I was just wondering why my hair down there seems to grow faster then the hair on my head. I shave the little suckers, but if I go a week without it, then they grow out to be like an inch long. If my head hair grew like that, then I’d have to get it cut like every 2 weeks! what is the medical reason for this happening? Is there anything I can do to stop it, or make it grow slower, or be less noticable? Thanks
Not sure, but I think that P-hair is actually fur and not hair. Am I wrong?
This column of Cecil’s has the answer to your question (the why question at least):
Hey, Chekmate, did you forget a “c” somewhere? Or maybe an “e”?
I have a related question, so I will pirate your post. What useful purpose does hair there serve? Hair, I suppose, in general evolved from fur, which was to keep us warm. But why didn’t we evolve not to have any at all, except perhaps on the head? Anyway, what really is a nuisance is the hair at the opposite end wherefrom you speak. Feces, if at all wet, tends to get stuck on those hairs. Uckkk! What a mess. (If you can’t eat your sandwich anymore, give it to me.) 
And we in America don’t even have a bidet. Hair there certainly doesn’t trap germs as nostril hairs do. They can’t possibly serve any useful purpose.
This has been answered before, but I have trouble with searching.
Pubic hair and underarm hair serve the purpose of dry lubrication in areas where skin would rub together otherwise, and be uncomfortable. In the case of pubic hair, this could impede efficient prolonging of the species.
Pubic and underarm hair also serves to enhance odor, by providing more surface area for sweat to evaporate from. Yes, we evolved in such a way as to maximize our odor.