By Julie Brensike
Geographic Range
Bongos predominantly inhabit the lowland forests of West Africa and Zaire to southern Sudan. Small populations reside in the montane or highland forest of Kenya and in the Congo.
Habitat
Bongos are predominantly found in the lowland forests of West Africa where they reside among the ground level shrubs and bushes. Smaller populations are often found in the montane forest regions of East Africa where they reside among the thick forest and bamboo zone. The habitat of this animal has a dual purpose. Bongos both feed and depend for cover on the bushes, herbs and bamboo found in these forested regions.
Terrestrial Biomes:
rainforest
; scrub forest
; mountains
.
Physical Description
(462 to 891 lbs; avg. 676.5 lbs)
Bongos are the largest and most colorful of the African antelope. They exhibit sexual dimorphism; females weigh between 210 and 235 kilograms and the males range from 240 to 405 kilograms. Females and young are chestnut red, with darker legs. The males start out this chestnut color and proceed to darken with age, eventually becoming a dark brownish black. Both males and females have long spiraling horns (75-99cm) covered by a blackish brown keratinous sheath. The females' horns tend to be more parallel than the males and make about one spiral turn as opposed to the males' one and one half turns. Other notable features include large broad ears, white markings on the cheeks and legs, a white chevron between the eyes, and between 10 to 15 whitish-yellow stripes along the torso and rump.
Bongos tend to have shorter legs than other African antelopes and a body shape characteristic of forest ruminants. These characters help the large animal to move relatively fast in its dense forest habitat.
Some key physical features:
endothermic
; homoiothermic; bilateral symmetry
.
Sexual dimorphism:
male larger.
Reproduction
Bongos breed seasonally in the Aberdares; however, the mating patterns of the forest dwelling groups are poorly known due to the density of their habitat and their tendency to retreat during the daytime. It is however known that females come into estrus every 21 or 22 days and remain in estrus for approximately 3 days. During this period, the male follows the estrus female in a "low stretch" posture while emitting soft vocalizations. The male approaches the female, rubbing his head against her side and rump to test her for mounting receptivity. Before attempting the mount, the male assumes a "frozen" posture. After fertilization, the gestation period lasts from 282 to 285 days. The female gives birth to a single calf weighing approximately 19.5 kilograms. On rare occasion multiple births may occur in which two calves are born, in which case the birth weights are slightly less.
Key reproductive features:
gonochoric/gonochoristic/dioecious (sexes separate); sexual
.
Behavior
Bongos are the only forest antelope to form herds. These herds range anywhere from 5 or 6 bongos foraging for food together, all the way up to 50. More than one male was included in a number of the herds seen, indicating that bongos are fairly non-territorial. These animals are both diurnal and nocturnal. They stay within the bushes and shrubs of the forest during the day and only come out to the salt licks during the night. They tend to stay out of sight, and it is for this reason that the behavior of bongos has been difficult to study. Relatively little else is known about the activities of these reclusive creatures.
Food Habits
Bongos are grazers and browsers. They typically eat leaves, flowers, twigs, thistles, garden produce and cereals. Additionally, bongos favor younger leaves, suggesting that high protein and low fibre content influence their plant choice. Furthermore, bongos are known to regularly visit natural salt licks. In these salt lick areas they often graze, feeding on grasses and herbs. Bongos have also been known to eat burned wood as a means of getting salt or minerals. They use their long prehensile tongue for grasping leaves and their broad horns for pulling or breaking high branches.
Economic Importance for Humans: Negative
None
Economic Importance for Humans: Positive
Although these animals are difficult to shoot, they are rather easily hunted by dogs and hence provide a food source for African populations. Additionally, as browsers, bongos are important factors in keeping the vegetation of the forests from becoming overgrown. Since many other game animals depend on the health of this vegetation for food, this attribute secondarily affects humans.
Ways that people benefit from these animals:
food
; body parts are source of valuable material.
Conservation Status
IUCN Red List: [link]:
Lower Risk - Near Threatened.
US Federal List: [link]:
No special status.
CITES: [link]:
Appendix III; No special status.
Habitat destruction, poaching and illelgal trapping are all factors that contribute to the decline of bongo populations in Africa. Projects to halt rainforest destruction and laws prohiting entrapment contribute to the conservation of the species.
Other Comments
Bongos are unusual in the genus Tragelaphus in that both sexes have horns. Only one other species, T. oryx, shares this trait. The name Tragelaphus eurycerus comes from the Greek words tragos, meaning "goat," elaphos, meaning "deer," eurys, meaning "broad/widespread," and keras, meaning "horns."
Contributors
Julie Brensike (author), University of Michigan.
Phil Myers (editor), Museum of Zoology, University of Michigan.
