Scientists have discovered two big holes in the skull of the Tyrannosaurus rex (T-rex) which were likely used to cool down the mighty predator. These attributes in the T-rex’s head probably served as a type of built-in air-conditioner, although they were previously believed to be packed with muscles. The group of scientists now think that it’s more plausible that these cavities were filled with blood vessels that aided the T-rex with temperature regulation.
Bigger animals require more specialized methods of keeping cool, as their enormous bodies can generate a lot of heat, leaving them exhausted in particularly warm conditions.
Casey Holliday, of the University of Missouri, and his associates, utilized thermal imaging technology – which converts readings of heat into observable light – to study alligators at Florida’s St Augustine Alligator Farm Zoological Park.
“It’s really hard to get a picture of an alligator skull in the wild, because they’re always off away from you and they’re dangerous to approach,” said Holliday. “Being at the farm allowed us to get up and over fences and take images and video from the top down.”
Blood vessels for temperature control
The team found that the reptiles have blood-vessel-filled holes in their skulls.
“An alligator’s body heat depends on its environment,” said co-author Kent Vliet, from the University of Florida. “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.”
After looking at fossils and 3D imaging of the T-rex skull, the group realized that the iconic dinosaur possessed similar holes to that of the alligators. These holes were thought to contain muscles that helped with the movement of the predator’s jaw.
“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,” explained Holliday. “We now have a lot of compelling evidence for blood vessels in this area, based on our work with alligators and other reptiles.”
Professor of anatomy at Ohio University, Larry Witmer, said, “We know that, similarly to the T-rex, alligators have holes on the roof of their skulls, and they are filled with blood vessels. 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.”
Holliday further comment, “If you’re an active predator, as we think T-rex probably was, at some point, you want to be able to shed heat, as much as you want to gather heat. Having a bed of capillaries up here in the skull roof provides a mechanism for these types of animals to collect heat or shed heat.”