 Researchers were like, why don't we actually study what they're saying to each other instead? So they've come up with, at the time that I wrote this book, I want to say it was at least 150 gestures and or sounds that were meaningful, including some relating to emotion, like being sad or dislike. And some of them are very human. Like sometimes a chimp will walk up to another one and gently tap it on the back of the shoulder. And that just means I don't like what you're doing. Can you stop that?