A plaintive meow rises from the deep grass inside a large enclosure at the San Diego Wild Animal Park. Suddenly, the grass rustles and a black-spotted golden cat, the size of a large dog, stalks into view. This sleek, powerful animal with amber eyes and the voice of a tiny tomcat is Punchow, a magnificent male cheetah.

Punchow and his kind are the fastest sprinters on Earth, and human beings have admired, captured, and even hunted with them for thousands of years. But now, as humanity carves up the cat's native habitat in Africa, the survival of the cheetah is at stake. So for decades, researchers at zoos and cheetah breeding centers have been trying to boost the cheetah population by encouraging captive cats like Punchow to breed.

Scientists' limited understanding of cheetah biology has made this task extremely difficult, and Punchow himself symbolizes the puzzle biologists face as they work to save these animals from extinction. Punchow may be genetically almost identical to all other members of his species, a possibility that some experts believe accounts for the health problems they have observed in captive cheetahs—for example, poor breeding success and a high susceptibility to disease. Indeed, a researcher armed only with Punchow's lab tests might conclude that the cat is sterile. What is puzzling is that Punchow managed to father nine cubs by two different females the first two times he was bred.

Punchow's reproductive success—and that of other cheetahs in the 1990's—has sparked a debate over how the cheetah's genetic makeup affects the species' chances for survival. Researchers looking at the cats in the wild point out that free-living cheetahs are endangered primarily because their habitat is shrinking and because cheetah behavior prevents the animals from thriving in game reserves. For cheetahs in captivity, changing the way zoos manage the cats appears to boost the success of breeding programs. These developments have led many researchers to look anew at the cheetah—and to conclude that, at least for captive cheetahs, the outlook may not be as gloomy as they had thought.