Blue Wildebeest / Brindled gnu

Connochaetes taurinus (Burchell, 1823)

Photo: Doug Lee

IUCN Conservation Status:

Lower risk, Conservation dependent (LR/cd).

Serengeti – the first provoked thought that comes to mind by the hearing of the name, is thousands of wildebeest crossing savannah plains. In contrast to the black wildebeest that are endemic to the temperate and Highveld grasslands of South Africa, the blue wildebeest or brindled gnu is both a subtropical and semi-arid savannah antelope that evolved in central-East Africa.

Taxonomy

Classification

The tribe Alcelaphini evolved in Africa about 6 million years BP and includes the three genera Connochaetus or wildebeest, Alcelaphus the hartebeest, and Damaliscus the blesbok and tsessebe. There are two species and possibly five extant subspecies of wildebeest

• Connochaetes gnou the black wildebeest of South Africa
• Connochaetes taurinus the blue wildebeest; subspecies
• C.t. taurinus the southern brindled gnu (blue wildebeest), to the south and west of the Zambezi River
• C.t. cooksoni the Nyassa, Cookson’s or Luangwa Valley wildebeest, from the Luangwa Valley in Zambia
• C.t. johnstoni the Mozambique wildebeest, from northern Mozambique and southern Tanzania
• C.t. albojubatus the East African white-bearded gnu, from Kenya and in Tanzania to the east of the Rift Valley
• C.t. hecki the Serengeti white-bearded gnu, from Tanzania, between Lake Victoria and the Rift Valley

Early authors divided the blue wildebeest in as many as 12 subspecies, but this has been terminated. The golden wildebeest that game farmers currently breeds is no subspecies, but a colour variant of the southern blue wildebeest, similar as the white and yellow blesbok, the black impala, and the white, black and copper springbok. The name red wildebeest is used to refer to genetic hybrids of southern blue wildebeest that has cross-bred with black wildebeest. Such hybrids produce fertile offspring and are banned by South African authorities. Their trophies are not accepted by official game trophy registries.

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Description

A large antelope with heavier front, than hind quarters, a black mane that lies flat on the neck and spine, a black beard that ends at the end of the throat, and a horse-like tail with long black hair. The body is dark bluish-grey or silver-grey, giving rise to the name “blue” wildebeest. The forehead, face and muzzle is darker in colour than the body. Calves are prominent light fawn-brown. The English name “brindled” gnu refer to the dark vertical stripes, caused by skin-rimples, on either side of the neck and shoulders, whereas “gnu” refers to the bulking sound of the animal. The white-bearded gnu from the Serengeti and East Africa has a distinctive white beard down the chin and throat, where as the Mozambique wildebeest has a horizontal white band across the muzzle. Several blue wildebeest populations on game farms in the northern regions of South Africa have signs of a white marking either on the forehead or on the muzzle. This creates possibilities that such wildebeest might share genetic elements of prior hybridization or origin, with the Mozambique subspecies.

Comparison To Man

Trophy

Both sexes bear well developed, smooth horns that grow from thickened bosses on the head. They extend horizontally, side-ways and slightly downwards and then turn in an upwards curve towards the ends, with the tips projected almost vertical. The horns of cows are thinner, lighter in colour, and have smaller bosses than that of the bulls. Horn development is relative rapid and trophy status can be reached after 3 years.

Habitat requirement

Short grass (less than 12 cm in height), sweet-veld, in medium thick to open woodland, savannah plains. The eco-tones on the perimeter of bushveld vegetation. Sour-veld, bush thickets, forests, mountain slopes and highland plateaus is marginal to unsuitable. The availability of surface water for daily drinking is essential. Optimal annual rainfall is 250-450 mm. Heavy frost and snow are not tolerated. The climate needs to be either subtropical or semi-arid, but not temperate. In optimal habitat and at optimal climatic conditions, blue wildebeest tend to have little impact on veld, but in marginal habitat, and with poor conditions, they can become highly destructive.

Past and Present Distribution

Feeding & Nutrition

Blue wildebeest are highly selective, short-grass grazers of sweet-grass species. Feeding and roaming activity takes place both in daylight and any time of night, but during hot midday hours they tend to rest in the shade of trees while ruminating, sometimes lying down for short durations. The diet consists of 95% short, sweet grasses and 4% dicot forbs & browse. They tend to migrate when fodder become insufficient. With annual rainfall exceeding 300 mm, the veld needs to be burnt frequently to retain suitable grazing for blue wildebeest. They drink 9-12 litre water every 1-2 days, and drinking water must be at ground level. Build up livestock troughs is not suitable.

Social structure

Blue wildebeest are social animals. The structure of a population consists of:

• family groups of 10-150 individuals consisting of adult cows, heifers and calves of both sexes
• bachelor groups of 6-20 sub-adult bulls of 2-2.4 years age and non-active dominant adult bulls
• territorial breeding bulls which are dominant and mostly solitary.

No hierarchy order of dominance exists amongst either cows in family groups or bulls in bachelor groups. Family bonding between cows and their offspring are weak and members of different family groups exchange frequently. Sub-adult bulls are chased out of the family groups by dominant bulls during the rut, and join bachelor groups. At 4.5 years age they leave the bachelor groups to establish own territories. Some bulls remain with the bachelor herds and only break away during the rutting season for territorial behaviour. Other bulls maintain their territories for as long as environmental conditions remain favourable. Due to their migratory behaviour blue wildebeest do not have fixed home ranges. During good years they do not migrate but keep in a temporarily home range. Bachelor herds keep to the periphery of the roaming grounds of the family herds. When in transit the territories become floating islands that move along with the migration. The bull then defends a 30–50 m zone around himself and any cows associated with him. Territorial behaviour is mostly restricted only to the rutting period.

Photo: Doug Lee

Diseases

Blue wildebeest are resistant to most tropical diseases except for the larvae of the nasal butt-flies Kirkioestrus minentus, ocular-vascular myiasis caused by the larvae of the fly Gidoelstia sp. and malignant catarrhal fever. As the latter two diseases are highly contagious in domestic livestock, especially in cattle, both black and blue wildebeest must be separated from them by a corridor of at least 1 km.

Information Table

 Bibliography