The gemsbok is remarkably adapted to its arid environment; particularly noteworthy is its ability to survive without drinking water for most of the year (5). It conserves water within its body by lying in the shade during the hottest part of the day, and restricts activity to early mornings, late afternoons or the cool nights. The gemsbok does not waste precious moisture on panting or sweating, but instead allows its body temperature to rise by a few degrees above normal on hot days (5). Gemsboks are gregarious animals, usually found in herds of up to 30 individuals (2), but occasionally herds of several hundred animals can be encountered as they move to fresh grazing grounds (2). Gemsbok feed primarily on grass but when this is not available they will browse on shrubs, trees and herbs (6). During periods of drought, they obtain moisture from roots and tubers which are dug up with their hooves (6). From the age of five or six, male gemsboks establish territories. These territories are around 25 square kilometres and may be defended for up to three years (2). During this period, the male rounds up herds of females and young gemsbok into his territory to gain sole mating rights with receptive females (2). Single calves are born to females older than two years (5), after a pregnancy of around 264 days (6). The calf remains hidden during the day, but may venture out at night with the mother to a new site. At three to six weeks of age, the calf will join the herd (2). Gemsboks have a lifespan of around twenty years (6).

The most distinctive features of this heavily built antelope are its long, rapier-shaped horns and striking black and white facial markings (2). The beautiful horns of the gemsbok are sought after as charms in many cultures and were even sold as unicorn horns in medieval England (3). The body is fawn-grey with a black stripe along the side separating the upperparts from the white underparts (2). There are five subspecies of Oryx gazella including the gemsbok (Oryx gazella gazella), the beisa oryx (O.g. beisa) and the fringe-eared oryx (O.g. callotis) (4). The gemsbok has a broader black side stripe than the beisa and fringe-eared oryx, and also has more extensive black on its upper legs (2). The fringe-eared oryx can be distinguished from the beisa oryx by the long tufts of hair growing from the tips of the ears, from which it gets its name (2). All subspecies have long, horse-like tails, and whilst both sexes possess the impressive horns, those of the male are shorter and more robust than the female's. Gemsbok calves lack any black body markings (2).

The Gemsbok formerly occurred widely in the semi-arid and arid bushland and grassland of the Kalahari and Karoo and adjoining regions of southern Africa, with a marginal intrusion into south-west Angola (East 1999; Knight in press). The extensive contraction of its distribution and decline of its numbers which accompanied the expansion of human activities in Southern Africa during the 19th and 20th centuries have been partly compensated in the last 10 - 20 years by the widespread reintroduction of Gemsbok to private land and protected areas. Today, they remain widely, albeit patchily, distributed in south-western southern Africa, although populations in Angola are now considered extirpated, even from the former stronghold in Iona N.P. (East 1999). They have also been introduced in small numbers to areas outside their natural range, such as private game ranches in Zimbabwe (East 1999).

The range of gemsbok, Oryx gazella, mostly consists of southern east Africa, though formerly the range included South Africa.

Gemsbok have been introduced into Mexico, as well as the southwestern United States.

Biogeographic Regions: nearctic (Introduced ); ethiopian (Native )

occurs (regularly, as a native taxon) in multiple nations

United States

Origin: Exotic

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Global Range: Southwestern Angola (extirpated?), Botswana, Namibia, northern South Africa, and western Zimbabwe (Grubb, in Wilson and Reeder 2005). Introduced in the White Sands area of New Mexico (Reid and Patrick 1983).

O.g. gazella has an extensive distribution in south-west Africa, O.g. beisa has a widespread but fragmented distribution in the Horn of Africa, whilst O.g. callotis has the most limited distribution, in eastern Kenya and north-east Tanzania (2) (4).

Gemsbok are large bovids with very thick, muscular necks, covered in dense, inelastic skin. Oryx gazella is the largest of the Oryx species. Gemsbok measure 115 to 125 cm high at the shoulder, and have total body lengths between 180 and 195 cm. Females weigh from 180 to 225 kg, whereas males are slightly larger, weighing between 180 and 240 kg. The slightly curved, ringed horns range from 60 to 150 cm in length. The horns of females are often shorter and more slender than those of males.

Black markings on the face extend down from the base of the horns to above the muzzle, and sweep back in stripes over the eyes and cheeks. Black continues down the neck and around the underbody, forming bands around all four legs. A stripe also runs up the spine, starting at the tip of the tail and ending at a short thick mane of black. There are black markings on the front of all four legs. The lower portion of the legs, muzzle, and underbelly are all white, whereas the body and neck are a gray or tan color. In instances of high productivity grazing, fat deposits under the skin become noticeable.

Inidividuals in northern populations have characteristic black tufts on the ears and are generally darker in color with thinner black markings than are individuals from southern populations.

Gemsbok are able to increase their body temperature to 45 degrees from 35.7 degrees C in order to delay evaporative cooling.

Range mass: 180 to 240 kg.

Range length: 180 to 195 cm.

Other Physical Features: endothermic ; heterothermic ; bilateral symmetry

Sexual Dimorphism: male larger

Habitat and Ecology

Systems

• Terrestrial

Gemsbok are found at elevations from 900 to 1,200 meters, in wooded grasslands as well as wetter grasslands. They can survive in areas of low productivity. Gemsbok prefer stony plains with at least limited water access, but can subsist in areas of dunes, rocky mountainous areas, and arid habitats with little seasonal water. Gemsbok also frequent open areas more than areas with increased tree density.

Range elevation: 900 to 1200 m.

Habitat Regions: tropical ; terrestrial

Terrestrial Biomes: desert or dune ; savanna or grassland

Comments: Generally on arid plains.

Gemsboks generally occur in semi-arid to arid grasslands and bushlands, but also inhabit light woodland and, in the southern part of its range, sand dunes (2) (5).

Non-Migrant: No. All populations of this species make significant seasonal migrations.

Locally Migrant: No. No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).

Locally Migrant: No. No populations of this species make annual migrations of over 200 km.

Although generally a grazer, O. gazella will revert to browsing during droughts or whenever grasses are not available. These animals will also dig up to a meter to find tubers and roots. These, supplemented with wild tsama melons and cucumbers, provide all the water needed to sustain gemsbok (approximately three liters per 100 kg daily).

The dentition is highly adapted to cutting coarse desert grasses short, with high crowned molars and a wide incisor row. Desert dwellers can eat dry grass, but prefer green grasses. Activity at dawn and dusk allow for the consumption of the condensation present on the grasses.

Plant Foods: leaves; roots and tubers; wood, bark, or stems; fruit

Primary Diet: herbivore (Folivore )

Gemsbok exploit areas that few other animals can inhabit; they tend not to interact with many other species. Also, because they are nomadic, they tend not to overgraze areas.

In regions of the North American Southwest where gemsbok (and other exotic species) have been introduced, overgrazing has occurred, leading to the degradation of the areas populated by these herds.

Ecosystem Impact: biodegradation

Commensal/Parasitic Species:

• Rhipicephalus, Agriostomum equidentatum, Cooperia, Longistrongylus meyer, Tenia hydatigena, Fasciola hepatica, Haemonchus contortus, Griostomum equidentatum, Paracooperia serrata, Impalaia nudicollis, Strongyloides, 13 nematode species (Nematodirus spathiger and Trichostrongylus rugatus most prominant), Bronchonema magna, Longistrongylus curvispiculum, Ostertagia ostertagi, Trichostrongylus deflexus, Trichostrongylus pietersei and Trichostrongy/us thomasi as well as intestinal helminths.

Top predators of African grasslands are threats to the gemsbok. These include lions, cheetahs, leopards, and spotted hyenas. Even hunting dogs will attack them. Humans occasionally hunt these animals. The primary response to predation is flight, despite impressive weaponry. The young are typically targeted, since attacking the adults involves a risk of puncture wounds. However, it is debatable whether or not fatal stab wounds have ever been inflicted upon a predator, or whether predators show any avoidance of gemsbok in general. Predation may account for the high mortality rate in young. In the northern part of their range, 80% of spotted hyena kills are gemsbok calves.

Known Predators:

• lions
• cheetahs
• leopards
• spotted hyenas
• hunting dogs
• humans

Basically gregarious, with herds of up to dozens or hundreds; herds may be allfemale or all male; males sometimes are solitary and territorial (Nowak 1991).

Communication is particularly evident through dominance displays and aggressive behaviors. However, more subtle communication is conveyed by scent glands in the hooves, as well as urine sampling (primarily used to determine fertility). The animals have excellent hearing and smell, accounting for the prominence of stripe displays and scent marking. Although not specifically reported for these animals, as mammals it is likely that they use some accoustic means of communication. Tactile communication is also likely to play a role in reproductive activities.

Communication Channels: visual ; tactile ; acoustic ; chemical

Other Communication Modes: scent marks

Perception Channels: visual ; acoustic

The average life span is approximately 18 years in the wild, and 20 in captivity.

Average lifespan

Status: wild: 18 years.

Average lifespan

Status: captivity: 22 years.

Average lifespan

Status: captivity: 20.0 years.

Maximum longevity: 23.8 years (captivity) Observations: One captive specimen lived at least 23.8 years (Richard Weigl 2005).

Gemsbok are polygynous. The resident bull of the herd mates with receptive females. Solitary territorial males are known to attempt to herd mixed or nursery herds onto their territories, thereby securing exclusive mating access to the females.

Mating System: polygynous

There is not a specific breeding season for gemsbok, though young within a herd tend to be of similar ages, indicating a reproductive synchrony in females. Females become sexually mature at about 2 years of age, and can conceive almost immediately after an 8.5 month gestation. Gemsbok are classified as "hiders", meaning the young are not seen present with the mother, but are hidden in the general vicinity, with the mother returning to nurse the calf 2 to 3 times each day. The young weigh between 9 and 15 kg at birth. At birth, calves are entirely brown in color. They develop the characteristic markings at about 3.5 months. At this point, the young are weaned. The males disperse and females join the maternal herd about a month after weaning.

Breeding interval: Gemsbok tend to breed every 9 months, and usually with little time between giving birth and becoming pregnant again.

Breeding season: Breeding season is year round, pending water availability.

Range number of offspring: 1 to 2.

Average number of offspring: 1.

Average gestation period: 8.5 months.

Average weaning age: 3.5 months.

Average time to independence: 4.5 months.

Range age at sexual or reproductive maturity (female): 1.5 to 2 years.

Average age at sexual or reproductive maturity (female): 2 years.

Range age at sexual or reproductive maturity (male): 1.5 to 2 years.

Average age at sexual or reproductive maturity (male): 2 years.

Key Reproductive Features: iteroparous ; year-round breeding ; gonochoric/gonochoristic/dioecious (sexes separate); post-partum estrous

Average birth mass: 12000 g.

Average gestation period: 270 days.

Average number of offspring: 1.

Like most ungulates, pregnant gemsbok isolate themselves from the herd before calving. The single neonate is kept concealed, usually within sight of the mother. This hiding behavior continues up to six weeks of age, ending with reconciliation with the herd.

Males are not reported to participate directly in parental care, so the feeding, sheltering, protection, and grooming of the young are all accomplished by the mother. As is the case with most bovids, the young are able to stand shortly after birth, and can move around with the mother as needed.

Parental Investment: precocial ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female, Protecting: Female); pre-independence (Protecting: Female); post-independence association with parents

Adult females give birth at approximately 9-month intervals; gestation period is about 8.5 months; litter size usually is 1 (see Nowak 1991).

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 0
Species: 1
Species With Barcodes: 1

The current total population of gemsbok is around 275,000 individuals. Though the numbers do not indicate a threatened population, large declines in several areas have resulted from livestock overgrazing, human encroachment on land, climate change, and habitat destruction. Other gemsbok populations have been declining due to over hunting.

US Federal List: no special status

CITES: no special status

IUCN Red List of Threatened Species: least concern

United States

Rounded National Status Rank: NNA - Not Applicable

Rounded Global Status Rank: G4 - Apparently Secure

Classified as Lower Risk / Conservation Dependent (LR/cd) on the IUCN Red List 2007 (1). The status of the gemsbok is currently under review for the IUCN Red List 2008. The IUCN Red List currently classifies the gemsbok as one species with five subspecies (as described here); however, current taxonomy suggests it is likely to be two separate species: Oryx gazella and Oryx beisa, with the latter having two subspecies, Oryx beisa beisa and Oryx beisa callotis.

Population

Population Trend

Major Threats

Comments: Some populations have been extirpated by hunters.

All subspecies of gemsbok have suffered population and range declines (2). The Beisa oryx and fringe-eared oryx have particularly declined in Somalia, Uganda and Sudan, but are still quite widespread in Ethiopia and pars of Kenya and Tanzania (6) (7). The habitat of the gemsbok continues to be encroached upon by humans and their livestock (1) (6). In addition, gemsboks face the threat of hunting (1), for their meat, hides and horns (3), which has the potential to greatly impact populations due to their slow reproductive rate (4).

Conservation Actions

The gemsbok occurs in many major national parks (6), where it receives protection from the threats of habitat loss and hunting. Therefore, whilst the gemsbok is not considered to yet be threatened with extinction, it is somewhat reliant on the continued enforcement of protected areas, and thus IUCN has classified it as Lower Risk / Conservation Dependent (1).

There are no negative economic impacts of this species on humans.

Gemsbok are hunted for their thick skin, which is used for shield covers by local African peoples. The horns are also used in making spears.

This species is a common game ranch species since both females and males have horns, making trophies cheaper to produce.

Positive Impacts: food ; body parts are source of valuable material

Comments: Does not include O. beisa (Grubb, in Wilson and Reeder 2005).