Did Eating Insects Make Early Humans Smarter?

Finding new ways to chow down on a nice, juicy bug may have helped early humans develop advanced intelligence, researchers suggest in a recent study.

The study, published in the Journal of Human Evolution, details how researchers from Washington University in St. Louis determined that foraging for well-hidden insects and slugs during lean food seasons may have helped humanity's ancestors develop brains for advanced tool use.

Lead author Amanda Melin spent nearly a decade studying the visual and foraging ecology of white-faced capuchins in the tropical forests of Costa Rica. According to her study, these tiny monkeys have remarkably large brains and are very adept at using simple tools, such as sticks, when foraging for insects. She suggests there is a connection between this task and cognitive development, especially when the task becomes a life-or-death situation when more accessible food is scarce.

"Accessing hidden and well-protected insects living in tree branches and under bark is a cognitively demanding task, but provides a high-quality reward: fat and protein, which is needed to fuel big brains," Melin said in a statement.

The differences between various lineages of these intelligent monkeys help further support Melin's argument. According to the study, the tufted Sapajus genus appears far smarter than the untufted Cebus genus, at least when it comes to clever tool use. This may be because the Sapajus occupies more seasonal habitats, which are more susceptible to food shortages.

"Primates who extract foods in the most seasonal environments are expected to experience the strongest selection in the 'sensorimotor intelligence' domain, which includes cognition related to object handling," Melin elaborated. "This may explain the occurrence of
tool use in some capuchin lineages, but not in others."

Melin and her colleagues argue that traveling human ancestors, who were exposed to significant seasonal changes, resorted to eating insects to survive. If this was the case, clever and increasingly complex tool use would have helped them survive - a trait favoring large and fast-thinking brains.

The study was published in the June issue of the Journal of Human Evolution.