Ancient populations were game for growth

Recent investigations of genetic variation in living populations have suggested that the

numbers of Stone Age people rose sharply sometime between 100,000 and 50,000 years ago.

Better clues to the timing and extent of ancient population shifts may reside among the fossil

bones of tortoises, hares, and other small game that supplemented Stone Age diets.

“Many archaeologists may not have appreciated the unique potential of small-game data for

examining when and where [ancient population] increases took place,” say anthropologist Mary

C. Stiner of the University of Arizona in Tucson and her coworkers.

The proportion of small game in the human diet and the number of species of these animals

captured varied little from 200,000 to 9,000 years ago, Stiner’s team reports. In contrast, a dramatic

change in the type of small game eaten toward the end of that period reflected sharp

growth of the human population, the researchers find.

For much of the Stone Age, inhabitants of coastal sites in Italy and Israel sought shellfish,

tortoises, and other easy-to-capture small game to supplement the large gazelle-like creatures

they also hunted. Between about 36,000 and 26,000 years ago, small-game preferences at these

locations shifted to much swifter prey, such as partridges and hares.

Earlier Stone Age folk probably lived in small, widely separated groups that could regularly

eat slow-footed or immobile prey without wiping them out, according to Stiner’s team.

The ensuing culinary shift to speedier prey followed declines in numbers of easy-to-catch

animals due to pressure from a budding human population, in their view. The challenges of

hunting small, elusive animals encouraged the development of snares, nets, and other implements

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People gained consistent access to more meat, the scientists theorize. Unlike slower prey,

birds and hares have short breeding cycles that enable them to maintain their numbers in the face

of intensive hunting. A meatier diet, in turn, improved childhood nutrition and instigated even

steeper human-population growth, Stiner’s team contends in the February Current Anthropology.

The researchers analyzed animal remains excavated at five Italian rock shelters and a rock

shelter and a cave site in Israel. Radiocarbon dates range from 110,000 to 9,000 years ago for

the Italian fossil finds and from 200,000 to 11,000 years ago for the Israeli specimens.

Mathematical simulations allowed the investigators to estimate the effects of modest and intensive

hunting, over a 200-year span, on modern species of tortoises, hares, and partridges.

The evidence of a shift to swift prey in the late Stone Age supports an earlier proposal that

an expansion of food sources in western Asia at that time set the stage for population growth,

agriculture, and livestock raising. In the same issue of Current Anthropology, that theory’s originator,

anthropologist Kent V. Flannery of the University of Michigan in Ann Arbor, remarks that

scientists need to examine slow and quick prey at other ancient human sites.

Bruce Bower has written about the behavioral sciences for Science News since 1984. He writes about psychology, anthropology, archaeology and mental health issues.

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