Over 7,000 years ago, before agriculture had even taken hold in human subsistence, humans survived year-round in the harsh Andean mountains, reports a team from the University of Wyoming. The team looked at human remains and archaeological evidence from a site with an elevation of 12,500 feet in Peru and determined that hunter-gatherer people were able to live in the extreme conditions of low oxygen and cold temperatures.
"These results constitute the strongest evidence to date that people were living year-round in the Andean highlands at least 7,000 years ago," Randy Haas, the team’s leader, 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."
The researchers excavated the remains of 16 people and 80,000 artifacts that date back to 8,000 years ago. They came to their conclusion from several interdisciplinary methods, including studying the human bones for oxygen and carbon isotopes, assessing the travel distances from the site to low-elevation zones, analyzing the demographic mixture of the human remains, and classifying the types of tools and other materials found with them. There is further evidence that hunter-gatherers had been living in the Andes as early as 9,000 years ago, although it is uncertain if that was seasonally or permanently.
Their results point towards permanent high-elevation residency. For instance, the human bones had low oxygen and high carbon isotope values, which shows that the people were adapted to high-altitude living conditions. Additionally, the travel distances to low-elevation zones were too long for seasonal human migration and the presence of small children would have made migration very difficult. Furthermore, most of the tools the researchers found were made from stone from the highlands of the Andes.
The study explains the importance of this multi-method strategy explicitly, writing, “These independent lines of evidence converge to support a model of permanent occupation of high elevations and refute logistical and seasonal use models. The results constitute the strongest empirical support to date for permanent human occupation of the Andean highlands by hunter–gatherers before 7 ka.”
Haas adds that this discovery is crucial for filling in gaps about the genetic history of the region. "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," he says.