The last several years have seen an enormous growth of interest in many aspects of animal cognitive and emotional capacities. Animals, it has been shown, can learn to solve problems by observing others, can experience complex emotions, and can communicate with others about resources and danger, sometimes deceptively. Dogs and parrots can understand the meaning of human words, and chimpanzees can solve memory-retrieval tasks at rates faster than most people. Nonetheless, those committed to an essential discontinuity between the human and nonhuman often point to the supposed lack of moral and ethical behavior among animals. Although many humans pay attention to our ethical responsibilities to other species, no one has much studied whether other species have moral and ethical codes that may operate in their lives and serve as evolutionary precursors to the purportedly advanced moral behavior of human beings.