The Ethics of Killing “Surplus” Zoo Animals

As zoos have developed more successful captive breeding programs, they now face a question of what to do about “surplus” animals. One strategy used by European zoos in recent years has been to allow animals to breed freely, then kill unwanted offspring. I argue that this strategy wrongs the animals in question and that the justifications that have been offered for the practice are inadequate. I provide background on the practice, discuss the moral status of animals and potential grounds for the prima facie duty not to kill, and then examine and ultimately dismiss justifications for killing in this case.