The intelligence of animals can be estimated by the size of the holes in the skull which the arteries pass through, according to novel research by biologists at the University of Adelaide.
The scientists found that the connection between intelligence and hole size results from brain activity being related to brain metabolic rate – and this can be estimated from the size of the arteries that supply the brain with blood.
“Arteries continually adjust their diameter to match the amount of blood that an organ needs by sensing the velocity next to the vessel wall. If it is too fast, then the artery grows larger, too slow and the artery shrinks,” project leader Professor Emeritus Roger Seymour said. “If an artery passes through a bone, then simply measuring the size of the hole can indicate the blood flow rate and in turn the metabolic rate of the organ inside.”
Seymour, and a former honours student, Sophie Angove, measured the ‘carotid foramina’ which allow passage of the internal carotid arteries servicing the brain in primates and marsupials and found large differences. <Read more.>