If chimps are our closest relative why aren't we hairy like they are? The answer lies somewhere in the far distant past. Imagine how hot it must have been on the savannah after our ancestors left the safety of the trees to hunt for food. Homo Erectus did this almost 2 million years ago, and perhaps as recently as 70,000 years ago. They made their homes on the savannahs. They ran, played, and hunted. They fought for survival. And one of the byproducts of all of that activity is sweat. Wouldn't it be a benefit to have less hair?