Selasa, 05 Februari 2013

Cibhelank

Are they black with white stripes, or white with black?

Some say it depends on how you look at it. But it's probably a combination of factors that make the zebra striped-- a pattern of dark striping, plus another pattern that makes light hair.



 In most horse color patterns, white is a secondary pattern imposed over a base color. For example, a pinto is never white with black spots, no matter how small the black area is; it is always black with white patterns.



In most horse colors, white hairs appear over pink skin. Zebras, however, have black skin. So their base color is probably dark with a white pattern.






However, when zebras are bred to horses-- the offspring is called a zorse-- the babies are often horse-colored with darker stripes! 





The striping isn't always black, however; sometimes it is just a darker version of the base color (for example, a chestnut zorse will have deeper red stripes).





This shows that the black striping is a dominant pattern that can be imposed over other colors.




I also saw one zorse (a bay) who had darker stripes on its head, and in between the dark stripes, were lighter bay stripes! 




So perhaps the pattern isn't simply two separate black-and-white patterns, but a genetic mechanism that repositions the pigment into darker and lighter bands.






This might be similar to how the dun gene acts in the horse. 




. Zorse breeders have noted that dun mares crossed with zebra stallions tend to have nicely striped foals



From the Congolese word for the animal (possibly meaningstriped) via Old Portuguese zevra. This etymology is disputed.




No animal has a more distinctive coat than the zebra. Each animal's stripes are as unique as fingerprints—no two are exactly alike—although each of the three species has its own general pattern.



Why do zebras have stripes at all? Scientists aren't sure, but many theories center on their utility as some form of camouflage. The patterns may make it difficult for predators to identify a single animal from a running herd and distort distance at dawn and dusk. 



Or they may dissuade insects that recognize only large areas of single-colored fur or act as a kind of natural sunscreen. Because of their uniqueness, stripes may also help zebras recognize one another.



Zebras are social animals that spend time in herds. They graze together, primarily on grass, and even groom one another.



Plains (Burchell's) zebras are the most common species. They live in small family groups consisting of a male (stallion), several females, and their young. These units may combine with others to form awe-inspiring herds thousands of head strong, but family members will remain close within the herd.



Zebras must be constantly wary of lions and hyenas. A herd has many eyes alert to danger. If an animal is attacked, its family will come to its defense, circling the wounded zebra and attempting to drive off predators.



Any of three species of black-and-white-striped equines that subsist almost entirely on grass. Zebras stand 4755 in. (120140 cm) tall. 


The Burchell's zebra, or bonte quagga (Equus quagga), of eastern and southern African grasslands, has wide, widely spaced stripes. 




Grevy's zebra (E. grevyi), of arid areas in Kenya, Ethiopia, and Somalia, has narrow, closely spaced stripes and a white belly.



 The small mountain zebra (E. zebra), of dry upland plains in Namibia and western South Africa, has a gridlike pattern on the rump.




Small zebra groups consisting of a stallion and several mares and foals may coalesce into large herds but retain their identity.



Three species belonging to the family Equidae and indigenous to Africa. These animals are odd-toed ungulates (order Perissodactyla) which are monodactyl; that is, the middle digit is functional while the second and fourth digits are vestigial.



 The striped coat is considered to be an example of protective coloration since they live on open plains. Zebras are sociable and graze with other animals, such as deer, gnu, and ostriches. 



The gestation period is 13 months and a single young is born. The maximum life-span is 30 years. See also Perissodactyla.



zebra, herbivorous hoofed African mammal of the genus Equus, which also includes the horse and the ass.



It is distinguished by its striking pattern of black or dark brown stripes alternating with white. In size and body form it is intermediate between the larger horse and the smaller ass. It has a heavy head, stout body, short, stiff mane, and tufted tail.



 There are three living zebra species; a fourth species, the quagga, became extinct in the late 19th cent.



Most zebras inhabit open plains or brush country, while mountain zebras favor rocky hillsides. Zebra herds on the Serengeti of E Africa can be as large as 200,000 individuals, but all are organized in family groups led by a stallion.



 The plains zebras usually mix with other grazing animals, such as wildebeest and antelopes. They are swift runners, achieving speeds of up to 40 mph. Some authorities believe that the stripes evolved as visual identification to reinforce social bonds with other zebras, rather than for disguise or insect protection. 



The zebra's natural enemies are the lion and the leopard. The plains zebra, Equus burchelli, is found throughout Africa S of the Sahara.




  It stands about 4 ft (120 cm) tall at the shoulder and has small ears. It has very broad stripes, which vary greatly in their pattern among the several races of the species, as well as among individuals of the same race. 



Grevy's zebra, E. grevyii, is a large zebra found in E Africa. It stands 41/2 to 5 ft (140-150 cm) at the shoulder and weighs about 600 lb (270 kg).



 It has large, rounded ears and numerous very narrow stripes. 



Most distinctive is the mountain zebra, E. zebra, with a donkeylike build, long ears, and a characteristic stripe pattern. 



Unlike any other member of the genus Equus,its throat has a dewlap.



 One race of the mountain species, Hartmann's zebra, found in the arid mountains and coastal plains of SW Africa, increased in numbers in the 1980s to an estimated 15,000 from about 7,000 in 1967.




 The other race, the endangered Cape mountain zebra, is rarely found outside a protected area in South Africa. 




Zebras have been hunted extensively for their flesh and skins, but the plains zebra and Grevy's zebra are still numerous. 



Zebras have been crossed with horses in an attempt to produce a draft animal, but the offspring have proved sterile and unreliable. 



Zebras are classified in the phylum Chordata, subphylum Vertebrata, class Mammalia, order Perissodactyla, family Equidae.




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