This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (February 2013)

A zebroid (also zedonk, zorse, zebra mule, zonkey, and zebrule) is the offspring of any cross between a zebra and any other equine: essentially, a zebra hybrid. In most cases, the sire is a zebra stallion. Offspring of a donkey sire and zebra dam, called a zebra hinny, or donkra, do exist but are rare. Zebroids have been bred since the 19th century. Charles Darwin noted several zebra hybrids in his works.

Types [edit]

Zebroid is the generic name for all zebra hybrids. The different hybrids are generally named using a portmanteau of the sire's name and the dam's name. There is generally no distinction made as to which zebra species is used. Many times when zebras are crossbred, they develop some form of dwarfism. Breeding of different branches of the equine family, which does not occur in the wild, generally results in infertile offspring. The combination of sire and dam also affects the offspring.

A zorse is the offspring of a male zebra and a female horse. This cross is also called a zebrula, zebrule, zebra mule or golden zebra. The rarer reverse pairing is sometimes called a horbra, hebra, zebrinny or zebret. Like most other animal hybrids, the zorse is sterile.^[1]

A zony is the offspring of a zebra stallion and a pony mare. Medium-sized pony mares are preferred to produce riding zonies, but zebras have been crossed with smaller pony breeds such as the Shetland, resulting in so-called "Zetlands".^[2]

A zebra/donkey hybrid

A zonkey is a cross between a zebra and a donkey. "Zonkey" is not the technically correct name for such a cross. The most commonly accepted terms are zebonkey (or zebronkey), zebrinny, zebrula, zebrass, and zedonk (or zeedonk). Another name that is sometimes used is "zebadonk". Donkeys are closely related to zebras and both animals belong to the horse family. Zonkeys are very rare.^[3] In South Africa, they occur where zebras and donkeys are found in proximity to each other. Like mules, however, they are generally genetically unable to breed, due to an odd number of chromosomes disrupting meiosis.

Genetics [edit]

Donkeys and wild equids have different numbers of chromosomes. A donkey has 62 chromosomes; the zebra has between 32 and 46 (depending on species). In spite of this difference, viable hybrids are possible, provided the gene combination in the hybrid allows for embryonic development to birth. A hybrid has a number of chromosomes somewhere in between. The chromosome difference makes female hybrids poorly fertile and male hybrids generally sterile due to a phenomenon called Haldane's Rule. The difference in chromosome number is most likely due to horses having two longer chromosomes that contain similar gene content to four zebra chromosomes.^[4] Horses have 64 chromosomes, while most zebroids end up with 54 chromosomes.

Common wisdom states that hybrids only occur when the zebra is the sire, but the Barbados hybrid demonstrates otherwise. Two other known zebra hinnies have been foaled, but did not survive to adulthood. The rarity of zebra hinnies indicates the smaller number of chromosomes must generally be on the male side if a viable hybrid is to be produced. Before this comes into account, a successful mating needs to be accomplished in the first place. As courtship in horses involves the mare kicking at the stallion's head for some time before allowing him to mount, and as this behavior is stronger in wild equids than in domestic horses, it is difficult enough to get a horse stallion to mate and not be put off by the rough behavior of the non-horse mare.^{[dubious – discuss][citation needed]}

Zonkeys are interspecific hybrids bred by mating two species from within the same genus. The offspring have traits and characteristics of both parents. Zonkeys vary considerably depending on how the genes from each parent are expressed and how they interact.

Physical characteristics [edit]

A zorse

Zebroids physically resemble their nonzebra parent, but are striped like a zebra. The stripes generally do not cover the whole body, and might be confined to the legs or spread onto parts of the body or neck. If the nonzebra parent was patterned (such as a roan, Appaloosa, Pinto horse/paint, piebald, or skewbald), this pattern might be passed down to the zebroid, in which case the stripes are usually confined to nonwhite areas. The alternative name golden zebra relates to the interaction of zebra striping and a horse's bay or chestnut colour to give a zebra-like black-on-bay or black-on-chestnut pattern that superficially resembles the quagga. In zebra-donkey hybrids, there is usually a dorsal (back) stripe and a ventral (belly) stripe.

Zebroid Eclyse

Zorses combine the zebra striping overlaid on colored areas of the hybrid's coat. Zorses are most often bred using solid color horses. If the horse parent is piebald (black and white) or skewbald (other color and white) (these are known in the United States as pinto), the zorse may inherit the dominant depigmentation genes for white patches, it is understood that tobiano (the most common white modifier found in the horse) directly interacts with the zorse coat to give the white markings. Only the nondepigmented areas will have zebra striping, resulting in a zorse with white patches and striped patches. This effect is seen in the zebroid Eclyse (a hebra rather than a zorse) born in Stukenbrock, Germany in 2007 to a zebra mare called Eclipse and a stallion called Ulysses.

Zebroids are preferred over zebra for practical uses, such as riding, because the zebra has a different body shape from a horse or donkey, and consequently it is difficult to find tack to fit a zebra. However, a zebroid is usually more inclined to be temperamental than a purebred horse and can be difficult to handle. Zebras, being wild animals, and not domesticated like horses and donkeys, pass on their wild animal traits to their offspring.^{[citation needed]} Zebras, while not usually very large, are extremely strong and aggressive. Similarly, zorses have a strong temperament and can be aggressive.

Historical and notable zebroids [edit]

Zebra-horse hybrid foal with quagga-like markings, Walter Rothschild Zoological Museum, Tring, England.

In 1815, Lord Morton mated a quagga stallion to a chestnut Arabian mare. The result was a female hybrid which resembled both parents. This provoked the interest of Cossar Ewart, Professor of Natural History at Edinburgh (1882–1927) and a keen geneticist. Ewart crossed a zebra stallion with pony mares to investigate the theory of telegony, or paternal impression. In Origin of Species (1859), Charles Darwin mentioned four coloured drawings of hybrids between the ass and zebra. He also wrote "In Lord Morton's famous hybrid from a chestnut mare and male quagga, the hybrid, and even the pure offspring subsequently produced from the mare by a black Arabian sire, were much more plainly barred across the legs than is even the pure quagga." In his book The Variation of Animals and Plants under Domestication, Darwin described a hybrid ass-zebra specimen in the British Museum as being dappled on its flanks. He also mentioned a "triple hybrid, from a bay mare, by a hybrid from a male ass and female zebra" displayed at London Zoo. This would have required the zebroid sire to be fertile.

During the South African War, the Boers crossed the Chapman's zebra with the pony, to produce an animal for transport work, chiefly for hauling guns. A specimen was captured by British forces and presented to King Edward VII by Lord Kitchener, and was photographed by W S Berridge.^[5] Zebras are resistant to sleeping sickness, whereas purebred horses and ponies are not, and it was hoped that the zebra mules would inherit this resistance.

Grevy's zebra has been crossed with the Somali ass in the early 20th century. Zorses were bred by the US Government and reported in Genetics in Relation to Agriculture by E. B. Babcock and R. E. Clausen (early 20th century), in an attempt to investigate inheritance and telegony. The experiments were also reported in The Science of Life by H G Wells, J Huxley and G P Wells (c. 1929).

The 1970s continued the interest in zebra crosses. A New York Times article from 16 June 1973 mentioned the birth of a cross between a zebra and a donkey at the Jerusalem Zoo. They called it a "hamzab." In the 1970s, the Colchester Zoo in England bred zedonks, at first by accident and later to create a disease-resistant riding and draft animal. The experiment was discontinued when zoos became more conservation-minded. A number of hybrids were kept at the zoo after this; the last died in 2009.^[6] One adult and a foal remain at the tourist attraction of Groombridge Place^[7] near Tonbridge in Kent.

21st century [edit]

Today, various zebroids are bred as riding and draft animals, and as curiosities in circuses and smaller zoos. Zorses are bred in Africa and used for trekking on Mount Kenya;^[8] the zebra parent gives resistance to the nagana pest disease. A zorse (more accurately a zony) was born at Eden Ostrich World, Cumbria, England in 2001 after a zebra was left in a field with a Shetland pony. It was referred to as a Zetland. Usually, a zebra stallion is paired with a horse mare or donkey mare, but in 2005, a Burchell's zebra named Allison produced a zonkey called Alex sired by a donkey at Highland plantation in the parish of Saint Thomas, Barbados. Alex, born 21 April 2005, is apparently the first zonkey in Barbados.^[9] In 2007, a stallion, Ulysses, and a zebra mare, Eclipse, produced a zebroid named Eclyse, displaying an unusually patchy color coating.^[10][11] The Wild Animal Safari in Springfield, Missouri, and its sister location in Pine Mountain, Georgia, have several zedonks as of 31 March 2010.^{[citation needed]} In July 2010, a zedonk was born at the Chestatee Wildlife Preserve in Dahlonega, Georgia.^[12] Another zebra–donkey hybrid, like the Barbados zonkey sired by a donkey, was born 3 July 2011 in Haicang Safari Park, Haicang, Xiamen, China.^[13]

Popular culture [edit]

Zorses have appeared in several TV shows and movies. In the Viva La Bam episode "Groundhogs Day" in the final race, Brandon Dicamillo's sled is a zorse. It was colored pink, blue, purple and red and on the 'uncommentary' on the DVD seasons of Viva La Bam, Tim Glomb says "If you send me a list of all the episodes where the zorse is I'll give you a dollar". Also, the 2007 movie I'm Reed Fish features a zorse named Zabrina. In the movie Racing Stripes, an animated zorse appears in the alternate ending. It is the son of Stripes (a zebra) and Sandy, a grey Arabian mare. Zorses have also appeared in books. They are briefly mentioned several times in George R.R. Martin's A Song of Ice and Fire series of fantasy novels. Sutton Coleman wrote a sonnet about zorses and published it in his 2007 book, Ligers, Tigons, and Zorses, Oh My! In Roald Dahl's book Going Solo, he and several other characters speculate on how nice it would be to own a zorse, although they admit it would be difficult to train.

References [edit]

Wikimedia Commons has media related to: Zorses

Zebras (/ˈzɛbrə/ ZEB-rə or /ˈziːbrə/ ZEE-brə)^[1] are several species of African equids (horse family) united by their distinctive black and white stripes. Their stripes come in different patterns, unique to each individual. They are generally social animals that live in small harems to large herds. Unlike their closest relatives, horses and asses, zebras have never been truly domesticated.

There are three species of zebras: the plains zebra, the Grévy's zebra and the mountain zebra. 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 ass, 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 grasslands, savannas, woodlands, thorny scrublands, mountains, and coastal hills. 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 quagga, became extinct in the late 19th century – though there is currently a plan, called the Quagga Project, that aims to breed zebras that are phenotypically similar to the quagga in a process called breeding back.

Etymology [edit]

Zebra in English dates back to c.1600, from Italian Zebra, perhaps from Portuguese, which in turn is said to be Congolese (as stated in the Oxford English Dictionary). 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".

Taxonomy and evolution [edit]

Zebras in Mikumi, Tanzania

Zebras evolved among the Old World horses within the last 4 million years. Grévy's zebras (and perhaps also Mountain Zebras) are, together with asses and donkeys, in a separate lineage from other zebra lineages.^[2] This means either that striped equids evolved more than once, or that common ancestors of zebras and asses were striped and only zebras retained the stripes. 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).^[3]

Fossils of an ancient equid were discovered in the Hagerman Fossil Beds National Monument in Hagerman, Idaho. It was named the Hagerman horse with a scientific name of Equus simplicidens. It is believed to have been similar to the Grévy's zebra.^[4] The animals had stocky zebra-like bodies and short, narrow, donkey-like skulls.^[5] Grévy's zebra also has a donkeylike skull. The Hagerman horse is also called the American zebra or Hagerman zebra.

Classification [edit]

Zebras in Botswana

There are three extant species. Collectively, two of the species have eight subspecies (seven extant). Zebra populations are diverse, and the relationships between, and the taxonomic status of, several of the subspecies are not well known.

• Genus: Equus
  • Subgenus: Hippotigris
    • Plains zebra, Equus quagga
      • Quagga, Equus quagga quagga (extinct)
      • Burchell's zebra, Equus quagga burchellii (includes Damara Zebra)
      • Grant's zebra, Equus quagga boehmi
      • Selous' zebra, Equus quagga borensis
      • Chapman's zebra, Equus quagga chapmani
      • Crawshay's zebra, Equus quagga crawshayi
    • Mountain zebra, Equus zebra
      • Cape mountain zebra, Equus zebra zebra
      • Hartmann's mountain zebra, Equus zebra hartmannae
  • Subgenus: Dolichohippus
    • Grévy's zebra, Equus grevyi

An albino zebra in captivity

The plains zebra (Equus quagga, formerly Equus burchelli) is the most common, and has or had about twelve subspecies distributed across much of southern and eastern Africa. It, or particular subspecies of it, have also been known as the common zebra, the dauw, Burchell's zebra (actually the subspecies Equus quagga burchellii), Chapman's zebra, Wahlberg's zebra, Selous' zebra, Grant's zebra, Boehm's zebra and the quagga (another extinct subspecies, Equus quagga quagga).

The mountain zebra (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 vulnerable.

Grévy's zebra (Equus grevyi) is the largest type, with a long, narrow head, making it appear rather mule-like. It is an inhabitant of the semi-arid grasslands of Ethiopia and northern Kenya. Grévy's zebra is the rarest species, and is classified as endangered.

Although zebra species may have overlapping ranges, they do not interbreed. This held true even when the quagga and Burchell's race of plains zebra shared the same area. In captivity, plains zebras have been crossed with mountain zebras. The hybrid foals lacked a dewlap 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) equines have produced several distinct hybrids, including the zebroid, zeedonk, zony, and zorse. In certain regions of Kenya, plains zebras and Grévy's Zebra coexist, and fertile hybrids occur.^[6]

Physical attributes [edit]

Size and weight [edit]

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. Grévy's Zebra is considerably larger, while the mountain zebra is somewhat smaller.^[7]

Stripes [edit]

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.^[3] It is likely that the stripes are caused by a combination of factors.^[8]

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. The "zebra crossing" is named after the zebra's black and white stripes.

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 & 2, below) relate to camouflage.

1. The vertical striping may help the zebra hide in grass by disrupting its outline. In addition, even at moderate distances, the striking striping merges to an apparent grey.

2. The stripes may help to confuse predators by motion dazzle—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.^[9]

3. The stripes may serve as visual cues and identification.^[3] Although the striping pattern is unique to each individual, it is not known whether zebras can recognize one another by their stripes.

Zebra in Ngorongoro: its pattern may reduce its attractiveness to large biting flies.

4. Experiments by different researchers indicate that the stripes are effective in attracting fewer flies, including blood-sucking tsetse flies and tabanid horseflies.^[8][10] A 2012 experiment in Hungary 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.^[11][12]

Gaits [edit]

Like horses, zebras walk, trot, canter and gallop. They are generally slower than horses, but their great stamina helps them outpace predators. When chased, a zebra will zig-zag from side to side, making it more difficult for the predator. When cornered, the zebra will rear up and kick or bite its attacker.

Senses [edit]

Zebras have excellent eyesight. It is believed that they can see in color.^{[citation needed]} Like most ungulates, the zebra has its eyes on the sides of its head, giving it a wide field of view. Zebras also have night vision, although not as advanced as that of most of their predators.

Zebras have excellent hearing, and tend to have larger, rounder ears than horses. Like horses and other ungulates, zebras can turn their ears in almost any direction. In addition to eyesight and hearing, zebras have an acute sense of smell and taste.

Ecology and behavior [edit]

This section does not cite any references or sources. Please help improve this section by adding citations to reliable sources. Unsourced material may be challenged and removed. (March 2013)

Harems [edit]

Zebras in Tanzania

Like most members of the horse family, zebras are highly social. Their social structure, however, depends on the species. Mountain zebras 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 hyenas or wild dogs 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.

Communication [edit]

A 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.

Hartmann's Mountain Zebra with a Barbary sheep behind it, in captivity at Ueno Zoo, in Japan. (video)

Food and foraging [edit]

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.

Reproduction [edit]

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.

Interaction with humans [edit]

Lord Rothschild with his famed zebra carriage (sp. Equus quagga burchellii), which he frequently drove through London

Domestication [edit]

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 zebroids (crosses between any species of zebra and a horse, pony, donkey or ass) are preferred over purebred zebras.

In England, the zoological collector Walter Rothschild frequently used zebras to draw a carriage. In 1907, Rosendo Ribeiro, the first doctor in Nairobi, Kenya, used a riding zebra for house calls. In the mid-19th century, Governor George Grey imported zebras to New Zealand from his previous posting in South Africa, and used them to pull his carriage on his privately owned Kawau Island.

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 Burchell's zebra easy to break, and considered it ideal for domestication, as it was immune to the bite of the tsetse fly. He considered the quagga (now extinct) well-suited to domestication due to being easy to train to saddle and harness.^[13]

Conservation [edit]

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,^[14] 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 Botswana coat of arms.

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.

Cultural depictions [edit]

Zebras have been the subject of African folk tales which tell how they got their stripes. According to a Bushmen folk tale of Namibia, the zebra was once all white, but acquired its black stripes after a fight with a baboon 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.^[15] In the film Fantasia, two centaurs are depicted being half human and half zebra, instead of the typical half human and half horse.^[16]

Illustration of a zebra by Ludolphus

Zebra are a popular subject in art.^[17] The fourth Mughal emperor Jahangir (r.1605–24), commissioned a painting of the zebra, which was completed by Ustad Mansur.^[18] 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 Madagascar and Racing Stripes. One of the recurring characters in My Little Pony: Friendship is Magic is a zebra named Zecora. Zebras also serve as mascots and symbols for products and corporations, notably Zebra Technologies and Fruit Stripe gum as well as Investec. Zebras are featured on the coat of arms of Botswana.

See also [edit]

• Zebroid
• Tijuana Zebra

References [edit]

Further reading [edit]

• Churcher, C.S. 1993. Mammalian Species No. 453. American Society of Mammalogists.
• Estes, R. (1991). The Behavior Guide to African Mammals, Including Hoofed Mammals, Carnivores, Primates. Los Angeles, The University of California Press.
• McClintock, Dorcas. "A Natural History Of Zebras" September 1976. Scribner's, New York. ISBN 0-684-14621-5

This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (February 2009)

Look up Equus, equus, or equine in Wiktionary, the free dictionary.

Equus is a genus of animals in the family Equidae that includes horses, donkeys, and zebras. Within Equidae, Equus is the only extant genus. Like Equidae more broadly, Equus has numerous extinct species known only from fossils. This article deals primarily with the extant species.

The term equine refers to any member of this genus, including any horse. The word comes from Latin equus, "horse",^[1] cognate with Greek "ἵππος" (hippos),^[2] which was derived from the earlier Ionic "ἴκκος" (ikkos), "horse",^[3][4] which in turn derives from the Mycenaean Greek i-qo. I-qo is the earliest attested form of the word, and was found written in Linear B syllabic script.^[5]

Characteristics [edit]

Equines are medium to large mammals, with long heads and necks with a mane. Their legs are slender and end in a single, unguligrade toe, protected by a horny hoof. They have long, slender tails, either ending in a tuft, or entirely covered in flowing hair. They are adapted to generally open terrain, from plains and savannas, to mountains or deserts.

The range of equine monocular vision. Shaded areas represent blind spots.

The pinnae (outer ears) of equines are mobile, enabling them to easily localise the origin of sounds. They have two-color, or dichromatic vision. Their eyes are set back far on the head, giving them a wide angle of view, without entirely losing binocular vision. Equines also have a vomeronasal organ, that allows males to use the flehmen, or 'lip-curling' response to assess the sexual state of potential mates. Equines are one of only two mammals (the other is the human) capable of producing copious sweat perspiration for thermoregulatory cooling, enabling fast running over long distances.

Equines are herbivores, and feed predominantly on tough, fibrous food, such as grasses and sedges. When in need, they will also eat other vegetable matter, such as leaves, fruits, or bark, but are normally grazers, not browsers. Unlike ruminants, with their complex stomachs, equines break down cellulose in the "hindgut" or caecum, a part of the colon. Their dentition is almost complete, with cutting incisors to crop food, and grinding molars set well back behind a diastema. The dental formula for equines is:

A feral horse herd in the western United States

Mounted fossil of Equus occidentalis from the La Brea Tar Pits

Equines are social animals, living in herds or bands. Horses, along with Plains and Mountain Zebras, have permanent herds generally consisting of a single male and a band of females, with the remaining males forming small "bachelor" herds. The remaining species have temporary herds, lasting only a few months, which may be either single-sexed or mixed. In either case, there are clear hierarchies established amongst the individuals, usually with a dominant female controlling access to food and water resources and the lead male controlling mating opportunities.

Females, usually called mares in horses and zebras, or, in the case of asses and donkeys, jennies, usually bear a single foal, after a gestation period of approximately 11 months. Young equines are able to walk within an hour of birth, and are weaned after four to thirteen months (animals living in the wild naturally wean foals at a later date than those under domestication). Depending on species, living conditions and other factors, females in the wild may give birth every year or every other year.^[6][7]

Equines which are not in foal generally have a seasonal estrous cycle, from early spring into autumn. Most females enter an anestrus period during the winter and thus do not cycle in this period. The reproductive cycle is controlled by the photoperiod (length of the day), with estrus triggered when the days begin to lengthen. Anestrus prevents the female from conceiving in the winter months, as that would result in her foaling during the harshest part of the year, a time when it would be more difficult for the foal to survive.^[8] However, equines who live near the equator, where there is less change in length of day from season to season, have no anestrus period, at least in theory.^[9] Further, for reasons that are not clear, about twenty percent of domestic mares in the Northern Hemisphere will cycle the year round.^[10]

Classification [edit]

Family Equidae in addition to Equus, the family includes approximately 35 other genera, all extinct.

Extant species [edit]

• Genus Equus
  • Subgenus Equus
    • Equus ferus Wild horse^[11][12]
  • Subgenus Asinus
    • Equus africanus African Wild Ass^[12][13]
    • Equus hemionus Onager or Asiatic Ass
    • Equus kiang Kiang
  • Subgenus Dolichohippus
    • Equus grevyi Grevy's Zebra
  • Subgenus Hippotigris
    • Equus quagga Plains Zebra
    • Equus zebra Mountain Zebra

All species and subspecies [edit]

[extinct species are marked with †]

• Genus Equus
  • Subgenus Equus
    • Equus ferus Wild horse^[11][12]
      • Equus ferus caballus Domestic horse
      • †Equus ferus ferus Tarpan (historically extinct)
      • Equus ferus przewalskii Przewalski's horse or Mongolian Wild Horse or takhi
      • †Equus algericus (Pleistocene of Algeria)
      • † North American caballid horses (Pleistocene; most likely synonymous with E. ferus):
        • †Equus lambei Yukon Wild Ass (or Yukon Wild Horse)
        • †Equus niobrarensis
      • Subgenus †Amerhippus Hoffstetter, 1950 (jr synonym subgenus Tomolabis Cope, 1892) (this subgenus and the species therin are possibly synonymous with E. ferus)^[14]
        • †Equus andium
        • †Equus neogeus
        • †Equus fraternus Leidy, 1860 (North America)
        • †Equus santaeelenae
        • †Equus scotti Gidley
        • †Equus niobrarensis Hay
        • †Equus conversidens Owen, 1863 (Mexican horse) (North America)
    • †New World stilt-legged horse (all following species within the group may be synonyms or regional races of a single species)^[15]
      • †Equus francisci Hay, 1915
      • †Equus semiplicatus Cope, 1893 (North America)
  • Subgenus Asinus
    • Equus africanus African Wild Ass^[12][13]
      • Equus africanus africanus Nubian Wild Ass
      • Equus africanus asinus Domestic Donkey, Ass or Burro
      • †Equus africanus atlanticus Atlas Wild Ass
      • Equus africanus somalicus Somali Wild Ass
    • Equus hemionus Onager or Asiatic Ass
      • Equus hemionus hemionus Mongolian Wild Ass, Dziggetai or Gobi Kulan
      • †Equus hemionus hemippus Syrian Wild Ass
      • Equus hemionus khur Indian Wild Ass or Khur
      • Equus hemionus kulan Turkmenian Kulan
      • Equus hemionus onager Persian Onager
    • Equus kiang Kiang
      • Equus kiang chu Northern Kiang
      • Equus kiang kiang Western Kiang
      • Equus kiang holdereri Eastern Kiang
      • Equus kiang polyodon Southern Kiang
    • †Equus hydruntinus European Ass (late Paleolithic of southern Europe)
    • †Equus altidens (middle Pleistocene of Tadjikistan)
    • †Equus tabeti (early middle Pleistocene of Algeria, known only from teeth and limb bones)
    • †Equus melkiensis (late Paleolithic of Algeria, based on teeth and limb bones)
    • †Equus graziosii (late Pleistocene of Italy)
  • Subgenus Dolichohippus
    • Equus grevyi Grevy's Zebra
    • †Equus koobiforensis Eisenmann, 1983 (East Africa, ~2 million years (late Pliocene), similar but more derived than E.simplicidens and E.sanmeniensis
      • †Equus oldowayensis Hopwood, 1937 (East Africa, late Pleiocene, early Pleistocene, likely conspecific with E.koobiforensis
  • Subgenus Hippotigris
    • Equus quagga Plains Zebra
      • Equus quagga boehmi Grant's Zebra
      • Equus quagga borensis Maneless Zebra
      • Equus quagga chapmani Chapman's Zebra
      • Equus quagga crawshayi Crawshay's Zebra
      • Equus quagga burchellii Burchell's Zebra
      • †Equus quagga quagga Gmelin, 1788 Quagga (South Africa, extinction in early 20th century)
      • Equus quagga selousi Selous' Zebra
    • Equus zebra L.,1758 Mountain Zebra
      • Equus zebra hartmannae Hartmann's Mountain Zebra
      • Equus zebra zebra Cape Mountain Zebra
    • †Equus mauritanicus Pomel, 1897 (Pleistocene transitional form between E. (Dolichohippus) and E. (Hippotigris), possibly via E. koobiforensis)
  • Subgenus †Parastylidequus
    • †Equus parastylidens Mooser’s Horse
  • incertae sedis
    • †Equus simplicidens Hagerman Horse (North American Pleiocene - earliest known species of genus Equus) (perhaps closest to Dolichohippus^[16])
    • †Equus cumminsii Cope, 1893 (North America; based on a single, 3 million year old tooth)
    • †Equus livenzovensis Baihusheva, 1978 (southern Russia and western Europe, Pleiocene - highly similar to E. simplicidens
    • †Equus sanmeniensis Teilhard&Piveteau, 1930 (south China, late? Pliocene; similar but more derived than E.livenzovensis
    • †Equus teilhardi Eisenmann, 1975 (south China, late(?) Pliocene; similar to E.sanmeniensis but smaller, likely synonym)
    • †Equus numidicus Pomel, 1897
    • †Equus plicidens Owen, 1844 (late Pliocene, only teeth known)
    • †Equus stenonis group
      • †Equus stenonis Cocchi, 1867 (Europe to China, late Pleiocene)
        • †Equus stenonis guthi (late Pliocene, France)
        • †Equus stenonis senezensis (late Pliocene)
        • †Equus stenonis pamirensis (Hippotigris pamirensis) (late Pliocene, central Asia)
        • †Equus stenonis petraloniensis Tsoukala (Greece - Petralona cave)
        • †Equus stenonis vireti (late Pliocene)
      • †Equus sivalensis (late Pleiocene (?), India; similar to E.stenonis in skull shape)
      • †Equus stehlini (early Pleistocene, ~1 million years ago; similar but smaller than E. stenonis
      • †Equus bressanus (early Pleistocene, ~1 million years ago; similar but much larger than E. stenonis
      • †Equus sussenbornensis Wüst, 1901 (early middle Pleistocene of Europe)
      • †Equus verae Sher, 1971 (middle Pleistocene of north eastern Asia)
      • †Equus namadicus (middle paleolithic sites in India)
    • †subgenus Allozebra & Hesperohippus (N. American lineage of middle to late Pleistocene)
      • †Equus idahoensis
      • †Equus (A.) occidentalis
      • †Equus (A.) excelsus
      • †Equus (H.) pacificus
    • †Equus complicatus
    • †Equus fraternus
    • Equus major Boule (nomen dubium)
    • †Equus giganteus group
      • †Equus giganteus
      • †Equus pectinatus
      • †Equus crinidens

• 

  Przewalski's horse, the only remaining type of "wild" horse that has never been domesticated

• 

  A domesticated horse

• 

  An onager, one type of wild ass

• 

  A pair of kiangs

• 

  Quagga (now extinct)

• 

  Plains zebra

• 

  Grévy's zebra

• 

  Equus conversidens (extinct)

Cross-breeds [edit]

Different species of Equus can crossbreed, though the ensuing offspring are usually infertile. Hybrids include:

a mule

• Mule, a cross between a male donkey and a female horse. Mules are the most common type of hybrid equine and are renowned for their toughness, surefootedness, and working ability.
• Hinny, a cross between a female donkey and a male horse. Considered a less desirable cross than a mule, generally smaller in size and not as hardy.

Any equine with partial zebra ancestry is called a zebroid.

See also [edit]

• Domestication of the horse
• Evolution of the horse

References [edit]

Sources [edit]

• Burke, et al. 2003. The systematic position of Equus hydruntinus, an extinct species of Pleistocene equid. Quaternary Research 59(3):459-469.
• Duncan, P. (ed.). 1992. Zebras, Asses, and Horses: an Action Plan for the Conservation of Wild Equids. IUCN/SSC Equid Specialist Group. IUCN, Gland, Switzerland.
• Equid Specialist Group 1996. Equus ferus. In: IUCN 2004. 2004 IUCN Red List of Threatened Species. <www.iucnredlist.org>. Downloaded on 21 January 2006.
• Equid Specialist Group 1996. Equus ferus ssp. przewalskii. In: IUCN 2004. 2004 IUCN Red List of Threatened Species. <www.iucnredlist.org>. Downloaded on 21 January 2006.
• Groves, C.P.; Bell, H.B. (2004). "New investigations on the taxonomy of the zebras genus Equus, subgenus Hippotigris". Mammalian Biology 69: 182–196. doi:10.1078/1616-5047-00133. 
• Higuchi, RG, Wrischnik, LA, Oakes, E, George, M, Tong, B, Wilson, AC (1987). "Mitochondrial DNA of the Extinct Quagga: Relatedness and Extent of Postmortem Change". Journal of Molecular Evolution 25 (4): 283–287. doi:10.1007/BF02603111. PMID 2822938. 
• International Commission on Zoological Nomenclature. 2003. Opinion 2027 (Case 3010). Usage of 17 specific names based on wild species which are pre-dated by or contemporary with those based on domestic animals (Lepidoptera, Osteichthyes, Mammalia): conserved. Bull.Zool.Nomencl., 60:81-84.
• Moehlman, P.D. 2002. Equids. Zebras, Assess and Horses. Status Survey and Conservation Action Plan. IUCN/SSC Equid Specialist Group. IUCN, Gland, Switzerland. (http://www.iucn.org/themes/ssc/publications/actionplans.htm#Equids2002)
• Orlando, L; Mashkour, M; Burke, A; Douady, CJ; Eisenmann, V; H�nni, C (2006). "Geographic distribution of an extinct equid (Equus hydruntinus : Mammalia, Equidae) revealed by morphological and genetical analyses of fossils". Molecular Ecology 15 (8): 2083–2093. doi:10.1111/j.1365-294X.2006.02922.x. PMID 16780426. 

v t e Equine Equine science and management Equine anatomy Equine nutrition Horse behavior Horse care Horse breeding Horse genome Equine conformation Equine coat color Horse gait Equestrianism and sport Glossary of equestrian terms List of Equestrian Sports Horse tack Bit Bridle Saddle Harness English riding Western riding Driving Horse training Horse racing Equestrian at the Summer Olympics (medalists, venues) Horse show Equitation Evolution and history Domestication of the horse Horses in warfare Horses in the Middle Ages Horses in East Asian warfare History of the horse in South Asia Horses in the Napoleonic Wars Horses in World War I Horses in World War II History of the horse in Britain Horse worship Horse burial Horse breeds, types and other Equidae Horses List of horse breeds Draft horse Feral horse Gaited horse Mountain and moorland pony breeds Sport horse Stock horse Warmblood Wild horse Other Equus List of donkey breeds Donkey Zebra Onager Hybrids Hinny Mule Zebroid Category: Equidae

The Atlas wild ass (Equus africanus atlanticus), also known as Algerian wild ass, is a purported extinct subspecies of the African wild ass that was once found across North Africa and parts of the Sahara.^[1] It was last represented in a villa mural ca.300 AD in Bona, Algeria, and went extinct as a result of Roman sport hunting.^[2]

Taxonomy

Purported bones have been found in a number of rock shelters across Morocco and Algeria by paleontologists including Alfred Romer (1928, 1935) and Camille Arambourg (1931).^[3]

While the existence of several rock art depictions and Roman mosaics leave no doubt about the former existence of African wild asses in North Africa, it has been claimed that the original bones that were used to describe the subspecies atlanticus actually belonged to a fossil zebra. Therefore, the name E. a. atlanticus might not be valid to refer to the Atlas wild ass.^[4]

Description

Based on ancient drawings, the Atlas wild ass had stripes on its legs as well as a shoulder cross.^[5] Of the living subspecies of African wild ass, the Somali wild ass has only leg stripes, and the Nubian wild ass only the shoulder stripe.^[6] One or both features appear sometimes in the domestic donkey, the domestic descendant of the African wild asses.

Range and ecology

The Atlas wild ass was found in the region around the Atlas Mountains, across modern day Algeria, Tunisia and Morocco.^[7] It might also have occurred in rocky areas of the Saharan Desert, but not in sands which are avoided by wild asses.^[8]

References

This article includes a list of references, but its sources remain unclear because it has insufficient inline citations. Please help to improve this article by introducing more precise citations. (March 2012)