Crossing the roughly 150-mile mosaic of savanna grassland and woodland that lies between the Okavango and the pans will take the zebras anywhere from 10 to 20 days. Foraging their way southeast, they stop to drink from occasional puddles and seasonal water holes. The grass is poor, but the plains zebras are impressive eaters, able to digest and extract vital nutrients from grasses that other ungulates couldn't deal with. Their digestion also requires that they eat continually throughout the day and even during night.
At the northern edge of Makgadikgadi they reach the only consistent water in this dry world, the life-nourishing Boteti River. In a good year of plentiful rain, it flows freely. In dry years there are always water holes along its bed that promise rare, much needed moisture. Whatever the season holds, at the Boteti the Okavango migrants will probably find wildebeests and others of their own kind—some of the Makgadikgadi's permanent population of 15,000 zebras will be gathered at Boteti as well.
Within these larger herds are the harems that define zebra society: a male, his mates—as many as six of them—and their mutual offspring. The mares follow a strict hierarchy, the first chosen in the harem remaining the males' favorite. This matriarch takes the dominant role, leading the phalanx, her offspring right behind her, as the harem moves on. The rest of the females follow after her in order of their arrival in the harem, carefully adhering to a system as rigid as any human hierarchy.
Keeping an eye on his brood, the stallion often brings up the rear. Not only does he have to guard against bickering among his mares and occasionally even step in to protect a new female in the harem, but he has to stave off any competing males. This is the breeding season, and alert bachelors hover around, hoping to steal mares away from an established harem. The fierce fighting that often ensues when this happens is a pugilistic feat of kicking and biting that can result in serious injury. To the victor go the spoils—mating privileges with the fought-over mare.
For a mare pregnant from the year before, this is the time to foal. The young calf she drops stays close, nursing on her rich milk for months to come. But within the first month of the birth, the calf also learns to forage on the nutrient-filled grasses of the Makgadikgadi.
The mare's barks and whinnies and smell and pattern of stripes are distinguishing features, well known to her calf. Ironically, the very stripe patterns that make zebras distinctive to each other make them less individuated to predators. When lions scan a herd of foraging zebras, looking for an individual to hone in on, what they see is a weltering confusion of stripes, a camouflage that makes the hunting harder but not impossible.
