I discuss controversial claims about the status of non-human animals as moral beings in relation to philosophical claims to the contrary. I address questions about the ontology of animals rather than ethical approaches as to how humans need to treat other animals through notions of, for example, animal rights. I explore the evolutionary origins of behavior that can be considered vices or virtues and suggest that Thomas Aquinas is closer to Darwin's view on nonhuman animals than we might suppose. An (...) appreciation of the complexity of the emotional lives of social animals and their cooperative behaviors in light of the work of animal ethologists such as Frans de Waal and Marc Bekoff suggests that social animals can be considered moral in their own terms. I discuss the charge of anthropomorphism, drawing on the work of archaeologist Steven Mithen, and consider arguments for the evolution of conscience in the work of anthropologist Christopher Boehm. Only the biological basis for the development of conscience and religion has evolved in nonhuman animals, and this should not be confused with sophisticated moral systems of analysis or particular religious beliefs found in the human community. (shrink)