Ancient Baby Boom Shows the Dangers of Over-population

Researchers have constructed the sequence of events that led to the greatest baby boom among southwestern Native Americans between 500 and 1300 A.D. The study also reveals how overpopulation led to an eventual decline of civilization in the region.

Around seven billion people live in the world today, which is more than at any other time in history. However, Native Americans living in the Southwest had birth rates that likely "exceeded the highest in the world today," researchers said.

The rise in birth rate was associated with key features of civilization such as farming and better storage. The population grew steadily, but crashed within a few decades.

The new study by researchers at the Washington State University explains why population crashed in the Southwest region and what we can learn from the ancient people that lived in the Sonoran Desert and Tonto Basin.

For the study, researchers looked at thousands of human remains from Four Corners region of the Southwest U.S. "This research reconstructed the complexity of human population birth rate change and demographic variability linked with the introduction of agriculture in the Southwest U.S.," said Alan Tessier, from the National Science Foundation's (NSF) Directorate for Biological Sciences, according to a news release.

The remains helped researchers sketch the history of the ancient people who lived in the region. The team found evidence of Neolithic Demographic Transition, in which stone tools reflected a transition from being used to cut meat to pounding grain.

Researchers found that maize or corn was grown in the region since 2000 B.C. Population grew steadily from 400 B.C. to about 500 A.D. However, from 900 A.D. population began to fluctuate due to a severe drought in the region, IBT reported.

During the mid-1200s, as many as 40,000 people lived in the region, but the population suddenly decreased within a few decades. Tim Kohler, WSU Regents professor of anthropology, and colleagues suspect that the population grew too large and that there wasn't enough food for the people, Discover Magazine reported. Climate change also worsened the condition, forcing people to relocate.

The decline of the ancient Puebloans shows the consequences of over-population, researchers said.

The study is published in the journal Proceedings of the National Academy of Sciences. It was funded by the National Science Foundation.