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
Black wildebeest of the muscles to use large amounts of oxygen help explain the rapid running speed of the black wildebeest and its high resistance to fatigue. Individuals may live for about 20 years. The black wildebeest is particularly susceptible to anthrax, and rare and widely scattered outbreaks have been recorded and have proved deadly. Ataxia related to myelopathy and low copper concentrations in the liver have also been seen in the black wildebeest. Heartwater ("Ehrlichia ruminantium") is a tick-borne rickettsial disease that affects the black wildebeest, and as the blue wildebeest is fatally affected by rinderpest and foot-and-mouth disease, it is