Aspects Of The Biology Of Cheetahs Acinonyx Jubatus (schreber)

Abstract

The data used in this thesis are the results of over 1600 hours observation of cheetahs in Nairobi National Park, Kenya. During most, of the study period, the resident population (11 animals) consisted of three completely independent groups, two families (a mother and cubs) and a pair of males, but 21 different transients cheetahs were also observed. All individuals were recognized by distinctive facial spot patterns. Data on sex ratios, composition of groups, and productivity are presented: Cheetahs are essentially diurnal and their activity patterns are correlated with successful hunting during the day. Various methods of communication are described and mother-cub relations from birth to independence of cubs documented. Play patterns of cubs and their significance in the ontogeny of hunting behaviour are considered. On the basis of range overlap, scent and visual marking, and behaviour between groups during encounters, it is concluded tnat cheetahs are probably not territorial. Interactions between family groups and males frequently involve a high level of aggression. Encounters between cheetahs and other carnivores are described. Predatory behaviour of cheetahs is discussed at length. The overall rate of predation success is 37%, but if juveniles are chased, it is 76%. Other factors influencing hunting and chasing success are discussed. Chases against vulnerable prey are initiated with little hesitation, are most successful, and account for most of the kills. The maximum size of prey normally killed is 60 Kg. Most adult prey taken are from the prime age classes and are in good health at the time of capture. A total of 183 known cheetah kills of 12 species was collected. Numbers of the four main prey spec i.esvt aken , impala, (Aepyce., r.os melampus Lichtenstein) i. Grant's gazelle, (Gazella granti Brooke) i Thomson's gazelle, (Gazella thomsonii Gunther) i and hartebeest, (Alcelaphus buselaphus (Pallas)) are compared with Park populations of those species. Juveniles of all species accounted for 54% of the kills in contrast to their presence of approximately 20% in the living population. They are therefore heavily selected. The estimated number of prey individuals taken between June 1, 1968 and June 1, 1969 (640) is compared with the total number of prey available to cheetahs during that year. Cheetah predation is probably a significant proximal factor limiting the population size of the two gazelles and to a lesser extent, impala. Trends in prey selection of cheetahs in different areas of Africa are compared.