Overview
Distribution
Range Description
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Geographic Range
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 )
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Physical Description
Morphology
Physical Description
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
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Ecology
Habitat
Habitat and Ecology
Systems
- Terrestrial
- Freshwater
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Habitat
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
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Trophic Strategy
Food Habits
Nile lechwes are herbivorous, eating grasses, herbs, and waterplants.
Plant Foods: leaves
Primary Diet: herbivore (Folivore )
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Associations
Ecosystem Roles
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.
- Keay, R., S. Eyre. 1971. An Example of Sudan Zone Vegetation in Nigeria. Pp. 70-80 in World Vegetation Types. London, England: The Macmillan Press Ltd.
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Predation
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:
- lions (Panthera leo)
- leopards (Panthera pardus)
- cape hunting dogs (Lycaon pictus)
- crocodiles (Crocodylidae)
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Known predators
Crocodylidae
Panthera leo
Panthera pardus
Lycaon pictus
This list may not be complete but is based on published studies.
- Myers, P., R. Espinosa, C. S. Parr, T. Jones, G. S. Hammond, and T. A. Dewey. 2006. The Animal Diversity Web (online). Accessed February 16, 2011 at http://animaldiversity.org. http://www.animaldiversity.org
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Life History and Behavior
Behavior
Communication and Perception
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 ; acoustic
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Life Expectancy
Lifespan/Longevity
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.
- Falchetti, E., B. Mostacci. 1995. A case study of inbreeding and juvenile mortality in the population of Nile lechwe (Kobus megaceros) at Rome Zoo. International Zoo Yearbook, 34/0074-9664: 225-231.
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Lifespan, longevity, and ageing
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Reproduction
Reproduction
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); 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)
- Nowak, R. 1999. Walker's Mammals of the World, Sixth Edition. Baltimore and London: The Johns Hopkins University Press.
- Estes, R., V. Geist, F. Walther. 1971. Social Organization of the African Bovidae. Pp. 166-205 in The Behaviour of Ungulates and its Relation to Management. Morges, Switzerland: Unwin Brothers Unlimited.
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Conservation
Conservation Status
IUCN Red List Assessment
Red List Category
Red List Criteria
Version
Year Assessed
Assessor/s
Reviewer/s
Contributor/s
Justification
History
- 1996Lower Risk/near threatened
- 1994Vulnerable(Groombridge 1994)
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Conservation Status
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
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Trends
Population
Population Trend
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Threats
Threats
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Management
Conservation Actions
Falchetti (1998) outlined priorities for both in situ and ex situ conservation of this species. The urgent need to address these priorities as opportunity permits is underlined by plans to resuscitate the construction of the Jonglei canal, introduce irrigation and exploit oil reserves in southern Sudan (in the Sudd and in Zeraf; Fay et al. 2007), which could result in a dramatic deterioration of the Nile Lechwe's status (East 1999).
There is an increasing population of Nile Lechwe held in captivity (Falchetti 1998).
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Relevance to Humans and Ecosystems
Benefits
Economic Importance for Humans: Negative
There is apparently no negative impact of this species on humans.
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Economic Importance for Humans: Positive
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
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Wikipedia
Nile lechwe
The Nile lechwe, wasserbock or Mrs Gray's lechwe or waterbuck[2] (Kobus megaceros) is an endangered species of antelope found in floodplains in Southern Sudan and far south-western Ethiopia. The wild population were estimated at 30,000 to 40,000 animals in 1983, but no full surveys have been completed since.
Contents |
Description
Nile lechwe stand 90 to 100 centimetres at the shoulder and weigh from 70 to 110 kilograms. The 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 lechwes exhibit extreme sexual dimorphism.[3] Females are golden-brown (juveniles also have golden-brown coat, but the color changes to dark brown in young males when they reach 2–3 years of age) with a white underbelly and no horns. Males are chocolate brown to russet with a white 'hood' over the shoulders and small white patches over the eyes.[2][4] They have long ridge structured horns which are vaguely 's' shaped in profile. The horns, that grow 50-80 centimeter long, are strongly ridged at their bases and are curved at the tips. Nile lechwes live an average of 10 to 11.5 years, and most uncommonly 19 years. Yearlings are usually infected by warble flies, which can also make them unhealthy.[5]
Ecology
Nile lechwes can visually signal and vocalize to communicate with each other. They rear high in the air in front of their opponent and turn their head 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, cape hunting dogs and leopards. They flee to water if disturbed, but females defend their offspring from smaller predators by direct attack, mainly kicking.[5]
Nile lechwes are crepuscular, which means that they are active in the early morning and late afternoon. They gather in herds of up to fifty females and one male or in smaller all male herds. They divide themselves into three social groups: females and their new offsprings, bachelor males, and mature males with territory. Males with territory sometimes allow a bachelor male into their territory who is to guard the region and not to copulate.[5]
Diet
Nile Lechwes feed on succulent grasses and water plants, forming herds. 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. Nile lechwes have the special capability to wade in shallow waters and swim in deeper waters. It 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]
Reproduction
Both sexes reach sexual maturity when they are 2 years old. Mating occurs throughout the year, but is peak between February to 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.[4] 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.[4][5]
The gestation period is 7–9 months long at an average, after which a single calf is born. Infants weigh about 4.5 to 5.5 kg. Females experience estrus again about a month after producing young. After its birth the calf is kept hidden in thick vegetation for 2–3 weeks, where the mother nurses it. It is weaned for the next 5–6 months, and between 6–8 months of its life the calf is ready to be independent and join the herd.[4][5]
Habitat and distribution
Nile lechwes usually live in swamplands (where the water is 10-40 centimeters deep), wetlands, coastal areas, grasslands, steppes, high reed and cane thickets.[3][4] These are mostly found in Sudan in the Sudd swamps, with smaller numbers in the Machar marshes near the Ethiopia border. In Ethiopia, the Nile lechwe occurs marginally in the south-west, in the Gambela National Park, but its population here is unstable due to human activities.[1]
Uses and conservation
Nile lechwes may help reduce grass fires by trampling the grass when grazing, making a natural firewall. They 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. This endangered species (as of 2008)[1] is gradually becoming rare due to excessive hunting and habitat loss. Still, conservation efforts are being made. According to the IUCN, in Sudan, the Nile lechwe occurs in three protected areas: Zeraf (however here the situation for wildlife is likely to worsen as a result of oil exploration and exploitation in the region), Fannyikang and Shambe, and in Ethiopia the species occurs in Gambela National Park.[1] Special license is required to hunt these animals in Sudan. In Ethiopia only six animals per year are allowed to be captured with a special license.[5]
References
- ^ a b c d IUCN SSC Antelope Specialist Group (2008). Kobus megaceros. In: IUCN 2008. IUCN Red List of Threatened Species. Downloaded on 5 April 2009. Database entry includes a brief justification of why this species is of endangered.
- ^ a b Groves, Colin; Peter Grubbs (2011) (PDF). Ungulate Taxonomy. USA: The Johns Hopkins University Press. p. 191. ISBN 978-1-4214-0093-8. http://books.google.co.in/books?id=v3uZtA1ZpTAC&pg=PA191&dq=kobus+megaceros&hl=en&ei=C-evTsvGLYKqrAf11K1y&sa=X&oi=book_result&ct=result&resnum=1&ved=0CC0Q6AEwAA#v=onepage&q=kobus%20megaceros&f=false.
- ^ a b c d "Nile lechwe". ARKive. http://www.arkive.org/nile-lechwe/kobus-megaceros/.
- ^ a b c d e Huffman, Brent. "Nile lechwe (Kobus megaceros)". UltimateUngulate. http://www.ultimateungulate.com/Artiodactyla/Kobus_megaceros.html.
- ^ a b c d e f Corrie, Julia. "Kobus megaceros". University of Michigan Museum of Zoology. Animal Diversity Web. http://animaldiversity.ummz.umich.edu/site/accounts/information/Kobus_megaceros.html.
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