Zebra
Three species of the genus Equus of Africa, Equus quagga (common zebra), Equus grevyi (Grevy's zebra) and Equus zebra (mountain zebra) are known as zebras (or zebras, disused form) [1]. the horses and donkeys belong to the same genus.
Introduction
The word fox »does not represent a reality from the evolutionary point of view, but artificially groups three species according to a character (the striped coat) that is not derived, but primitive. The stripes also appear to a greater or lesser extent on the legs and the back of donkeys and wild horses, and are manifested more strongly in the hybrids, although among the parents there is no zebra in between (case of the mules), showing that the presence of stripes is an ancient character within the genus Equus, and not one derived from a subgroup within it. Zebras have simply gone a step further in the development of stripes they already possessed, while horses and donkeys have tended to lose them or, at least, to mask them.
Although the taxonomy of zebras remains uncertain, certain studies, such as that of Debra K. Bennett (published under the expressive title "Stripes do not make zebra"), indicate that the plain and Grevy's zebra are sister species , but that the mountain zebra is more related to the horse than to them. [citation needed] [2] [3] Within the current equidae, the traditional group formed by the African ass and the Asian would be the only one with a history evolutionary behind to back it up. Zebras are smaller than their relative the horse and very similar in appearance and habits to wild asses.
Zebras are one of the best-known animals in Africa, where they live in a variety of ecosystems, such as grass plains, savannas, forested regions or with shrubs, mountains and coastal hills. They are especially famous for their characteristic black and white stripes, which not only vary between species but also from one individual to the other, and for their erect cricket. Unlike their closest relatives, horses and donkeys, zebras have never been really domesticated.
With the exception of some common zebra populations that live in central Kenya, zebras live only in the southern half of the African continent. Although the regions of two different species may overlap, they do not cross due to the different number of chromosomes; Grevy's zebras are forty-six, common zebras forty-four and mountain zebras thirty-two.
The word fox »does not represent a reality from the evolutionary point of view, but artificially groups three species according to a character (the striped coat) that is not derived, but primitive. The stripes also appear to a greater or lesser extent on the legs and the back of donkeys and wild horses, and are manifested more strongly in the hybrids, although among the parents there is no zebra in between (case of the mules), showing that the presence of stripes is an ancient character within the genus Equus, and not one derived from a subgroup within it. Zebras have simply gone a step further in the development of stripes they already possessed, while horses and donkeys have tended to lose them or, at least, to mask them.
Although the taxonomy of zebras remains uncertain, certain studies, such as that of Debra K. Bennett (published under the expressive title "Stripes do not make zebra"), indicate that the plain and Grevy's zebra are sister species , but that the mountain zebra is more related to the horse than to them. [citation needed] [2] [3] Within the current equidae, the traditional group formed by the African ass and the Asian would be the only one with a history evolutionary behind to back it up. Zebras are smaller than their relative the horse and very similar in appearance and habits to wild asses.
Zebras are one of the best-known animals in Africa, where they live in a variety of ecosystems, such as grass plains, savannas, forested regions or with shrubs, mountains and coastal hills. They are especially famous for their characteristic black and white stripes, which not only vary between species but also from one individual to the other, and for their erect cricket. Unlike their closest relatives, horses and donkeys, zebras have never been really domesticated.
With the exception of some common zebra populations that live in central Kenya, zebras live only in the southern half of the African continent. Although the regions of two different species may overlap, they do not cross due to the different number of chromosomes; Grevy's zebras are forty-six, common zebras forty-four and mountain zebras thirty-two.
Definition
Mammal native of Africa well known for its characteristic striped fur. Three species of zebras are distinguished, each with a specific striped pattern: the royal zebra or Grévy's zebra, the mountain zebra and the common zebra or Burchell's zebra.
Zebras belong to the Équidos family, which also includes horses and donkeys. The oldest ancestor of the members of this family was a small animal called Hyracotherium, or more commonly Eohippus, which lived 60 million years ago during the Pleistocene. The direct ancestors of horses, donkeys and zebras, appeared in Europe, Africa and Asia about 4 million years ago, during the Piocene. They were smaller than their relative the horse and very similar in appearance and habits to the wild ass. They had a mane of erect hairs along the neck, large ears and a tail ending in a tuft of dark hairs.
House
The water needs of each species are different and that explains the preferences of each of them for the different habitats.
Grévy's zebra is the species that best endures drought. It lives in grasslands and lowland areas of northern Kenya, Somalia and Ethiopia, in inhospitable areas of high temperatures. During the dry season, when rivers, streams and other water sources dry up, Grévy's zebras survive thanks to the holes they make with their legs in the sandy beds of the rivers.
Mountain zebra lives in rugged areas of South Africa and in the coastal hills of Namibia and Angola. This species is also adapted to drought conditions, such as Grévy's zebra, and digs for water when reserves begin to be scarce. However, to survive during the dry season the mountain zebra travels to more mountainous areas, where moisture condenses and forms rain or snow.
The common zebra or Burchell's zebra has a wider area of distribution than the previous species. He lives in grasslands and savannas in East Africa, reaching Angola in the west. Unlike the Grévy zebra and the mountain zebra, the common zebra needs to access water surfaces every day and in some areas migrates to find places with enough water to drink.
Mammal native of Africa well known for its characteristic striped fur. Three species of zebras are distinguished, each with a specific striped pattern: the royal zebra or Grévy's zebra, the mountain zebra and the common zebra or Burchell's zebra.
Zebras belong to the Équidos family, which also includes horses and donkeys. The oldest ancestor of the members of this family was a small animal called Hyracotherium, or more commonly Eohippus, which lived 60 million years ago during the Pleistocene. The direct ancestors of horses, donkeys and zebras, appeared in Europe, Africa and Asia about 4 million years ago, during the Piocene. They were smaller than their relative the horse and very similar in appearance and habits to the wild ass. They had a mane of erect hairs along the neck, large ears and a tail ending in a tuft of dark hairs.
House
The water needs of each species are different and that explains the preferences of each of them for the different habitats.
Grévy's zebra is the species that best endures drought. It lives in grasslands and lowland areas of northern Kenya, Somalia and Ethiopia, in inhospitable areas of high temperatures. During the dry season, when rivers, streams and other water sources dry up, Grévy's zebras survive thanks to the holes they make with their legs in the sandy beds of the rivers.
Mountain zebra lives in rugged areas of South Africa and in the coastal hills of Namibia and Angola. This species is also adapted to drought conditions, such as Grévy's zebra, and digs for water when reserves begin to be scarce. However, to survive during the dry season the mountain zebra travels to more mountainous areas, where moisture condenses and forms rain or snow.
The common zebra or Burchell's zebra has a wider area of distribution than the previous species. He lives in grasslands and savannas in East Africa, reaching Angola in the west. Unlike the Grévy zebra and the mountain zebra, the common zebra needs to access water surfaces every day and in some areas migrates to find places with enough water to drink.
Cuchi cuchi
The gestation period is about 12 months; One baby is born every time. After two years or before he becomes independent from his parents.
Nature
The zebra has helmets similar to those of the horse, characterized by the reduction of two fingers to one, adapted for the fast race and the hard ground. The stripes reach below the belly; His ears are short and narrow. He runs very fast, but after five minutes he loses his breath and has to slow down.
stripes
Zebras are black or dark animals with white stripes, and with a large white spot on the belly that serves to camouflage. [7] Some zebras have brown "shadow stripes" between black and white stripes.
There are three reasons why zebras are considered black with white stripes, and not vice versa: [8]
White equidae could not survive in the plains and forests of Africa. The quagga, an extinct subspecies of the common zebra, has the typical stripes on the front of the body, but a dark back. When the region between the pigmented stripes becomes too wide, secondary stripes appear, as if the suppression was weakening. The fact that some zebras have bellies and legs of pure white color is not very conclusive proof that they are white animals, since many animals of different colors have bellies and legs of white or a light color.
A mother who takes care of her young is camouflaged among dry branches, and the stripes of the zebras are absent in the fetus, which is completely black. The stripes appear later, in bands of about 400 micrometers (twenty times the size of a cell). Therefore, the stripes are wider the larger the animal is, and they grow together with the size of the body. According to Bard, the species of zebras differ in terms of the embryonic stage in which the stripes appear. Bard discovered an abnormal zebra, without stripes; his black fur had white dots, which would prove that the stripes are formed by inhibition of melanin production, and therefore the zebra is undoubtedly a black equidae with white stripes. [9]
The stripes are usually vertical on the head, neck, shoulder and trunk, and horizontal behind and on the animal's legs. Zebra footsteps take their name from the black and white stripes of zebras.
Some zoologists believe that stripes are a camouflage mechanism. This mechanism works in several ways. For starters, vertical stripes help hide the zebra among the herbs. Although this may seem absurd at first sight, considering that the grass is neither white nor black, it is supposed to be effective against the main predator of zebras, lions, which are colorblind. In theory, a zebra that remains still among tall grasses could go unnoticed by a lion. Also, since zebras are gregarious animals, stripes help confuse predators - several zebras that are or move together may seem like a single large animal, causing the lion to have trouble choosing a single zebra to attack. [ 10] A herd of zebras that disperse to flee from a predator will seem like a confusing mass of vertical stripes moving in different directions, making it difficult for the predator to visually follow an individual who separates from his companions. [11] Even so, biologists have never observed lions that seem confused by zebra stripes.
It is believed that stripes also play a role in sexual behavior; Slight variations in patterns allow zebras to distinguish different individuals. On rare occasions, zebras are born without stripes, and these specimens tend to be separated from the group; This would reinforce the theory that these lines also have a social function.
A more recent theory, which is supported by experiments, argues that disruptive coloration is also an effective means of confusing the visual system of the tsé-tsé, blood-sucking fly. [12] Another alternative theories are the one that says that the stripes coincide with the distribution of fat under the skin, thus serving as a thermoregulatory mechanism for the zebra, or the one that maintains that any wound disrupts the pattern of stripes, clearly indicating the state of shape of the Zebra potential couples.
The gestation period is about 12 months; One baby is born every time. After two years or before he becomes independent from his parents.
Nature
The zebra has helmets similar to those of the horse, characterized by the reduction of two fingers to one, adapted for the fast race and the hard ground. The stripes reach below the belly; His ears are short and narrow. He runs very fast, but after five minutes he loses his breath and has to slow down.
stripes
Zebras are black or dark animals with white stripes, and with a large white spot on the belly that serves to camouflage. [7] Some zebras have brown "shadow stripes" between black and white stripes.
There are three reasons why zebras are considered black with white stripes, and not vice versa: [8]
White equidae could not survive in the plains and forests of Africa. The quagga, an extinct subspecies of the common zebra, has the typical stripes on the front of the body, but a dark back. When the region between the pigmented stripes becomes too wide, secondary stripes appear, as if the suppression was weakening. The fact that some zebras have bellies and legs of pure white color is not very conclusive proof that they are white animals, since many animals of different colors have bellies and legs of white or a light color.
A mother who takes care of her young is camouflaged among dry branches, and the stripes of the zebras are absent in the fetus, which is completely black. The stripes appear later, in bands of about 400 micrometers (twenty times the size of a cell). Therefore, the stripes are wider the larger the animal is, and they grow together with the size of the body. According to Bard, the species of zebras differ in terms of the embryonic stage in which the stripes appear. Bard discovered an abnormal zebra, without stripes; his black fur had white dots, which would prove that the stripes are formed by inhibition of melanin production, and therefore the zebra is undoubtedly a black equidae with white stripes. [9]
The stripes are usually vertical on the head, neck, shoulder and trunk, and horizontal behind and on the animal's legs. Zebra footsteps take their name from the black and white stripes of zebras.
Some zoologists believe that stripes are a camouflage mechanism. This mechanism works in several ways. For starters, vertical stripes help hide the zebra among the herbs. Although this may seem absurd at first sight, considering that the grass is neither white nor black, it is supposed to be effective against the main predator of zebras, lions, which are colorblind. In theory, a zebra that remains still among tall grasses could go unnoticed by a lion. Also, since zebras are gregarious animals, stripes help confuse predators - several zebras that are or move together may seem like a single large animal, causing the lion to have trouble choosing a single zebra to attack. [ 10] A herd of zebras that disperse to flee from a predator will seem like a confusing mass of vertical stripes moving in different directions, making it difficult for the predator to visually follow an individual who separates from his companions. [11] Even so, biologists have never observed lions that seem confused by zebra stripes.
It is believed that stripes also play a role in sexual behavior; Slight variations in patterns allow zebras to distinguish different individuals. On rare occasions, zebras are born without stripes, and these specimens tend to be separated from the group; This would reinforce the theory that these lines also have a social function.
A more recent theory, which is supported by experiments, argues that disruptive coloration is also an effective means of confusing the visual system of the tsé-tsé, blood-sucking fly. [12] Another alternative theories are the one that says that the stripes coincide with the distribution of fat under the skin, thus serving as a thermoregulatory mechanism for the zebra, or the one that maintains that any wound disrupts the pattern of stripes, clearly indicating the state of shape of the Zebra potential couples.
An African legend tries to give a folk explanation to the stripes of this equine:
Long ago, the zebras did not have the black and white stripes they have today, but they were all white. When they saw a zebra, some said it was a cross between a white horse and a donkey, or perhaps a mule. At that time, people were still trying to tame the wild horses so they could ride them and show them in front of everyone, because they were very beautiful. Zebras had another name because they were different from horses and mules. But it was very difficult to capture and train a zebra. One day, a zebra that was still very young was lost and ended up in a village. People started looking at her and whispering, thinking how they could capture her. The zebra freaked out, and realized what they wanted to do. He started running while people came home to look for a net to hunt. He ran and ran, until he finally had an idea. He found a boat of black paint and knocked it down; the paint spread in many wavy stripes. The zebra wallowed until the stripes were painted on the body, thinking that it would be ugly and people would not want to capture it. The townspeople found her, and saw what she had done. As they thought she was no longer beautiful with all those black stripes on the fur, they released her. Soon, all zebras began to do the same so that people would not bother them. With the passage of time, they no longer needed to do so, because they began to be born in this way. But now the stripes made them beautiful.
Long ago, the zebras did not have the black and white stripes they have today, but they were all white. When they saw a zebra, some said it was a cross between a white horse and a donkey, or perhaps a mule. At that time, people were still trying to tame the wild horses so they could ride them and show them in front of everyone, because they were very beautiful. Zebras had another name because they were different from horses and mules. But it was very difficult to capture and train a zebra. One day, a zebra that was still very young was lost and ended up in a village. People started looking at her and whispering, thinking how they could capture her. The zebra freaked out, and realized what they wanted to do. He started running while people came home to look for a net to hunt. He ran and ran, until he finally had an idea. He found a boat of black paint and knocked it down; the paint spread in many wavy stripes. The zebra wallowed until the stripes were painted on the body, thinking that it would be ugly and people would not want to capture it. The townspeople found her, and saw what she had done. As they thought she was no longer beautiful with all those black stripes on the fur, they released her. Soon, all zebras began to do the same so that people would not bother them. With the passage of time, they no longer needed to do so, because they began to be born in this way. But now the stripes made them beautiful.
Daily routine
They live in family groups of 5 to 20 heads. The families consist of a stallion, half a dozen females and the foals with their mother. The tendency to show a vigilance position, one with the head on the back of the other, is common because of the danger of being hunted by lions.
During the mating season, fights between two male kicks and bites are often frequent. The dominant male keeps the others away from their females. Young males leave their parents towards two years of age. The females do it somewhat earlier, which shows that the degree of kinship is stronger between the stallion and their children than among the females.
On certain occasions they allow other animals to join their group, for example ostriches, cranes and buffaloes. But ostriches are the most faithful companions of these wild equidae, who know that they obtain great advantages from the vigilance and innate prudence of those gigantic birds.
Cousins and brothers
There are three species of zebras, which contain a total of nine subspecies. Broves, C.P. & Bello, H.B. 2004. New investigations where the taxonomy of the zebras genus Equus, subgenus Hippotigris. Mammalian Biology 69: 182-196. The quagga is the only extinct subspecies.
Genus Equus (equidae)
Subgenus Dolichohippus
Grevy's zebra (Equus grevyi) is the largest species of all, measuring 2.5 to 2.75 meters in length and 1.45-1.6 meters high at the back. It weighs between 350 and 440 kg. Other differences of this species with respect to the others are its large ears and the fact that its stripes are narrower. It is also the species that can withstand more time without drinking water.
Subgenus Hippotigris
The common zebra (Equus quagga) is the most numerous and geographically extensive species. It is also the one with the most different subspecies. It measures about 2.3 meters in length and 1.4 meters high at the back, weighing almost 300 kg. It has a great importance within the field of tourism in some of the countries in which it lives, as it is one of the most famous African animals. The northern populations have rather defined stripes than the southern ones.
Quagga (E. q. Quagga)
Burchell's Zebra (E. q. Burchellii)
Grant Zebra (E. q. Boehmi)
Selous Zebra (E. q. Borensis)
Chapman's Zebra (E. q. Chapmani)
Crawshay Zebra (E. q. Crawshayi)
Mountain Zebra (Equus zebra) is a species that lives in small groups and, unlike the common zebra, is not grouped in herds. It measures about 2.2 meters in length and 1-1.4 meters in height at the back. Its weight is between 240 and 370 kg. It has two subspecies, one of which, E. z. Zebra has sexual dimorphism, as females are larger than males. He lives in arid mountainous areas.
Cape Mountain Zebra (E. z. Zebra)
Hartmann's mountain zebra (E. z. Hartmannae)
Etymology
Etymologically, the word zebra used by Castilian speakers comes from the Galician-Portuguese word zevra, which means "wild ass." [5] The generic name Equus comes from Latin and means "horse." As for the specific names, grevyi is in honor of the President of France Jules Grévy; Quagga is the name given by the Khoikhoi people to these animals; and zebra refers to the Galician-Portuguese word mentioned above.
The name zevra derives from the name of "zebro" or "encebro" (Equus hydruntinus), a species of wild donkey, or perhaps wild horse similar to the tarpan, of striped hindquarters that inhabited the Iberian Peninsula at least until quite late in the Age Half. When the Portuguese began to explore the African coast and arrived at the Cape of Good Hope, at the end of the fifteenth century, they found striped equines that, due to their shape and size, were remarkably similar to the zebra females, so they they gave the name zevras.
They live in family groups of 5 to 20 heads. The families consist of a stallion, half a dozen females and the foals with their mother. The tendency to show a vigilance position, one with the head on the back of the other, is common because of the danger of being hunted by lions.
During the mating season, fights between two male kicks and bites are often frequent. The dominant male keeps the others away from their females. Young males leave their parents towards two years of age. The females do it somewhat earlier, which shows that the degree of kinship is stronger between the stallion and their children than among the females.
On certain occasions they allow other animals to join their group, for example ostriches, cranes and buffaloes. But ostriches are the most faithful companions of these wild equidae, who know that they obtain great advantages from the vigilance and innate prudence of those gigantic birds.
Cousins and brothers
There are three species of zebras, which contain a total of nine subspecies. Broves, C.P. & Bello, H.B. 2004. New investigations where the taxonomy of the zebras genus Equus, subgenus Hippotigris. Mammalian Biology 69: 182-196. The quagga is the only extinct subspecies.
Genus Equus (equidae)
Subgenus Dolichohippus
Grevy's zebra (Equus grevyi) is the largest species of all, measuring 2.5 to 2.75 meters in length and 1.45-1.6 meters high at the back. It weighs between 350 and 440 kg. Other differences of this species with respect to the others are its large ears and the fact that its stripes are narrower. It is also the species that can withstand more time without drinking water.
Subgenus Hippotigris
The common zebra (Equus quagga) is the most numerous and geographically extensive species. It is also the one with the most different subspecies. It measures about 2.3 meters in length and 1.4 meters high at the back, weighing almost 300 kg. It has a great importance within the field of tourism in some of the countries in which it lives, as it is one of the most famous African animals. The northern populations have rather defined stripes than the southern ones.
Quagga (E. q. Quagga)
Burchell's Zebra (E. q. Burchellii)
Grant Zebra (E. q. Boehmi)
Selous Zebra (E. q. Borensis)
Chapman's Zebra (E. q. Chapmani)
Crawshay Zebra (E. q. Crawshayi)
Mountain Zebra (Equus zebra) is a species that lives in small groups and, unlike the common zebra, is not grouped in herds. It measures about 2.2 meters in length and 1-1.4 meters in height at the back. Its weight is between 240 and 370 kg. It has two subspecies, one of which, E. z. Zebra has sexual dimorphism, as females are larger than males. He lives in arid mountainous areas.
Cape Mountain Zebra (E. z. Zebra)
Hartmann's mountain zebra (E. z. Hartmannae)
Etymology
Etymologically, the word zebra used by Castilian speakers comes from the Galician-Portuguese word zevra, which means "wild ass." [5] The generic name Equus comes from Latin and means "horse." As for the specific names, grevyi is in honor of the President of France Jules Grévy; Quagga is the name given by the Khoikhoi people to these animals; and zebra refers to the Galician-Portuguese word mentioned above.
The name zevra derives from the name of "zebro" or "encebro" (Equus hydruntinus), a species of wild donkey, or perhaps wild horse similar to the tarpan, of striped hindquarters that inhabited the Iberian Peninsula at least until quite late in the Age Half. When the Portuguese began to explore the African coast and arrived at the Cape of Good Hope, at the end of the fifteenth century, they found striped equines that, due to their shape and size, were remarkably similar to the zebra females, so they they gave the name zevras.
Comments
Post a Comment