Bovids II: Hartebeests, wildebeests, gemsboks, oryx, and reedbucks

(Hippotraginae)

Class: Mammalia

Order: Artiodactyla

Suborder: Ruminantia

Family: Bovidae

Subfamily: Hippotraginae

Thumbnail description
Medium to large grazing antelopes, slender to heavily built; male horned (also female in some species); color white, gray, brown, red-brown, or black; some with prominent facial markings

Size
Body length 3.5–8.8 ft (105–265 cm); shoulder height 2.1–5.3 ft (65–160 cm); tail 4 in to 3.3 ft (10–100 cm); 42–680 lb (19–309 kg); horns 6 in to 5.5 ft (15–165 cm)

Number of genera, species
7 genera; 23 extant species, 1 recently extinct

Habitat
Dry to wet grasslands, wetlands, light woodland, savanna, and deserts up to 16,400 ft (5,000m)

Conservation status
Recently Extinct: 1 species; Extinct in the Wild: 1 species; Critically Endangered: 2 species; Endangered: 1 species; Lower Risk/Near Threatened: 1 species; Lower Risk/Conservation Dependent: 18 species

Distribution
Africa and Arabia

Evolution and systematics

The subfamily Hippotraginae, the grazing antelopes, includes 24 species in 11 genera. Fossil bovids first appear in early Miocene deposits; the earliest African material being from Libya about 20 million years ago. Analysis of mitochondrial DNA suggests there was a rapid radiation of the family in that period, perhaps in association with the emergence of savanna habitat in Africa, and that all living lineages had arisen by 16–17 million years ago (mya).

The subfamily classification used recognizes three tribes. The Reduncini includes nine species in three genera: Redunca (reedbucks) comprises the southern reedbuck (R. arundinum), bohor reedbuck (R. redunca), and mountain reedbuck (R. fulvorufula). Kobus contains the waterbuck (K. ellipsiprymnus), the lechwe (K. leche) and Nile lechwe (K. megaceros), the kob (K. kob), and the puku (K. vardonii). The gray rhebok (Pelea capreolus) is also included, although its classification is controversial and it is sometimes placed in its own subfamily (Peleinae), or even with the dwarf antelopes (Antilopinae; Neotragini) or goats (Caprinae).

The Alcelaphini, with eight species in five genera, includes the black wildebeest (Connochaetes gnou), the blue wildebeest (C. taurinus), the sassabies, and the hartebeests. The sassabies comprise three species: Hunter's hartebeest (D. hunteri), the blesbok and bontebok (D. pygargus), and the topi (D. lunatus), while the hartebeests include the hartebeest (Alcelaphus buselaphus) and Lichtenstein's hartebeest (A. lichtensteini). The impala (Aepyceros melampus) is sometimes placed in the Antilopinae, or in its own subfamily (Aepycerotinae), but it is now thought to be an early offshoot of the Alcelaphini.

The horse-like antelopes (Hippotragini) have seven species in three genera. Hippotragus contains the extinct bluebuck (H. leucophaeus), the roan (H. equinus), and the sable (H. niger), plus three oryx species, the scimitar-horned oryx (Oryx dammah), the Arabian oryx (O. leucoryx), and the gemsbok (O. gazella). The addax (Addax nasomaculatus) is also included.

Some authorities elevate these tribes to subfamily status (Reduncinae, Alcelaphinae, and Hippotraginae).

Alcelaphines appeared first in the fossil record about five mya and appear to be almost wholly African in their evolution. Early Pleistocene remains of Pelea are known, while Hippotragus species and the southern reedbuck first appear in the middle and upper Pleistocene. Earlier Redunca species appeared in the late Pliocene or lower Pleistocene, at which time the first Kobus fossils are recorded. Fossil Aepycerotine over three million years old are known from East Africa.

Physical characteristics

The Reduncini is an assemblage of medium to large species, the males having strongly ridged horns that are short and curve forward at the tips in reedbucks, but long and lyreshaped in most Kobus species. The reedbucks are pale brown in color, with short hair. Kobus species have a long, rough coat. Color varies from yellowish brown to mid-brown or bright chestnut, males being darker, some almost black. The underparts are white, and there is also white on the rump and often on the face. Lechwes are higher at the hindquarters than at the shoulders, and have long pointed hooves and large pseudo-claws, an adaptation to their semi-aquatic existence. The smallest species, the gray rhebok, is lightly built with short, almost vertical horns and a grayish woolly coat.

With the exception of the impala, the Alcelaphini are medium to large, with horns in both sexes, either smooth and initially curving downward (Connochaetes) or upright, ridged basally and twisted (other genera). They have long heads, elevated shoulders, and thin legs. Color varies from gray to reddish brown or almost black. Wildebeests have a mane, a beard, and a very long, tufted tail; the black wildebeest also has a tuft of stiff hairs on the face. The impala is medium sized, slender and gazelle-like, with long, lyrate horns only in the male.

The Hippotragini are large and horse-like, with a long, tufted tail. Both sexes have long, ridged horns that may be straight, backwardly curved, or spirally twisted. All species except the addax have a mane. Colors range from white, cream, or gray (desert species) to chestnut; sable bulls are black. There is often a conspicuous head pattern. Desert species have large, widely splayed hooves for traveling in sand. The extinct blue antelope was a smaller, lightly built species, standing only 3.3–3.9 ft (100–120 cm) high at the shoulder, with a blue-gray coat and curved, swept-back horns.

Distribution

The Hippotraginae are confined to Africa and Arabia. The members of the tribe Reduncini are grassland and wetland antelopes, the bohor and southern reedbuck occupying northern and southern lowland savannas, respectively, while the mountain reedbuck occurs in three widely separated relict populations in Cameroon, East Africa, and southeast Africa. The waterbuck is widespread in sub-Saharan savannas, the ellipsiprymnus group of subspecies ranging from East Africa to southern Africa, almost entirely east of the Great Rift Valley, and the defassa group occurring west of the rift. The lechwes are confined to wetlands of central-southern Africa and Sudan/Ethiopia, while the kob and the puku occur in the northern and southern savanna zones, respectively. The gray rhebok is confined to upland areas of South Africa, Lesotho, and Swaziland.

In the Hippotragini, the roan antelope ranges from Senegal east to Ethiopia and south to South Africa, while the sable antelope is largely confined to eastern Africa. The other members of this tribe are dry-country species: the addax and the scimitar-horned oryx occur in the Sahel and Sahara zones, the Arabian oryx in the Arabian peninsula, and the gemsbok in East Africa and southwestern Africa.

Restricted-range species within the Alcelaphini include the blesbok/bontebok of South Africa and Hunter's hartebeest of Kenya and Somalia. The topi has a fragmented distribution in savannas from Senegal east to Ethiopia and south to South Africa. Lichtenstein's hartebeest occurs in savanna from East Africa to southern Africa, while the red hartebeest ranges from Senegal to Somalia and south to Tanzania, and from southern Angola to Zimbabwe and South Africa. The blue wildebeest occurs in grasslands from Kenya and Angola to South Africa, but the black wildebeest only in South Africa. The impala is widespread in savanna woodland from Kenya to Angola and South Africa.

Habitat

The Hippotraginae have colonized all African grassland habitats from permanently inundated swamps to montane grasslands, the dry Sahel region, and the Sahara and Namib deserts.

Oryx species and the addax frequent the most arid areas. Addax are true desert antelopes, while gemsbok occur in grassland, dry steppe, light open woodland, brush savannas, and stony plains, as well as semi-desert and desert. Scimitar-horned oryx favored semi-desert and grassy steppes, while Arabian oryx occupied similar habitat in the Arabian and Sinai peninsulas. The other two members of the Hippotragini, the roan and sable antelopes, inhabit moist grasslands and open woodlands.

The Alcelaphini occupy the fertile grasslands and woodlands of the moist northern and southern savannas. The topi specializes on the grass of valley bottoms and intermediate vegetation zones. Red hartebeest favor the margins of woods, scrub, and grassland, while Lichtenstein's hartebeest prefers mixed open woodland and floodplain grassland. Blesbok, bontebok, and black wildebeest occur in South African grasslands, while the blue wildebeest ranges over open grasslands and woodlands of the southern savannas, being particularly common where grass is short after fire or grazing by other species. The impala inhabits the open woodlands in central and southern Africa.

Wetlands and montane grasslands are the home of the Reduncini. The southern and bohor reedbucks inhabit lowland floodplains and inundated grasslands of the southern and northern savannas, respectively, while the waterbuck lives in savanna and woodland adjacent to wetlands. Lechwe occur at floodplains and seasonally inundated swamps, while the puku and the kob inhabit moist savannas, floodplains, and the margins of adjacent light woodland. The mountain reedbuck and gray rhebok inhabit upland grasslands, the rhebok often in more exposed and rocky situations.

Behavior

Most species are most active in the early morning and late afternoon. Some such as the roan antelope and the desert oryx species are also active at night. The southern reedbuck is largely nocturnal when food and water are plentiful, but becomes more active during the day in the dry season. Desert oryx species and the addax excavate scrapes with their front legs in the shade of bushes or rocks, in which they rest during the heat of the day.

Socialization is poorly developed in the reedbucks and the gray rhebok, which live singly or in pairs, or in small groups of females and young that either live within the territories of single males or range over a few male territories. The other species in the subfamily are more social and occur in larger groups. In most species, adult males hold territories (often year-round), females and young form herds, often with a distinct hierarchy and led by a dominant female, and non-territorial adult males form bachelor herds. During the rutting season, territorial males mate with females from herds entering their territories.

Lechwe occur in large aggregations, while kob and topi also sometimes occur at a high density. In such situations, these species usually maintain territorial breeding grounds (leks) during the rut. When population density is not high, kob and topi do not lek, but individual males hold small territories.

Addax and oryx have a tight social structure, with a smallish herd centered on one or more adult bulls and with a hierarchy of adults of both sexes.

Several different methods are used to mark territories. Reduncines lack functional pedal and pre-orbital glands and do not physically mark the habitat; reedbuck advertise the territory by whistling. Rhebok mark the territory with urine and preputial gland secretions. The Alcelaphini use pedal glands and dung middens, while facial or pre-orbital gland secretions are mainly used to mark the body. Sable use visual marks (vegetation damage), feces, pedal scent, and display.

Elaborate dominance displays and appeasement behavior often replace or reduce aggression, and it is uncommon for serious injury to result from fighting. However, gray rhebok sometimes have serious fights in which individuals are killed. Sable, roan, and the Alcelaphini are unusual in that males fight in a kneeling position. The demands of a hierarchical society have given rise to unique ritualized oryx tournaments, in which herd members run around in circles with sudden spurts of galloping and ritualized pacing interspersed with brief horn clashes.

Courtship displays include approaching in an erect or a low stretch posture, prancing with nose-lifting, male walking behind female (mating march), foreleg-lifting, and urine testing (in gray rhebok, impala, the Hippotragini, and the wildebeests).

Many species wander in response to the availability of food. Lechwe follow the rising and falling waters of their floodplain habitats, feeding on exposed grasses. Scimitar-horned oryx migrate seasonally in search of grazing areas. Blue wildebeest may be sedentary, nomadic, or migratory, depending on the local distribution of rain and green grass; the regular and spectacular migrations of the herds in the Serengeti of Tanzania are famous.

Feeding ecology and diet

The Hippotraginae are primarily grazers, although several species also browse during the dry season, while desert and semidesert species supplement a basic diet of grass with food such as acacia seed pods, wild melons, cucumbers, tubers, and bulbs.

The addax is adapted to coarse food and the absence of water in its desert habitat. It can apparently sense patches of vegetation at long distance and obtains sufficient water from its food. The scimitar-horned oryx eats a variety of grasses and forbs, utilizing plants with relatively high water and protein content. Because of its ability to locate these plants, and to physiologically conserve water, it is capable of going for long periods without drinking. The gemsbok can go without water for several days, but drinks at streams and waterholes when water is available. Oryx are experts at finding water and often dig into dried riverbeds to access ground water. Roan and sable are mainly grazers, but will also browse, particularly during the dry season.

The mountain reedbuck is adapted to a coarse, fibrous diet and can go for long periods without water. The other reedbuck species, and the waterbuck, predominantly graze on grasses and reed shoots. Lechwe eat mainly grasses, but also eat sedges and other semi-aquatic plants, and often graze in water up to shoulder height. Pukus also predominantly eat grasses. The gray rhebok predominantly browses on shrubs and forbs.

Wildebeest eat grass, but the black wildebeest will browse during the winter. Blue wildebeest prefer areas of short grass, especially that sprouting on burnt areas or after rain. The sassabies are almost exclusively grazers, while the impala is an intermediate mixed feeder, largely grazing in the rains, but often browsing extensively in the dry season.

Reproductive biology

Reproductive cycles are often closely linked to the annual rainfall pattern so that, in regions with distinct rainy and dry seasons, births often peak in or near the rains. However, several species show no marked seasonal peak in breeding, for example, the Arabian oryx and the beisa oryx produce calves in any month, while roan produce a calf about every 10.5 months.

All Hippotraginae species bear single offspring, although waterbuck occasionally have twins. Estrus lasts for a day in territorial species and several days or more in non-territorial species. Gestation is 8–9 months in larger species and 6.5–8 months in the smaller species, but the gray rhebok has a nine-month gestation period.

In most species, the female leaves the herd or family group to give birth. Most species produce relatively helpless young that lie hidden for a period varying from only 1–2 days (impala) to two months or more (reedbucks). However, female wildebeest bear calves within the herd and the young can run a few minutes after birth. Young tsessebe (Damaliscus l. lunatus) are also able to keep up with the herd from shortly after birth.

Females return to hidden calves to suckle them. In herding species, calves associate together when they rejoin the herd, returning to the mother for nursing and in emergencies.

In most species, weaning takes place at 6–8 months, but blesbok, topi (Damaliscus lunatus jimela), and black wildebeest are weaned at four months. Addax and scimitar-horned oryx, which live in very arid environments where water is at a premium, wean their young at only 3.5 months. In contrast, young Lichtenstein's hartebeest are not weaned until they are 12 months old.

In most species, females begin breeding when 1–2 years old. Males may be sexually mature at 18 months to 2 years, but often have to wait for several more years before they can occupy a territory; they do not breed until 4–6 years of age. Longevity varies with species, being about 10 years in some (e.g., reedbuck) and reaching 20 years in the black wildebeest, scimitar-horned oryx, and Lichtenstein's hartebeest.

Conservation status

Populations of all species have suffered declines in recent years, and their ranges have been reduced, largely as a result of habitat loss (especially due to agriculture and competition from domestic stock), human disturbance, hunting, and poaching. Droughts and disease have also seriously affected some species. Wetland-dependent species have been affected by damming and draining; for example, after the damming of the Kafue River for a hydroelectric scheme in 1978, the population of the Kafue lechwe (Kobus leche kafuensis), originally about 94,000, was halved. As a result of these factors, the survival of all species is of concern.

The bluebuck is the first historically recorded African mammal to become extinct. It may have been declining from natural causes since the Pleistocene and its grazing habitat may have been adversely affected by the introduction of domestic sheep from about A.D. 400. In the eighteenth century, the first European settlers found it relatively uncommon, occurring only in a small coastal area of the southwestern Cape. It was quickly driven to extinction by hunting and settlement pressure, and was last recorded in 1799–1800.

Two races of living species have also become extinct recently. Roberts' lechwe (Kobus leche robertsi) occurred in northwestern Zambia, while the bubal hartebeest (Alcelaphus b. buselaphus) was formerly widespread in North Africa, but died out in the late 1920s.

The scimitar-horned oryx once ranged through much of the Sahelian grassland and scrubland on the northern and southern fringes of the Sahara. There have been no sightings in the wild since the late 1980s, and it is listed as Extinct in the Wild. It is a victim of habitat loss from overgrazing, droughts, warfare, hunting, and competition with domestic cattle. Worldwide, at least 1,250 are kept in zoos and private facilities, and more than 2,000 are on ranches in Texas. It is the second most common antelope in captivity. Since 1985, reintroductions have been made to national parks in Tunisia, Morocco, and Senegal.

Two species and one race are Critically Endangered. The addax is now reduced to about 250 individuals in the wild. Hunter's hartebeest had declined to about 300 individuals in 1995; apparently, only one exists in captivity. Competition with domestic cattle played a large role in its decline, although severe drought and poaching are also factors. The giant sable (Hippotragus niger variani) of northern Angola has an uncertain future.

The Endangered Arabian oryx has been saved from extinction by captive breeding in zoos. The red hartebeest, formerly abundant and widespread throughout much of Africa, has suffered a great reduction in range and numbers from hunting, habitat modification, and competition from cattle. The subspecies swaynei and tora, formerly occurring from Egypt to Somalia, are Endangered. Much of their remaining range in Sudan and Ethiopia was devastated by drought in the 1980s and few are thought to survive. Also Endangered is the western mountain reedbuck (Redunca fulvorufula adamauae), confined to Cameroon and Nigeria.

The five Vulnerable races include the bontebok, the black-faced impala, and the korrigum (Damaliscus lunatus korrigum), found from Senegal to Cameroon. Two races of the lechwe are Vulnerable: the black lechwe (K. l. smithemani) of northeastern Zambia and the Kafue lechwe (K. l. kafuensis) of the Kafue Flats in southern Zambia.

In addition, 18 species are classed as Lower Risk/Conservation Dependent, and the Nile lechwe as Lower Risk/Near Threatened.

Significance to humans

The Arabian oryx was one of the earliest semi-domesticated animals. Herds were kept in ancient Egypt, and oryx meat was apparently a regular food item of Solomon's household. The species also appears in Roman mosaics and Juvenal records that gourmets approved its meat. Oryx horns have had a phallic significance for many cultures and are sought after as charms. The legendary unicorn was possibly based on the Arabian oryx.

Addax were also kept in large numbers in ancient Egypt. They were stabled, fed from troughs, led on a bridle, and were probably slaughtered for ceremonies. The ancient Egyptians are also said to have domesticated hartebeest, but probably not particularly successfully, as in captivity this animal is difficult to breed and is aggressive.

In some parts of Masailand, East Africa, blue wildebeest were formerly captured as calves and run with cattle, while lactating females were used to feed cattle calves and thus save cows' milk for human consumption. In East Africa, young bohor reedbuck are sometimes reared in captivity and herded with goats.

Hippotraginae species have always been hunted for their meat, hides, and horn by the indigenous peoples of Africa and Arabia. The more recent history of these antelopes has been one of increasing persecution and elimination, not only by subsistence hunting, but also for sport and trophies, and because they potentially compete with expanding agriculture and human settlement for habitat.

The diet of the Alcelaphini and of cattle is broadly similar so that these antelope have come to be regarded as competitors for grazing land, and populations have thus been persecuted and often largely exterminated as a result of livestock expansion. Large populations of kob and other reduncines are unlikely to survive unless their potential for sustained yield cropping is realized. The kob is especially suited to this, while the topi can coexist with cattle after the carrying capacity for livestock has been reached and thus has potential for multiple land-use. Impala, which are numerous on many cattle ranches, are commonly cropped for their meat and hides.

Hippotragine antelopes are very popular in zoos and on farms and ranches, and such institutions have played a great part in maintaining captive populations of several endangered species and in building up stocks for reintroductions.

Species accounts

Resources

Ansell, W. F. H. The Mammals of Zambia. Chilanga, Zambia: The National Parks and Wildlife Service, 1978.

Kingdon, J. East African Mammals: An Atlas of Evolution in Africa, Volume III Parts C & D (Bovids). London: Academic Press, 1982.

Macdonald, D., ed. The Encyclopaedia of Mammals. London: George Allen & Unwin, 1984.

Meester, J., and H. W. Setzer. The Mammals of Africa: An Identification Manual. Washington, DC: Smithsonian Institute Press, 1977.

Nowak, Ronald M. Walker's Mammals of the World. 6th ed. Vol. 2. Baltimore: Johns Hopkins University Press, 1999.

Skinner, R., and R. H. N. Smithers. The Mammals of the Southern African Subregion. 2nd ed. Pretoria, South Africa: University of Pretoria, 1998.

Wilson, Don E., and D. M. Reeder, eds. Mammal Species of the World: A Taxonomic and Geographic Reference. Washington, DC: Smithsonian Institute Press, 1992.

IUCN Species Survival Commission, Antelope Specialist Group, Dr. Richard D. Estes, Chair. 5 Granite Street, Peterborough, NH 03458 USA. Phone: (603) 924-9804. Fax: (603) 924-9804. E-mail: richard.estes2@verizon.net Web site:

[Article by: Barry Taylor, PhD]