Great Animal Migrations
Any creatures that live in the Kalahari must therefore either survive without relying on easy access to surface water or migrate through the area during the times when the scarce rains fall. Perhaps the most distinctive feature of the Kalahari is the way in which it blends into the larger, surrounding stretch of arid grasslands, which accounts for the remarkable migrations of game animals through and around the desert. This migration and the human reaction to it may help explain the cultural and environmental shifts that helped human beings spread out of Africa and populate the globe perhaps as recently as 70,000 years ago.
One of the most striking, seasonal, migratory residents of the region is the African elephant. The adult males stand 10 feet (3.05 m) tall at the shoulder and weigh up to six tons. They have life spans of 70 years and a crucial and intimate social structure. During much of the year, the females and the young keep to themselves, all responding to the leadership of a dominant female. During the breeding season, dominant males gather up harems. Experiments have shown that young male elephants learn how to behave from the dominant male elephant. If poachers or accidents kill off the patriarch and the young males are raised in a group without a dominant male, they will become the elephant equivalent of juvenile delinquents who get into fights, destroy farmland, knock down houses, and generally misbehave. The elephants mostly migrate through the Kalahari during wet seasons when they can find water temporarily collected in the pans or salt flats.
The Kalahari also boasts a great variety of antelope species, perhaps because these fleet, hardy, wary creatures are well adapted to desert conditions. Most antelope have hardy dispositions and remarkable metabolisms that allow them to withstand greater heat and make prolonged physical exertions, even in desert heat that would quickly debilitate most other hoofed animals. Moreover, most antelope are blessed with tough, efficient kidneys that enable them to withstand otherwise lethal dehydration and to extract most of the moisture they need from their food.
As a result of their adaptation to the desert, many species of antelope and their close relatives roam the Kalahari. The antelope have sustained the Bushmen for 30,000 years and may have provided a food source and a nomadic lifestyle for the very first human beings as well. The hoofed migrants include springbok, gemsbok, kudu, and the big, placid eland, a now endangered creature that was once the mainstay of the Bushmen. Other migrating grass-eaters and browsers include water buffalo and zebra. Stalking the flanks of those migrating herds lurk the inevitable predators, including cheetahs, African hunting dogs, hyenas, and even the tough, adaptable Kalahari lion, a golden, desert-adapted subspecies. The lions can go weeks without a drink of water because they get the moisture they need from the flesh and blood of their prey.
Many of these animals move with the seasons. They cross the desert and grassland to arrive in the northern reaches near the Okavango River when water comes cascading down from the highlands to the north. The seasonal floods filter out into a marshy delta. The marsh glimmers with fish, shrimp, and insects, which attracts birds from vast distances. The crocodiles and hippopotamus who have waited out the dry season in small, permanent water sources expand out into the seasonal marshes to eat their fill. The buffalo, elephants, springboks, wildebeests, and zebras graze on the sudden flourishing of grasses, keeping a wary eye out for the lions, cheetahs, hyenas—and the occasional surviving human hunter. Ironically, tourism and the scope of long-lens cameras seem to be drawing more humans these days than the old, subsistence hunting of the Bushmen.
Still, the Kalahari remains an invaluable place to gain insight into human evolution and our impact on the environment. For instance, one recent study found evidence of a 40,000-year-old trade network in Africa, which suggests that the ancestors of the Bushmen came here in the first days of the rise of complex human societies. Researchers found some of the earliest stone tools ever documented plus tiny beads made of ostrich eggshells in the Central Rift Valley of Kenya, according to University of Illinois archaeologist Stanley Ambrose. The stone tools may date back 50,000 years, close to the time that the first human beings reached Australia, near when the Bushmen settled into the Kalahari, and perhaps as few as 20,000 years after modern humans begin moving north out of Africa.
But perhaps the most intriguing finding was the beads, which Ambrose suggests ancient artisans made to trade with other groups. Such a trade network suggests a complex, cooperative culture and economy more than 30,000 years before the first signs of agriculture. Ambrose argues that the beads suggest first a culture sufficiently complex to care about a useless item used purely for ornamentation. Moreover, the possibility of trade networks to exchange the beads indicates that people had begun to develop relationships and interconnections. Other work done with shell beads used in later trade networks suggest that a band of hunter-gatherers might shift camps hundreds of miles in a single year. That contrasts to the evidence suggesting a much simpler culture among competing groups like the Neanderthals in Europe, who appear to have died out shortly after modern Homo sapiens arrived in their planet-girdling migration out of Africa.
“The ancient beads may thus symbolize a mechanism for increased social solidarity and adaptations to risky environments. They may be a symbolic currency for exchange and obligations that can be saved for times of need, like money in the bank. People who have this social security system would compete better with others, the Neanderthals, for example, who didn't. So this improved system of regional networks and social solidarity may have allowed modern humans, when they left Africa, to out-compete and replace the Neanderthals,” Ambrose concluded. So while the Kalahari Desert seems harsh and the Bushmen who know it best seem impoverished, all Homo sapiens may owe a huge debt to both the hunter-gather cultures that spawned all modern civilizations and to the environmental challenges of places like the Kalahari that honed their skills and forced their innovations.