Tyrannosaurus rex, everyone’s favorite dinosaur, is still yielding surprises despite having gone extinct roughly 60 million years ago.

Image: My homie, T. rex.

Researchers at Ohio University (Go Bobcats!), the University of Florida, and the University of Missouri looked back at some of the numerous, high-quality T. rex fossils available. An anatomical feature in the possible insertion points of the jaw muscles lead to a surprise. These skull holes might also be a part of a cooling system.

T. rex was one the largest known terrestrial carnivores. Some dinosaurs such as Spinosaurus might have been bigger, but Spinosaurus was probably a fish eater. T. rex was likely a large predator and scavenger, doing a bit of both, like modern eagles and wolves. To do so, it must have been able to maintain its body temperature at a comfortable level. Somehow…

Video by Mizzou News.

Scientists have long believed large holes in T. rex skulls somehow were involved in jaw muscles, but these holes mean muscles would bend at weird angles. So, scientists decided to look at some living relatives, specifically alligators. It seems the holes in their skull contain lots of blood vessels to help heat them up when it’s cold and cool them down when it’s warm.

Scientists found that alligators are using similar structures in their skulls for temperature regulation:

“[W]e 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. This is consistent with prior evidence that alligators have a cross-current circulatory system — or an internal thermostat, so to speak.”

-Kent Vilet, University of Florida

There is debate on whether dinosaurs were all able to control their internal temperatures (“warm-blooded”) like the only living dinosaurs, birds, or if they had something in between birds and alligators, having a mix of warm- and cold-blooded features. Though… SCIENCE FACT… warm-blooded and cold-blooded aren’t real distinctions. Many animals like alligators can maintain internal temperatures due to large size (gigantothermy), or some animals merely have anti-freeze in their blood or other regulatory means. All animals though, have ways to warm up and cool down. If T. rex did have jaw muscles filled with blood vessels to help them do so, that’s just one more fascinating fact we can add to the universe of dinosaurs.

What’s your favorite dinosaur fact? Let Nerdbot know in the comments!