The blue wildebeest is a herbivore, feeding primarily on the short grasses. It forms herds which move about in loose aggregations, the animals being fast runners and extremely wary. The mating season begins at the end of the rainy season and a single calf is usually born after a gestational period of about eight and a half months. The calf remains with its mother for eight months, after which time it joins a juvenile herd.
The blue wildebeest exhibits sexual dimorphism, with males being larger and darker than females. The blue wildebeest is typically between 170–240 cm (67–94 in) in head-and-body length. The average height of the species is 115–145 cm (45–57 in). While males weigh up to 290 kg (640 lb), females seldom exceed 260 kg (570 lb). A characteristic feature is the long, black tail, which is around 60–100 cm (24–39 in) in length. All features and markings of this species are bilaterally symmetrical for both sexes. The average life span is 20 years in the wild.
The blue wildebeest is mostly active during the morning and the late afternoon, with the hottest hours of the day being spent in rest. These extremely agile and wary animals can run at speeds of up to 80 km/h (50 mph), waving their tails and tossing their heads.
Bulls mark the boundaries of their territories with heaps of dung and with secretions from their scent glands. The territories are advertised by their behaviour as well as by the physical marking. Body language used by a territorial male includes standing tall with an erect posture, profuse ground pawing and horning, frequent defecation, rolling and bellowing, the sound "ga-noo" being produced. When competing over territory, males grunt loudly, paw the ground, make thrusting motion with their horns, and perform other displays of aggression.
As one of the major herbivores of southern and eastern Africa, the blue wildebeest plays an important role in the ecosystem and is a main prey item for large predators such as the lion. It is one of the animals that draws tourists to the area to observe big game and as such it is of major economic importance to the region. Traditionally blue wildebeest have been hunted for their hides and meat, the skin making good quality leather though the flesh is coarse, dry and rather hard.