A frequent argument is that Darwin’s theory of evolution has or should revolutionize our conception of the relation between humans and animals, though society has yet to take account of that revolution in our treatment of animals. On this view, after Darwin demonstrated the essential continuity of humans and animals, traditional morality must be rejected as speciesist in seeing humans as fundamentally distinct from other animals. In fact, the argument is of dubious merit. While there is plenty of room for improving our treatment of animals, it is unlikely that these shortcomings can be blamed on scientific ignorance, or that knowledge of the theory of evolution has any clear moral implications for our treatment of animals.