Question: why do we have hair

Kate Salmon answered on 12 Mar 2014:

We have hair because we are mammals and most mammals have hair (like dogs and monkeys). What’s actually surprising is how little hair we have compared to these animals! But generally the reason that mammals have hair is to protect ourselves, either from the sun or from the cold. What’s interesting is that we used to have a lot more hair… so where did it all go? Scientists think that when humans learnt to walk upright on two legs, instead of 4 (like monkeys), we started getting showing less of our body to the sun so we no longer needed hair on the rest of our bodies apart from our heads. Keeping hair on our heads protects us from getting sunburnt at the same time as keeping one of our vital organs warm in the winter.