Zoos have come a long way since their beginnings in ancient times as diversions for the rich and powerful. Many zoos today see their primary purpose as breeding endangered species in captivity and reintroducing them into the wild. But critics in the animal-welfare community say reintroduction efforts have been unsuccessful and that zoos would better serve the cause of wildlife conservation by devoting more time and resources to helping preserve threatened habitats around the globe. Others argue that zoos, regardless of their good intentions, are fundamentally immoral because they imprison thousands of helpless animals merely for the sake of human amusement. But advocates of zoos argue that they play a crucial role in awakening the public to wildlife-conservation issues.

David Masci specializes in social policy, religion and foreign affairs. Before joining CQ Researcher as a staff writer in 1996, he was a reporter at CQ's Daily Monitor and CQ Weekly. He holds a BA in medieval history from Syracuse University and a law degree from The George Washington University.