Here’s what Professor Hallux has to say:
Great question! Let’s comb through the facts! Humans evolved from primates – that’s animals like chimpanzees and gorillas, and just like them we used to live in forests and eat the food around us. And we would have been much hairier then!
Over 1.6 million years ago, the climate changed and forests turned into savannahs – which are like dry grasslands. Our ancestors would have had to travel further to find food. We evolved to walk upright and have longer limbs – and less hair so that we could travel in the warmer climate without over-heating.
Thick hairy coats would have been sweltering! And it must have been hot because humans’ wouldn’t start wearing clothes for another million years!
Hmmm, although I don’t think clothes had zips back then. So it’s thanks to evolution that humans lost most of their hair. Even today, though, humans who live in colder parts of the world tend to be hairier than those living in the tropics – a bit of extra insulation!