Why does hair on a human head grow indefinitely?

dmatador

Given that we humans are descended from the great ape, as well as are gorillas and chimpanzees and bonobos, why do we have hair that grows indefinitely, while they do not? I've read something about a sexual selection aspect to evolution, surmising that hair is a means to finding a mate, like strength and intelligence, but I am not completely convinced by this idea.

Vagn

Why do you doubt it out of curiosity? Also human head hair doesn't grow indefinately, it typically reaches a length where it falls out, for example, I have shoulder-length hair and I need to vacuum the floor frequently, just because of the hair that falls out naturally.

dmatador

Perhaps I question more so the seriousness of the article I read, not necessarily the principle itself. I would just like to read something more cogent and detailed. And yes, hair does fall out a lot; my sister's hair frequently clogs the drain in the shower. However, one could grow his hair out to his buttocks if he wished, yet a chimpanzee, for example, could not.