Eli5: Why are human babies born so ill prepared for the world, compared to some other mammals who are born much more well equipped?

Question

Eli5: Why are human babies born so ill prepared for the world, compared to some other mammals who are born much more well equipped?

In: 2

Answer 1

Humans have large heads (because we’ve got large brains) and narrow hips (because we’re bipedal). These factors make birth very difficult. Babies can’t spend any longer developing in the womb or birth would become impossible, so they have to come out “half finished”.