Brain Region Size Impacts Social Behavior of Carnivores, Not Just Humans and Primates

Humans and primates are extremely social creatures. They conduct complex social interactions, their brains uniquely suited to this type of behavior. Now, scientists have discovered that the part of the brain that makes humans and primates social creatures may also play a similar role in carnivores.

"Most neuroscience research that looks at how brain evolve has focused primarily on primates, so nobody really knows what the frontal cortex in a carnivore does," said Sharleen Sakai, one of the researchers, in a news release.

That's why researchers decided to examine three species in the Procyonid family--the raccoon, the coatimundi and the kinkajou. Although the frontal cortex is thought to regulate social interaction, the researchers weren't sure whether the different species would show different brain sizes in this region. In all, the scientists examined 45 adult Procyonid skulls and used computed tomography, or CT scans, in order to digitally "fill in" the areas where the brains would have been.

In the end, the scientists discovered that the female coatimundi had the largest anterior cerebrum volume consisting mainly of the frontal cortex. This, in particular, made sense; the female coatimundi is highly social while the male coatimundi, once grown, typically lives on its own or with another male. In addition, the researchers found that the raccoon, the most solitary of the three animals, had the smallest frontal cortex.

"These findings suggest the frontal cortex is processing social information in carnivores perhaps similar to what we've seen in monkeys and humans," said Sakai in a news release.

The findings reveal that it's not only humans and primates that have a frontal cortex that's implicated in social interactions. Carnivores also possess this trait. In fact, brain size variations in this small family of carnivores seem to be related to differences in behavior. By analyzing their brains, the researchers could learn a little bit more about how behavior and brain shape are related. This, in turn, could help with future studies

The findings are published in the journal Brain, Behavior and Evolution.