They are specialized for running and for grazing on siliceous grasses, which rapidly wear down the teeth. There are also variations in size, color, color patterning, hoof size and shape, mane length, presence or absence of a forelock, tail hair length and distribution, number and size of chestnuts and vocalizations. One reason all equids are vulnerable in the face of hunting pressures and habitat loss is that they reproduce slowly. I dropped each season. Most researchers, however, report that mares foal only every other year.
Sexual maturity occurs at age two in females and age three to five in males.
Life span can extend twenty or more years. Grevy's Zebras The Grevy's zebra is the largest of the wild equids and is usually considered the most primitive morphologically. Its very narrow and closely spaced stripes make the Grevy the most strikingly beautiful of the zebras. The stripes extend all the way to the broad hooves, leaving only the belly white. A broad black dorsal stripe is set off by a narrow zone of white on either side.