Zebra


ORDER: Perissodactyla

FAMILY: Equidae

GENUS: Equus

SPECIES: burchelli bohmi

DESCRIPTION:
Black ground color with bold contrasting stripes continuing all the way down to hooves; rarely any shadow stripes, except occasionally and faintly on hindquarters. Seven to ten neck stripes; three to four vertical body stripes. Short, upright mane. Tail terminally haired. Shoulder height 50"; weight 500-600 pounds.

GEOGRAPHICAL RANGE AND HABITAT:
From northern Zimbabwe to the Sudan in East Africa. Inhabits grasslands, especially those with scattered trees.

DIET:
In the wild, non-selective grazing of available grasses, especially grass stems and sheaths. Teeth very high crowned, an adaptation to chewing silica-rich grasses. Large barrel-shaped body holds a very large amount of relatively un-nutritious grass. Very dependent on water. At the zoo, they eat hay and alfalfa pellets fed inside at night.

LIFE CYCLE/SOCIAL STRUCTURE:
Live in stable family groups of up to 17 animals headed by a single stallion (Sometimes two stallions are part of the group, but one will be dominant). Mares stay with the group; offspring leave. Females establish a dominance hierarchy. During travel, group is led by the dominant female and her foal, followed by other females in their order of dominance. Members recognize each other by sight primarily, but also by voice and smell. Families maintain close bonds even during extended migrations with thousands of other zebra and wildebeest. The stallion is the rear guard when the family flees from a predator. Zebras are gregarious under conditions of abundant food or around water holes. Males have displays, including a sort of barking whinny, that seem to minimize aggression at such times. Males are not sexually mature until 5 to 6 years of age, although in zoos breeding may occur at 3 years of age. Until old enough to establish their own breeding groups, young males remain with their families or leave to form bachelor herds of 2 to 10 individuals. However, they retain good relationships with their fathers. Females have first estrous at 13-18 months but do not become fertile for another year. Young females have a characteristic stance during estrous which attracts nearby males who then attempt to abduct her. The abductor may have to fight her father to acquire her. She may be abducted by several males until she learns not to show estrous. This forceful removal from the family acts to prevent inbreeding. Under ideal conditions, a female may produce a foal every year. One young is born after a gestation of 361-390 days (about one year). Newborn has brown stripes and is short-bodied and long-legged. Weight 66-76 pounds; height 33". Female guards her baby from other members of the herd when it is first born, perhaps giving it time to learn her pattern of stripes. Foals are very attached to their mothers; bond lasts until birth of next foal. Life span is up to 28 years.

SPECIAL ADAPTATIONS:
Capable of running 40 mph. Zebras use hooves and teeth in defense. There is much discussion about the adaptive value of stripes, but none of the theories has consensus. One theory is that all those black and white stripes break up the shape and make it not so recognizable as prey; another is that the stripes of a herd exploding in all directions make it difficult for a predator to focus on one animal. The stripes also confuse the tsetse flies who cannot see the zebra for the stripes. And finally, the stripe pattern on each zebra is individual and the learned pattern of each serves to bond zebras together as a family group.

INTERPRETIVE INFORMATION:
The zebra is the only grazer to have both upper and lower incisors; it can thus snip the grass blade (rather than yanking it out), exposing the tender under grasses for others. The antelope of the plains rely on the zebra to open up the grasslands for them, removing the tough outer layers to expose nutritious parts.

OUR ANIMALS:
1 Male. 3 Females.

STATUS IN WILD:
Plains zebras are not in danger yet. They can eat coarse grass and are resistant to diseases that affect cattle, so as long as the African plains exist, so will the plains zebra. Two rarer species are in danger, however.

BIBLIOGRAPHY:

  1. Kingdon, Jonathan 1979. East African Mammals, Vol III, Part B.Academic Press, San Francisco.
  2. MacDonald, David 1984. The Encyclopedia of Mammals. Facts on File.
  3. Moss, Cynthia 1982. Portraits in the Wild. University of Chicago Press.
  4. Nowak, Ronald. 1991. Walker's Mammals of the World, 5th Ed, Vol II, Johns Hopkins University Press.

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