Why do humans have pubic hair, when other 鈥渉airless鈥� mammals, like pigs and elephants, manage without it?
Tony Cooke
Gunning, New South Wales, Australia
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I think humans have pubic hair because of the structure of the human pelvis and the position of the genitals: people鈥檚 thighs tend to rub together when they walk. Pubic hair reduces the friction between the skin surfaces that would otherwise chafe.
This becomes apparent if you remove some of your pubic hair. A small reduction in pubic hair will result in the skin of the groin sticking together, particularly in warmer weather. The same idea applies to the armpit, where a patch of hair also grows.
Other animals, such as elephants, have different anatomies, with their legs tending to be more separated from each other. Thus, their legs don鈥檛 rub together to the same extent, reducing the need for pubic hair. Their legs are also often at right angles to their bodies, and so the area of contact between their legs and bodies is low.
Matthew Stevens
Sydney, Australia
I propose a hypothesis that relies on the evolutionary history of our ancestors in the grasslands of Africa. The brief explanation is that, in becoming essentially hairless and upright, our ancestors could more effectively hunt down prey in grasslands.
But they acquired greater agility at the cost of an increased risk of injury to the reproductive organs resulting from collision with grasses, many of which have sharp seeds and razor-edged leaf blades. A wiry mat of hair will deflect sharp grasses away from the vagina鈥檚 entrance, for instance. As well as surrounding pubic hair, the penis has evolved a foreskin for protection.
Ellen Bolton
Millmerran, Queensland, Australia
Perhaps humans developed pubic hair in order to deter smaller things, such as insects, as well as bigger things from entering our private parts.
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