June 28 (UPI) -- Archaeologists have confirmed humans occupied year-round settlements in the Andean highlands as early as 7,000 years ago.
Excavations at archaeological sites in southern Peru suggest early hunter-gatherers began occupying Andean settlements some 9,000 years ago. But researchers haven't been able to agree on when those settlements became permanent.
As part of the latest study, scientists excavated and analyzed the remains of 16 people, as well as 80,000 artifacts. To determine when the hunter-gatherers' use of the settlement became permanent, researchers looked at oxygen and carbon isotope ratios in the human remains. Scientists also considered the population's demographic makeup, the distance to the nearest low-elevation settlements and the types of tools found among the highland sites.
The human bones revealed high levels of carbon isotopes and low levels of oxygen isotopes, suggesting the settlers spent their entire lives at the highland site. Researchers also argue the distances between the highlands and low-elevation settlements were too great to traverse seasonally. The presence of women and children confirms the population wasn't migrating seasonally. Scientists determined the tools found among the highland settlements were made from nearby rock sources.
All together, the evidence confirms early hunter-gatheres began occupying Andean settlements permanently at least 7,000 years ago.
"This gives us a very strong baseline to help understand the rates of cultural and genetic change in the Andean highlands, a region known for the domestication of alpaca, potatoes and other plants; emergence of state-level political and economic complexity; and rapid human adaptation to high-elevation life," Randy Haas, a postdoctoral research associate in anthropology at the University of Wyoming, said in a news release.
Haas and his colleagues published their work this week in the journal Royal Society Open Science.
"These results constitute the strongest evidence to date that people were living year-round in the Andean highlands at least 7,000 years ago," Haas said. "Such high-elevation environments were among the last frontiers of human colonization, and this knowledge holds implications for understanding rates of genetic, physiological and cultural adaption in the human species."