Scientists have long counseled against interpreting animal behavior in terms of human emotions, warning that such anthropomorphizing limits our ability to understand animals as they really are. Yet what are we to make of a female gorilla in a German zoo who spent days mourning the death of her baby? Or a wild female elephant who cared for a younger one after she was injured by a rambunctious teenage male? Or a rat who refused to push a lever for food when he saw that doing so caused another rat to be shocked? Aren't these clear signs that animals have recognizable emotions and moral intelligence? Marc Bekoff and Jessica Pierce unequivocally answer yes. Marrying years of behavioral and cognitive research with compelling and moving anecdotes, Bekoff and Pierce reveal that animals exhibit a broad repertoire of moral behaviors, including fairness, empathy, trust, and reciprocity. Underlying these behaviors is a complex and nuanced range of emotions, backed by a high degree of intelligence and surprising behavioral flexibility. Animals, in short, are incredibly adept social beings, relying on rules of conduct to navigate intricate social networks that are essential to their survival. Ultimately, Bekoff and Pierce draw the astonishing conclusion that there is no moral gap between humans and other species: morality is an evolved trait that we unquestionably share with other social mammals. Sure to be controversial, this book offers not just cutting-edge science, but a provocative call to rethink our relationship with—and our responsibilities toward—our fellow animals.