Elizabeth Preston

And one of the ways it's different is that the baby gorilla does not make loud sounds.

But this makes sense when you think about that history I mentioned earlier of cooperative caretaking.

So if the human baby has evolved to be cared for by many different people, it might be getting passed around all day long.

It needs a way to let its mom know or let its caretakers know that it's hungry.

and it needs to go back and nurse.

Or maybe say, you know, my cousin put me down in a pile of leaves and now I'm cold.

Help, help, help.

Exactly.

It needs to be able to get attention.

Whereas that baby gorilla who's clinging to its mother's fur all day, it doesn't need to tell anyone anything.

It can just move its head and get milk when it needs to.

So human infants do have a reason to make noise more than our relatives.

Another interesting thing

is that when you look across all of the primates, so the apes and the monkeys, you do find some other cooperatively breeding animals.

They're not close relatives of ours.

They're monkeys called marmosets and tamarins, and they live in South America in the treetops.

They're these small monkeys.

And the mothers have twins usually.

And it's a ton of work to take care of these twins.

And so they rely on their family groups to cooperate and care for these babies.