for National Geographic News
A new study of prehistoric cemeteries in North America is adding weight to the theory that the development of agriculture helped fuel baby booms around the world.
According to the theory, populations swell when societies shift from a nomadic hunter-gatherer lifestyle to one based on the more sedentary routine of farming.
Staying put allows women to have more babies, and a farming economy provides more food to support the growing population, explained Jean-Pierre Bocquet-Appel, a researcher at the National Center for Scientific Research in Paris.
North America's first baby boom is reflected in the number of skeletons of children ages 5 to 19 found in ancient cemeteries across the continent, he said.
"That doesn't mean the living condition was worsening," Bocquet-Appel said. "It means there were plenty of young people everywhere, and because there were plenty of young everywhere, there were plenty of young who died."
When populations are stagnant or decreasing, by contrast, graveyards are full of old people but few young, he added. According to the theory, a cemetery's population reflects the living population around it.
Bocquet-Appel and anthropology graduate student Stephan Naji analyzed skeletal remains in 62 prehistoric North American cemeteries.
They found that the number of immature skeletons increased by 37 percent over a 600-to-800 year period that coincides with the adoption of farming in North America about 2,500 years ago.
The researchers will report their findings in the March-April issue of the journal Current Anthropology.
The baby-boom pattern has been observed in African and European cemeteries dating about 5,000 to 7,000 years earlier, according to Bocquet-Appel. This period also coincides with the shift in those regions from foraging to agriculture at the end of the Stone Age.
The researcher said the current study is the first to expand the theory to a worldwide scale.
SOURCES AND RELATED WEB SITES