The Skinny

Interesting perspective on human skin and evolution of brainpower...

Nina G. Jablonski - Always Revealing, Human Skin Is an Anthropologist's Map - New York Times:
"On an evolutionary level, there are three remarkable facts about skin. It comes in colors, of course. Compared to other mammals, our skin is relatively hairless. And it%u2019s sweaty. In the last few million years, humans became the sweatiest of mammals.

Q. Is that important?

A. Absolutely. It%u2019s often said that our large brains are what made it possible for us to evolve from ape to human. But those big brains could never have developed if we didn%u2019t have exceptionally sweaty skin.

It happened this way. There was a tremendous takeoff in human evolution about two million years ago when primates who could no longer be called apes appeared in the savannahs of East Africa. These early humans ran long distances in open areas. In order to survive in the equatorial sun, they needed to cool their brains. Early humans evolved an increased number of sweat glands for that purpose, which in turn permitted their brain size to expand. As soon as we developed larger brains, our planning capacity increased, and this allowed people to disperse out of Africa. There's fossil evidence of humans appearing in Central Asia around this time."