Roan Antelope

Hippotragus equinus (Geoffrey Saint-Hilaire, 1803)

Photo: Marius Saunders

Conservation Status:

LR/cd = Lower Risk, conservation dependent.

Taxonomy

Classification

Although roan are thought be related to the oryx or gemsbuck Oryx gazella they are actually related to the sable antelope Hippotragus niger and the extinct Cape blue buck Hippotragus leucophaeus as they share similarities in body form, facial mask and horn structure.

Six subspecies are recognized:

• the Southern roan Hippotragus equines equinus of Zimbabwe, southern Malawi, Mozambique, eastern Botswana, Namibia and South Africa
• the Angolan roan H.e. cottoni of northern Botswana, Angola, southern Congo and Zambia
• the East African roan H.e. langheldi of Mozambique and Tanzania
• the Sudanese roan H.e. bakeri of Sudan and western Ethiopia
• the Western roan H.e. koba of the central Sahel region
• the Northern roan H.e. sharicus of the western Sahel region

Recent genetic studies indicate that there is no sub-speciation within the South African population which brings the validity of translocation restrictions into contention. Protection through government legislation has limited the translocation and re-distribution of roan in southern Africa and severely restricted the animals’ game farming potential. This policy is still in dispute.

Description

The second largest antelope in Africa. The forequarter being larger than the hindquarter and adult cows are smaller than adult bulls by an average of 25 kg and 10 cm height. Most prominent is the long ears, 25-30 cm, which point sideways away from the head and are tipped with a tuft of reddish hairs. The black and white facemask is shared in common with the sable but differs slightly from that of the gemsbuck. The pink-greyish brown hair colour of the hide is similar to that of the gemsbuck giving rise to the Afrikaans name of “baster-gemsbok” (bastard oryx). The legs are slightly darker and reddish brown. A well developed mane on the neck.

Comparison To Man

Trophy

Horns are present in both sexes although the horn development of the cow is inferior to that of the bull. Trophy status in bulls is reached after seven years. The horn curves back 45° and is similar to that of the sable cow. The average adult horn length ranges from 50 to 75 cm and is heavily grooved along the majority of the length.

Habitat requirement

Roan is extremely selective in habitat preference which is a major cause of its former endangered status. Roan has been displaced from large areas of its former habitat due to the change in vegetation caused by overgrazing of domestic livestock. Habitat preferences are for open bushveld or broken woodland with a continual access to surface water and a thick, tall grass layer of predominantly sweet grass species of 50-150 cm height. Sourveld is marginal to generally unsuitable. Transitional ecotone zones between tall grassland and relatively open bushveld is preferred, especially when it is on turf-like soils derived from basalt, a volcanic rock. Unlike most other grazers, roan are not attracted to new grass growth on recently burnt veld; conversely, it has the effect of driving them away.

Distribution

Feeding & Nutrition

Roan are intermediate height grazers feeding above 8 cm height. Most grazing takes place during the cooler hours of the days. Browsing is restricted to mid-dry seasons and contributes 5-10% towards the dietary intake. Broad leafed forbs contribute 5% and a broad spectrum of palatable sweet grass species provides the balance. Water consumption is 9-10 litres daily.

Social structure

Roan are semi-gregarious animals that tend to keep in small groups of * Breeding herds of 5-25 individuals consisting of one dominant breeding bull, a few adult cows, a few heifers and calves from both sexes * Bachelor herds of 2-8 young sub-adult bulls of 2.5-6 years * Nomads, which are single post-mature bulls pushed out of the breeding herd by younger, dominant bulls

A adult cows sustain a hierarchy of dominance that is related to physical strength and age with the most dominant cow acting as a group leader. A hierarchy of dominance also exists in bachelor herds. Heifers appear to stay with the breeding herds and equally aged individuals form a tight, social family bond that may last for several years. Calves may form a temporary crèche along the side of a breeding herd and are often accompanied by a single, young bachelor bull. Breeding herds are stable and may sustain their structure for several years within the same home range.

Natural population structure:

• 16% adult bulls >5 years
• 46% adult cows >4 years
• 10% sub-adult bachelor bulls of 2.5 - 4 years
• 12% heifers of 2 - 4 years
• 16% calves <2 years.

Intensive production

Roan adapt well to confined, manipulated, intensive production systems. The minimum camp size for intensive production vary from 50-200 ha depending upon habitat suitability and the degree of fodder supplementation. One adult breeding bull and 8-12 adult cows may be kept per camp.

Information Table

Bibliography