In this essay I argue that many nonhuman animal beings are conscious and have some sense of self. Rather than ask whether they are conscious, I adopt an evolutionary perspective and ask why consciousness and a sense of self evolved—what are they good for? Comparative studies of animal cognition, ethological investigations that explore what it is like to be a certain animal, are useful for answering this question. Charles Darwin argued that the differences in cognitive abilities and emotions among animals are differences in degree rather than differences in kind, and his view cautions against the unyielding claim that humans, and perhaps other great apes and cetaceans, are the only species in which a sense of self-awareness has evolved. I co...