Two black rhinoceroses (Diceros bicornis), largely solitary animals, which mainly tend to socialise at waterholes, involved in a skirmish at night. Black rhinos are browsers, which are crepuscular. Solitary individuals or mothers with calves often meet at waterholes where tensions can result in fighting especially when a female is in oestrous. 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 at the Okaukeujo waterhole, Etosha National Park, Namibia, Southern Africa.