said in the statement. "Therefore, we noticed when it was cooler and the alligators are trying to warm up, our thermal imaging showed big hot spots in these holes in the roof of their skull, indicating a rise in temperature."

"Yet, later in the day when it's warmer, the holes appear dark, like they were turned off to keep cool," he said. "This is consistent with prior evidence that alligators have a cross-current circulatory system—or an internal thermostat, so to speak."

After collecting the thermal imaging data from the crocodiles, the scientists investigated the fossilised remains of both dinosaurs and crocodiles to understand more about the evolution and development of these holes. This research led them to the conclusion that the dorsotemporal fenestra in T. rex were used to cool the animal's skull.

"We discovered that many dinosaurs and crocodilians have a vascular device on the roof of their skull that probably helps them control their body and brain temperature," Eric Stann, another author of the study, told Newsweek. "These particular blood vessels might help T. rex control its body temperature, and they also could be used to support fleshy display structures on their heads."

"We know that, similarly to the T. rex, alligators have holes on the roof of their skulls, and they are filled with blood vessels," Larry Witmer, a professor of anatomy from Ohio University, said in a statement. "Yet, for over 100 years we've been putting muscles into a similar space with dinosaurs. By using some anatomy and physiology of current animals, we can show that we can overturn those early hypotheses about the anatomy of this part of the T. rex's skull."

T. rex was one of the largest carnivorous dinosaurs that ever lived, standing up to 20 feet tall and measuring as much 40 feet in length, according to National Geographic. It is estimated that the dinosaur could consume around 500 pounds of meat in a single bite of its 4-foot-long jaws, which featured an array of razor-sharp, serrated teeth.

T. rex lived in North America during the Late Cretaceous period (100.5 million-66 million years ago) before disappearing around 65 million years ago during a mass extinction event caused by an asteroid impact, which is thought to have wiped out all non-avian dinosaurs.

T. rex, alligators
A graphic thermal image of a T. rex with its dorsotemporal fenestra glowing on the skull. Illustration courtesy of Brian Engh
Tyrannosaurus Rex Had Weird Holes in Its Skull That Acted As an 'Air Conditioner' for Its Head, Scientists Discover | Tech & Science