About a thousand Hadza live in their traditional homeland, a broad plain encompassing shallow, salty Lake Eyasi and sheltered by the ramparts of the Great Rift Valley. Some have moved close to villages and taken jobs as farmhands or tour guides. But approximately one-quarter of all Hadza, including those in Onwas's camp, remain true hunter-gatherers. They have no crops, no livestock, no permanent shelters. They live just south of the same section of the valley in which some of the oldest fossil evidence of early humans has been found. Genetic testing indicates that they may represent one of the primary roots of the human family tree—perhaps more than 100,000 years old.
What the Hadza appear to offer—and why they are of great interest to anthropologists—is a glimpse of what life may have been like before the birth of agriculture 10,000 years ago. Anthropologists are wary of viewing contemporary hunter-gatherers as "living fossils," says Frank Marlowe, a Florida State University professor of anthropology who has spent the past 15 years studying the Hadza. Time has not stood still for them. But they have maintained their foraging lifestyle in spite of long exposure to surrounding agriculturalist groups, and, says Marlowe, it's possible that their lives have changed very little over the ages.
For more than 99 percent of the time since the genus Homo arose two million years ago, everyone lived as hunter-gatherers. Then, once plants and animals were domesticated, the discovery sparked a complete reorganization of the globe. Food production marched in lockstep with greater population densities, which allowed farm-based societies to displace or destroy hunter-gatherer groups. Villages were formed, then cities, then nations. And in a relatively brief period, the hunter-gatherer lifestyle was all but extinguished. Today only a handful of scattered peoples—some in the Amazon, a couple in the Arctic, a few in Papua New Guinea, and a tiny number of African groups—maintain a primarily hunter-gatherer existence. Agriculture's sudden rise, however, came with a price. It introduced infectious-disease epidemics, social stratification, intermittent famines, and large-scale war. Jared Diamond, the UCLA professor and writer, has called the adoption of agriculture nothing less than "the worst mistake in human history"—a mistake, he suggests, from which we have never recovered.
The Hadza do not engage in warfare. They've never lived densely enough to be seriously threatened by an infectious outbreak. They have no known history of famine; rather, there is evidence of people from a farming group coming to live with them during a time of crop failure. The Hadza diet remains even today more stable and varied than that of most of the world's citizens. They enjoy an extraordinary amount of leisure time. Anthropologists have estimated that they "work"—actively pursue food—four to six hours a day. And over all these thousands of years, they've left hardly more than a footprint on the land.