Wildebeest
Both species of wildebeest are even-toed, horned, greyish-brown ungulates resembling cattle. Males are larger than females and both have heavy forequarters compared to their hindquarters. They have broad muzzles, Roman noses, and shaggy manes and tails. The most striking morphological differences between the black and blue wildebeest are the orientation and curvature of their horns and the color of their coats. The blue wildebeest is the bigger of the two species. In males, blue wildebeest stand 150 cm tall at the shoulder and weigh around 250 kg, while the black wildebeest stands 111 to 120 cm tall and weighs about 180 kg. In females, blue wildebeest have a shoulder height of 135 cm and weigh 180 kg while black wildebeest females stand 108 cm at the shoulder and weigh 155 kg. The horns of blue wildebeest protrude to the side, then curve downwards before curving up back towards the skull, while the horns of the black wildebeest curve forward then downward before curving upwards at the tips. Blue wildebeest tend to be a dark grey color with stripes, but may have a bluish sheen. The black wildebeest has brown-coloured hair, with a mane that ranges in color from cream to black, and a cream-coloured tail. The blue wildebeest lives in a wide variety of habitats, including woodlands and grasslands, while the black wildebeest tends to reside exclusively in open grassland areas. In some areas, the blue wildebeest migrates over long distances in the winter, whereas the black wildebeest does not. The milk of the female black wildebeest contains a higher protein, lower fat, and lower lactose content than the milk of the blue wildebeest. Wildebeest can live more than 40 years, though their average lifespan is around 20 years.
Wildebeest
Aerial photography has revealed that a level of organisation occurs in the movement of the herd that cannot be apparent to each individual animal; for example, the migratory herd exhibits a wavy front, and this suggests that some degree of local decision-making is taking place. Numerous documentaries feature wildebeest crossing rivers, with many being eaten by crocodiles or drowning in the attempt. While having the appearance of a frenzy, recent research has shown a herd of wildebeest possesses what is known as a "swarm intelligence", whereby the animals systematically explore and overcome the obstacle as one. Major predators that feed on wildebeest include the lion, hyena, cheetah, leopard, and crocodile, which seem to favour the wildebeest over other prey. Wildebeest, however, are very strong, and can inflict considerable injury even to a lion. Wildebeest have a maximum running speed of around . The primary defensive tactic is herding, where the young animals are protected by the older, larger ones, while the herd runs as a group. Typically, the predators attempt to cut out a young or ill animal and attack without having to worry about the herd. Wildebeest have developed additional sophisticated cooperative behaviours, such as animals taking turns sleeping while others stand guard against a night attack by invading predators. Wildebeest migrations are closely followed by vultures, as wildebeest carcasses are an important source of food for these scavengers. The vultures consume about 70% of the wildebeest carcasses available. Decreases in the number of migrating wildebeest have also had a negative effect on the vultures. In the Serengeti ecosystem, Tanzania, wildebeest may help facilitate the migration of other, smaller-bodied grazers, such as Thomson's gazelles ("Eudorcas thomsonii"), which eat the new-growth grasses stimulated by wildebeest foraging.