User:Piri/Zebra
A Wikipédiából, a szabad lexikonból.
Sablon:Alternateuses
| Zebras | |||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Rendszertan | |||||||||||||||
|
|||||||||||||||
|
|
|||||||||||||||
| Hegyi zebra(Equus zebra) Hartmann-hegyizebra(Equus hartmannae) Kvagga(Equus quagga) Grévy-zebra(Equus grevyi) |
The Zebra is a part of the horse family, Equidae, native to central and southern Africa. They are most well known for their distinctive black and white stripes.
Tartalomjegyzék |
[szerkesztés] Stripes
They are black with white stripes[1]. These 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 white on black stripes.
Zoologists believe that the stripes act as a camouflage mechanism. This is accomplished in several ways. First, the vertical striping helps the zebra hide in grass. At first glance, this may seem absurd considering that grass is neither white nor black, but it makes sense because the zebra's main predator, the lion, is color blind. A zebra standing still in tall grass may not be noticed at all by a lion. However, zebras are herd animals and do not usually travel alone, so the second way the stripes help in camouflage is by confusing the lion — a number of zebras standing or moving close together may appear as one large animal, making it more difficult for the lion to pick out any single zebra to attack.[2]
Stripes are also believed to play a role in social interactions, with slight variations of the pattern allowing the animals to distinguish between individuals.
A more recent theory, supported by experiment, posits that the disruptive coloration is also an effective means of confusing the visual system of the blood-sucking tsetse fly.Sablon:Cn Alternative theories include that the stripes coincide with fat patterning beneath the skin, serving as a thermoregulatory mechanism for the zebra, and that wounds sustained disrupt the striping pattern to clearly indicate the fitness of the animal to potential mates.
[szerkesztés] Species
-->
Négy faj és számos zebra alfaj létezik. A zebra populációk nagymértékben különböznek egymástól, és az alfajok besorolása közötti kapcsolatok jól ismertek.
Az alföldi zebra (Equus quagga, hivatalosan Equus burchelli) a legáltalánosabb faj, melynek tizenkét alfaja létezik Dél- és Kelet-Afrikában. Ez a faj, illetve ennek fő alfajai a közönséges zebra, a dauw, a Burchell-zebra (jelenleg az Equus quagga burchelli alfajként ismert) és a kvagga (a kihalt alfaj az Equus quagga quagga).
A Délnyugat-Afrikában elterjedt hegyi zebra (Equus zebra) fényes bőre van, fehér hastájékkal és keskenyebb csíkokkal rendelkezik, mint az alföldi zebra. Két alfaja létezik és státusza szerint veszélyeztetett.
A Grévy-zebra (Equus grevyi) a legnagyobb, egyenes sörénnyel és hosszú, keskeny fejjel, mely megjelenését öszvérszerűvé teszi. Etiópia, Szomália és Észak-Kenya félszáraz füves vidékén él. A grévy-zebra egyika napjaink legritkább fajainak és státusza szerint veszélyeztetett.
Habár a zebrafajok előfordulási területei fedik egymást, nincs kereszteződnek. Ez még akkor is igaz volt, amikor az alföldi zebra kvagga és a burchelli fajai ugyanazon a területen osztoztak. Dorcas McClintock "A Natural History Of Zebras" című művében írta, hogy a Grévy-zebrának 46 kromoszómája van; az elföldi zebráknak 44 kromoszómájuk van és a hegyi zebrák 32 kromoszómával rendelkeznek. Fogságban az alföldi zebrák kereszteződnek a hegyi zebrákkal. A hibrid csikóknál nincs lebernyeg és felirmerhető bennük az alföldi zebrák jellegzetesen nagyobb fülei és hátsófelük mintázata. A grévy-zebra mén és a hegyi zebra kanca keresztezése általában elvetéléssel végződik.
[szerkesztés] Zebra classification
- Plains Zebra, Equus quagga
- Quagga, Equus quagga quagga (extinct)
- Burchell's Zebra, Equus quagga burchellii
- Grant's Zebra, Equus quagga boehmi
- Selous' zebra, Equus quagga borensis
- Chapman's Zebra, Equus quagga chapmani
- Crawshay's Zebra, Equus quagga crawshayi
- Cape Mountain Zebra, Equus zebra
- Hartmann's Mountain Zebra, Equus hartmannae
- Grevy's Zebra, Equus grevyi
For the remaining species of the genus and family see Equidae.
[szerkesztés] Uses
Attempts have been made to train zebras for both riding and draft use, both for novelty value and due to their better resistance than horses to diseases in Africa. Although easily broken for both uses, they are highly strung and zebra-mules or zebroids (crosses between any species of zebra and a horse, pony, donkey or ass) are preferred over pure-bred zebras.
In England, Lord Rothschild frequently used zebras for drawing carriages. In 1907, Rosendo Ribeiro, the first doctor in Nairobi, Kenya, used a riding zebra for doing house-calls. Captain Horace Hayes, in "Points of the Horse" (circa 1899) compared the use of different zebra species.
Hayes saddled and bridled a Mountain Zebra in less than one hour, but was unable to give it a "mouth" during the two days it was in his possession. He noted that the zebra's neck was so stiff and strong that he was unable to bend it in any direction. Although he taught it to do what he wanted in a circus ring, when he took it outdoors he was unable to control it. He found the Burchell's Zebra easy to break in and considered it ideal for domestication as it was also immune to the tsetse fly bite. He considered the quagga well-suited to domestication due to being stronger, more docile and more horse-like than other zebras.
[szerkesztés] References
- ↑ Gould, S. J. (1983) Hen's Teeth and Horse's Toes: Further Reflections in Natural History. New York: W. W. Norton and Company.
In particular refer to Chapter 29: How the Zebra Gets Its Stripes. One of the strongest pieces of evidence for black with white stripes, rather than white with black stripes comes from abnormal zebras where the 'stripes' form as dots and blotches rather than lines. These appear as white blotches on a black background, which is only understandable if it is normally a black animal with white stripes. An interesting picture of this phenomenon can be found here.
- ↑ How do a zebra's stripes act as camouflage?. How Stuff Works. Meglátogatva: 2006-11-13.
- McClintock, Dorcas. "A Natural History Of Zebras" September 1976. Scribner's, New York. ISBN 0684146215
- Hayes, Horace. "Points of the Horse" (circa 1899)
[szerkesztés] Lásd még
- Zebroid
[szerkesztés] External links
- PBS Nature: Horse Tigers (Zebras)
- Zebra Pictures, Rare Illustrations, and Fun Facts
- 19th Century Riding Zebras and Harnessed Zebras
Kategória:

