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Tragelaphus eurycerus
bongo


By Julie Brensike

Kingdom: Animalia
Phylum: Chordata
Subphylum: Vertebrata
Class: Mammalia
Order: Artiodactyla
Family: Bovidae
Genus: Tragelaphus
Species: Tragelaphus eurycerus

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.

Biogeographic Regions
ethiopian (Native )

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

Range mass
210 to 405 kg
(462.56 to 892.07 lb)

Bongos are the largest and most colorful of the forest African antelopes. 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.

Other Physical Features
endothermic ; homoiothermic; bilateral symmetry

Sexual Dimorphism
male larger

Reproduction

Range number of offspring
1 (low)

Average number of offspring
1

Average number of offspring
1
[External Source: AnAge]

Range gestation period
9.4 to 9.93 months

Average birth mass
19800 g
(697.80 oz)
[External Source: AnAge]

Average age at sexual or reproductive maturity (female)
Sex: female

806 days
[External Source: AnAge]

Average age at sexual or reproductive maturity (male)
Sex: male

914 days
[External Source: AnAge]

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.

Parental Investment
altricial ; precocial ; post-independence association with parents

Lifespan/Longevity

Average lifespan
Status: captivity

21.9 years
[External Source: AnAge]

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.

Key Behaviors
solitary ; social

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: 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.

Positive Impacts
food ; body parts are source of valuable material

Economic Importance for Humans: Negative

None

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."

For More Information

Find Tragelaphus eurycerus information at

Contributors

Julie Brensike (author), University of Michigan, Phil Myers (editor), Museum of Zoology, University of Michigan.

References

10/98. "Animal Bytes" (On-line). Accessed 10/13/99 at http://www.seaworld.org/animal_bytes/bongoab.html.

Jewell, P., G. Maloiy. 1989. The Biology of Large African Mammals in Their Environment. Oxford, England: Oxford Science Publications.

Klaus-Hugi, C., G. Klaus, B. Schmid, B. Konig. 1998. Feeding ecology of a large social antelope in the rainforest. Oecologia, 119: 81-90.

Ralls, K. 1978. Tragelaphus eurycerus. Mammalian Species, 111: 1-4.

To cite this page: Brensike, J. 2000. "Tragelaphus eurycerus" (On-line), Animal Diversity Web. Accessed February 12, 2012 at http://animaldiversity.ummz.umich.edu/site/accounts/information/Tragelaphus_eurycerus.html

Disclaimer: The Animal Diversity Web is an educational resource written largely by and for college students. ADW doesn't cover all species in the world, nor does it include all the latest scientific information about organisms we describe. Though we edit our accounts for accuracy, we cannot guarantee all information in those accounts. While ADW staff and contributors provide references to books and websites that we believe are reputable, we cannot necessarily endorse the contents of references beyond our control.

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