Humans Are Hairier Than You Think
Humans and chimps have about the same amount of hair follicles on our bodies. However, chimps have retained their long, thick fur, whereas our hairs are short and fine. Scientists haven't yet nailed down the exact reason why we evolved to be relatively naked, but they have a few theories. One is that we lost our fur when we began wandering hot environments. Another is that a lack of hair could have advertised a lack of parasites to potential mates. The hair on our head stuck around, however, perhaps to shield our sensitive scalps from the sun.
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Key Facts In This Video
All hair is made of the protein keratin. (0:37)
Different types of hair have growth phases of differing lengths, which is why your underarm hair can only grow to a few inches long. (1:30)
Humans may have evolved pubic and underarm hair to trap and transmit pheromones to potential mates. (3:24)