Individuals did it when there was nearly no food and you could get eaten by lions in your sleep. Humans are also one of the few species of mammals that can get

Individuals did it when there was nearly no food and you could get eaten by lions in your sleep. Humans are also one of the few species of mammals that can get pregnant year-round. Our breeding works in a shotgun approach - make as many as you can and hope that one makes it. Coupled with the fact that we have large heads that make birthing one of the most difficult among mammals, it's very unoptimised. But it works. I'm not saying it's rational by any means, I'm just pointing out things.