Kobus megaceros (Fitzinger, 1855)
|
publication ID |
https://doi.org/ 10.5281/zenodo.6512484 |
|
DOI |
https://doi.org/10.5281/zenodo.6581652 |
|
persistent identifier |
https://treatment.plazi.org/id/03F50713-9971-FFCB-065F-F81BFD9AF50F |
|
treatment provided by |
Conny |
|
scientific name |
Kobus megaceros |
| status |
|
Nile Lechwe
French: Cobe du Nil / German: Weil 3nacken-Moorantilope / Spanish: Kob del Nilo
Other common names: Mrs. Gray's Lechwe, Mrs. Gray's Waterbuck
Taxonomy. Adenota megaceros Fitzinger, 1855 ,
Awan, Bahr-el-Ghazal.
This species is monotypic.
Distribution. S Sudan and W Ethiopia. View Figure
Descriptive notes. Head-body ¢.160-180 cm (males) and ¢.130-170 cm (females), tail 45-50 cm, shoulder height ¢.100-105 cm (males) and c.80-85 cm (females); weight c.90-120 kg (males) and c.60-90 kg (females). The Nile Lechwe exhibits significant sexual dimorphism in both bodysize and coloration. Pelage is relatively long and shaggy in both sexes, especially on the sides and underside of the jaw (giving the appearance of bulging cheeks); adult males may have a mane of longer hair on the neck. The tail is long and slender, with a terminal tuft. The hooves are elongated. In females and juveniles, the overall color is ocher-yellow; the dorsal coloration is richer than on the flanks and underparts. A distinct horizontal demarcation between the ocher dorsum coloration and the paler haunches is present on either side of the tail base. Facial markings are indistinct; a pale superciliary streak is present, and the area below and in front of the eyesis often washed with darker gray. In contrast, adult males are rich blackish-brown with striking white markings. A large patch of white hair sits saddle-like above the shoulders; the nape of the neck may also be white. In males, the face is dark with white markings: on the chin and upperlip, a stripe that passes in front of and over each eye, a wedge between the back of eye and ear, and a large spot on the back of the head. The middle of the abdomen, inner surfaces of the hindlegs, and the underside of the otherwise dark tail are also white. Horns are present in males only; these are lyrate in form, diverging and curving backward from the base and bending upward and inward toward the tips. Prominent transverse ridges occur along the entire horn, save for the very tips. Horn length is typically 50-87 cm. Dental formulais 10/3, C0/1,P 3/3, M 3/3 (x2) = 32.
Habitat. Swamps and seasonally flooded grasslands. Flooded plains are used during the wet season, when water levels are typically 10-40 cm deep across large tracts of land. As the water recedes in the dry season (beginning in October), Nile Lechwes concentrate in permanent marshy areas. The inundated nature of these habitats results in low predator densities, and this reduced predation risk may have permitted the bold coloration of males to evolve. Areas dominated by Cyperus papyrus appear to be avoided.
Food and Feeding. A grazer on marsh vegetation. Oryza longistaminata is consumed during the early wet season; grasses from the genera Leersia, Echinochloa, and Vossia are used during the rest of the year.
Breeding. Wild births of Nile Lechwes are apparently concentrated in November— January; breeding activity is highest in April. In captivity, births may occur throughout the year, but tend to be concentrated from March to May. Based on observations in captivity, a dominant male will segregate an estrous female from a group and use horn displays and contact to prevent other individuals of either sex from approaching. Gestation has only been imprecisely estimated: the reported range is 210-290 days, averaging c.240 days. Litter size is one. Recorded captive birth weights average 6-4 kg for males and 5-62 kg for females. Infants lie concealed in protected areas away from the herd for up to two weeks. During this time, the neonate lies pressed to the ground, rising only when visited by the mother to nurse. Mothers are protective of their young and may threaten other herd members that approach their calf in a captive setting. Weaning usually occurs at 5-6 months. The average interbirth interval in captivity is 11-6 months; in the wild, this is likely an annual cycle. Sexual maturity in captive individuals of both sexes occurs at 19-20 months (sometimes as early as twelve months); males tend to mature slightly later than females. Horn development occurs more rapidly than the development of mature coloration: males with well-developed horns may still show some ocher and lack the white markings of mature individuals. Several captive individuals have lived to 21 years.
Activity patterns. There is no information available for this species.
Movements, Home range and Social organization. Poorly known in the wild. Seasonal movements may extend over 30-40 km as the animals follow flood lines. This speciesis found closer to the permanent swamps than the similar White-eared Kob ( K. leucotis ), which makes large-scale migrations. Nile Lechwe herds with 50 to several hundred individuals have been observed; group size appears to be linked to habitat quality. Mixed groups, composed of adult females, several adult males, and juveniles are most common; adult and subadult males also associate in bachelor herds. Around female herds, males form a strict hierarchy that appears to be closely linked with coloration. Mature males will tolerate lower-ranking males (fully horned, but lacking the distinctive white patches) in relative proximity to females. Closely matched adult males, however, may fight intensely for dominance or possession of females; in captivity, such fights have resulted in injury or death. Dominance fights in the wild tend to be intense but brief (horn wrestling often involves submerging heads under water); the victor will then chase the loser for a short distance. Males dominate females and juveniles in captive herds, displacing them from food resources. Dominant males will urinate onto their throat mane, and may subsequently rub this onto females. Females also sort themselves into a loose hierarchy through aggressive interactions such as displays, biting, and head-butting.
Status and Conservation. Classified as Endangered on The IUCN Red List. Population estimates from 1977 to 1983 were of 30,000 to 40,000 individuals. No full surveys have since been performed, but an aerial survey in 2007 counted approximately 4300 animals in the Jonglei region of southern Sudan. The population from eastern Sudan and western Ethiopia is at risk due to its low numbers (less than 1000 animals) and rapidly expanding human activities in the area. Three protected areas within Sudan (Zeraf, Fanyikang, and Shambe game reserves) are home to the Nile Lechwe. However, the seasonal movements typical ofthis species result in frequent movements outside of these protected zones into adjacent lands used by herds of cattle. Increased resource competition with livestock is a principal threat, as is the habitat destruction and fragmentation resulting from extensive livestock use. Long-term civil war in Sudan has negatively impacted the Nile Lechwe, principally from increased hunting due to increased availability of weapons and resettlement of displaced people. The inaccessible core habitat of this species is its primary protection against human threats, although the ongoing reconstruction of the Jonglei Canal in southern Sudan could have a profound negative impact by eliminating vast tracts of habitat.
Bibliography. Bercovitch et al. (2009), Dittrich (1972), East (1999), Falchetti & Mostacci (1993a, 1993b), Falchetti, Bianco, & Mostacci (1994), Falchetti, Ceccarelli & Mantovani (1995), Falchetti, Guillet, & Mostacci (1993), Fay et al. (2007), Green & EI-Moghraby (2009), IUCN/SSC Antelope Specialist Group (2008af), Kingdon (1997), Lydekker (1913), Weigl (2005).
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.
