Washington, July 1 IANS | 1 year ago  In what may hold lessons
for modern society, scientists have sketched out one of the
greatest baby booms in North American history, a centuries-long
"growth blip" among south-western Native Americans between 500
and 1300 A.D.  It was a time when the early features of
civilization, including farming and food storage, had matured to
a level where birth rates likely exceeded the highest in the
world today, said the researchers.  "Then a crash followed,
offering a warning sign to the modern world about the dangers of
overpopulation," said Tim Kohler, an anthropologist at
Washington State University (WSU) in the US.  "We can learn
lessons from these people," he said.   At first, populations
were slow to respond, probably because of low productivity, said
Kohler, but by 400 B.C. the crop provided 80 percent of the
region's calories.  Crude birth rates were by then on the rise,
mounting steadily until about 500 A.D.   The mid-1100s A.D. saw
one of the largest known droughts in t