A nomadic species, the slender-horned gazelle wanders widely in search of food, grazing on grass, and browsing on succulents, herbs and shrubs (7) (8). Although it gains enough moisture from its food to survive, it will drink water when it is available. It feeds mainly during the night and early morning, retiring to rest in the shade through the hottest hours of the day. The slender-horned gazelle is specially adapted for its desert lifestyle, with the nose enlarged to allow the blood to cool in a network of blood vessels (3). Like other desert gazelles and antelopes, social organisation is likely to be flexible and adaptable to variation in conditions. But in general they are observed to form groups of three to ten individuals, made up of one dominant male, several females and their young (3) (7). If conditions are good the slender-horned gazelle may become territorial during the mating season, typically from August to September (3) (7). The male attempts to herd more females into his territory to gain extra mating opportunities, but not all females will co-operate all of the time and younger satellite males may try to intervene in the confusion (7). After a gestation period of 156 to 169 days, females give birth to one, or sometimes two calves during January and February (3). The calves are weaned at three months, but do not mature until six to nine months in females and 18 months in males (3). Young males usually form bachelor herds until they can successfully compete for females. Adult males occasionally battle brutally to assert their dominance. Slender-horned gazelles were formerly preyed upon by cheetahs throughout their range, and may have encountered Cape hunting dogs, lions, leopards and spotted hyenas in some of the more southerly parts of the distribution (2) (7).

Male, on average, larger and heavier than female. Upper parts pale buff to cream, flanks with lighter stripe and then darker one, demarcating white of underside. Limbs very pale to white, color of upper parts not extending onto them. Face much paler than the Dorcas Gazelle with much less distinct facial markings and no brown or red-brown. Ears very large, elongated, and pale. Horns long (up to 41cm in male, shorter in female) and only slightly curved, never as strongly lyre-shaped as in Dorcas Gazelle, and thinner with prominent rings but smooth tips that can occupy as much as half of the horn's length. Female horns more slender still, and straighter. Tail blackish brown, very distinct against pale rump.

The palest of all gazelle species, the slender-horned gazelle has a creamy-buff upper body, pale brown flank stripe and pure white underside (2) (7). The dark brown tail contrasts with a pure white rump (7). Darker bands run from the eyes to the nose, and a rufous stripe runs between the eyes to the nose. The slender-horned gazelle has large and slender ears behind the upright, slightly S-shaped horns. In males the horns are long and thin, reaching 30 to 41 centimetres and clearly ridged. Females' horns, by comparison, reach just 20 to 35 centimetres and are slimmer and smoother. The hooves are broadened to ease travel across sand (2).

Occurs across the Sahara, west of the River Nile. Distribution coincides with the larger ergs, though rare or absent on the south-east periphery and apparently absent from the western dune complexes (Devillers et al. 2005). It has disappeared from most of its former range in Egypt’s Western Desert (Saleh 2001, El Alqamy and Baha El Din 2006). A single report from Morocco (Loggers et al. 1992) is unconfirmed.

The center of its distribution is found in the Great Western Erg, the Great Eastern Erg, the sandy zone which stretches from the Hamada de Tinrhert in Algeria to the Fezzan in Libya, and the smaller ergs in the periphery of the central Saharan massifs of the Hoggar and the Tassili des Ajjers (Beudels and Devillers, in press).

It is believed that the slender-horned gazelle was very widely distributed in the Sahara until relatively recently. In the last 10 years, its presence has been confirmed only in the Great Ergs of Algeria, Tunisia, Libya and the extreme Western desert of Egypt. No reports to the south of these locations have been supported by any hard evidence (Beudels and Devillers, in press).

40 records. Latest 1998 (North of Farafra oasis).

Localized (Western Desert). AOO=109.2 km². EOO=506514.3 km². 7 locations. No obvious decline in occupancy from 1950 but the decline is more recent, since it is known to have declined in abundance from hunting and currently to occupy a different distribution from its former range.

Restricted (Egypt to Algeria).

Historic Range:
Sudan, Egypt, Algeria, Libya

Once the most common gazelle in the Sahara Desert, the slender-horned gazelle suffered serious decline in the 1970s, leaving its populations highly fragmented (3). It is found in low numbers across Algeria, Chad, Egypt, Libya, Mali, Niger, Sudan and Tunisia (1), but its presence in the more southern Saharan countries in this list has been unverified for many years (7).

Length 100-110 cm, weight 20-30 kg.

Type specimen from desert between Giza and Wadi Natrun. Two supposed ssp, the type ssp from Egypt, SE Libya and Chad, isolated from ssp loderi from Algeria and W Libya.

Habitat and Ecology

Systems

• Terrestrial

Generally a gazelle of sandy desert and dune areas with sufficient vegetation. Also found in more rocky areas. Absent from Mediterranean coastal desert where Dorcas Gazelle is, or was, pres­ent. Desert species and report­ed to be able to survive without standing water, but will drink if water is available.

Inhabits sandy and stony deserts with acacia groves and sandy depressions with sparse vegetation (3). Most known populations are associated with the major Saharan sand seas of the western desert (Egypt to Libya), the Erg Oriental and Erg Occidental (Tunisia and Algeria) (7).

Little known in Egypt, or indeed elsewhere. Like most large desert herbivores, most active during cooler parts of the day and pos­sibly at night, resting up in shade of Acacia spp. or shrub during hot­ter parts of the day. Sociability little known but probably in pairs or small parties with a lead male. Probably nomadic. Diet is vegetarian, feeding on grasses, shrubs, and Acacia spp. from which it can obtain most of its water needs. Has been known to associate with the Dorcas Gazelle. Gestation 156-169 days. Calf or calves born with eyes open and remains hidden until 2 weeks, then follows mother and suckles for up to 3 months.

Maximum longevity: 14.6 years (captivity) Observations: These animals have been estimated to live up to 14 years in the wild (Bernhard Grzimek 1990). One specimen lived 14.6 years in captivity (Richard Weigl 2005).

Year Assessed

Assessor/s

Reviewer/s

Contributor/s

Native, resident.

Endangered.

Rare; global estimate is only 2500 individuals, mainly ssp loderi in Algeria; now very sparse and scattered distribution; Egypt has most of population of type ssp.

Current Listing Status Summary

Status: Endangered
Date Listed: 06/02/1970
Lead Region: Foreign (Region 10) 
Where Listed:


Population detail:

Population location: entire
Listing status: E

For most current information and documents related to the conservation status and management of Gazella leptoceros , see its USFWS Species Profile

The slender-horned gazelle is classified as Endangered (EN) on the IUCN Red List 2007 (1) and is listed on Appendix I of the Convention on Migratory Species (CMS or Bonn Convention) (4). It is also listed as Endangered by the United States Fish and Wildlife Service and therefore protected under the United States Endangered Species Act (5). It is listed on Appendix I of CITES (6).

Population

Population Trend

Major Threats

Hunting.

As an occupant of particularly poor countries, several of which have much civil unrest, the slender-horned gazelle has suffered through habitat loss and warfare. It is hunted for meat and its horns are sold as ornaments (3). Unmanaged recreational hunting is a major threat throughout its range and the rapid expansion of disturbance and intrusion caused by desert tourism based on 4x4 and other forms of motorised transport also affects some of the remaining populations in North Africa (7).

Conservation Actions

A small number of slender-horned gazelle are in captivity around the world. All are part of an international captive breeding programme but are derived from a very small initial founder group of original wild-caught Tunisian stock (7) (8). There are also very small captive groups held by national conservation institutions in Algeria and Tunisia. In the wild formation of the Djebil and Senghar National Parks in Tunisia, and the Siwa protected area in western Egypt (all during the 1990s) are important initiatives in the conservation of this species (7).