In most zebras the social unit is a harem: one stallion, a few mares and their young, holding together for years. Grevy's zebra follows the pattern seen in the African wild ass instead. Adult males establish territories that can exceed ten square kilometres, marked with dung piles, and hold them for months to years. Females range across several territories with their foals, forming temporary groups that dissolve and reform.
The arrangement fits an arid landscape. Where water and forage are patchy and unpredictable, defending a productive area is more effective for a male than herding animals that must keep moving. Lactating females need water more often than non-lactating ones, which concentrates them near permanent water in territories held by dominant stallions.
The species is in serious trouble. Its range has contracted to northern Kenya with small remnants in Ethiopia, and the global population is generally reported in the low thousands. Competition with livestock for water is a central pressure, and it is worth noting that the animal's name commemorates a nineteenth-century French president, not a naturalist.