Zebroid
Encyclopedia
A zebroid is the offspring of any cross between a zebra
Zebra
Zebras are several species of African equids 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...

 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. The extinct quagga
Quagga
The quagga is an extinct subspecies of the plains zebra, which was once found in great numbers in South Africa's Cape Province and the southern part of the Orange Free State. It was distinguished from other zebras by having the usual vivid marks on the front part of the body only...

 was also crossed with horses and donkeys. Charles Darwin
Charles Darwin
Charles Robert Darwin FRS was an English naturalist. He established that all species of life have descended over time from common ancestry, and proposed the scientific theory that this branching pattern of evolution resulted from a process that he called natural selection.He published his theory...

 noted several zebra hybrids in his works.

Types

Zebroid is the generic name for all zebra hybrids. The different hybrids are generally named using the portmanteau convention of sire's name + 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
Zebra
Zebras are several species of African equids 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...

 and a female horse
Mare (horse)
A mare is an adult female horse or other equine.In most cases, a mare is a female horse over the age of three, and a filly is a female horse age three and younger. However, in Thoroughbred horse racing, a mare is defined as a female horse more than four years old; in harness racing a mare is a...

. 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.

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".

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
Equidae
Equidae is the taxonomic family of horses and related animals, including the extant horses, donkeys, and zebras, and many other species known only from fossils. All extant species are in the genus Equus...

. Zonkeys are very rare. In South Africa
South Africa
The Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...

, they occur where zebras and donkeys are found in proximity to each other. Like mule
Mule
A mule is the offspring of a male donkey and a female horse. Horses and donkeys are different species, with different numbers of chromosomes. Of the two F1 hybrids between these two species, a mule is easier to obtain than a hinny...

s, however, they are generally genetically unable to breed, due to an odd number of chromosomes disrupting meiosis
Meiosis
Meiosis is a special type of cell division necessary for sexual reproduction. The cells produced by meiosis are gametes or spores. The animals' gametes are called sperm and egg cells....

.

Genetics

Donkeys and wild equids have different numbers of chromosome
Chromosome
A chromosome is an organized structure of DNA and protein found in cells. It is a single piece of coiled DNA containing many genes, regulatory elements and other nucleotide sequences. Chromosomes also contain DNA-bound proteins, which serve to package the DNA and control its functions.Chromosomes...

s. 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
Haldane's rule
Haldane's rule or Haldane's law was formulated in 1922 by the British evolutionary biologist J.B.S. Haldane. It describes hybrid sterility in species and is extended to describe speciation in evolutionary theory, in two parts: the rule of hybrid sterility and the rule of hybrid inviability...

. The difference in chromosome number is most likely due to horses having two longer chromosomes that contain similar gene content to four zebra chromosomes. 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.

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

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
Roan (horse)
Roan is a horse coat color pattern characterized by an even mixture of colored and white hairs on the body, while the head and "points"—lower legs, mane and tail—are more solid-colored. The roan pattern is dominantly-inherited, and is found in many horse breeds...

, Appaloosa
Appaloosa
The Appaloosa is a horse breed best known for its colorful leopard-spotted coat pattern. There is a wide range of body types within the breed, stemming from the influence of multiple breeds of horses throughout its history. Each horse's color pattern is genetically the result of various spotting...

, Pinto horse
Pinto horse
A pinto horse has a coat color that consists of large patches of white and any other color. The distinction between "pinto" and "solid" can be tenuous, as so-called "solid" horses frequently have areas of white hair. Various cultures throughout history appear to have selectively bred for pinto...

, paint
American Paint Horse
The American Paint Horse is a breed of horse that combines both the conformational characteristics of a western stock horse with a pinto spotting pattern of white and dark coat colors. Developed from a base of spotted horses with Quarter Horse and Thoroughbred bloodlines, the American Paint Horse...

, piebald
Piebald
A piebald or pied animal is one that has a spotting pattern of large unpigmented, usually white, areas of hair, feathers, or scales and normally pigmented patches, generally black. The colour of the animal's skin underneath its coat is also pigmented under the dark patches and unpigmented under...

, or skewbald
Skewbald
Skewbald is a color pattern of horses. A skewbald horse has a coat made up of white patches on a non-black base coat, such as chestnut, bay, or any color besides black coat. Skewbald horses which are bay and white are sometimes called tricoloured...

), 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
Quagga
The quagga is an extinct subspecies of the plains zebra, which was once found in great numbers in South Africa's Cape Province and the southern part of the Orange Free State. It was distinguished from other zebras by having the usual vivid marks on the front part of the body only...

. In zebra-donkey hybrids, there is usually a dorsal (back) stripe and a ventral (belly) stripe.
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
Piebald
A piebald or pied animal is one that has a spotting pattern of large unpigmented, usually white, areas of hair, feathers, or scales and normally pigmented patches, generally black. The colour of the animal's skin underneath its coat is also pigmented under the dark patches and unpigmented under...

 (black and white) or skewbald
Skewbald
Skewbald is a color pattern of horses. A skewbald horse has a coat made up of white patches on a non-black base coat, such as chestnut, bay, or any color besides black coat. Skewbald horses which are bay and white are sometimes called tricoloured...

 (other color and white) (these are known in the United States as pinto
Pinto horse
A pinto horse has a coat color that consists of large patches of white and any other color. The distinction between "pinto" and "solid" can be tenuous, as so-called "solid" horses frequently have areas of white hair. Various cultures throughout history appear to have selectively bred for pinto...

), the zorse may inherit the dominant depigmentation genes for white patches, it is understood that tobiano
Tobiano
Tobiano is a spotted color pattern commonly seen in Pinto horses, produced by a dominant gene. The tobiano gene produces white-haired, pink-skinned patches on a base coat color. The coloration is present from birth and does not change throughout the horse's lifetime, unless the horse also carries...

 (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
Horse
The horse is one of two extant subspecies of Equus ferus, or the wild horse. It is a single-hooved mammal belonging to the taxonomic family Equidae. The horse has evolved over the past 45 to 55 million years from a small multi-toed creature into the large, single-toed animal of today...

 or donkey
Donkey
The donkey or ass, Equus africanus asinus, is a domesticated member of the Equidae or horse family. The wild ancestor of the donkey is the African Wild Ass, E...

, and consequently it is difficult to find tack
Horse tack
Tack is a term used to describe any of the various equipment and accessories worn by horses in the course of their use as domesticated animals. Saddles, stirrups, bridles, halters, reins, bits, harnesses, martingales, and breastplates are all forms of horse tack...

 to fit a zebra. However, a zebroid is usually more inclined to be temperamental than a purebred
Purebred
Purebreds, also called purebreeds, are cultivated varieties or cultivars of an animal species, achieved through the process of selective breeding...

 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. 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

In 1815, Lord Morton mated a quagga stallion to a chestnut Arabian
Arabian horse
The Arabian or Arab horse is a breed of horse that originated on the Arabian Peninsula. With a distinctive head shape and high tail carriage, the Arabian is one of the most easily recognizable horse breeds in the world. It is also one of the oldest breeds, with archaeological evidence of horses...

 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
Telegony (pregnancy)
Telegony is a theory in heredity, now discredited but widely believed until the late 19th century, holding that offspring can inherit the characteristics of a previous mate of the female parent; thus the child of a widowed or remarried woman might partake of traits of a previous husband...

, or paternal impression. In Origin of Species (1859), Charles Darwin
Charles Darwin
Charles Robert Darwin FRS was an English naturalist. He established that all species of life have descended over time from common ancestry, and proposed the scientific theory that this branching pattern of evolution resulted from a process that he called natural selection.He published his theory...

 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
The Variation of Animals and Plants under Domestication
The Variation of Animals and Plants under Domestication is a book written by Charles Darwin that was first published in January 1868.A large proportion of the book contains detailed information on the domestication of animals and plants but it also contains in Chapter XXVII a description of...

, 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
London Zoo
London Zoo is the world's oldest scientific zoo. It was opened in London on 27 April 1828, and was originally intended to be used as a collection for scientific study. It was eventually opened to the public in 1847...

. This would have required the zebroid sire to be fertile.

During the South African War, the Boer
Boer
Boer is the Dutch and Afrikaans word for farmer, which came to denote the descendants of the Dutch-speaking settlers of the eastern Cape frontier in Southern Africa during the 18th century, as well as those who left the Cape Colony during the 19th century to settle in the Orange Free State,...

s 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
Herbert Kitchener, 1st Earl Kitchener
Field Marshal Horatio Herbert Kitchener, 1st Earl Kitchener KG, KP, GCB, OM, GCSI, GCMG, GCIE, ADC, PC , was an Irish-born British Field Marshal and proconsul who won fame for his imperial campaigns and later played a central role in the early part of the First World War, although he died halfway...

, and was photographed by W S Berridge. 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
The New York Times
The New York Times is an American daily newspaper founded and continuously published in New York City since 1851. The New York Times has won 106 Pulitzer Prizes, the most of any news organization...

 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
Colchester Zoo
Colchester Zoo is a zoo in Essex, England. The zoo had 547,495 visitors in 2003 and 464,684 in 2004. It features big cat and primate collections as well as many others.Colchester Zoo is supported by a charitable organisation called Action for the Wild...

 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. One adult and a foal remain at the tourist attraction of Groombridge Place
Groombridge Place
Groombridge Place is a moated Manor house in the village of Groombridge near Tunbridge Wells, Kent, England. It has become a tourist attraction, noted for its formal gardens, vineyards and a bird of prey sanctuary. -History:...

  near Tonbridge in Kent.

21st century

Today, various zebroids are bred as riding and draft animals, and as curiosities in circuses and smaller zoos. Zorses are bred in Africa
Africa
Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...

 and used for trekking on Mount Kenya
Mount Kenya
Mount Kenya is the highest mountain in Kenya and the second-highest in Africa, after Kilimanjaro. The highest peaks of the mountain are Batian , Nelion and Point Lenana . Mount Kenya is located in central Kenya, just south of the equator, around north-northeast of the capital Nairobi...

; the zebra parent gives resistance to the nagana pest disease. A zorse (more accurately a zony) was born at Eden Ostrich World, Cumbria
Cumbria
Cumbria , is a non-metropolitan county in North West England. The county and Cumbria County Council, its local authority, came into existence in 1974 after the passage of the Local Government Act 1972. Cumbria's largest settlement and county town is Carlisle. It consists of six districts, and in...

, 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 ass mare, but in 2005, a Burchell's zebra
Burchell's Zebra
Burchell's Zebra is a southern subspecies of the Plains Zebra.-Range:Formerly Burchell's zebra ranged north of the Vaal/Orange river system, extending northwest via southern Botswana to Etosha and the Kaokoveld, southeast to Swaziland and Kwazulu-Natal...

 named Allison produced a zonkey called Alex sired by a donkey at Highland plantation in the parish of Saint Thomas, Barbados
Barbados
Barbados is an island country in the Lesser Antilles. It is in length and as much as in width, amounting to . It is situated in the western area of the North Atlantic and 100 kilometres east of the Windward Islands and the Caribbean Sea; therein, it is about east of the islands of Saint...

. Alex, born 21 April 2005, is apparently the first zonkey in Barbados. In 2007, a stallion, Ulysses, and a zebra mare, Eclipse, produced a zebroid named Eclyse, displaying an unusually patchy color coating. The Wild Animal Safari in Springfield, MO, and its sister location in Pine Mountain, GA has several zedonks as of March 31, 2010. In July 2010, a zedonk was born at the Chestatee Wildlife Preserve in Dahlonega, Georgia. Another zebra–donkey hybrid, like the Barbados zonkey sired by a donkey, was born July 3, 2011 in Haicang Safari Park, Haicang
Haicang Town
Haicang Town is a town in Haicang District, Xiamen, Fujian province, China.-Village:* Shitang * Zhongshan * Dongyu * Wencuo * 渐美村* 吴冠村* 囷瑶村* 海沧村* 青礁村* 后井村* 锦里村* 贞庵村* 古楼村* 新垵村* 霞阳村* 祥露村...

, Xiamen
Xiamen
Xiamen , also known as Amoy , is a major city on the southeast coast of the People's Republic of China. It is administered as a sub-provincial city of Fujian province with an area of and population of 3.53 million...

, China.

Zebra–donkey hybrids in popular culture

Zorses have appeared in several TV shows and movies. In the Viva La Bam
Viva La Bam
Viva La Bam is an American reality television series that stars Bam Margera and his friends and family. The show was a spin-off from MTV's Jackass, in which Margera and most of the main cast had appeared...

 episode Groundhogs Day in the final race, Brandon Dicamillo
Brandon DiCamillo
Brandon Ralph DiCamillo is an American actor, stuntman and screenwriter. He was a founding member of the CKY Crew and rose to fame through appearances in the CKY video series and MTV's Jackass, Viva La Bam and Bam's Unholy Union.-Personal life:He previously worked for Neiman-Marcus, and is the...

'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
I'm Reed Fish
I'm Reed Fish is an American film, based on a story by Reed Fish, and released theatrically on June 1, 2007. The film was directed by Zackary Adler and stars Alexis Bledel, Jay Baruchel, and Schuyler Fisk. Jay Baruchel won the Best Actor award at the U.S. Comedy Arts Festival in 2007 for his role...

features a zorse named Zabrina. In the movie Racing Stripes
Racing Stripes
Racing Stripes is a 2005 comedy film directed by Frederik Du Chau, the director of Quest for Camelot. Although set in Kentucky, the movie was filmed in Pietermaritzburg and Nottingham Road, South Africa.-Plot:...

, an animated zorse appears in the alternate ending. It is the son of Stripes (a zebra) and Sandy, a grey Arabian mare
Mare
Female horses are called mares.Mare is the Latin word for "sea".The word may also refer to:-People:* Ahmed Marzooq, also known as Mare, a footballer and Secretary General of Maldives Olympic Committee* Mare Winningham, American actress and singer...

. Zorses have also appeared in books. They are briefly mentioned several times in George R.R. Martin's A Song of Ice and Fire
A Song of Ice and Fire
A Song of Ice and Fire is a series of epic fantasy novels by American novelist and screenwriter George R. R. Martin. Martin began writing the series in 1991 and the first volume was published in 1996. Originally planned as a trilogy, the series now consists of five published volumes; a further two...

 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
Roald Dahl
Roald Dahl was a British novelist, short story writer, fighter pilot and screenwriter.Born in Wales to Norwegian parents, he served in the Royal Air Force during the Second World War, in which he became a flying ace and intelligence agent, rising to the rank of Wing Commander...

's book Going Solo
Going Solo
Going Solo is a memoir by Roald Dahl, first published by Jonathan Cape in London in 1986. It is a continuation of his autobiography describing his childhood, Boy. The Book starts with Roald Dahl on a boat heading towards Dar es Salaam for his new job working for Shell Oil...

, 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.

External links

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