>>2
Anyway the first question is what is the ev. adv. of losing hair that our ancestors did have.
It significantly reduced the problem of lice, and other parasites that live in hair. By this time we had learned to shelter ourselves somewhat so body hair was no longer needed.
We still have hair on our head and crotch because those are the critical areas we need to stay warm, and we still have hair under our arms to grow fungus because the smell keeps bugs away.