A system is described for estimating the age of the African lion by studying the eruption sequence of deciduous and permanent teeth of both jaws and the wear of permanent teeth. This system is supplemented by observing criteria such as height of the cemento‐enamel line of permanent canines above the alveolar margin, the closure of the apical foramen of the pulp chamber and the discolouration of permanent teeth. Where skulls are available curves and equations describing closure rate with age of the pulp chambers of maxillary and mandibular canines measured at their maximum mesio‐distal width, are provided. These measurements can be taken by either sectioning the canines transversely at a certain point or by X‐raying the teeth. Sex‐specific von Bertalanffy growth curves and equations describing skull growth with age for four skull measurements are also provided while the use of cranial sutures for age determination in the lion is evaluated. Canine root sections were removed, decalcified, sectioned and stained for incremental cementum line counts. The results of this method were in close agreement with the ages of known‐age lions and those aged by the previously mentioned methods (r=0.973; P<0–001). A series of photographs and a description is provided whereby lions observed in the field can be classified into age classes. Sexual dimorphism in the permanent canines is described and appropriate measurements given whereby a single permanent canine can be used to decide on the sex of an animal. The use of oxytetracycline and lead acetate for the in vivo“labelling” of teeth in wild lions is examined.

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Annual home range sizes were determined for 49 marked zebra family groups in the Kruger National Park. Sizes varied from 49 to 566 sq. km, the mean for the Park being 164 square kilometre. Mean home range sizes for different zebra sub-populations and biotic areas were found to differ considerably. Present herbivore densities have not influenced intra- and inter-specific tolerance levels to the extent that home range sizes have increased. Local habitat conditions, and particularly seasonal vegetational changes, were found to have the most profound influence on the shape and mean size of home ranges. The large home range sizes obtained in the Kruger Park, when compared to an area such as the Ngorongoro Crater, can be ascribed to a lower carrying capacity with respect to zebra, large portions of the habitat being sub-optimal, either seasonally or annually.

Hippopotamus Hippopotamus amphibius reproduction in the Kruger National Park, Republic of South Africa, is described and compared with that of other populations in Africa and with captive reared specimens. Information collected during drought and pluvial periods indicates that adult hippo cows react to adverse environmental conditions (reduced shelter in pools, overcrowding and food scarcity) by marked declines in conception rates (from 36,7 @ 5,6). Indirect evidence indicates that when environmental conditions are unfavourable calf survival is improved by extending the period of lactation and by calves suckling more than one cow. During favourable years some calves mature early (S S, 2 years, and 9 9 5 years) but generally sexual maturity is attained at six and 9-10 years for males and females respectively. The calving interval, when environmental conditions are favourable, is about two years and reproductive senescence and sterility are insignificant factors. The population sex ratio is 1:1. Hippos appear to be typical K-selected species. Environmental constraints have caused them to adopt a low reproductive rate and high survival rate and consequently a close adjustment to the long-term carrying capacity of the environment.

Lion growth was studied by fitting sex specific Von Bertalanffy curves and linear regressions to data on body mass, heart girth, shoulder height and vertebral column length. Measurements were recorded for 344 lions (Panthera leo) (158 ♂♂ and 186 ♀♀), from Kruger National Park, South Africa. Growth in mass for males and females was linear up to about 36 months of age 0 = 0–98 and 0–99 respectively). The other age‐specific measurements were clearly curvilinear. Mean weights for adult lions (excluding stomach contents) were 187–5 kg (♂♂) and 124–2 kg (♀♀) respectively. Lions tended to continue growing up to about seven years in males and nine to 10 years in females after which they usually started to lose condition. Body mass and heart girth measurements of Kruger Park lions were compared with samples from three other populations. These showed that lions from East Africa were smaller than those from more southern populations in Rhodesia, Kalahari and Kruger Park.