(Agencies)
Updated: 2008-04-21 22:49

Survival smarts

The researchers suspect the extra brainpower allows primates to learn savvy food-finding techniques, as well as predator avoidance and social skills.

For instance, studies by Barrickman's colleagues showed the brainiac of all lemurs, called the aye-aye, also has one of the most bizarre food-finding techniques. These bat-eared lemurs are thought to need extra brainpower to master the skill of tap-foraging, in which they locate insect larvae by tapping on tree trunks and listening for the telltale sounds of a tasty morsel.

"It takes a year-and-a-half to learn it, and the babies need to spend a lot of time watching the mom," Barrickman said.

Human helpers

While humans fit in with the basic pattern of brain size and longevity, we stood out in one respect. Humans in hunter-gatherer societies don't take much of a break between babies, just three years on average, the researchers found.

"In a hunter-gatherer [society], three years is short," Barrickman told LiveScience. "You've got a three-year-old toddling around the African bush and another baby on your back. That's really difficult to juggle."

Our secret: family helpers, such as grandmas, fathers, older siblings and others. "It's not just mom," Barrickman said.

The study was supported by the scientific research society Sigma Xi, the American Museum of Natural History in New York and the Ruggles Gates Fund for Biological Anthropology in the UK.

   1 2   

   1 2