Why don’t we have more hair?

From birth, almost all of our skin has a fine covering of hair. It varies a diameter from 0.005mm (0.0002in) in the baby-hair know as lanugo to 0.2mm (0.008in) in the hairs in an average beard. Our body hair – vellus – is now almost invisible. That wasn’t always so. Early humans had a thick covering of hair over just about everything except their eyeballs, lips, palms and soles of their feet.

The hair served the same purpose as it does in other primates – warmth and protection. Over the ates, heated homes and a range of clothing have taken over those basic needs, and a thick mat of hair on the body and head is no longer essential. Our body hair has almost vanished and cranial hair has become much finer. The process is almost certain to continue. In fact, anthropologists predict with some certainty that future humans will have hairless domes but bigger skulls to accommodate larger brains.

Just as our hair is vanishing, so our bodies will change shape in response to how we use them. Jaws, for example, may recede, because our food needs less chewing. Molar teeth, used now for grinding, may diminish in size until they fail to appear, as has already happened to some wisdom teeth.

The current vogue for strenuous exercise may not be enough to offset changes in our general body structure. IF that is so, many muscles will grow weaker, legs and arms more spindly and stick like with less use and some parts, such as the small toe, may in time wither away.