Eastern Bongo

Tragelaphus eurycerus isaaci

Bongos have many adaptations that help them survive in the wild.  The markings on the sides and backs of a bongo camouflage them in forest shadows.  Their large ears help them hear approaching predators. When running from a predator, they do so with their head up and back, so their horns do not catch in the dense forest trees and plants.



Habitat & Range

Bongo are only found in montane rain forests with dense undergrowth. They thrive at the forest edge and in new growth areas that occur after disturbances.

Eastern (or mountain) bongos are much less prevalent than the western bongo and are only found in a mountain forested region of central Kenya – near Mt. Kenya and the Aberdare mountains.


Map of Africa


  • They are mainly nocturnal but also graze during the morning and evening (crepuscular).
  • They are very shy and reclusive. When disturbed they run at full speed through the thick undergrowth to seek cover. They will then stand with their back to the disturbance to be in a good position to flee, and their back is less conspicuous.
  • They run with their head up so the horns lie along the back and do not impede their flight in the forest; the horns may even help deflect branches.
  • The stripes provide added camouflage from predators when they are in the forest.
  • They rely less on scent than other antelopes because they have no special secretion glands.
  • The red fur pigment stains the undergrowth when they brush against it. Although helpful for finding each other, it also assists predators.
  • The large ears help provide sharp hearing – a good adaptation for forest dwellers.

Physical Description

  • They are one of the largest forest antelopes. At full maturity, they stand between 3.5 to 4.5 ft (1–1.4m) high at the shoulder, are 7-10 ft (2-3m) long, and weigh between 460 and 900 lbs (200-408kg), with males being heavier than females; eastern bongos are larger than western bongos.
  • Bongos have a red-brown chestnut coat with 10-15 narrow vertical white stripes running over the back and down the sides and a single chest stripe. They have white underparts. The front legs are blackish with thick white stripes or spots and there is a white crescent above the hooves on all four legs. Males are darker than females.
  • The face has a black muzzle with a white chevron under the eyes and there are 1 or 2 white cheek patches on either side of the face. The ears are large with some white spotting.
  • Both sexes have lyre shaped smooth horns with 1 to 1.5 turns. The horns can grow to 2.5 ft long. They are hollow and are made out of keratin.
  • The tail is long and tufted at the tip.


What Does It Eat?

In the wild:
Leaves and bark from bushes along with grasses, flowers and roots. They require salt in their diet and will often visit mineral licks at night

At the zoo:
A variety of grain, browse, alfalfa, fruit and vegetables

What Eats It?
They are hunted by leopards and sometimes hyenas and lions but humans are now the main predators.

Social Organization

Although adult males of a similar size or age seem to be solitary, younger males may join with an older male temporarily. Males are relatively non-territorial and, although serious male fights may occur, males will try to avoid these by visually displaying or resorting to ritualized sparring. Visual displays include neck bulging, eye rolling and holding horns in a vertical position while slowly pacing back and forth in front of the other male. Males only seek out females at mating time and, when with female herds, do not restrict movement of the females (unlike other antelope). Females usually stay in herds of 6-8 individuals and young – the herds may have been larger in the past.

Life Cycle

Bongo births are concentrated in discreet traditional calving grounds. They bear a single calf after a gestation period of about 9.5 months. To limit predation, calves are hidden in the undergrowth, with the mother visiting for short periods to allow the calf to nurse. After about 1-2 weeks, the calf is able to join the herd and is weaned after about 6 months. Eastern bongo males possibly live up to 9 years in the wild and females 12 years – but data is scarce. They can live about 19-21 years in managed care.