I know that first captive born generation of southern white rhinoceros breeds with difficulties in zoos, and that their offspring, breeds even more difficult in captivity, is this true? Is captive population of whites self-sustainable? On other hand, it seems that Indian rhinos shows most successfull breeding rate in captivity of the 3 rhino species held in captivity (excl. Sumatran on Sumatra), followed by black rhinos, and then the Southern white rhinos. Is the breeding success of Black rhinos in captivity, better than that of the Southern white rhinos? Are those differences linked with efforts of management of breeding, made by zoos, because the Indian and Black rhinos are threatened? Are the first captive born generation of Black rhinos breed with greater success than first captive born generation of Southern white rhinos?