Wild elephants walking along a trail stop and spontaneously try to protect and assist a weak and dying fellow elephant. Laboratory rats, finding other rats caged nearby in distressing circumstances, proceed to rescue them. A chimpanzee in a zoo loses his own life trying to save an unrelated infant who has fallen into a watery moat. The examples above and many others, argues Dale Peterson, show that our fellow creatures have powerful impulses toward cooperation, generosity, and fairness. Yet it is commonly held that we Homo sapiens are the only animals with a moral sense - that we are somehow above and apart from our fellow creatures.

This rigorous and stimulating book challenges that notion, and it shows the profound connections - the moral continuum - that link humans to many other species. Peterson shows how much animal behavior follows principles embodied in humanity's ancient moral codes, from the Ten Commandments to the New Testament. Understanding the moral lives of animals offers new insight into our own.

Dale Peterson's biography Jane Goodall: The Woman Who Redefined Man was a New York Times Book Review Notable Book and Boston Globe Best Book of 2006. His other publications include Visions of Caliban (with Jane Goodall) and Demonic Males (with Richard Wrangham). Peterson lectures in English at Tufts University.