The Zebra | ||
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The Zebra | ||
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Zebras are not all alike -- striped horse-like animals roaming Africa, eaten by lions for food. "Zebra" is a general term referring to any number of breeds of African equine mammals. While there is uncertainty about its evolution, the zebra shares the Dawn Horse, "Eohippus," as a common ancestor with the horse. Within the equine family, horses, asses and zebras are all separated species within the same genus "Equus" (which is a related group of animals).
Today there are three distinct species of zebras in Africa, Grevy's zebra, mountain zebra, and plains zebra. There is much controversy over including the now extinct quagga as a fourth zebra species or as a subspecies of the plains zebra. All species have stripes, though they differ in coat color, stripe patterns, length of bars, shape of tail and by the number of chromosomes. Each species has a different rang, and in some areas the ranges overlap.
Zebras must outrun jackals, lions, hyenas and panthers. Without his stripes, he'd probably be extinct. The same unique quality that has allowed him to survive, may be the very thing that can cause his downfall. The zebra's flesh and hide are both valuable and it is often hunted by man.
Individual zebras each have a unique pattern of stripes, much like a fingerprint. No two are marked exactly alike, but a general pattern within the general species is followed. Even both sides of the same zebra are different. This distinct coloration creates an optical illusion for predators as the stripes blur and blend when the animal runs, disrupting the predator's perception of speed and distance. Many zebras have very dark brown stripes, not black, and it is especially noticeable on young animals.
The zebra has powerful hindquarters and well-muscled upper limbs to aid in his chief defense of running and speed. He can average 30-40 miles per hour for several miles, but amazingly he can reach speeds up to 60 mph for short distances. He will often live in small family groups or bachelor groups within herds. When migrating in search of suitable grasses, they will
often join a larger herd, or mingle into a mixed herd with wildebeests. Zebras are very social creatures, spending a great deal of time grooming and nuzzling each other's manes and withers with their front teeth. The zebra mare's gestation period is a full year, sometimes longer, giving birth to one foal. Twins are rare.
There are two behavioral types found in zebras. Type 1 behavior is like that found in a horse, and is also found in the plains and mountain zebras. They form non-territorial, long-term cohesive family bands of one stallion with one to six mares and their young. Sub-adult mares are abducted from the parental bands by bachelor stallions starting new families, or by family stallions to increase their harems. Stallions will guard and protect their own foals and mares, but not a territory. This social organization type is adapted from the demands of migration and unpredictable environment conditions. There is a definite and powerful dominance hierarchy within the larger group. When a large herd is migrating, the dominant stallion keeps the herd moving from the rear, wile the dominant mare is usually the leader. All other zebras follow in their order of dominance, foals following mothers in order of age with the youngest first.
Type 2 behavior is like that of the domestic donkey, and can be seen in Grevy's zebra. Males are territorial, guarding their large territories for long periods, often exceeding 10 years. Adults do not form lasting bonds and mares can range over several male territories, and can be mated by all of these males. Stallions will not mate unless they can hold a territory, and young males will often roam in bachelor groups without access to mares until they have their own territory. this social organization type is adapted from predictable conditions and specialized environments, as semi-desert and hot arid regions. This behavior type may represent the original form of equine social organization.
No species was ever used by African people as pack animals, possibly for cultural reasons. In the 1890's there were experiments in training plains zebras as draught animals by Europeans. It began to be very successful, but since the Boer War, nothing more has become of the experiments. Zebras are one of the most dangerous animals kept in zoos, often attacking keepers without warning and badly injuring them. A zebra will usually attack with their powerful teeth, but will lash out with their feet as well, kicking forward with the forefoot as well as back as a horse would. A zebra will fight discipline, and like most animals, eventually, with exhaustion, will go into a state of shock if pushed too far. In the wild, when they are attacked by lions or hyenas, they seem to fight back at first, but when they realize they can win, they go into a trance-like state when they may not even feel pain. Restraint to any wild animal is a life-threatening situation and zebras may not handle intensive restraint due to fear. Driving and riding are forms of restraint that contradicts wild instincts. Unable to defend themselves or flee, zebras in a circus or parade can cause an uproar at the slightest outside stimulus they find threatening.
If you have been wondering why all these different types of zebras migrating and running free in wild Africa haven't somehow crossed paths and interbred with each other, they all have different chromosome counts, as those in the wild ass, mule and horse. They can interbreed and produce living young, but these hybrids are generally sterile and will not produce offspring. Zebras seldom do interbreed in the wild, but will when they are encouraged in captivity. Mountain zebras carry 32 chromosomes, plains zebras carry 44, and Grevy's zebras have 46. All are much less than the domestic horse, which has 64, and Przewalski's horse, which has 66.
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© 1997-2007
NW Breyer Horse Club & Refiner of Gold Creations Equinealities in place since 1997, Section in place 2001, Updated 3/13/2007 |
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