Nile lechwes are herbivorous, eating grasses, herbs, and waterplants.
Plant Foods: leaves
Primary Diet: herbivore (Folivore )
Natural predators of Nile lechwes include lions, leopards, cape hunting dogs, and crocodiles. Humans are also major predators of these animals. Nile lechwes are particularly vulnerable to cooperative hunting because of their close association with aquatic habitats. In the 1950's, traditional lechwe drives (chilas) were common, each one killing about 3,000 individuals.
Known Predators:
Nile lechwes exhibit sexual dimorphism so extreme that males and females look as if they belong to different species. Males and females can easily be distinguished from one another based on pelage color, size, and ornamentation. However, both sexes have long, coarse hair; elongated, narrow hooves; a short nose; and a long tail (with a length between 40 and 50 cm).
Older males are blackish-brown, with a white spot behind the horns. This white spot connects to a white band on the neck, which broadens on the withers. Males have long, lyre-shaped horns that are 48 to 87 cm in length. Males are an average of 165 cm long, 100 to 105 cm tall at the shoulders, and weigh between 90 amd 120 kg.
Females are pale yellow, and lack horns. Young males look like females until they reach 2 or 3 years of age. At this time, the color of the pelage changes and the horns begin to grow. Females are an average of 135 cm long, 80 to 85 cm tall at the shoulders, and weigh between 60 and 90kg.
Range mass: 60 to 120 kg.
Average length: 135-165 cm.
Other Physical Features: endothermic ; homoiothermic; bilateral symmetry
Sexual Dimorphism: male larger; sexes colored or patterned differently; ornamentation
Adults live an average of 10 to 11.5 years in captivity. The lifespan in the wild is similar. The species is reported to have a maximum longevity of 19 years in captivity. In spite of their potential lifespan, most K. megaceros do not live a very long time. The infant mortality rate is high in the wild because yearling Nile lechwes are infected with warble flies, which bring many down. The 30-day infant mortality rate (36%) is high in captivity because of inbreeding.
Range lifespan
Status: captivity: 19 (high) years.
Typical lifespan
Status: wild: 10 to 11.5 years.
Typical lifespan
Status: captivity: 10 to 11.5 years.
Nile lechwes are found in swamps, dry and flooded grass marshes, and steppes. The species is known to inhabit short grass, high reed, and cane thickets.
Habitat Regions: tropical ; terrestrial
Terrestrial Biomes: savanna or grassland
Wetlands: marsh ; swamp
Nile lechwes (Kobus megaceros) have a very restricted geographic range. They are found only in the Bahr-el-Ghazel district of the Southern Sudan, and in Machar Gambella marshes of Ethiopia in Africa.
Biogeographic Regions: ethiopian (Native )
Nile lechwes may help reduce grass fires by trampling the grass when grazing, making a natural firewall. They are also an important source of food for crocodiles because of the amount of time these animals spend in the water.
Nile lechwes are a highly prized trophy to an African hunter and may be traded for food or other resources. They were also traditionally hunted as a source of food.
Positive Impacts: food ; body parts are source of valuable material
There is apparently no negative impact of this species on humans.
Nile lechwes are not on the IUCN red list or in CITES, but they are in need of conservation efforts. Populations are confined to two small areas where any change in conditions would be detrimental to their status. The regions they inhabit are also places of severe political and social unrest, which contributes to a dim outlook for their survival.
The main threats to K. megaceros are habitat loss and hunting pressures. Hunting in the Sudan requires a special license. In Ethiopia only six animals per year are allowed to be captured with a special license. In 1971, a law limited hunters to two animals per a lifetime, making the animal a rare commodity.
The most recent census found 30,000 to 40,000 in the wild and 150 in captivity. Their current IUCN status is "Satisfactory" in Sudan and "Rare" in Ethiopia.
Better conservation efforts are needed in zoos. Falchetti (1993) believes that the genetic make-up of most of the captive individuals is not adequate for a long-term survival program aiming at preserving 90% of the average heterozygosity of the original population for 200 years. Capturing wild individuals in Ethiopia is possible and would reduce the inbreeding and consequently the infant mortality rate in captive animals.
US Federal List: no special status
CITES: no special status
IUCN Red List of Threatened Species: endangered
Nile lechwes communicate much like other waterbucks and kobs. There is a mixture of visual signaling and tactile communication. When displaying, they will rear high in the air in front of their opponent and turn their head to the side. They achieve a submissive posture by stretching their neck and head forward horizontally. The submissive female may also make snapping movements while stretching her neck. When fighting, males will 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.
In addition, during the reproductive season, males urinate on themselves, then smear the urine onto the female before mounting her. It is difficult to see this as anything other than soem form of chemical, as well as tactile, communication.
Although vocalizations were not reported in the literature reviewed here, because they are mammals, it is likely that they do vocalize, and that these vocalizations play some role in communication.
Communication Channels: visual ; tactile ; chemical
Perception Channels: visual ; tactile ; acoustic ; chemical
Kobus megaceros has a harem mating system where only the dominant male is sexually active. Mating starts with a unique form of marking. The male 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, and mating ensues.
Mating System: polygynous
Both sexes are sexually mature at 2 years of age. The gestation period averages 235.5 days, after which a single calf is born. newborns weigh about 4.5 to 5.5 kg.
Female can ovulate again approximately one month after giving birth, leading to a mean interbirth interval of 11.6 months. Most females have a calf every year. The sex ratio at birth is 1:1. Calving takes place in the wet season in the wild, however, in captivity this species mates throughout the year, and so can produce young throughout the year. However, even in captivity, there is a birth peak, and this occurs between February and May.
Calves exhibit hiding behaviors, and are independent from their mothers between 6 and 8 months of age, which is the time of weaning in other members of this genus.
Breeding interval: Kobus megaceros breeds once yearly.
Breeding season: In the wild, matings occur between February and May.
Range number of offspring: 1 (low) .
Average number of offspring: 1.
Average gestation period: 7.85 months.
Range time to independence: 6 to 8 months.
Average age at sexual or reproductive maturity (female): 2 years.
Average age at sexual or reproductive maturity (male): 2 years.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization ; viviparous
Average birth mass: 5100 g.
Average gestation period: 235 days.
Average number of offspring: 1.
Average age at sexual or reproductive maturity (male)
Sex: male: 730 days.
Average age at sexual or reproductive maturity (female)
Sex: female: 730 days.
Most artiodactyls are precocious at birth, and are able to keep up with their mother during foraging at a young age. It is likely that this species is similar.
Females care for their young, nursing them, and protecting them. Calves remain with their mothers until they are weaned at 6 to 8 months of age. Male parental care has not been reported for these animals.
Parental Investment: no parental involvement; altricial ; pre-fertilization (Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female, Protecting: Female); pre-independence (Protecting: Female)
The Nile lechwe or Mrs Gray's lechwe (Kobus megaceros) is an endangered species of antelope found in swamps and grasslands in South Sudan and Ethiopia.[1]
Males are an average of 165 cm (65 in) long and 100–105 cm (39–41 in) tall at the shoulders, and weigh between 90 and 120 kg (200 and 260 lb), while females are an average of 135 cm (53 in) long, 80–85 cm (31–33 in) tall at the shoulders, and weigh 60–90 kg (130–200 lb). Nile lechwes live an average of 10 to 11.5 years, and most uncommonly 19 years.[2]
Their coats are shaggy with the hair on the cheeks particularly long in both sexes, and males may have even longer hair on their necks. Nile lechwe exhibit extreme sexual dimorphism.[3] Females are golden-brown with white underbellies and no horns. Juveniles also have a golden-brown coat, but the color changes to dark brown in young males when they reach two to three years of age. Adult males are blackish-brown to russet with white 'hoods' over their shoulders and small white patches over their eyes.[4][5] The horns of the adult males are 50–87 cm (20–34 in) long, strongly ridged at their bases and are curved at the tips.[5]
Nile lechwe can visually signal and vocalize to communicate with each other. They rear high in the air in front of their opponents and turn their heads to the side while displaying. Females are quite loud, making a toad-like croaking when moving.[3] When 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. Known predators are humans, lions, crocodiles, cheetahs, wild dogs and leopards. They flee to water if disturbed, but females defend their offspring from smaller predators by direct attack, mainly kicking.[2] Yearling Nile lechwes are often infected by warble flies, which can make them unhealthy and result in high mortality rates.[2]
Nile lechwe are crepuscular, active in the early morning and late afternoon. They gather in herds of up to 50 females and one male or in smaller all-male herds. They divide themselves into three social groups: females and their new offspring, bachelor males, and mature males with territories. A males with territory sometimes allows a bachelor male into his territory to guard the region and not to copulate.[2]
Nile lechwe feed on succulent grasses and water plants. Wild rice is thought to be a preferred food at the start of the flood season, while a larger proportion of swamp grasses are consumed when the waters recede. They have the special capability to wade in shallow waters and swim in deeper waters, and may feed on young leaves from trees and bushes, rearing up to reach this green vegetation. Nile lechwe are also found in marshy areas, where they eat aquatic plants.[3]
Both sexes reach sexual maturity when they are two years old.[5] Mating occurs throughout the year, but peaks between February and May. During mating season, young males bend their horns to the ground as if to poke the earth. Males fight in the water, their heads submerging in horn-to-horn combat, for dominance. These contests are usually short and violent. As in many other animals, the dominant male copulates with the female. A unique form of marking is seen with the start of mating. The male 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.[2][6]
The gestation period is seven to 9 months long on average, after which a single calf is born. Infants weigh about 4.5 to 5.5 kg (9.9–12.1 lb). Females experience estrus again about a month after producing young. After its birth, the calf is kept hidden in thick vegetation for two to three weeks, where the mother nurses it. It is weaned at five to six months, and a few months later is ready to be independent and join the herd.[2]
The Nile lechwe typically occur in shallow waters bordering deeper swamps, where the water is 10–40 cm (3.9–15.7 in) deep.[7] Nile lechwe are endemic to South Sudan and Ethiopia. In Sudan, the majority of the population occurs in the Sudd swamps, and in the Machars near the Ethiopian border in smaller numbers. In Ethiopia occurs in the southwest, in Gambela National Park, but in very less numbers possibly due to human settlement and habitat degradation. The habitat of the Nile lechwe has been severely affected by civil wars, human displacement and resettlement, firearm attacks and increased hunting.[8] Even its seasonal movements were restricted due to large populations of cattle in and around its range. The Nile lechwe population in the Sudds, however, remained somewhat stable throughout this period.[9]
The Nile lechwe has been classified under the Endangered category by the International Union for Conservation of Nature and Natural Resources (IUCN). In 1983, aerial surveys gave a total population estimate of 30,000-40,000 individuals, of which 95 percent were concentrated in the Sudds and the rest occurred between Sudan and Ethiopia.[7] In the 1980s, the population in the Machars was estimated at 900.[10] A population of around 150 was also reported from the swamps in Gilo River in 1967.[11] There is also an increasing population held in captivity.[8] In 2007, the population of the Sudd region was estimated to be of 4,291 animals, indicating that the species has declined rapidly since the previous survey in 1983.
In South Sudan, Nile lechwe populations occur in three protected areas : Zeraf Game Reserve, that extends over 9,700 km2 (3,700 sq mi) along the Bahr el Zeraf; Fanyikang Game Reserve, north of Bahr el Ghazal, covering over 480 km2 (190 sq mi); and Shambe National Park, that stretches over 620 km2 (240 sq mi) along Bahr al Jabal. The Nile lechwe keep moving in and out of these areas. In Ethiopia they occur in the Gabella National Park. A study outlined priorities for both in situ and ex situ conservation of this species.[8]
The Nile lechwe or Mrs Gray's lechwe (Kobus megaceros) is an endangered species of antelope found in swamps and grasslands in South Sudan and Ethiopia.
