A zonkey (also known as zebrass, zebronkey, zeass, zeedonk, zedonk, zebadonk, zenkey, donbra, donbri, donkra, zebrinny, zebrula, and noochie) 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 zebrinny, zebrula, and zedonk. Donkeys are closely related to zebras and both animals belong to the horse family. Zonkeys are very rare.
Like mules, they are genetically unable to breed, due to an odd number of chromosomes disrupting meiosis. However, in The Origin of Species, Charles Darwin reported a case of a zonkey that apparently bred with a bay mare to produce a "triple hybrid."