John Mitani

It really isn't precisely like that.

I'm not sure that any one individual was, you know, the instigator of this.

It was a collective of some males on one side and males on the other side.

These intergroup encounters are principally male affairs, so it was a collection of males on each side that were the...

principal participants in the fighting and the individuals who are primarily responsible for the split.

Well, the split occurred along lines of maternal kinship.

Right.

So individuals who they knew who they're related to.

That happened for the most part.

But in terms of why they split, you know, the honest answer here is we don't really know.

I think, and we've talked about how a combination of factors probably led to this split.

First, as we've already discussed, the group grew to an unusually large size.

And as a consequence, feeding and reproductive competition within the group intensified.

And these are probably two factors that played a role.

Second, as a group continued to grow,

Some chimps died, others matured, integrating themselves into the social world of adults.

When this happens, social relationships change, probably leading to hostilities that might have not been there before.

And then finally, you did hint at this, but...

Right at the start of hostilities, there was a change in the alpha male.

And studies we've conducted at Ngogo and studies that have been conducted elsewhere indicate when this happens, aggression intensifies.