Why did we go bald? The love and loss of human hair

Roughly two million years ago we were living in a golden age of hairiness. Then we became balding apes neurotically preoccupied with the state of our hair. But why did it disappear? Andy Martin reports

Hair: the less we have of it the more important it becomes (Getty)

Where hair is concerned, you don’t know what you’ve got until it’s gone. On an evolutionary scale, we only acquired “hair” at the very point at which we started losing it. We transitioned from creatures with fur or a pelt to people with hair, little clumps of it scattered around the body in odd places, and always liable to drop out.

Humanity was born out of a steaming vat of follicular nostalgia. Around two million years ago, we became what we are now – balding apes neurotically preoccupied with the state of our hair. And there are at least two strong and conflicting theories about how and why this crucial development in our deep history took place. Each of them focuses on a different aspect of who we are now: mother love and the joy of jogging. But what is clear is that hair is us. Hair is the great universal, even when it’s gone. Especially when it’s gone.

Our distant hominid ancestors were once covered in hair from head to toe (setting aside eyes and lips and a few other body parts). Like other primates, we were extremely hirsute. Hair was immensely important to us. In the absence of clothing it kept us warm. It offered a flexible defence against the elements, protecting from cold and sun alike. And a thick mat of hair stopped you getting smacked and scratched quite so much by the branches of trees (try swinging through trees naked and you’ll soon see what I mean). Possibly it made us slightly less appealing as a tasty takeaway to passing predators. Who wants to eat a hairy sausage?