"Skull size" refers to the physical measurement or dimension of a person's skull, which is the bony structure that protects their brain. Full definition
Whereas the last of the nonavian dinosaurs certainly perished 64.5 million years ago, many other animals survived — crocodiles, for example, along with almost all the mammals, which at the time were small, some with skulls the size of a thimble. (discovermagazine.com)
They found that both the overall skull volume and the volume of the eye socket increased with latitude, but the increase in eye socket volume — which is thought to relate to eyeball size — was larger than expected from the change in skull size alone. (newscientist.com)
«Decreasing skull size may be an early indicator of population change,» Vucetich says. (sciencedaily.com)