Black wildebeest the hybrid as compared to either of its parents. In some animals, the auditory bullae are highly deformed, and in others, the radius and ulna are fused. Black wildebeest are sexually dimorphic, with females being smaller in size and more slender than males. The head-and-body length is typically between . Males reach about at the shoulder, while females reach . Males typically weigh and females . A distinguishing feature in both sexes is the tail, which is long and similar to that of a horse. Its bright-white colour gives this animal the vernacular name of "white-tailed gnu", and also distinguishes
Wildebeest "Gorgon", while the black wildebeest belonged to the genus "Connochaetes". Today, they are united in the single genus "Connochaetes", with the black wildebeest being named ("C. gnou") and the blue wildebeest ("C. taurinus"). According to a mitochondrial DNA analysis, the black wildebeest seem to have diverged from the main lineage during the Middle Pleistocene and became a distinct species around a million years ago. A divergence rate around 2% has been calculated. The split does not seem to have been driven by competition for resources, but instead because each species adopted a different ecological niche and occupied a different trophic