This hybrid (Equus asinus × Equus burchelli) is known as a zonkey (or zedonk, zebrass, zeedonk, zebradonk, zebrinny, zenkey, zebronkey, or deebra). Reports say hybrids of both sexes have produced offspring. Usually a zebra stallion is paired with a she-ass, but the reciprocal cross is sometimes produced. For example, in 2005, an E. burchellii mare named Allison produced a zebrass called Alex sired by an ass on the island of Barbados, and a hybrid from the reciprocal cross is also shown in the video below.
Hybrids have striping on their legs, but usually not on their bodies. Individuals with body striping may represent backcrosses to zebra. In general, the stripes are narrower in hybrids than in the pure zebra parent. Grevy’s zebras, with their big heads, large and rounded ears, and thick, erect manes look more like mules than do other zebras. Indeed, the website of the National Zoo (Washington) asserts that many experts view Grevy’s zebras as striped asses, not closely related to zebras (NATZ). Z. grevyi is also geographically intermediate between asses and zebras and is capable of hybridization with both. These facts suggest Z. grevyi as a PHP of crossing between asses and zebras, but the matter should be further investigated.
Darwin (1868, vol. II, p. 42) says, "Many years ago I saw in the Zoological Gardens a curious
Many types of hybrids, and not just zonkeys, show this sort of variation in characteristics with age, so that when young they resemble one parent with respect to a given trait, but later the other.
Sources: Ewart 1898, 1899; Flower 1929a (p. 253); Grubb 1981; International Zoo Yearbook 1960, 1961, 1962 (p. 232), 1968 (p. 304), 1969 (p. 232), 1971 (p. 279), 1972 (p. 332); King et al. 1966; Riley 1911 (p. 229); Treus et al. 1963; von Lehmann 1982†. See also The Bartlett Society’s page on hybrids and the figure in Geoffroy Saint-Hilaire and Cuvier (1824-1842, vol. 3, pl. 315).
Note: Gray (1873, p. 38) stated that a skull of a hybrid of this type was in the British Museum .
Human Origins: Are we hybrids?
On the Origins of New Forms of Life
Cat-rabbit Hybrids: Fact or fiction?
Georges Cuvier: A Biography
Prothero: A Rebuttal
Branches of Biology