A zorse or zebrula is the offspring of a zebra stallion and a horse mare; the rarer reverse pairing is sometimes called a hebra. It is a zebroid: this term refers to any hybrid equine with zebra ancestry.
The zorse is shaped more like a horse than a zebra, but has boldly striped legs and, often, stripes on the body or neck. Like most other interspecies hybrids, it is infertile.
Cossar Ewart, Professor of Natural History at Edinburgh (1882-1927) and a keen geneticist, crossed a zebra stallion with horse and pony mares in order to investigate the theory of telegony, or paternal impression. Cossar Ewart used Arabian mares. Similar experiments were carried out by the US Government and reported in "Genetics in Relation to Agriculture" by E.B. Babcock and R.E. Clausen and in "The Science of Life" by H.G. Wells, J. Huxley and G.P. Wells (c.1929).
Zebras, donkeys and horses are all members of the genus equus -- equines. Equines can be crossbred to produce hybrids. They are all slightly different in genetic makeup, but still all equines. That is, horses have 64 chromosomes, zebra have between 44 and 62 (depending on species). Most zorses have 63 chromosomes.
Zorses combine the zebra striping overlaid on colored areas of the hybrid's coat. Zorses are most often bred using solid colour horses. If the horse parent is piebald (black and white) or skewbald (other color and white) (these are known in the USA as paint/pinto) the zorse may inherit the dominant de-pigmentation 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 non-depigmented 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
Zorses and humans
"It soon became apparent that zorses are not the most easiest of the equine family to get along with."
-- Trainer Pat Parelli, on working with zorses.
Zorses are preferred over purebred zebras for riding and draught for several reasons, although they are still not as easily handled as purebred horses and should not be ridden or purchased by novices. Their more horselike shape, particularly in the shoulder region, makes it easier to obtain harness.
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.
- 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. This was the inspiration for the 2003 'Song For the Zorse' by London band The Coronets.
- According to local lore brown zorses have been spotted in the foot hills of the Appalachians in and around Charlottesville, Virginia.
- 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 episode where the Zorse is I'll give you a dollar".
- The 2007 movie I'm Reed Fish features a zorse named Zabrina.
- An animated zorse appears in the alternate ending of the movie Racing Stripes. It is the son of Stripes (a zebra) and Sandy, a white filly.
- Zorses 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!"