The three extant species include the plains zebra, the Grévy's zebra, and the mountain zebra. The former two belong to the subgenus hippotigris, whereas the latter belongs to the subgenus Dolichohippus. The Grevy's zebra and the mountain zebra are endangered, and the quagga went extinct in the late 1800s, but has since been rebred from zebra DNA. Of the three remaining species, both the mountains and the Grevy's Zebra are in the threatened category, the mountains zebra classified as Vulnerable and the Grevy's endangered.
Unlike their close relatives, the horse and donkey, zebras have never truly been domesticated due to their unpredictability and liability to startle under stress. Therefore, hybrids are prefered for domestication. Hybrids of zebras and any other equine species are known as zebroids. Such hybrids include the zorse, zony, and zebronk.