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
Blue wildebeest traditional calving and breeding ranges. Similarly, drastic declines have recently occurred in the Tarangire wildebeest migration. The total number of blue wildebeest is estimated to be around 1,550,000. The population trend overall is stable and the numbers in the Serengeti National Park (Tanzania) have increased to about 1,300,000. The population density ranges from 0.15/km in Hwange and Etosha National Parks to 35/km in Ngorongoro Crater and Serengeti National Park, where they are most plentiful. Blue wildebeest have also been introduced into a number of private game farms, reserves, and conservancy areas. For these reasons, the International Union for Conservation of