The composition of the white rhino population in the south-western KNP was determined by ground surveys during 1988 and 1989. This population contained 16,8% adult males, 27,3% adult females, 32,4% subadults and 23,5% calves (N =469). This was very similar to the composition Owen-Smith described for the Umfolozi Game Reserve. The lower number of adult white rhino males in the KNP is probably a result of emigration by males out of the high density study area. In 1961 the first white rhino were reintroduced to the KNP from the Umfolozi Game Reserve. By 1973 a total of 337 white rhino had been successfully relocated in the KNP. By 1993 this population had grown to 1876 animals. From 1980 to 1993 the white rhino population in the KNP showed an average annual growth of 8,4%'. Even the serious droughts of the 1980s did not affect this growth. Owen-Smith described a rate of increase of 8-9% per annum for the white rhino population in the Umfolozi-Hiuhluwe complex. Table 2. Comparison of the demographic parameters of the white rhino populations in the Kruger National Park (KNP) and the Umfolozi Game Reserve (UGR). Adults Subadults Subadult Calves Calves Post-pubertal Pre-pubertal Juvenile Infant Male Female Male Female Age (years) 10-45 7-45 6-10 6-7 2,5-6 0,5-2,5 0-0,5 % of KNP 16,8 27,3 7,9 2,1 22,4 23,5 population % of UGR 19,5 26,1 7,7 3,0 21,4 21,9 population End
In the southern KNP 1415 white rhinos were counted in 1993 for a mean density of 0.4 per km? . In the high-density study areas white rhino densities were about 1,4 per km? (1900 kg/ km?). In the Umfolozi Game Reserve mean white rhino density was 3.2 per km? (4300 kg/ km?) with local densities as high as 5,7 animals per km?, equivalent to a biomass of about 7 600 kg/ km? The size of the founder population is also an important factor when establishing new populations, with larger founder populations being more successful. If one introduced 10 white rhino on a 20 km? game farm with suitable habitat, this would generate a density of 0,5 rhino per km?. A suitable sex and age structure for such an introduced population would be: 2 adult males, 3 adult females and their 3 calves, one subadult male and one subadult female.
Kruger NP. Young females underwent their first oestrus at about 5 years of age, but remained in subadult groups until the birth of their first calf at 6,5-7 years of age. Thereafter they are usually accompanied only by their offspring and are regarded as adult cows. Young males are regarded as adult once they became solitary between 10 and 12 years of age and assume either territorial male or subordinate male behaviour patterns. White rhino cows being accompanied by bulls is an indication of oestrus. A flush of green grass after rains seems to induce the onset of oestrus in cows. The proportion of cows in oestrus remains high through the wet season and early dry season months and thereafter drops to low levels. Dominant white rhino bulls investigated cows encountered within their territories, while cows responded with threatening snorts or roars. If a bull remained with a cow for more than a day, this was a sign that the cow was coming into oestrus. During the pre-oestrus consort period, the bull followed behind the cow and her companions. However, if a cow approached a territory boundary, the bull moved in front to block her progress. A confrontation sometimes ensued, with roars from the cow and squeals from the bull. If a cow was able to evade the bull and cross into the next territory, the bull did not follow and she was joined by the neighbouring bull. The pre-oestrus consort period typically lasted 1-2 weeks. The onset of oestrus was indicated by the commencement of repeated approaches by the bull, accompanied by a hic-throbbing sound. Eventually the cow would let the bull mount her. Copulations lasted 15-30 minutes, with ejaculations every 4-5 minutes. The gestation period in white rhino is about 16 months and the mean intercalving interval is 2,5 years. Younger cows have shorter calving intervals than older cows.
Territorial bulls ejected their urine in powerful sprays, while subordinate bulls and cows urinated in a conventional stream.
Predation does not have a big influence on a white rhino population. There have been a few cases in the KNP where white rhino calves were killed by lions. Animals with pieces of tail or ear missing that could indicate predation by hyaena are also seldom seen. Other accidental white rhino deaths include drowning, getting stuck in mud, failing off cliffs, being killed by elephants and burning in runaway fires.
The annual natality for adult cows (7-45 years) was 40%.
In the southern KNP 1415 white rhinos were counted in 1993 for a mean density of 0.4 per km? . In the high-density study areas white rhino densities were about 1,4 per km? (1900 kg/ km?). In the Umfolozi Game Reserve mean white rhino density was 3.2 per km? (4300 kg/ km?) with local densities as high as 5,7 animals per km?, equivalent to a biomass of about 7600 kg/ km? .
Kruger NP. When white rhino are released into a foreign environment they tend to wander far and wide before settling. Some of the first white rhino that were released in the KNP, to the north of Pretoriuskop, moved eastward and eventually settled north of Crocodile Bridge, a distance of 75 km. With subsequent releases the animals settled in the areas that had already been colonised by white rhino. When introducing white rhino to a game farm it will be a good idea to collect dung from the animals in the boma and place it at waterpoints and other exposed areas on the farm. This could help the animals in settling down sooner.
Dominant white rhino bulls investigated cows encountered within their territories, while cows responded with threatening snorts or roars. The onset of oestrus was indicated by the commencement of repeated approaches by the bull, accompanied by a hic-throbbing sound.
At the end of the dry season when water is scarce some mates have to cross other territories on their way to water. This leads to a increase in conflict and more fighting ensues. In the Kruger National Park this contributes to an increase of adult male mortalities at end of dry season. On a game farm more than one waterpoint would lessen the friction between territorial males. Typical fighting wounds seen on male white rhino other than obvious lacerations on the head include broken jaw bones, wounds between hind legs, punctured abdomens, broken front legs and dislocated hind legs. These wounds are usually fatal. A game farmer should also be able to distinguish territorial adult males from subordinate adult males.
Predation does not have a big influence on a white rhino population. There have been a few cases in the KNP where white rhino calves were killed by lions. Animals with pieces of tail or ear missing that could indicate predation by hyaena are also seldom seen. Other accidental white rhino deaths include drowning, getting stuck in mud, failing off cliffs, being killed by elephants and burning in runaway fires.
Territorial males scattered their dung after defecating, while subordinate males, females and subadults did not scatter their dung or only made a few ineffectual kicking movements.
Predation does not have a big influence on a white rhino population. There have been a few cases in the KNP where white rhino calves were killed by lions. Animals with pieces of tail or ear missing that could indicate predation by hyaena are also seldom seen. Other accidental white rhino deaths include drowning, getting stuck in mud, failing off cliffs, being killed by elephants and burning in runaway fires.
Kruger NP. A white rhino cow giving birth every 2,5 years between ages 6-40 years would produce 14 offspring in her lifetime. There is evidence from captive white rhinos in zoos that indicate that cows do not come into oestrus if there is only one bull with her. Although this is not always the case in free-ranging populations, a game farmer should keep this in mind if his white rhino population is not breeding successfully. It is always a good policy to have at least two mature bulls in a population just in case one gets injured accidentally.
Gestation period 16 months
Kruger NP. The mean intercalving interval is 2,5 years. Younger cows have shorter calving intervals than older cows..
Kruger NP. Copulations lasted 15-30 minutes, with ejaculations every 4-5 minutes.
