Zebra

STRIPES & SHADOWS

Few animals are as strongly synonymous with the African continent as zebras - the only wild members of the horse family south of the Sahara.

Three Species

There are three true species of zebra: the well-known and common Burchell's Zebra Equus burchelli, the Mountain Zebra Equus zebra, and the Grevy's Zebra Equus greyvi of East Africa; all three species are further divided into regional sub-species.The extinct Quagga is considered to have been a sub-species of the Burchell's Zebra.

Need Protection in Reserves

The Burchell's and Mountain Zebras have suffered major decreases in their range in southern Africa in recent times; both were slaughtered in large numbers by the white colonists. Indeed, this massacre led to the complete extinction of the Quagga.

Today, the two sub-species of Mountain Zebra - Cape and Hartmann's - survive in isolated populations in the Western Cape and Namibia respectively. Populations of both appear to be adequately protected within national parks and on private land.

In southern Africa, Burchell's Zebra still occur in large numbers in reserves such as Kruger, Sabi-Sand, Umfolozi, Hwange and Pilanesberg. Really large herds are, however, only to be found in northern Namibia(Etosha) and northern Botswana (Savuti/Nxai Pan). Spectacular congregations may still be seen in these areas of vast open plains. Burchell's Zebra is also abundant in East Africa, where up to 500 000 occur in the Serengeti-Mara ecosystem - there are smaller populations in most other protected areas. The East African zebras lack the pale brown 'shadow' stripes and appear to be more boldly patterned.

Grazers of Grass

Zebras are almost exclusively grazers, favouring short grasses. They are particularly fond of freshly sprouted grass on recently burnt ground and will move large distances in search of this nutritious fodder. They do feed on slightly longer grass than the wildebeest, however, and precede these gregarious antelope in the Great Migration of the Serengeti-Mara. Zebra are dependent upon water and this limits their range and movements.

'Harem' Family

Burchell's Zebra live in small family groups, usually consisting of between four and eight individuals led by a single dominant stallion - the true 'harem family'. The adult mares in a group are usually related, being sisters, or 'aunts, nieces and daughters'. Once they are able to fend for themselves, male offspring are evicted from the herd by the dominant stallion.

To prevent interbreeding between 'fathers and daughters', zebras have devised a rather clever strategy. When the young mares first come into oestrus, they adopt an inviting stance to attract nearby members of bachelor groups (adult mares do not show-off in this fashion). Fights often ensue between the stallions, but inevitably the 'father' cannot attend to the many advances, and loses each of his 'daughters' to her suitor.

The catch, however, is that the young mares will not permit copulation during their first oestrus, and will wait until they are settled into a family before beginning to breed. The Burchell's Zebra has a gestation period of 12 months, with a single foal being born at any time of the year.

Social Hierarchy

The adult mares within the family have a social hierarchy which is clearly evident when they are on the move - the stallion at the rear, the dominant mare leading the group, and the lower-ranking members following in sequence. So, in effect, the dominant mare leads the family. Large congregations of zebra consist of numerous harem families which retain their identity within the big herd.

Social with Other Species

Zebras frequently associate with antelopes, gazelles, giraffe, and even ostrich. This activity is thought to be an anti-predator device. Nevertheless, zebras feature high on the list of lion and Spotted Hyena prey. Youngsters are particularly susceptible to these social predators which, hunting in groups, are able to separate the young from the adults. Stallions will defend their harem vigorously, sometimes badly mauling or even killing the attacker.

Familiar Call

In all areas where the Burchell's Zebra occurs, their familiar bray "Kwa-ha, Kwa-ha, Kwa-ha-ha-ha" will be heard, often after dark. This contact call led to the Afrikaans name - Quagga.

Posted: Mammals by CC Africa, Date: 21 November 2006