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 recorded when a dispute between two males occurred. Wildebeest do not form permanent pair bonds and during the mating season, or rut, the males establish temporary territories and try to attract females into them. These small territories are about 3000 m, with up to 300 territories per km. The males defend these territories from other males while competing for females that are coming into oestrus. The males use grunts and distinctive behaviour to entice females into their territories. Wildebeest usually breed at the end of the rainy season when the animals are well fed and at their peak of fitness.