A zebroid (also zebra mule 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 mare, called a zebra hinny, or donkra, do exist but are rare. Zebroids have been bred since the 19th century. The extinct quagga was also crossed with horses and donkeys. Charles Darwin noted several zebra hybrids in his works.
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. See individual entries for more information on the different types of zebroid. Many times when Zebras are cross-bred they develop some form of dwarfism.
- Zebra (stallion) + horse (mare): zorse, zebra mule, zebrule or golden zebra
- Zebra (stallion) + pony (mare): zony
- Zebra (stallion) + Shetland pony (mare): zetland
- Zebra (stallion) + any ass species (jenny): zebrass
- Zebra (stallion) + donkey (jenny): zedonk, zeedonk, zonkey, zebronkey, zebadonk
- Zebra (mare) + donkey (jack): zebret, zebrinny
- Zebra (mare) + horse (stallion): hebra, horbra
Zebras, donkeys and horses are equines, and can be crossbred to produce hybrids despite having different numbers of chromosomes. Horses have 64 chromosomes, zebra have between 32 and 44 (depending on species). Most zebroids have 54 chromosomes (44 x 64).
Zebroids physically resemble their non-zebra 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 non-zebra 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-ass hybrids, there is usually a dorsal (back) stripe and a ventral (belly) stripe.
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.
Historical and notable zebroids
Today, various zebroids are bred as riding and draft animals and as curiosities in circuses and smaller zoos.
- In 1815, Lord Morton mated a quagga stallion to a chestnut Arabian mare. The result was a female hybrid which resembled both parents.
- In Origin of Species (1859), Charles Darwin mentioned four coloured drawings of hybrids between the ass and zebra.
- 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 Chapman's zebras and ponies to use as transport animals. Zebras are resistant to sleeping sickness, whereas pure-bred 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.
- A New York Times article from June 16, 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, 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.
- In 2005, a Burchell's zebra mare named Allison produced a zebra hinny called Alex sired by a donkey at Highland plantation in St. Thomas Parish, Barbados. This is notable as the zebra is usually the sire.
- In 2007, a stallion, Ulysses, and a zebra mare, Eclipse, produced a zebroid named Eclyse, displaying an unusually patchy color coating.
- Hybrid Equines Information and images of different zebroids
- Eclyse - Photo of a zebroid named Eclyse