Zebra herbs, twigs, leaves and bark. Their digestive systems allow them to subsist on diets of lower nutritional quality than that necessary for other herbivores. Female zebras mature earlier than the males, and a mare may have her first foal by the age of three. Males are not able to breed until the age of five or six. Mares may give birth to one foal every twelve months. She nurses the foal for up to a year. Like horses, zebras are able to stand, walk and suckle shortly after they are born. A zebra foal is brown and white instead of
Grévy's zebra Abyssinia. Traditionally, this species was classified in the subgenus "Dolichohippus" with plains zebra and mountain zebra in "Hippotigris". Fossils of zebra-like equids have been found throughout Africa and Asia in the Pliocene and Pleistocene deposits. Notable examples include "E. sanmeniensis" from China, "E. cautleyi" from India, "E. valeriani" from central Asia and "E. oldowayensis" from East Africa. The latter, in particular is very similar to the Grévy's zebra and may have been its ancestor. The modern Grévy's zebra arose in the early Pleistocene. Zebras appear to be a monophyletic lineage and recent (2013) phylogenies have placed Grevy's zebra in a