Why Humans don’t have fur
Humans, unlike just about every land mammal, have no fur coat. Why is this? Well, it turns out humans are naked because we sweat, because we walk upright and because we have big brains.
Sweating is very good for controlling the bodies temperature, no other animal on earth sweats as well as a human. A fur coat, or indeed clothing, is a massive hindrance to the performance of our bodies cooling system’s performance.
Human brains are very large compared to our bodies, one major factor in the human’s success as a species is all that brain power, but a mere two-degree rise in body temperature inhibits normal brain function, a four degree rise is usually fatal – in order to have a big brain we need to have a very powerful cooling system too and hair just gets in the way.
Hair does have other benefits however such keeping us warm and shielding us from the sun. We use clothes to keep us warm and at some point between walking upright and loosing our body hair evolution caused us to keep some fur where it was most vulnerable to direct sun, on the tops of our heads.
Human head hair and pubic hair are very different and correspondingly have their own types of mite, head lice and pubic lice (crabs). There is also a third type of human mite called the clothing louse. Using this information and by comparing human mites to other primate’s mites it is possible to estimate how long human ancestors have been naked for, and it turns out to be a very long time indeed, even in evolution terms.
