A fish knows how to swim the instant it hatches, and off it darts to fend for itself. When a duckling hatches, it can follow its mother over land and across the water within moments. Foals, still dripping with amniotic fluid, spend a few minutes bucking around to get the feel of their legs, then join the herd. Not so with humans. We come out limp and squalling and utterly dependent on round-the-clock care and supervision. We mature glacially, and do not approach anything resembling adult competence for many, many years. Obviously we must gain some very large advantage from this costly, not to mention risky up-front investment, and we do: It’s called culture.