Of the large cats, cheetahs are the most endangered. Scientists theorize that some 10,000 years ago a genetic "bottleneck" developed. Perhaps some disease wiped out all but a small group of cheetahs. Virtually all of the cheetahs alive today trace their heritage back to these relatively few survivors. As a result, the gene pool for cheetahs is not very diverse and they could easily fall victim to another epidemic.
While humans are not implicated in the cheetahs' lack of genetic diversity, people are making the cheetahs' lives more difficult today. Unlike most other cats, cheetahs hunt chiefly by day – precisely the time when the parks and game reserves are the most crowded with tourists. Vehicles moving through the parks often disrupt the hunting by scaring off the game or distracting the hunters.
Cheetahs, of course, are well known as the fastest animals on earth, at least over short distances. Nevertheless, they are very vulnerable to lions and hyenas, both of which will kill the cheetahs (and especially their cubs) in order to reduce the competition for game. The light body structure that enables cheetahs to accelerate so quickly and turn so rapidly also makes them vulnerable to injury by the very prey that they hunt. Bigger game, such as adult zebra or wildebeest, are usually beyond the cheetah's ability to bring down safely.
During my first trip to Africa (in 1998), I was on the continent for more than seven weeks before I saw my first cheetah and I was beginning to fear that I never would. Then I came to Masai Mara in Kenya, where my luck changed dramatically. First, news came over the radio in the vehicle that two young males had been spotted. Although male cheetahs are typically solitary animals, these two were probably brothers that had stayed together to improve their hunting chances.
Later that same day, two Masai herders recognized our driver and called us over. A female cheetah and two cubs were just over the rise. We watched the group for a couple of hours, then it was time to return to the nearby camp for lunch. After lunch, we decided to return and see how the group was doing. During the hour or so that we were away, the mother cheetah had killed a Thomson's gazelle and brought it back for the cubs. The Thomson's gazelle is the second fastest animal in Africa, second only to the cheetah.
In July 2002 I visited Djuma Reserve, near South Africa's Kruger Park. One day we came upon a very photogenic male cheetah that had climbed up onto a fallen tree to investigate some scent markings, presumably left by another cheetah. Once up on the tree, however, it wasn't quite sure how to get down again and took a little while to manage a dignified descent.