A Handbook of Horse-Shoeing with Introductory Chapters on the Anatomy and Physiology go the Horse's Foot

The surviving members of the genus Equus can be divided into two groups— the non-caballine zebras and asses, and the caballine horses (see opposite). All are grazers with one functional toe and high-crowned teeth that grow throughout life. Probably the best known of the non-caballine equids are the zebras. There are three species—Grevy’s, mountain, and plains—which are easily recognized by their black-and-white-striped coats. Grevy’s zebra is the largest and has the narrowest stripes. The smaller mountain zebra from southern Africa is unique in having a dewlap (fold of skin under the throat). The plains zebra has six subspecies or races, each with a different pattern of stripes, depending on where in Africa it comes from.