A tree felled by an elephant provides a perfect vantage point for two cheetah males searching for suitable prey. Although they are ill-equipped for climbing, cheetah will climb trees with sloping trunks to survey the surroundings. Male cheetah, usually brothers, form co-operative associations that may last for years.
A female cheetah rests after successfully catching and feeding on an impala, this cat's principal prey in Kruger. Cheetah hunt mostly in the early morning or late afternoon, but will also hunt at night when the moon is full. After bringing down an impala, cheetah feed quickly while keeping constant watch for rival predators, and even the arrival of vultures will dislodge them from a kill.
Cheetah are usually solitary, but family parties of a mother and two subadult cubs are common. The cubs are always from the same litter, and leave the mother when about 18 months old and before the next litter is born. Cheetah occupy large home ranges and, despite an abundance of their favourite prey, in no region of the Park does their density exceed one cheetah to every 45 square kilometres.
A cheetah and her two young cubs near Duke water hole south of Lower Sabie. Mother cheetah give birth in tall grass or dense cover. The cubs are carefully hidden for the first few weeks, and the mother moves them frequently to new hiding places to avoid detection by other predators. While the cubs are small, the mother is vulnerable as she has to remain and hunt within a confined area, and is thus less able to avoid attacks from lion.
Members of a wild dog pack spare no time in devouring an impala that they have just caught. Aware of hyaena howling nearby, these dogs consumed their kill in under three minutes, and by the time the hyaena arrived on the scene there was no sign of the kill. Competition from other predators, and direct attacks by lion on both adults and cubs, reduces wild dog numbers even within optimum habitat.
A complex social arrangement governs wild dog and they are able to live in large packs with few signs of conflict. Wild dog travel over vast distances, but are sedentary for a three month period when the pups are raised in an underground den. Some adult members of the pack leave the den site daily in search of prey. Here, the 'baby-sitters' encourage a returning hunter to regurgitate food, which is done for both the pups and their minders.
The Kruger Park is a stronghold for the endangered wild dog, although nowhere can it be considered common. Researchers have identified 27 packs with an estimated total population of 360 for the entire park. Wild dog have a highly developed social system and produce large numbers of pups, but remain rare even in areas where their favoured prey animals are abundant.
While diseases and lion predation are major limiting factors, research has shown that there is a lack of genetic variability in the Kruger population and this may have resulted in inbreeding.
A wild dog pup displays some of the distinct markings that make it possible to identify individuals. Only one female usually breeds in a pack, but litters of up to 21 pups have been recorded. The pups are raised in an old aardvark or warthog burrow in a termite mound, and are carefully cared for by adults in the pack.
Wild dog pups are born after a gestation period of about 70 days, and are suckled by the dominant female for three months, either in the den or near its entrance. Other adult members of the pack take an active part in cleaning the pups, and will return strays to the den. The pups begin to beg for meat from the age of 14 days, and when old enough are led by the adult dogs in search of prey.
Juvenile wild dogs playfully interact at a den site south of Lower Sabie. Fighting among pack members is rare, and a relaxed tail indicates a dog's playful mood. The pups are boisterous, and the mother disciplines them by holding them down on the ground by their necks.
The spotted hyaena's powerful jaws can crush bones and slice through thick hides, useful for a scavenger that often feeds on a carcass that has had the tender meat removed by lion. The hyaena's skull is shaped to accommodate the strong muscles that operate the lower jaw.
A young spotted hyaena rests at a roadside den. Hyaena are largely nocturnal, and form clans dominated by females. Dominant females always feed first at a carcass and return to the den to suckle their pups, which rely on their mother's milk for the first nine months. A hierarchy also exists amongst males, but the highest ranked male is considered inferior to the lowest ranked female.
Hyaena have learned to use the culverts under the main roads in Kruger as dens to raise their young. During the heat of the day, especially in summer, these concrete tunnels can become exceptionally hot and the cubs may emerge to rest near the entrance.
Interesting comparisons have been drawn between the numbers of predators in Kruger and the hoofed animals on which they prey. In the Central Region, the ratio of lion to prey is 1:110, which is exceptionally high when compared to 1:1 000 in Tanzania's Serengeti. Lion in Kruger sometimes change their prey preferences during wet and dry cycles.
During wet cycles it is easier to stalk and catch zebra and wildebeest, while in times of drought they tend to kill more buffalo, often animals that would anyway have perished from lack of food. Most predators are small in comparison to the mass of their prey. In Kruger, the combined biomass of the major predators is equal to just one per cent of their prey species. This is because between each feeding level in the food chain there is substantial loss of energy, so a 60-kilogram hyaena is dependent on 6 000 kilograms of hoofed animals, equivalent to a herd of 105 impala. The fate of all predators is therefore intricately interwoven with that of their prey.
Young hyaena often rest outside their roadside dens. Hyaena clans are dominated by females, and a female pup inherits her mother's social status. Litters consist of one or two cubs, and if two females are born then one will invariably kill the other.
A large Nile crocodile emerges from the water to feed on a hippo calf that had died in Sunset Dam. Crocodiles prefer fresh food, however, and catfish form the major portion of their diet. They perform an important ecological function in keeping the numbers of these hardy fish in check. During periods of above-average rainfall, crocodiles colonise dams up to 45 kilometres from perennial rivers.
The black-backed jackal is a scavenger that is often seen on the fringes of a lion or cheetah kill, where it will wait for the opportunity to steal a morsel. An unusual behaviour pattern that has been observed is their tendency to follow larger predators, especially leopard, while emitting a repetitive yapping call that alerts other jackal to the possibility of a kill.
A serval listens attentively for rodents scurrying through the dense grassland of a vlei near Orpen Dam. Serval prey mainly on rodents, especially vlei rats, and show a marked preference for tall grassland habitat situated near water.
Many animals, especially predators like the small spotted genet and even antelope such as bushbuck and grey duiker, are active mainly at night and depend on their keen senses of smell and hearing to locate food.
By Nigel Dennis & Michael Brett.