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Module 6 A trip to the zoo 教案
官方公共微信From Wikipedia, the free encyclopedia
For other uses, see .
) are several species of
(horse family) united by their distinctive black and white striped coats. Their stripes come in different patterns, unique to each individual. They are generally social animals that live in small
to large . Unlike their closest relatives,
and , zebras have never been truly .
There are three species of zebras: the , the
and the . The plains zebra and the mountain zebra belong to the subgenus Hippotigris, but Grévy's zebra is the sole species of subgenus Dolichohippus. The latter resembles an , to which it is closely related, while the former two are more horse-like. All three belong to the genus Equus, along with other living equids.
The unique stripes of zebras make them one of the animals most familiar to people. They occur in a variety of habitats, such as , , , thorny , , and coastal . However, various anthropogenic factors have had a severe impact on zebra populations, in particular hunting for skins and habitat destruction. Grévy's zebra and the mountain zebra are endangered. While plains zebras are much more plentiful, one subspecies, the , became extinct in the late 19th century – though there is currently a plan, called the , that aims to breed zebras that are phenotypically similar to the quagga in a process called .
The name "zebra" in English dates back to c.1600, from Italian zebra, perhaps from , which in turn is said to be
(as stated in the ). The Encarta Dictionary says its ultimate origin is uncertain, but perhaps it may come from Latin equiferus meaning "wild horse"; from equus ("horse") and ferus ("wild, untamed"). The word was traditionally pronounced with a long initial vowel, but over the course of the twentieth century, the pronunciation with the short initial vowel became the usual one in the UK and Commonwealth. The pronunciation with a long initial vowel remains standard in the United States.
Zebras evolved among the Old World horses within the last 4 million years. It has been suggested that zebras are
and that striped equids evolved more than once. Extensive stripes are posited to have been of little use to equids that live in low densities in deserts (like asses and some horses) or ones that live in colder climates with shaggy coats and annual shading (like some horses). However, molecular evidence supports zebras as a
There are three
. Collectively, two of the species have eight
(seven extant). Zebra populations are diverse, and the relationships between, and the
status of, several of the subspecies are not well known.
Subgenus: Hippotigris
, Equus quagga
+, Equus quagga quagga (extinct)
, Equus quagga burchellii (includes Damara Zebra)
, Equus quagga boehmi
, Equus quagga selousi
, Equus quagga borensis
, Equus quagga chapmani
, Equus quagga crawshayi
, Equus zebra
, Equus zebra zebra
, Equus zebra hartmannae
Subgenus: Dolichohippus
, Equus grevyi
zebra in captivity
(Equus quagga, formerly Equus burchelli) is the most common, and has or had about six subspecies distributed across much of southern and eastern Africa. It, or particular subspecies of it, have also been known as the common zebra, the ,
(actually the subspecies Equus quagga burchellii), Chapman's zebra, 's zebra, ' zebra, , Boehm's zebra and the
subspecies, Equus quagga quagga).
(Equus zebra) of southwest Africa tends to have a sleek coat with a white belly and narrower stripes than the plains Zebra. It has two subspecies and is classified as .
(Equus grevyi) is the largest type, with a long, narrow head, making it appear rather -like. It is an inhabitant of the semi-arid
and northern . Grévy's zebra is the rarest species, and is classified as .
Although zebra species may have overlapping ranges, they do not interbreed. In captivity, plains zebras have been crossed with mountain zebras. The hybrid foals lacked a
and resembled the plains zebra apart from their larger ears and their hindquarters pattern. Attempts to breed a Grévy's zebra stallion to mountain zebra mares resulted in a high rate of miscarriage. In captivity, crosses between zebras and other (non-zebra)
have produced several distinct , including the , zeedonk, zony, and zorse. In certain regions of Kenya, plains zebras and Grévy's Zebra coexist, and fertile hybrids occur.
The skull of a .
The common plains zebra is about 50–52 inches (12.2–13 hands, 1.3 m) at the shoulder with a body ranging from 6–8.5 feet (2–2.6 m) long with an 18-inch (0.5 m) tail. It can weigh up to 770 pounds (350 kg), males being slightly bigger than females.
is considerably larger, while the
is somewhat smaller.
The black and white stripes may have one or several functions.
It was previously believed that zebras were white animals with black stripes, since some zebras have white underbellies. Embryological evidence, however, shows that the animal's background color is black and the white stripes and bellies are additions. It is likely that the stripes are caused by a combination of factors.
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.
A wide variety of hypotheses have been proposed to account for the evolution of the striking stripes of zebras. The more traditional of these (1 and 2, below) relate to .
striping may help the zebra hide in the grass by . In addition, even at moderate distances, the striking striping merges to an apparent grey.
2. The stripes may help to confuse predators by —a group of zebras standing or moving close together may appear as one large mass of flickering stripes, making it more difficult for the lion to pick out a target.
3. The stripes may serve as visual cues and identification. Although the striping pattern is unique to each individual, it is not known whether zebras can recognize one another by their stripes.
4. Experiments by different researchers indicate that the stripes are effective in attracting fewer flies, including blood-sucking
and . A 2012 experiment in
showed that zebra-striped models were nearly minimally attractive to tabanid horseflies. These flies are attracted to linearly polarized light, and the study showed that black and white stripes disrupt the attractive pattern. Further, attractiveness increases with stripe width, so the relatively narrow stripes of the three living species of zebras should be unattractive to horseflies.
5. Stripes may be used to cool the zebra. Air may move more quickly over black light-absorbing stripes while moving more slowly over white stripes. This would create convection currents around the zebra that would cool it. One study analyzes that zebras have more stripes in hotter habitats.
Zebras have four : walk, ,
and gallop. They are generally slower than horses, but their great
helps them outrun predators. When chased, a zebra will zig-zag from side to side, making it more difficult for the predator to attack. When cornered, the zebra will rear up and kick or bite its attacker.
Zebras have excellent eyesight. It is believed that they can see in color.[] Like most , the zebra's eyes are on the sides of its head, giving it a wide field of view. Zebras also have , although not as advanced as that of most of their predators.[]
Zebras have excellent hearing and have larger, roun like other ungulates, zebras can turn their ears in almost any direction. In addition to superb eyesight and hearing, zebras also have acute
of smell and taste.
Being an equid, zebras are subject to many of the same common
of the domestic .
Equid intestinal roundworms parascaris sp. and
in the zebra's
, which can serve as
for other diseases including
infection of the intestine
Acute heart lesions due to
Two Grévy's Zebras were
in 1995 by leaves from a hybrid red maple tree () at the . Horses were first reported in 1981 to be susceptible and even a small amount of the leaves can be toxic to . In 2000, a zebra was reported to be infected with a nematode, halicephalobus, usually associated with decaying plant material.
This section does not
any . Please help improve this section by . Unsourced material may be challenged and . (March 2013)
Like most members of the horse family, zebras are highly social. Their social structure, however, depends on the species.
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
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, Grévy'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 mothers, while adult males live alone. 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.
Zebra feeding on grass
Zebras communicate with each other with high-pitched barks and whinnying. Grévy's zebras make mulelike brays. A zebra's ears signify its mood. When a zebra is in a calm, tense or friendly mood, its ears stand erect. When it is frightened, its ears are pushed forward. When angry, the ears are pulled backward. When surveying an area for predators, zebras will stand in an alert posture with ears erect, head held high, and staring. When tense, they will also snort. When a predator is spotted or sensed, a zebra will bark (or bray) loudly.
Zebras feed almost entirely on grasses, but may occasionally eat shrubs, herbs, twigs, leaves and bark. Their digestive systems allow them to subsist on diets of lower nutritional quality than that necessary for other herbivores.
Further information:
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 are born. A zebra foal is brown and white instead of black and white at birth.
Plains and mountain zebra foals are protected by their mothers, as well as the head stallion and the other mares in their group. Grévy's zebra foals have only their mother as a regular protector, since, as noted above, Grévy's zebra groups often disband after a few months.
with his famed zebra carriage (sp. ), which he frequently drove through
Cavallery of
Attempts have been made to train zebras for riding, since they have better resistance than horses to African diseases. Most of these attempts failed, though, due to the zebra's more unpredictable nature and tendency to panic under stress. For this reason, zebra-mules or
(crosses between any species of zebra and a horse, pony, donkey or ass) are preferred over purebred zebras.
In England, the zoological collector
frequently used zebras to draw a carriage. In 1907, , the first doctor in Nairobi, Kenya, used a riding zebra for house calls. In the mid-19th century, Governor
imported zebras to
from his previous posting in , and used them to pull his carriage on his privately owned .
Jumping an obstacle: riding a zebra in East Africa, about 1900
Captain Horace Hayes, in "Points of the Horse" (circa 1893), compared the usefulness of different zebra species. In 1891, Hayes broke a mature, intact mountain zebra stallion to ride in two days time, and the animal was quiet enough for his wife to ride and be photographed upon. He found the
easy to break, and considered it ideal for domestication, as it was immune to the bite of the . He considered the
(now extinct) well-suited to domestication due to being easy to train to saddle and harness.
Modern man has had great impact on the zebra population. Zebras were, and still are, hunted for their skins, and for meat. They also compete with livestock for forage and are sometimes culled.
The Cape mountain zebra was hunted to near extinction, with less than 100 individuals by the 1930s. The population has since increased to about 700 due to conservation efforts. Both mountain zebra subspecies are currently protected in national parks, but are still endangered.
Zebras on the
The Grévy'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 affecting the entire species. Plains zebras are much more numerous and have a healthy population. Nevertheless, they too have been reduced by hunting and loss of habitat to farming. One subspecies, the quagga, is now extinct.
Zebras have been the subject of
which tell how they got their stripes. According to a
folk tale of , the zebra was once all white, but acquired its black stripes after a fight with a
over a waterhole. After kicking the baboon so hard, the zebra lost his balance and tripped over a fire, and the fire sticks left scorch marks all over his white coat. In the film , two
are depicted being half human and half zebra, instead of the typical half human and half horse.
Illustration of a zebra from Ludolphus A new History of Ethiopia (1682).
Zebras are a popular subject in art. The fourth
(r.1605–24), commissioned a painting of the zebra, which was completed by . Zebra stripes are also a popular style for furniture, carpets and fashion.
When depicted in movies and cartoons, zebras are most often miscellaneous characters, but have had some starring roles, notably in ,
and . One of the recurring characters in
is a zebra named Zecora. Zebras also serve as mascots and symbols for products and corporations, notably
gum as well as Investec. Zebras are featured on the .
Recent research has shown that TU-103, a strain of
bacteria found in Zebra feces, can convert nearly any form of cellulose into
from the original on .
Adalberto Alves (14 February 2014). . INCM. pp. 877–.  .
Wells, John (1997). . Transactions of the Yorkshire Dialect Society: xix.42–48.
from the original on .
Prothero D.R, Schoch R. M (2003). Horns, Tusks, and Flippers: The Evolution of Hoofed Mammals. .  .
Vilstrup, Julia T. et al. (2013). "Mitochondrial Phylogenomics of Modern and Ancient Equids".
8 (2): e55950. :.
Forstén, Ann (1992).
(PDF). Annales Zoologici Fennici 28: 301–309.
Ryder, O. A.; George, M. (1986). "Mitochondrial DNA evolution in the genus Equus".
3 (6): 535–546.
Cordingley, J. E.; Sundaresan, S. R.; Fischhoff, I. R.; Shapiro, B.; Ruskey, J.; Rubenstein, D. I. (2009).
(PDF). Animal Conservation 12 (6): 505. :.
. The Gale Encyclopedia of Science. 2008.
from the original on .
Gill, Victoria (). . .
from the original on .
Howard, Jacqueline (). . .
from the original on .
Morell, Virginia (). . .
from the original on .
Conger, Cristen (n.d.). . .
from the original on .
Waage, J. K. (1981). . J. Entom. Soc. South Africa 44: 351–358.
Egri, ?dám; Miklós Blahó; Gy?rgy K Róbert F Mónika G
and Gábor Horváth (March 2012). .
215 (5): 736–745. :.
from the original on .
Knight, Kathryn (2012). "How the Zebra Got Its Stripes". J Exp Biol 215 (5): iii. :.
Dell'Amore, Christine (). . .
from the original on .
from the original on .
Hayes, Capt. Horace (1893), , pp. 311–316, London: W. Thacker
Young, T.P. et al. (2005).
(PDF). Biological Conservation 121 (2): 351–359. :.
. Gateway Africa.
from the original on .
Dirks, Tim (n.d.). . .
from the original on .
. Artists for Conservation.
from the original on .
Cohen, M.J.; Major, John and Schama, Simon (2004) , , . p. 146.
Hobgood Ray, Kathryn (). . .
from the original on .
Churcher, C.S. 1993. Mammalian Species No. 453. .
Estes, R. (2012). The Behavior Guide to African Mammals, Including Hoofed Mammals, Carnivores, Primates 20th Anniversary Edition,
(8771): 81. .
from the original on .
Larison, B Harrigan, Ryan J.; Thomassen, Henri A.; Rubenstein, Daniel I.; Chan-Golston, Alec M.; Li, E Smith, Thomas B. (14 January 2015). .
2 (1). :.  .
from the original on .
McClintock, Dorcas. A Natural History Of Zebras September 1976. , New York.
Robert, Eric, dir. (2001). Zebras, in series, Families in the Wild (DVD, 53 min.). Goldhil Entertainment GH-1593. N.B.: "About the Grant zebras living in Tanzania."
Wikimedia Commons has media related to .
has the text of the
from the original on .
Delk, Katie (n.d.). . . Archived from
. Outtoafrica.nl. n.d.
from the original on .
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