The bigger the holes, the brainier the skull-bearer

Jul 16, 2015 09:54 GMT  ·  By

The human skull, just like the one of other animal species, is not just a simple bone-made helmet designed to protect the brain. Au contraire, it bears a slight resemblance to a watering pot in that it has holes in it. 

These holes, which medical experts like to call by the more fancy-sounding moniker foramina, are essentially pathways for cranial nerves, veins and arteries.

In a study in the Journal of Experimental Biology, scientists at the University of Adelaide argue that, according to evidence at hand, the size of the holes present in an animal's skull is an indicator of intelligence.

Specifically, they say that, having carried out a series of investigations, they found that big holes in the skull correlate with being, well, brainier. On the other hand, animals with small holes in their skull are not all that bright.

Oddly enough, this actually makes sense

As part of this research project, the scientists compared the brain power and the skull anatomy of primates and marsupials, and found the latter to have smaller foramina relative to the size of their brain and their skull.

In their report in the Journal of Experimental Biology, the researchers say that these differences in skull anatomy are perfectly understandable when brain activity is factored in.

Here's what it all boils down to: more active brains require more energy to keep up and running, and thus they have a higher metabolic rate. In turn, this means that more blood needs to flow their way.

The more blood arteries and veins carry to and from an organ, the bigger they get. In the case of skulls, this translates into wider foramina designed to let them pass through.

“The difference between primates and other mammals lies not in the size of the brain, but in its relative metabolic rate,” study leader Roger Seymour said in a statement.

“High metabolic rate correlates with the evolution of greater cognitive ability and complex social behavior among primates,” the University of Adelaide researcher went on to explain.