Zebra is a mammal of the horse genus of the horse family,[8]According to body shape and body stripes, it can be divided into three subspecies, namely, zebra, mountain zebra and common zebra.The zebra with fine stripes is one of the largest and most beautiful, with slightly round ears, wide ears, many and dense hip markings, and body side markings not reaching the abdomen;The mountain zebra is small, its hair is light yellow, and its body has black stripes. The arms and abdomen stripes are wide, the body side stripes do not reach the abdomen, and its hair is hard;Common zebras have short ears, some are brown, or have black stripes, or no stripes at the back and stripes at the whole body, the thick stripes at the back are sandwiched with light narrow stripes, and the side stripes extend below the abdomen.[9]
Zebras are native to eastern, southern and southwestern Africa,[10]It mainly inhabits tropical and subtropical forests and grasslands.Zebra is a social animal, usually in the number of dozens or hundreds of collective activities, will go to the pond or stream to drink in the morning and evening.Zebra is timid and cowardly. When it feels frightened, it will run away quickly, and the speed can reach 70 kilometers per hour;They rely on keen perception and fast running to avoid attacks from natural enemies.Zebras feed on grass and young leaves.Zebra is a year-round oestrus animal, with a sexual cycle of about 25 days, an oestrus duration of about 7 days, a gestation period of 11-13 months, a fetus, and a lactation period of 6-8 months.[9]The life span of zebras is about 30 years.[11]
Zebras are disease resistant and good at self-protection.[12]The zebra's black and white stripes can interfere with the line of sight of natural enemies in sunlight and moonlight, so people get inspiration from it and paint a pattern similar to the zebra stripes on the chariot to interfere with the enemy.[13]Zebra is a rare ornamental animal. People pursued its skin and meat and were killed in large numbers. The zebra is now on the verge of extinction.[8]
The zebra was born four million years agoprotohippus The earliest zebra evolved may beGrevy's zebra。The fossils of prehistoric equines are now in the National Museum of Kervan Culture in Kervan, Idaho, USA.The prehistoric horse of zebra is "Kewen horse" (American zebra or Kewen zebra), whose scientific name is“Equus simplicidens”, its posture is roughly the same as that of a zebra, and its bones are short and narrowdonkey, the body shape is more like a zebra.[1]
There are three species and subspecies of zebras.The number of zebras varies greatly, and the relationship between the taxonomic status of several subspecies is also quite famous.The most common species is the plain zebra（Equus quagga）, also known as the common zebra, mostly lives in South Africa and East Africa, and there are 6 confirmed subspecies: Brandt's zebra（E. q. burchellii）, Cha Zebra（E. q. chapmani）, Kirschner Zebra（E. q. crawshayi）, She's zebra（E. q. borensis）Grant Zebra（E. q. boehmi）And extinctZebra like（E. q. quagga）。
The mountain zebra in South Africa（Equus zebra）There are two subspecies of zebra with smooth skin, white belly and narrow stripes, but both are endangered animals.
Equus grevyi is the largest zebra.They are long and small, somewhat like donkeys.Its zebras live in Ethiopia and the semi dry grassland in northern Kenya.The zebra zebra is also the smallest zebra, and is nearly endangered.
Although the distribution areas of different kinds of zebras may overlap, they will never cross, such as the white zebra and Che's subspecies of plain zebra.The zebras raised in captivity are likely to cross, such as the plain zebra and the mountain zebra club, whose hybrids are similar to the plain zebra in appearance except for their large ears and some differences.If male zebra and female mountain zebra cross, the chance of abortion will be higher.
The stripes and intervals on the zebra are formed in the early pregnancy of the female. A fixed stripe form with the same interval has been determined in the embryo.Later, in the process of embryonic development, due to the different development of various parts of the body, the stripes formed in various parts of the body are different after the baby is born, some are wide, some are narrow.For example, the stripes on the zebra's neck are wide, so the earliest stripe form of the neck must be determined in the seventh week of embryonic development, before the neck stretches;The strand near the nostril is very thin, so the earliest stripe form of this part must be determined in the fifth week of embryonic development, before the nose expands;The stripes on the buttocks are the widest, indicating that the buttocks develop in proportion to the rest of the body.On the other hand, stripes cannot appear before the fifth week of embryonic development, because zebra has a tail with stripes, which has not appeared before the fifth week of embryonic development. At this time, the length of the embryo is about 32mm, and the number of stripes is about 80. According to this, it can be calculated that the width of each stripe initially determined is about 400 microns,That is, each stripe has the width of 20 embryonic cells.As for why the stripes on its limbs are horizontal, it may be that all stripes on the legs mechanically turn an angle during embryonic development.[2]
The stripes on the zebra are beautiful and elegant, which is one of the main marks of mutual recognition between the same kind. More importantly, it is to form a protective color that adapts to the environment, as an important means of defense to ensure its survival.In the open grassland and desert areas, the black brown and white stripes reflect different light under the sunlight or moonlight, which play a role in blurring or dispersing their body contours. It is difficult to distinguish them from the surrounding environment when looking at them.The protective effect of the target that is not easily exposed is very beneficial to the animals themselves.In recent years, studies also believe that stripes on zebras can distract and weaken the attention of stinging flies on the grassland, which is a means to prevent them from biting. This insect is the vector of spreading sleep disease. They often bite horses, antelopes and other monochromatic animals, but rarely threaten zebras' life.This protective color is gradually formed due to long-term adaptation to the environment and natural selection. Because there have been some zebras with no obvious stripes in history, they are easy to expose to natural enemies due to their obvious targets, be killed, and finally become extinct, gradually being eliminated in the long process of biological evolution.Only those clearly striped and conspicuous species can survive to the present.Humans get inspiration from this phenomenon. They apply the principle of stripe protection color to maritime operations, and paint the warships with colors similar to zebra stripes to blur the other party's line of sight, so as to conceal themselves and confuse the enemy.[2]
Also called grassland zebra and common zebra.The body length is 200-240 cm, the shoulder height is 120-140 cm, the tail length is 47-57 cm, and the weight is about 350 kg.In addition to the abdomen, the whole body is covered with wide black stripes, which has a protective effect.The male throat has dewlap.It is widely distributed in eastern, central and southern Africa, and inhabits the tropical grassland with abundant water and grass.Generally, they live in a small group of 10-12 headed by an adult male. Sometimes, other animals such as wildebeest, takin, impala, ostrich and so on mix together.Mass migration can occur when food is scarce.There are several subspecies, such as Cha's zebra (scientific name:Equus burchellii chapmani）。[3]
With a shoulder height of only 120 cm, it is the smallest zebra and the first zebra to be scientifically described and named.The ears are long and narrow, the mane is short, the snout is brown and yellow, and the body stripes are thick and few.It is only produced in the mountains of Southwest Africa and Cape Province of South Africa, and it refers to the subspecies (scientific name:E.z zebraDistributed in South Africa, now extinct;Southwest subspecies (scientific name:E.z hartmannae）It is distributed in southwest Africa and Angola.[3]
Also known as the narrow zebra, the Grignard zebra.It is the largest wild horse in existence, with a shoulder height of 145-155 cm.It is distributed in Somalia, southern Ethiopia and northern Kenya.The biggest recognition feature is that the stripes are finer than other zebras.It is distributed in Somalia, southern Ethiopia and northern Kenya.In 1882, after the Abyssinian emperor of Africa presented a horse to French President Grevi, it was known by people, so it was called the Grignard zebra.It is now in an endangered state.[3]
Habitat environment
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They live on dry, open grasslands and desert areas with more bushes, and mountain zebras like to live in mountainous and rugged mountain areas;Common zebras live on the plainGrassland；Grevy's zebraIt lives in hot and dry semi desert areas, and is occasionally found in scorched weedsplain。[4]
Life habits
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colony
Zebras have a strong sociality and belong to social animals. They feed together (mainly grass), and even comb each other's fur.Zebras form groups to live. Even the elderly individuals will not be expelled from the group and live alone.But the group is usually small, about 10 at most, mostly composed of female animals and male and female cubs who have not reached sexual maturity. The group is very compact but not loose. The cubs like to play together, fight, or play with the female animals.Adult males usually live alone, occupying an area of about 10 square kilometers. The excreted dung is used as a mark of the territory boundary. Only in the rainy season, when waiting for the females to come, can they live together as a couple, and then the females will return to the group.[5]
Cry
Within the habitat range, the population always migrates along a relatively fixed route.Although it looks extraordinary, its bark is very unpleasant, just like the braying of a donkey.Its vision is very good. Like other horses, its eyes can see things far away and near at the same time;Hearing is also very sharp. When eating, I also keep my ears alert to prevent sudden attacks.When looking for food, the members of the group take turns to act as the guard task. When there is danger, they will send out a long hissing warning signal, and the group will stop eating immediately and run away quickly.Its running speed is fast and lasting, reaching 60-80 kilometers per hour, which is unmatched by lions, leopards and other beasts, so it can often escape from predators.[6]
Feeding habits
Zebra isHerbivore。In addition to grass, shrubs, branches, leaves and even bark are their food.The adaptive digestive system enables zebras to survive under low nutrition conditions, which is superior to other herbivores.The main food is grass, and sometimes they eat tender leaves. Not only are the group members very friendly, but also they often mix with ostriches, giraffes, antelopes and other herbivores to live together, share the same food, and use each other and exchange information to avoid strong enemies.[6]
natural enemy
Their natural enemies, such as lions, leopards, wild dogs and hyenas, can only hunt by ambush. They often set an ambush on their way to drink water and wait patiently. When they are close to each other, they suddenly rush out, aiming at the sick and weak individuals or inexperienced cubs in groups rushing around because of fear, and have a good meal after falling down.[6]
Distribution range
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It is distributed in Botswana, the Democratic Republic of the Congo, Ethiopia, Kenya, Malawi, Mozambique, Namibia, Rwanda, Somalia, South Africa, Sudan, Swaziland, the United Republic of Tanzania, Uganda, Zambia and Zimbabwe.[7]
Reproductive mode
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Zebras are highly social animals.Different types have different social structures.Plain zebras and mountain zebras have a "family" structure. Each "family" also has one male zebra, up to six female zebras and their children.Some male zebras that have not yet married or mated will live alone or with other males until they are able to challenge the male zebras with "family".When zebras are attackedHyenaorWild dogWhen attacking, the adult zebra will form a circle and put the juvenile zebra in the circle, and its leader will protect its wife and children.
Unlike other zebras, zebras have no fixed social relations.Zebras rarely live together for long periods of time.Adult male zebras will live alone, while juvenile zebras will live with their mothers.Like the plain zebra and mountain zebra, the unmarried and mating male zebra will live with other males, but the relationship is not fixed.
In the breeding season, zebras are very nervous and active. The male animals will fight with each other in a fierce manner. The fighting methods include hitting each other's neck, biting with their mouths, and kicking with their front feet.The loser flees in confusion, while the winner lives with the female animal for a period of time, and then mates through intimacy, play and other behaviors.Each winning male will mate several females each year.The gestation period of female animals is about 11-13 months, and they give birth every three years.One litter per litter.The baby can stand and walk soon after birth.The lactation period is about 6 months, and the sexual maturity is 3.5-4 years old.The service life is about 20-30 years.[6]
Zebras not only have unique stripes, but also have unique behavior habits.They can be seen in various types of habitats, such as tropicalGrassland。However, due to human factors such as hunting and habitat destruction, the number of zebras has been greatly affected.The zebra and mountain zebra have been listed as endangered animals. Only the plain zebra has a healthy population.Zebra donkey(also known as "white zebra", "pseudo zebra") has been extinct in the 19th century.
