Head hair has lengthened only in those human populations that have lived in the temperate and Arctic zones, including some that have back-migrated to the .... Short, thin body hair in Homo sapiens can be explained by adaption to climate and wearing clothing, but why did our head hair grow so long? read more
(Curly hair, Tuttle says, does the best job at performing this task.) Head hair grows longer than other hair because these follicles remain in an active growth (or anagen) phase longer than other other hair follicles—generally a couple of years instead of just a couple of months. read more
Sexual selection and sexual dimorphism do not adequately explain why this evolved. read more