The bongo is a large, mostly nocturnal, forest-dwelling antelope, native to sub-Saharan Africa, belonging to the spiral-horned antelope tribe Tragelaphini. Bongos are characterised by a striking reddish-brown coat, black and white markings, white-yellow stripes and long slightly spiralled horns. Bongos have a complex social interaction and are found in African dense forest mosaics. They are the third-largest antelope in the world.
The bongo has short, sturdy legs and hindquarters that are higher and more developed than the forequarters. It is the only tragelaphid in which both sexes have horns. Male bongo horns are massive and make one tight spiral. The bongo sports a bright auburn or chestnut coat, with the neck, chest, and legs generally darker than the rest of the body. Coats of male bongos become darker as they age until they reach a dark mahogany-brown colour. Coats of female bongos are usually more brightly coloured than those of males.
The eastern bongo is darker in colour than the western and this is especially pronounced in older males which tend to be chestnut brown, especially on the forepart of their bodies. Bongos have two heavy and slightly spiralled horns that slope over their backs and like many other antelope species.
Like other forest ungulates, bongos are seldom seen in large groups. Males, called bulls, tend to be solitary, while females with young live in groups of six to eight. Bongos have seldom been seen in herds of more than 20. males weigh on average 300 kg and up to 400 kg and females weigh about 240 kg. Gestation is about 285 days, with one young per birth, and weaning occurs at six months. Sexual maturity is reached at 24–27 months. As young males mature and leave their maternal groups, they most often remain solitary, although rarely do they join an older male. Adult males of similar size/age tend to avoid one another. Occasionally, they meet and spar with their horns in a ritualised manner and it is rare for serious fights to take place.
Bongos are found in tropical jungles with dense undergrowth up to an altitude of 4,000 m (13,000 ft) in Central Africa, with isolated populations in Kenya, and West African countries. Historically, bongos are found in three disjunct parts of Africa: East, Central and West. Today, all three populations’ ranges have shrunk in size due to habitat loss for agriculture and uncontrolled timber cutting, as well as hunting for meat. Bongos favor disturbed forest mosaics that provide fresh, low-level green vegetation. Like many forest ungulates, bongos are herbivorous browsers and feed on leaves, bushes, vines, bark and pith of rotting trees, grasses/herbs, roots, cereals, and fruits.
Bongos require salt in their diets and are known to regularly visit natural salt licks. Bongos are also known to eat burnt wood after a storm, as a rich source of salt and minerals.
In the last few decades, a rapid decline in the numbers of wild mountain bongos has occurred due to poaching and human pressure on their habitat. The IUCN Antelope Specialist Group considers the western or lowland bongo, to be Lower Risk and the eastern or mountain bongo, of Kenya, to be Critically Endangered.