The capture of rhinos was preceded by a detailed study on the ecology and status of this species in South West Africa (Joubert, 1971; Joubert & Eloff, 1971). The findings revealed that only a small number were present in the Park at the time, the main concentration being in the vicinity of Otjovasandu. Solitary rhinos were encountered in the Okaukuejo area, while a small group was resident at Gobaub (Figure 1). A census conducted in 1966 (Joubert, 1971 ) revealed 90 rhinos for the whole territory, 17 per cent of which occurred within the Park. Following the release of two rhino during trial operations, an additional 37 rhinos have been set free between 1970 and 1972, of which 13 were released at Halali, 4 in the Okaukuejo area and 20 in the Koabendes-Kaross Paddock. Despite the difficulty in locating them and the initial setbacks, rhinos are not infrequently encountered by tourists and are particularly seen in the late afternoon, when they come to drink. Before the introductions, rhinos were rarely seen during aerial censuses conducted with a light, fixed-wing aircraft. However, with recent censuses it is not uncommon to count up to thirty individuals. It is estimated that the present black rhino population in the Park is now in the region of eighty animals. The largest concentration occurs in the Koabendes-Kaross paddock with an estimated population density of one rhino to 600 ha.