the family Bovidae, ruminant animals with cloven hooves. The generic name Connochaetes derives from the Greek words κόννος, kónnos, "beard", and χαίτη, khaítē, "flowing hair", "mane". The specific name taurinus originates from the Greek word tauros, which means a bull or bullock. The common name "blue wildebeest" refers to the conspicuous, silvery-blue sheen of the coat, while the alternative name "gnu" originates from the name for these animals used by the Khoikhoi people, a native pastoralist people of southwestern Africa. Though the blue and black wildebeest are currently classified in the same genus, the former was previously placed in a separate genus, Gorgon. In a study of the mitotic chromosomes and mtDNA, which was undertaken to understand more of the evolutionary relationships between the two species, the two were found to have a close phylogenetic relationship and had diverged about a million years ago. Subspecies C. taurinus has five subspecies: C. t. taurinus (Burchell, 1823), the blue wildebeest, common wildebeest, or brindled gnu is found in southern Africa. Its range extends from Namibia and South Africa to Mozambique (north of the Orange River) and from southwestern Zambia (south of the Zambezi River) to southern Angola. C. t. johnstoni (Sclater, 1896), the Nyassaland wildebeest, occurs from Mozambique (north of the Zambezi River) to east-central Tanzania. It is now extinct in Malawi. C. t. albojubatus (Thomas, 1912), the eastern white-bearded wildebeest, is found in the Gregory Rift Valley (south of the equator). Its range extends from northern Tanzania to central Kenya. C. t. mearnsi (Heller, 1913), the western white-bearded wildebeest, is found in northern Tanzania and southern Kenya. Its range extends from the west of the Gregory Rift Valley to Speke Bay on Lake Victoria. C. t. cooksoni (Blaine, 1914), Cookson's wildebeest, is restricted to the Luangwa Valley in Zambia. Sometimes, it may wander into the plateau region of central Malawi. In addition, the distinctive appearance of a western form, ranging from the Kalahari to central Zambia, suggests that subspecies mattosi (Blaine, 1825) may also prove distinct from subspecies taurinus. The western form can be recognised even at a distance by its upright mane, long beard, and minimal brindling. Hybrids The blue wildebeest is known to hybridise with the black wildebeest. The differences in social behaviour and habitats have historically prevented interspecific hybridisation, but it may occur when both species are confined within the same area, and the offspring are usually fertile.