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Nile lechwe, wasserbock or Mrs Gray's lechwe or waterbuck (Kobus megaceros)The Nile lechwe was described by Leopold Fitzinger in 1855 (Wikipedia).
The Nile lechwe is only found in the Bahr-el-Ghazel district of Southern Sudan and the Machar Gambella marshes of far southwestern Ethiopia (ADW, IUCN, Wikipedia). In Sudan, the bulk lives in the Sudd swamps, with smaller numbers in the Machar marshes near the Ethiopia border. In Ethiopia, it occurs marginally in the south-west, in the Gambella National Park (IUCN). The Nile lechwe lives in seasonally flooded swamps, dry and flooded grass marshes and steppes and inhabits short grass, high reed and cane thickets. It is almost always in shallow waters on the edge of deeper swamps where the water is 10-40 cm deep (IUCN, Wikipedia).
The Nile lechwe has long, coarse, shaggy hair, which is particularly long on the cheeks; elongated, narrow hooves; a short nose and a 40-50 cm long tail. Males and females differ in their pelage colour, size, and ornamentation. Older males are chocolate-, russet- or blackish-brown, with small, white patches over their eyes and a white spot behind the horns; the spot connects to a white band on the neck, which broadens on the withers. Males have white underbellies and may have longer hair on their necks and have 48-87 cm long, lyre-shaped horns, which are 'S'-shaped in profile, strongly ridged at their bases, curved at the tips and are about 165 cm long, 100-105 cm tall at the shoulders and weigh 90-120 kg. Females are pale yellow or golden-brown and lack horns. They are about 135 cm long, 80-85 cm tall at the shoulders and weigh 60-90kg. Young males resemble females until they are 2-3 years old, when the colour of the pelage changes and the horns begin to grow (Wikipedia).
The Nile lechwe is crepuscular, being active in the early morning and late afternoon (Wikipedia). It is gregarious, gathering in loose herds of up to 50 females and one male or in smaller all-male herds (Wikipedia). The lechwes divide themselves into three social groups: females and their new young, bachelor males and mature males with territories (Wikipedia). A male with territory may allowsa bachelor male into his territory to guard the region and not to copulate (Wikipedia). It uses a mixture of visual signaling, tactile communication and vocalizations in communication (ADW, Wikipedia). When displaying, it rears high in the air in front of its opponent and turns its head to the side while displaying (Wikipedia). It achieves a submissive posture by stretching its neck and head forward horizontally. The submissive female may also make snapping movements while stretching her neck. Fighting males duck their heads and use their horns to push against each other. If one male is significantly smaller than the other, he may move next to the larger male in a parallel position and push from there, which prevents the larger male from pushing with all his force (ADW, Wikipedia). Females are quite loud, making a toad-like croaking when moving (Wikipedia). The lechwe usually flees to water if disturbed (Wikipedia).
The Nile lechwe is herbivorous, eating mainly grasses, as well as herbs, foliage, water plants, fruits, and twigs. It may prefer ro eat wild rice at the start of the flood season and eats a larger proportion of swamp grasses (Wikipedia). It can wade in shallow waters and swim in deeper waters and may rear up to feed on young leaves from trees and bushes (Wikipedia). It eats aquatic plants in marshy areas (Wikipedia). It may help reduce grass fires by trampling the grass when grazing, making a natural firewall (Wikipedia). Its predators include humans, lions, leopards, African hunting dogs and crocodiles (Wikipedia).
The Nile lechwe has a harem mating system where only the dominant male is sexually active. During the mating season, young males bend their horns to the ground as if to poke the earth (Wikipedia) Males fight in the water, submerging their heads in horn-to-horn combat, for dominance. These contests are usually short and violent (Wikipedia). The dominant male copulates with the female. Before mating, he bends his head to the ground and urinates on his throat and cheek hair. He then rubs his dripping beard on the female's forehead and rump before mounting the female (Wikipedia). This is probably a form of chemical and tactile communication (ADW). A single calf is born in the wet season after about 9 months; it weighs about 4.5-5.5 kg. The sex ratio at birth is 1:1. The infant is precocious at birth and can keep up with its mother during foraging at a young age (ADW). The mother hides the calf in thick vegetation for two to three weeks, where she nurses it (Wikipedia). She uses direct attack, mostly kicking, to protect the calf from smaller predators (Wikipedia). Male parental care has not been seen (ADW). The infant mortality rate is high in the wild because yearlings are infected with warble flies, which make them unhealthy and bring many of them down (Wikipedia). Calves show hiding behaviours and are weaned at 5-6 months and are independent from their mothers at 6-8 months, when they join the herd (ADW, Wikipedia). Females can ovulate again about one month after giving birth, leading to a mean interbirth interval of 11.6 months (Wikipedia). Most females have a calf every year. The lechwe is sexually mature at 2 years of age (Wikipedia). Adults live until about 10 years in the wild (AnAge).
Captives mate and give birth throughout the year; the birth peak, and this occurs between February and May (Wikipedia). The 30-day infant mortality rate (36%) is high in captivity due to inbreeding (ADW). Captives live about 10-11.5 years, but may live up to 21.1 years (ADW, AnAge, Wikipedia).
The Nile lechwe is listed as Endangered on the IUCN red list or in CITES, but needs conservation efforts. A recent census found 30,000-40,000 in the wild and 150 in captivity; the wild population fell over 50% from 1980-2007 (IUCN, Wikipedia). The IUCN status is "Satisfactory" in Sudan and "Rare" in Ethiopia, where its population is unstable due to human activities (Wikipedia). Populations are confined to two small areas where any change in conditions would harm their status; these regions are places of severe political and social unrest (IUCN). The main threats are habitat loss and hunting pressures for meat and trophies (IUCN, Wikipedia). Hunting in the Sudan needs a special licence (Wikipedia). In Ethiopia, six animals per year are allowed to be captured with a special licence (Wikipedia). In 1971, a law limited hunters to two animals per lifetime. Oil exploration and exploitation in the Sudd threatens the lechwe and other wildlife (IUCN, Wikipedia). Cattle penetrate deep into the Sudd in the dry season and probably constrain the lechwe, which move into deeper water (IUCN). In the Sudan, populations of Nile lechwe occur in three nominal protected areas: Zeraf, along the Bahr-el-Zeraf; Fanyikang, north of Bahr-el-Gazal and Shambe, along Bahr-el-Gebel (IUCN, Wikipedia). In Ethiopia, they occur in the Gambella National Park (IUCN). Constructing the Jonglei canal and introducing irrigation and exploit oil reserves in southern Sudan could cause a deterioration of the Nile lechwe's status (IUCN). White Oak Conservation in Yulee, Florida has kept a and bred Nile lechwe since the mid-1980s; the habitat resembles the lechwe's native habitat of moist lowlands (Wikipedia).
The genetic make-up of most captive individuals may not be adequate for a long-term survival program aiming to preserve 90% of the average heterozygosity of the original population for 200 years. Capturing wild individuals in Ethiopia would reduce inbreeding and the infant mortality rate (ADW).