National Geographic : 1999 Dec
you in my territory, I will kill you." It's also a way to get the attention of passing females. Paternity is one of the great unknowns of cheetah biology, not just for researchers but for the cheetahs themselves. A female's home range may contain three or four male territo ries, and she may mate with any of the resi dent males, as well as with floater males that pass through. Durant has seen cheetahs mating just once. It involved a coalition of three males named Daniel, Day, and Lewis, after the actor, and a female named Florence. All of them disappeared into the bush. After a few sec onds Durant saw what she called "stacked cheetahs," Daniel, Day, and Lewis mounted one atop the other, with Florence "looking rather squashed" on the bottom. But confusion can be a good thing. Unlike lions, male chee tahs have never been known to kill cubs, per haps because they have no way of knowing whether the cubs are their own offspring. The question of who fathers the cubs is of special interest because cheetahs are a genetic mystery. In the 1980s researchers discovered that all cheetahs are genetically similar-so much so that skin grafts from one cheetah to another produce no immune reaction. The finding caused geneticists to rethink the chee tah's evolutionary history: Roughly 20,000 years ago cheetahs ranged around the world. At different times there were two species in North America. But cheetah populations apparently suffered a drastic decline about 10,000 years ago, and all cheetahs now living appear to be descended from a relative handful of survivors. No one really knows what this signifies for the future of the species. Some biologists suggest that, having survived the population bottle neck and recovered, cheetahs in the wild suffer no ill effects from their genetic homogeneity.