Attacks by lions (Panthera leo) on adult rhinos have been seen on two occasions in the Okaukeujo and Halali areas. Although the rhinos were able to ward off their offenders, they can by no means be considered safe when confronted by a large pride of lions. Herbert and Austen (1972) record the killing by lions of an adult rhino which was released in the Wankie National Park. The recruitment rate of the black rhinoceros is slow, and they take a considerable time to reach maturity. The influence, therefore, of lions, particularly on rhino calves and subadults, may have a significant bearing on black rhino populations, especially when they occur in areas commonly frequented by these predators.
The largest concentration occurs in the Koabendes-Kaross paddock with an estimated population density of one rhino to 600 ha.
After translocation Several individuals were involved in mortal combat, which took place two to ten weeks after being set free. Four animals (three bulls and one cow) were known to have succumbed from fatal wounds. A heifer died of an unknown cause. In one instance it was necessary to recapture a troublesome bull and transfer it to the Okaukuejo area. Although there was a resident population totaling approximately seven animals, fighting only developed between the rhinos introduced. Conflicts between black rhinos released in the Wankie National Park have also been recorded by Herbert and Austen (1972). The prolonged captivity of rhinos should be avoided wherever possible. A captivity period of approximately ten days was found to be the most suitable.
To avoid aimless wandering, especially in waterless areas, the rhino were kept in wooden constructed bomas for a variable period. They were released one by one over a period of a few days. Several animals frequently returned to the bomas, where water was available. They showed considerable respect for fences unless provoked and on no occasion did they attempt to leave the Park and return to their original home ranges. All rhinos translocated to Kaross had to be confined to the bomas for an extended period (60 days). and once released the majority did not disperse but remained in the vicinity of the bomas. Several individuals were involved in mortal combat, which took place two to ten weeks after being set free. Four animals (three bulls and one cow) were known to have succumbed from fatal wounds. A heifer died of an unknown cause. In one instance it was necessary to recapture a troublesome bull and transfer it to the Okaukuejo area. Although there was a resident population totalling approximately seven animals, fighting only developed between the rhinos introduced. Conflicts between black rhinos released in the Wankie National Park have also been recorded by Herbert and Austen (1972). The prolonged captivity of rhinos should be avoided wherever possible. A captivity period of approximately ten days was found to be the most suitable. Because of the black rhinos' solitary and elusive nature and the tendency to confine themselves to thickets and rocky outcrops, it has been a particularly difficult task to locate them and keep track of their movements. Although initially fairly concentrated, the rhinos released at Halali have become dispersed over an area of 1,500 km? and it appears that the majority have settled either singly or in pairs in the vicinity of permanent waterholes. The arrival of two calves was observed at Kaross and recently the tracks of a young calf were noticed in the vicinity of Halali.
