Black rhinoceros (Diceros bicornis). Adult black rhinos can reach a height of over 1.5 metres and can weigh up to 1400 kilograms. It is thought that in the wild males tend to become sexually active between 17 to 35 years of age. The numbers of black rhinos in the wild have reduced considerably over the last 40 years due to poaching and the species is currently classified as Critically Endangered by the IUCN. Photographed in Etosha National Park, Namibia, Southern Africa.