The YouTube video of Mama, a dying and previously unresponsive 59-year-old chimpanzee matriarch, greeting her human friend Jan Van Hooff, has been watched 9.5 million times.

In humans, we often get our information from language, a somewhat questionable source. With animals we don’t have this luxury, hence feelings remain inaccessible. But the emotions themselves are visible and measurable, as they are expressed in the body and lead to behavioral changes. Animal emotions have become a respectable topic of study.

Biologist, primatologist and best-selling author Frans de Waal reviews the evidence for animal emotions, starting with primate facial expressions. He will argue that all of our emotions can be found one way or another in other species. The whole idea that there is just a handful of “basic” or “primary” emotions (fear, anger, joy), and that all other emotions (jealousy, guilt, love, hope) are uniquely human doesn’t make sense. Emotions are like organs. We possess not a single organ that is unique to us. Similarly, although we have emotions that go deeper or are more varied than in other species, none of them is entirely new.