Dinosaur skulls had many cavities and openings, some of which may have held blood vessels to help cool off the animals’ heads

By comparing the skulls of extinct dinosaurs to those of living relatives, such as crocodiles and wild turkeys, researchers have conclude that the prehistoric beasts had sophisticated thermoregulation systems in their skulls.
(Brian Engh)


Dinosaur skulls have something in common with Swiss cheese—they’re both full of holes. From Tyrannosaurus to Triceratops, the skulls of the terrible lizards have the same eye and nasal passages common in many vertebrates, as well as additional pockets unique to reptiles. For example, a hole at the top and rear of the skull anchored jaw muscles for chomping through the Mesozoic world—and a new study suggests there was more to this peculiar anatomical window than just biting. The prehistoric skulls of dinos may have held special blood vessels that allowed the animals to keep their brains at just the right temperature.

The specialized pocket sits within an opening on the top rear of the skull called the dorsotemporal fenestra. This opening plays a role in jaw muscle attachment, and scientists previously thought it was filled with the fibrous tissues that allowed dinosaurs to bite. But a curious pocket within the larger hole, called the frontoparietal fossa, seems to have served a different purpose.

While researching jaw muscle attachments in reptiles, University of Missouri anatomist Casey Holliday noticed that the frontoparietal fossa didn’t seem to have much to do with chomping. “I wasn’t finding any evidence to support the presence of a muscle and so had to start figuring out what else it could be,” Holliday says. Among living reptiles, Holliday and colleagues fou

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