Why are humans mostly free of body hair, in comparison to other primates? Losing body hair was an evolutionary advantage in that it allowed early hominids to forage over a greater distance in harsher climates. In Scientific American, Mariette DiChristina writes:
Link | Photo: US Department of Energy
Our forebears abandoned their easier foraging habits, traveling longer distances through a tropical landscape to acquire sufficient food to survive. Adding meat to their diets meant more calories, but finding prey also took more work. Their activity level increased and with it their need to dissipate body heat to avoid tissue damage. By 1.6 mya, protohumans had long legs for sustained walking and running. Along with that trait came naked skin and a large number of eccrine sweat glands, which produce moisture that removes body heat through evaporative cooling. The hairs on our head also help to combat overheating, by shielding our big brain from direct sun.
Link | Photo: US Department of Energy
I don't think everybody knows about it. I'm not very convinced of it either.
It's too bad no one saw fit to write it down.
It's not a quack theory. It simply sits better with evidence found in other mammal species. There are not so many hairless savanna carnivores, but there are plenty of hairless aquatic or semi aquatic mammals. And when they say aquatic, think of hippo kind of aquatic not dolphin.
what i've learned today: i'm not human ;-))
http://www.ted.com/talks/elaine_morgan_says_we_evolved_from_aquatic_apes.html