Horse outward similarity is an unreliable measure of relatedness. Besides the horse, there are six other species of genus "Equus" in the Equidae family. These are the ass or donkey, "Equus asinus"; the mountain zebra, "Equus zebra"; plains zebra, "Equus quagga"; Grévy's zebra, "Equus grevyi"; the kiang, "Equus kiang"; and the onager, "Equus hemionus". Horses can crossbreed with other members of their genus. The most common hybrid is the mule, a cross between a "jack" (male donkey) and a mare. A related hybrid, a hinny, is a cross between a stallion and a jenny (female donkey). Other hybrids include the zorse,
The Adventures of a Donkey Mr Carter and whilst under his care Jemmy falls and breaks his knees. After the accident Mr Carter has no further use for Jemmy and sells him to a Laundress from Kensington named Mrs Dawes. During the care of Mrs Dawes Jemmy see Jenkins break into the yard and try to steal some linen, he is apprehended and transported overseas. After this incident Jemmy meets another donkey named Bobby who knows Balaam. He tells Jemmy that Balaam is ill and Jemmy contemplates escaping to be with him. Jemmy is sent to work for Mr Ford at a fair near Hampstead,