Sable Antelope

Hippotragus niger (Harris, 1838)

Photo: Doug Lee

IUCN Conservation Status:

• the southern sable LR/cd = Lower Risk, conservation dependent
• the Zambian sable VU = Vulnerable
• the giant sable CR/en = Critically endangered
• the eastern sable EN = Endangered.

Taxonomy

Classification

Four subspecies are recognized:

• H.n. niger the southern sable antelope found in southern Africa and eastern Africa as far north as southern Kenya
• H.n. variani the giant or royal sable of central Angola
• H n. kirkii the Zambian sable antelope of central Angola and western Zambia
• H.n.roosevelti the eastern sable antelope of Kenya

Genetic studies by Terry Robinson in the 1980s do not provide conclusive evidence of the sub-speciation of sable to the south of Kenya. Doubt also exists as to whether there is genetic differentiation between the northern form of the southern sable, found to the north of the Zambezi River, and the southern form, found south of the Zambezi River. At present both forms are still recognised as Hippotragus niger niger.

Giant Sable: The most notable of the sable subspecies is the giant sable, also known in Portuguese as the “Palanca Negra”. It is endemic to the Angolan peneplane and the adjacent ancient African plateau in central Angola between the Cuango and Luando rivers. This area includes the Luando Integral Nature Reserve and the Cangandala National Park. The habitat of the giant sable consists mainly of flat or gently undulating ecotones with open Brachystegia woodland and intersected edaphic grassland on sandy, acid soils where the annual rainfall exceeds 1 200 mm. It also includes extensive seasonal floodplains along the Luando and Cuanza rivers. It is the largest of the sable subspecies and its status has given rise to the name “royal sable”. An issue that requires further scientific investigation is the close resemblance between the giant and the large Zambian sable. Several populations of Zambian sable have been introduced into private game farms causing concern over the mixing of subspecies.

Description

A large, dark to black coloured antelope with an exceptionally long, upright mane along the neck. The face is white with a black blaze from the forehead to the nose. The belly and the hind of the buttocks is pure white. The front feet are larger than the hind. Calves are a light red-brown and the colour of cows ranges from a light brown to a dark chestnut-brown or brown-black. The back and saddle of young bulls are chestnut-brown, but turn black with age. The colour of the skin is also affected by the concentration of copper in the diet.

Comparison To Man

Trophy

The horns are up to 1.6 m long and are carried by both sexes. The horns of cows are 40% shorter than those of the bulls and do not reach trophy quality. The horns grow vertically for the first third of the length and then turn backwards to form a long curve of 85-110°. They are heavily grooved for 85% of the length. Poor forage quality and social stress may limit horn development.

Habitat requirement

The habitat preference parameters are:

• abundant stands of dense, intermediate to tall grasses 45-150 cm high of both sweet and sour species
• open savannah woodland with scattered large trees and a lower stratum of moderately dense shrubland
• flat to slightly undulating topography
• well drained, sandy soil especially those derived from granite and quartzite
• clean surface drinking water for daily consumption

Open grassy plains, short grass environments and thickets are avoided, except for adult bulls taking refuge in thickets. Sable are extremely susceptible to droughts with a severe, rapid depletion of forage quality. These often result in high mortalities. As they are intolerant of severe cold spells, it is essential that the habitat includes patches of thicket vegetation that allow refuge against cold and winds. However, if not confined by a lack of space or game fencing, they may migrate away from these conditions.

Distribution

Feeding & Nutrition

Sable require a constant, high crude-protein and low crude-fibre intake. Thus they are highly selective of specific plant parts and least selective towards plant species. Young shoots and new growths on mature stems of intermediate to tall perennial grasses are grazed in preference. The preferred feeding zones are in seepage lines, areas around termite mounds and in ecotones between woodland and adjacent grassland savannah.

The diet consists of 85% grass, 10% woody browse and 5% broadleaf forbs. Roaming is mostly restricted to cooler daylight hours and daily water consumption is approximately 9 litres. Sable teeth wear rapidly especially after 10 years. Most sable that reach 13 years or older, die from starvation as their molars are worn down to the gums and they are unable to chew.

Social structure

Sable are gregarious by nature and form stable family groups of 6-40 individuals (mean 14). Family groups consist of several adult cows of >3 years age, their young offspring of both sexes, some heifers and usually, one dominant bull of >6 years age. The young often form a crèche and are accompanied and guarded by 1-2 cows. Bachelor herds are unstable and consist of 2-10 bulls aged between 3-6 years. Post mature and non-dominant adult bulls of >10 years tend to become solitary nomads. Territorial bulls are single during the rut but outside it, most dominant bulls abandon their territories and join a family group. Family groups follow a matriarchal system with a strict hierarchical order of female dominance. Cohesion between family members is tight and females may bond for life.

Intensive production

Sable antelope adapt well to confined, manipulated, intensive production systems. In a natural optimal habitat without supplementary feeding, the size of breeding camps can be reduced to a minimum of 50-80 ha, while in marginal habitats such as the Kalahari Desert, a minimum size of 200 ha is advised.

Diseases

In contrast to the roan antelope Hippotragus equinus of the same genus, the sable antelope is immune to anthrax. Sable are susceptible to frostbite in the marginal habitats of the cold, frosty areas of South Africa and ear tips, nostrils and the outer tissue of the lips can be destroyed. This does not kill the animal but causes permanent scars that reduce the animal’s trophy status and commercial value. In habitats such as the central regions of the Eastern Cape Midlands where the diet lacks sufficient trace metals such as copper, the hide coloration of sable antelope turns a dirty yellow-white instead of being dark brown to black. This decolouration reduces the sable’s commercial market value. The copper problem can be overcome with a two monthly inoculation of copper-sulphate but requires the capture, darting and physical handling of each animal at great cost and effort.

Information Table

Bibliography