Decisions at the Zoo

N o doubt about it, the white tigers at the Cincinnati Zoo are beautiful animals. Instead of black stripes on an orange body, like most tigers, the white tigers' cream-colored bodies are set off by handsome chocolate brown lines. Perhaps because of their distinctiveness, they have long been one of the zoo's most popular exhibits. Naturally occurring, although rare in the wild, white tigers represent an anomaly in the animal kingdom. They are neither a species nor a subspecies. They are just the result of a recessive trait. To get more white tigers, zoo managers in India and the United States in the 1950s mated fathers with daughters, granddaughters, and even, on occasion, great granddaughters. Should zoos continue this practice?