In this ground-breaking and entertaining book, primatologist Frans de Waal draws on his renowned studies of the social and emotional lives of chimpanzees, bonobos, and other primates, and personal encounters with many other species, to illuminate new ideas and findings about animal emotions. Opening with the moving farewell between Mama, a dying chimpanzee matriarch, and her human friend - The video of which has been watched by millions online - Mama's last hug illustrates how profoundly we have underestimated animals' Emotional experiences. De Waal's radical proposal is that emotions are like organs: humans haven't a single organ that other animals don't have, and the same can be said of our emotions.