There are two subspecies of white rhinoceros: the southern white rhinoceros and the northern white rhinoceros. As of 2013, the southern subspecies has a wild population of 20,405 – making them the most abundant rhino subspecies in the world. However, the northern subspecies is critically endangered, with all that is known to remain being two captive females.
The name “black rhinoceros” was chosen to distinguish this species from the white rhinoceros. This can be confusing, as the two species are not truly distinguishable by color. There are four subspecies of black rhino: South-central, the most numerous, which once ranged from central Tanzania south through Zambia, Zimbabwe and Mozambique to northern and eastern South Africa; South-western which are better adapted to the arid and semi-arid savannas of Namibia, southern Angola, western Botswana and western South Africa; East African, primarily in Tanzania; and West African which was declared extinct in November 2011.