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From Wikipedia, the free encyclopedia

Zebras are generally 2.3 m (8ft) long, stand 1.25-1.5 m (4-5ft) at the shoulder, and weigh around 300kg (660 lbs), although some can grow to more than 410 kg (900 lbs). In addition to their stripes, zebras have erect, mohawk-like manes. Unlike their closest relatives, horses and donkeys, zebras have not been truly domesticated. There are three species of zebra: the Plains Zebra, Grevy's Zebra and the Mountain Zebra. They can be found in a variety of habitats, such as grasslands, savannas, woodlands, thorny scrublands, mountains and coastal hills.

The name "zebra" comes from the Old Portuguese word zevra which means "wild ass". The pronunciation (in IPA) is /ˈzɛbrə/ (ZEB-ra) internationally, or /ˈziːbrə/ (ZEE-bra) in North America.

Stripes

Zebras are black or dark animals with white stripes and their bellies have a large white blotch for camouflage purposes. Some zebras have brown "shadow stripes" in between the white and black coloring.

Zebras are described as black with white stripes rather than the reverse for the following three reasons:

1. White equids would not survive well in the African plains or forests.
2. The quagga, an extinct Plains zebra subspecies, had the zebra striping pattern in the front of the animal, but had a dark rump.
3. When the region between the pigmented bands becomes too wide, secondary stripes emerge, as if suppression was weakening.

The fact that some zebras have pure white bellies and legs is not very strong evidence for a white background, since many animals of different colors have white or light colored bellies and legs.

The stripes are typically vertical on the head, neck, forequarters, and main body, with horizontal stripes at the rear and on the legs of the animal. The "zebra crossing" is named after the zebra's black and white stripes.

Stripes are also believed to play a role in sexual attractions, with slight variations of the pattern allowing the animals to distinguish between individuals.

Senses

Zebras have excellent eyesight. It is believed that they can see in color. Like most ungulates the zebra has its eyes on the sides of its head, giving it a wide field of view. Zebras also have night vision, although not as advanced as that of most of their predators, but their hearing compensates.

Zebras have great hearing, and tend to have larger, rounder ears than horses. Like horses and other ungulates, zebra can turn their ears in almost any direction. In addition to eyesight and hearing, zebras have an acute sense of smell and taste.

Like most members of the horse family, zebras are highly sociable. Their social structure, however, depends on the species. Mountain zebras and Plains zebras live in groups, known as 'harems', consisting of one stallion with up to six mares and their foals. Bachelor males either live alone or with groups of other bachelors until they are old enough to challenge a breeding stallion. When attacked by packs of hyenas or wild dogs, a zebra group will huddle together with the foals in the middle while the stallion tries to ward them off.

Unlike the other zebra species, Grevy's zebras do not have permanent social bonds. A group of these zebras rarely stays together for more than a few months. The foals stay with their mother, while the adult male lives alone. However like the other two zebra species, bachelor male zebras will organize in groups.

Like horses, zebras sleep standing up and only sleep when neighbors are around to warn them of predators.

Communication

Zebras are very adaptable grazers. They feed mainly on grasses but will also eat shrubs, herbs, twigs, leaves and bark. Their well adapted digestive system allows them to subsist on diets of lower nutritional quality than that necessary for herbivores.

Reproduction

Like most animal species, female zebras mature earlier than the males and a mare may have her first foal by the age of three. Males are not able to breed until the age of five or six. Mares may give birth to one foal every twelve months. She nurses the foal for up to a year. Like horses, zebras are able to stand, walk and suckle shortly after they're born. A zebra foal is brown and white instead of black and white at birth.

Plains and Mountain zebra foals are protected by their mother as well as the head stallion and the other mares in their group. Grevy’s zebra foals have only their mother as a regular protector since, as noted above, Grevy's zebra groups often disband after a few months.

Conservation

Modern man have had great impact on the zebra population since the 19th century. Zebras were, and still are, hunted mainly for their skins. The Cape mountain zebra was hunted to near extinction with less than 100 individuals by the 1930s. However the population has increased to about 700 due to conservation efforts. Both Mountain zebra subspecies are currently protected in national parks but are still endangered.

The Grevy's zebra is also endangered. Hunting and competition from livestock have greatly decreased their population. Because of the population's small size, environmental hazards, such as drought, are capable of easily affecting the entire species. Plains zebras are much more numerous and have a healthy population. Nevertheless they too are threatened by hunting and habitat change from farming. One subspecies, the quagga, is now extinct.

To read the full Wiki article please visit: http://en.wikipedia.org/wiki/Zebra