cheetah running. One case is known of a cheetah that overtook a young male Pronghorn. Cheetahs can overtake a running antelope with head start of 150 yards (137.2 meters). Both animals are assumed to be clocked at 50 mph (80 Km/h) by speedometer reading when running alongside a vehicle at full gallop. Ecology and behaviour Cheetahs are active mainly during the day, whereas other carnivores such as leopards and lions are active mainly at night; These larger carnivores can kill cheetahs and steal their kills; hence, the diurnal tendency of cheetahs helps them avoid larger predators in areas where they are sympatric, such as the Okavango Delta. In areas where the cheetah is the major predator (such as farmlands in Botswana and Namibia), activity tends to increase at night. This may also happen in highly arid regions such as the Sahara, where daytime temperatures can reach . The lunar cycle can also influence the cheetah's routine—activity might increase on moonlit nights as prey can be sighted easily, though this comes with the danger of encountering larger predators. Hunting is the major activity throughout the day, with peaks during dawn and dusk. Groups rest in grassy clearings after dusk. Cheetahs often inspect their vicinity at observation points such as elevations to check for prey or larger carnivores; even while resting, they take turns at keeping a lookout. Social organisation Cheetahs have a flexible and complex social structure and tend to be more gregarious than several other cats (except the lion). Individuals typically avoid one another but are generally amicable; males may fight over territories or access to females in oestrus, and on rare occasions such fights can result in severe injury and death. Females are not social and have minimal interaction with other individuals, barring the interaction with males when they enter their territories or during the mating season. Some females, generally mother and offspring or siblings, may rest beside one another during the day. Females tend to lead a solitary life or live with offspring in undefended home ranges; young females often stay close to their mothers for life but young males leave their mother's range to live elsewhere. Some males are territorial, and group together for life, forming coalitions that collectively defend a territory which ensures maximum access to females—this is unlike the behaviour of the male lion who mates with a particular group (pride) of females. In most