Tragelaphus spekiisitatunga

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Geographic Range

Center of distribution is the southwestern African rainforest and the wetter regions of the southern savanna. Specifically Gambia to S.W. Ethiopia, south to Angola, Namibia, N.W. Botswana. (Estes, 1991; Honacki et al., 1982)

Habitat

The sitatunga is semiaquatic, and so specialized that it occurs only in swamps or permanent marshes. Partial to papyrus and phragmites within swamps, it may also occur in wetlands dominated by bullrushes, reeds, and sedges. They frequent the deepest parts of the swamp. (Estes, 1991; Nowak, 1991)

  • Aquatic Biomes
  • lakes and ponds

Physical Description

The Sitatunga, a swamp-dwelling antelope, exhibits great elongation of the hooves, which have a wide splay and naked padlike pattern. They possess unique flexibility of the joints at the feet, representing structural adaptations for walking on boggy and marshy ground.

Coloration varies geographically and individually. Males are gray-brown to chocolate-brown, females are brown to bright chestnut, and calves are bright rufous-red, woolly coated, spotted, and striped. Adults are long coated and have characteristic whiteish marks on the face, ears, cheeks, body, legs, and feet.

Males are considerably larger than females (100 cm tall vs. 75-90 cm tall). Males possess horns ranging in length from 508-924 mm. Horns are characterized by two twists and are ivory tipped. (Estes, 1991; Nowak, 1991)

  • Sexual Dimorphism
  • male larger
  • sexes colored or patterned differently
  • Range mass
    50 to 125 kg
    110.13 to 275.33 lb

Reproduction

Breeding occurs throughout the year, males are polygynous, and females produce a single young at an average interval of 11.6 months. The mean gestation period is 247 days, and sexual maturity is attained at approximately 1 yr. by females and 1.5 yrs. by males.

A male approaches a female in a low stretch posture while the female may back away slowly. When the male comes within a few inches of the female, she may suddenly bound away, causing considerable commotion in the swamp. The male persistently follows, but always stays behind. It is characteristic of this species that the male lay his head and neck on the female's back and lifts his forelegs off the ground in a mounting attempt. The female responds with neck winding, in which her neck angles down obliquely and her head turns sharply up, thrusting forward, upward and back with mouth wide open. The male then mounts with his head resting on her back, and her head and neck point forward and down.

Females hide their calves on platforms in secluded dry reeds growing in deep water. Calves are unable to move slowly and deliberately through the swamp like adults, and follow their mothers closely for several months only after learning how. A mother feeds near the calf's hiding spot, finishes, and walks up to the calf. It licks the young's snout, then moves away. The calf gets up and follows the mother, and she leads it to a protected place where it can suckle. (Estes, 1991; Nowak, 1991)

  • Key Reproductive Features
  • gonochoric/gonochoristic/dioecious (sexes separate)
  • sexual
  • Range number of offspring
    1 to 2
  • Average number of offspring
    1
  • Average number of offspring
    1
    AnAge
  • Range gestation period
    7.5 to 8.6 months
  • Average gestation period
    8.23 months
  • Average age at sexual or reproductive maturity (female)
    Sex: female
    401 days
    AnAge

Lifespan/Longevity

  • Average lifespan
    Status: captivity
    22.6 years
    AnAge

Behavior

Social organization: Sitatunga are semi-social, nonterritorial, and sedentary. Swamps are highly productive ecosystems and sitatungas can live at densities of 55/km^(2) or higher. Females tend to form herds and males associate together or with females until subadult. As adults, males avoid one another.

Activity: Sitatungas move through the swamp along established pathways. These have numerous side branches leading to feeding grounds and neighboring riverine forest. They are active both diurnally and nocturnally and may move into marshy land at night. They typically feed at any hour in areas where they are protected. They also lie on platforms of vegetation that each animal prepares for itself by repeated circling and trampling. They also stand and ruminate in the water.

Locomotion: Sitatungas are slow and clumsy land runners, but their plunging run works well in water. Their broad and splayed hooves keep them from sinking in soft ground as deeply as other ungulates. They are usually slow and inconspicuous, and are good swimmers.

Vocal communication: Males often bark at night, sometimes as an alarm signal, or perhaps as a way of announcing their location. Females have a single higher-pitched bark. A male following a female in a low stretch may utter a suppressed roar. (Estes, 1991)

Communication and Perception

Food Habits

Alchornea cordifolia, common around Lake Victoria, provides a favorite browse for sitatunga. Foraging takes place in both dry land and swamp. Sitatunga select plants in the flowering stage. They often emerge at night from swamplands to graze on nearby dry land, as well as in adjacent forests where they browse on foliage and creepers. Feeding activity is apt to be concentrated in a small area of swamp for many days at a time, then they suddenly shift to new grounds. Sitatunga feed while immersed up to their shoulders and move slowly through the vegetation. Sometimes forelegs may be immersed while hind legs are elevated. They may rear to reach flowers of tall reeds, sedges, grasses and foliage, and males have been known to break branches with their horns. When feeding on long leaves, a sitatunga wraps its tongue around a clump, pulls it into its mouth, and crops it with its incisors. (Estes, 1991; Kingdon, 1974)

Economic Importance for Humans: Positive

Snare trappers value Sitatunga as a food source, but they are also appreciated for their skins.

  • Positive Impacts
  • food
  • body parts are source of valuable material

Economic Importance for Humans: Negative

None

Conservation Status

Lions and wild dogs prey on sitatungas, and leopards catch some that venture into riverine forest. Sitatungas are vulnerable to snare-trappers due to their use of regular pathways. They may also be driven by beaters into nets or into deep water where spearmen in boats easily dispatch them. (Estes, 1991; Honacki et al., 1982)

Other Comments

The sitatunga and bushbuck are close enough genetically to produce viable hybrids in captivity, and almost indistinguishable from the nyala except for pelage and hooves. (Estes, 1991)

Sitatunga is a common host animal for the parasite Schistosoma, a blood fluke found in mesentery blood vessels. (Delany, 1979)

When being pursued, sitatungas may avoid detection by submerging in swamps until only their nostrils and eyes remain above water. (Estes, 1991)

Contributors

Marcy Coash (author), University of Michigan-Ann Arbor, Phil Myers (editor), Museum of Zoology, University of Michigan-Ann Arbor.

Glossary

Ethiopian

living in sub-Saharan Africa (south of 30 degrees north) and Madagascar.

World Map

altricial

young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

chemical

uses smells or other chemicals to communicate

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

food

A substance that provides both nutrients and energy to a living thing.

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

social

associates with others of its species; forms social groups.

tactile

uses touch to communicate

young precocial

young are relatively well-developed when born

References

Delany, M. 1979. Ecology of African Mammals. New York, New York: Longman group Inc..

Estes, R. 1991. The Behavior Guide to African Mammals. Berkeley and Los Angeles, Ca.: University of California Press.

Games, I. 1983. Observations on sitatunga (Tragelaphus spekii selousi) in the. Biological Conservation, 27: 157-170.

Honacki, J., K. Kinman, J. Koeppl. 1982. Mammal Species of the World. Lawrence, Kansas: Allen Press Inc., and The Association of Systematics Collections.

Kingdon, J. 1974. East African Mammals. Chicago, Il.: The University of Chicago Press.

Nowak, R. 1991. Walker's Mammals of the World. Baltimore, Md.: Johns Hopkins University Press.

Starin, E. 2000. Notes on Sitatunga in the Gambia. African Journal of Ecology, 38: 339-342.