How do you make sense of that? And how do you think about getting out of it?

I think when the conflict started, I mean, a lot of these questions are hard to answer scientifically, but I mean, what I'm really interested in is that shift.

Like, when did the new group identities really emerge and then override prior relationships? And there was always this ambiguity there because the first chimp that we saw killed, Errol, he was 16.

He was sort of a loner, even within the central group.

So when he met the Westerners, it made sense that they would sort of see him more as an outsider, right? And this was still a time when they accepted BF, they accepted this old male who they had a really close relationship to.

And so there's this emergence of in-group, out-group dynamic.

But there was still plausible deniability.

Why are these chimps at war?

Mm.

They got quiet all of a sudden.

They started touching each other in this reassurance, like they were really nervous.

And to me, this seemed like they were acting as if they were hearing outsider chimps.

And then when the chimps from the central neighborhood got closer, rather than reuniting in this typical chimpanzee fashion, where they're constantly mixing and mingling, and instead of doing that, the western chimpanzees ran, and the central chimpanzees chased them.

And nothing really like that had ever been observed before, and then they avoided each other for six weeks.

Uh, but is it also kinda sad?

Definitely.

Do you know what was going on? Why were they turning on each other? Jane Goodall saw something like this when, when she was studying chimps decades ago, too, right?

She did.

And, and it's, it's important that ...

I mean, this, this other case that we've documented, we have these two decades of research on the chimps prior to the split, which really enables us to be, be confident about what's happened, uh, who's involved, and, and potential causes.

Jane Goodall saw something very similar.

She and her team, who had been studying the chimpanzees in Tanzania at Gombe starting in 1960, in the early '70s they saw a similar sort of rift and then lethal violence.

That was the first time that we knew chimps were territorial.

Hmm.

What was this turning point, like, where things started to look different?

It was a little hard to detect at first.

This was when I was doing my PhD dissertation research.

I was there for fifteen months, and I'd been there a few summers before then, but I was still learning about chimpanzees.

So I would see chimps from the two main neighborhoods, the western neighborhood and the central neighborhood.

When they would meet each other, 'cause remember, chimps are splitting apart and rejoining throughout the day, when they would meet each other, it seemed really intense.

Sometimes there'd be screaming and chasing.

How do we make sense of that?