The kob (Kobus kob) is an antelope found across Sub-Saharan Africa from Senegal to South Sudan. Found along the Northern Savanna, often seen in Murchison Falls and Queen Elizabeth National Park, Uganda; Garamba and Virunga National Park, Democratic Republic of the Congo, as well as grassy floodplains of South Sudan.^[2] Kob are found in wet areas (such as floodplains) where they eat grass. Kob are diurnal, but inactive during the heat of the day. They live in groups of either females and calves or just males. These groups generally range from five to forty animals.

Among the Kobs of Eastern Africa, the Ugandan kob (Kobus kob thomasi) appears on the coat of arms of Uganda, and the white-eared kob (Kobus kob leucotis), found in South Sudan, south-west Ethiopia and extreme north-east Uganda, participate in large-scale migrations.

Description

Uganda kob at Murchison Falls NP

The kob resembles the impala but is more robust.^[3] However, males are more robust than females and have horns.^[4] Males have a shoulder height of 90–100 centimetres (3.0–3.3 ft) and an average weight of 94 kilograms (210 lb). Females have a shoulder height of 82–92 centimetres (2.69–3.02 ft) and weigh on average 63 kilograms (140 lb).^[3][4] The pelage of the kob is typically of the golden to reddish brown overall but with throat patch, eye ring and inner ear being white fore legs being black at the front.^[3] Males get darker as they get older. Those of the white-eared kob (K. k. leucotis) which is found in the Sudd region (the easternmost part of the kob's range) are strikingly different and overall dark; rather similar to the male Nile lechwe, though with a white throat and no pale patch from the nape to the shoulder. Both sexes have well-developed inguinal glands that secrete a yellow, waxy substance, as well as preorbital glands.^[3]

Ecology

Kob at Virungas

The kob's distribution from western Africa to central eastern African in a patchy range.^[1] It prefers flat areas and open country close to permanent water and consistent climate. It require fresh graze and drinks daily.^[4] During the rains, kob frequent short grasses and keep them short.^[3] Since, it is dependant on water, the kob does not wonder far into arid areas.^[4] Kobs gather on and move from one pasture to another, coinciding with seasonal changes.^[4] In flooded areas, kobs may travel hundreds of km and dry season walks to water may take 10 km or more.^[4] Grasses preferred by kobs are Hyparrhenia species, Brachiaria brizantha, Setaria gayanus, Chloris gayana, Echinochloa and Digitaria.^[5]

Social behavior and life history

Kobs have few strong social bonds, however females live in herds that can number in the thousands. They to move more and are more social than territorial males.^[4] Females are at the front of the daily movements to water. Individuals learn where to go from their mothers. However, in more densely populated herds the females will take their signals from other females.^[4] Males are also present in the migratory herds and will follow the females. All-males herds may number in the hundreds and accompany femals as they travel during dry season.^[4]

Gathering of kobs

The social and reproductive organization of kobs can vary. When in average or low population densities, males establish conventional territories and do not travel much.^[3] Adult males try to establish their territories in the best habitat available which are inhabited by herds of females and their young. Herds are fluid and change in size and structure as individuals travel to find green vegetation.^[3] Non-territorial males, particularly young males, live in bachelor herds and are segregated from the females by the territorial males. On floodplains, where kobs are densely populated, around two thirds of the territorial males establish traditional territories while the rest live in clustered territories known as leks.^[3] These clusters are sometimes smaller than a single traditional territory. Lek clusters are located patches of short grass or bare ground within comparably tall grassland. As such, these territories have little to no value other than the males that reside in them. 8-9 of every 10 females visit leks to mate, trading spacing and food for mating success.^[3] Females and bachelor males live in large herds of up to 2000 and move through the leks, which are surrounded by high quailty grass and are near waterholes and commonly travelled routes.

Kob at Cote d'Ivoire

Conflicts between territorial Ugandan kobs (K. k. thomasi) are usually settled with ritual and rarely actual fighting, whether in conventional territories or leks. A male usually needs only to walk in an erect posture towards the intruder to displace him.^[6] Neighboring males in leks do the same thing when they encounter their borders. Lek holding white-eared kobs fight more often.^[7] Ugandan kobs do sometimes sustain serious are fatal injuries, especially when control of a territory is at stake. Fights usually involve the combatants clashing, pressing and twisting each other with their horns head-on. However, a neighbor may attack from the rear or side.^[6][7] In lek clusters, the most dominant males occupy the center. The number of males in the center of a lek cluster ranges 3–7 and their leks are the most clustered and they monopolize copulations with estrous females.^[8] Replacement of males in leks are much more common than in traditional territores and most males are unable to stay in the to centre positions for only a day or two and rarely up to a week.^[3] This is in largely of intense competition and because most males leave their territories to feed and drink. Centrally located males reduce their chances of being replaced by leaving to feed during periods of relative calmness, yet they are not able to get enough food and water and have to eventually leave their leks.^[3] However, a male can gain enough energy after a week or two and try to take back his position. At every lek cluster, there is always males waiting take or retake a central lek.^[6] Males in traditional territories are able to stay for at least a year or two.^[3]

Females have their first ovulation at 13–14 month old and have 20–26 day intervals between estrous cycle until they are inseminated. Males from traditional territories and lek have different courtship strategies. Males of traditional territories will herd females and keep them in their territories.^[3] Lek males try to do the same but usually fail. They have to rely on advertising themselves. Kob courtship may last as little as 2–3 minutes and copulation may only last 1–2 seconds.^[6] At leks, a females may mate up to 20 times with at least one of the central males in a day. After an 8 month gestation period, estrous may continue 21–64 days later. For their first month, calves hide in dense vegetation. Mother and calf can identify each other by their noses. As they get older, calves gather into crèches.^[3] When they are 3–4 months old, the young enter the females herds and stay with mothers until 6–7 months by which time that are weaned. When they mature, males join bachelors groups.^[3]

Status

Kob populations have been decimated by hunting and human development. The Uganda kob's became extinct in south-western Kenya and north-western Tanzania due to the expansion of human settlements and agriculture.^[1] Buffon’s kob are protected in several parks including: Niokolo-Koba in Senegal, Comoe in Côte d’Ivoire, Arly-Singou in Burkina Faso, Mole and Bui in Ghana, Pendjari in Benin, Waza and Benoué and Faro National Parks of the North Province of Cameroon, Zakouma in Chad, and Manovo-Gounda-St. Floris and Sangba in the Central African Republic.^[1]

References

1. ^ ^{a b c d} IUCN SSC Antelope Specialist Group (2008). Kobus kob. In: IUCN 2008. IUCN Red List of Threatened Species. Downloaded on 10 May 2008.
2. ^ "Kob Antelope: Kobus kob". ThinkQuest library. http://library.thinkquest.org/16645/wildlife/kob_antelope.shtml. Retrieved 2007-06-16. 
3. ^ ^{a b c d e f g h i j k l m n o} Estes, R. (1991). The Behavior Guide to African Mammals, Including Hoofed Mammals, Carnivores, Primates. Los Angeles, The University of California Press. pgs. 98-102.
4. ^ ^{a b c d e f g h i} Kingdon, J. (1982). East African Mammals: An Atlas of Evolution in Africa, Volume 3, Part. C: Bovids. University Chicago Press, Chicago 367-381.
5. ^ Bindernagel, J. A. (1968) Game cropping in Uganda. Canadian International Development Agency, Ottawa.
6. ^ ^{a b c d} Buechner, H. K., Schleoth,R. K., (1965) Ceremonial mating behavior in Uganda kob (Adenota kob thomsi Neuman). Z. Tierpsychol, 22:209-25.
7. ^ ^{a b} Fryxell, J. (1985) Resource limitation and population ecology of white-earred kob. Ph.D thesis, Univ. of British Columbia.
8. ^ Floody, O. R., Arnold , A. P., (1975) Uganda kob (Adenota kob thomasi). Territoriality and the spatial distribution of sexual and agonistic behavior at a territorial ground. Z. Tierpsychol, 37:192-212.