But one thing I wonder is how do we know what came first? Is there a way to know if gathering and hunting and sharing came before or after we developed big brains? I think about the order of events here. You have to have the sharing

first, right? And apes share a little bit. They're actually really terrible at it. My favorite nugget of information on that is, is orangutan mothers share with their offspring when they're like the baby orang or in the tree, like reaching for the berries, please mom, help me out. And the mom shares with them about 10% of the time. So imagine that in your own. I mean, that's like that mother of the year stuff, exactly, right? That's kind of sad. So they share a little bit, mostly if at all with their offspring. You can imagine then that the sort of inklings that this are there already. You can imagine an early hominin or an ossalpithecus that was sharing about as much as apes share, then behaviorally things shift, ecologically things shift and sharing becomes a bigger part of their behavioral records bar. And it all, you know, all of a sudden you have more energy available. And so, you know, natural selection is going to favor using those extra calories. It's never going to favor throwing them away or not burning them. And they're not going to favor using them. So they'd behaviorize the change

to lead the physiology.

That makes a lot of sense to me. So obviously this is something that happens over millions of years and extra calories don't automatically mean big brains, right? City pigeons and rats have access to more easy calories than ever before. But I'm guessing we're not seeing birds or rodents with bigger brains just because they can get pizza or big tubs of fat from behind restaurants,

right? There's no guarantee that the extra calories go to big brains. It's something unique about our ecology that that was the favored place to put your extra calories. Most animals when they get extra calories are going to put them into reproduction. And we do that a bit. We have bigger babies more often, but it's not just that. It's mostly these other things. But it's interesting. The question about how do you know when it happened? Well, hard to know. Of course, these are things that is going to be speculative. We're talking about reconstructing behaviors that are happened billions of years ago. But the first time you've got cut marks on an animal that's too big to eat by yourself, it's probably sharing. And that happens around two to an half billion years ago.