Excavations at Cunchaicha rock shelter in Peruvian Andes is shown in this handout image released on October 22, 2014. 
 
 Cunchaicha rock shelter in Peruvian Andes is shown in this handout image released on October 22, 2014. 
 
 WASHINGTON In a bleak, treeless landscape high in the southern Peruvian Andes, bands of intrepid Ice Age people hunkered down in rudimentary dwellings and withstood frigid weather, thin air and other hardships. 
 
 Scientists on Thursday described the world's highest known Ice Age settlements, two archaeological sites about 2.8 miles (4.5 km) above sea level and about 12,000 years old packed with artifacts including a rock shelter, stone tools, animal bones, food remnants and primitive artwork. 
 
 "What this tells us is that hunter-gatherers were capable of colonizing a very extreme environment, the high Andes, despite the challenges at the end of the Ice Age," said archaeologist Kurt Rademaker of Germany's University of Tübingen, who led the study published in the journal Science. 
 
 "And they did so quite successfully. It pushes back the date of initial entry of humans to this kind of elevation." 
 
 The sites in an Andean locale called the Pucuncho Basin were occupied by small numbers of people, probably only in the dozens. 
 
 "Bands of hunter-gatherers are small and not many could fit into the rock shelter, perhaps just a few families," said University of Maine archaeologist Dan Sandweiss, another of the researchers. 
 
 The researchers said the sites show high-altitude human habitation was occurring nearly a millennium earlier than previously known. 
 
 "We look at the challenges and we say, 'Why would you do that when you could just live somewhere else?'" Rademaker said. "Whatever reason they initially went up there, there were reasons to stay despite the challenges." 
 
 At that altitude, temperatures averaged 37 degrees Fahrenheit (3 degrees Celsius), solar radiation was high and oxygen was low. But there also were animals like vicuña and guanaco - llama relatives - and taruca deer to hunt, the rock shelter, water in streams, bogs and wetlands, and stone like obsidian to make tools. 
 
 The tools included spear points, scrapers for working animal hides and implements for cutting and butchering. "A lot of the stone tools seem to be all about hunting and processing of animals," Rademaker said. 
 
 The ceilings of the natural rock shelters were blackened with soot from fires. The researchers found an abundance of animal bones as well as potato-like starchy tubers that apparently were gathered from lower elevations. 
 
 There also was art on the walls of the rock shelters including red ochre pictographs of animals, with some entire wall sections painted red. 
 
 "We don't know whether they date back to the earliest occupation of the site," Rademaker said. 
 
 An open-air site called Pucuncho 14,300 feet (4,355 meters) above sea level yielded hundreds of tools. The Cuncaicha rock shelter featured two alcoves and likely served as a base camp at 14,700 feet (4,480 meters). 
 
 Some experts think people need to acquire genetic adaptations over many thousands of years to withstand such altitudes. But the fact that people colonized these sites only about 2,000 years after humans first entered South America may suggest otherwise. 
 
 "We have to re-examine that idea," Rademaker said. 
 
 (Reporting by Will Dunham; Editing by Jonathan Oatis) ||||| Humans colonized the inhospitable high Andes at least 11.5 thousand years ago. Rademaker et al. unearthed evidence of hunter-gatherer occupation at heights of almost 4500 m in Peru in two open-air sites. The sites contained more than 750 tools, including likely spearheads and scrapers. A nearby rockshelter with sooted ceilings and floor detritus may have been a campsite. The sites were probably used seasonally for hunting vicuña and other high-altitude prey. 
 
 Abstract 
 
 Study of human adaptation to extreme environments is important for understanding our cultural and genetic capacity for survival. The Pucuncho Basin in the southern Peruvian Andes contains the highest-altitude Pleistocene archaeological sites yet identified in the world, about 900 meters above confidently dated contemporary sites. The Pucuncho workshop site [4355 meters above sea level (masl)] includes two fishtail projectile points, which date to about 12.8 to 11.5 thousand years ago (ka). Cuncaicha rock shelter (4480 masl) has a robust, well-preserved, and well-dated occupation sequence spanning the past 12.4 thousand years (ky), with 21 dates older than 11.5 ka. Our results demonstrate that despite cold temperatures and low-oxygen conditions, hunter-gatherers colonized extreme high-altitude Andean environments in the Terminal Pleistocene, within about 2 ky of the initial entry of humans to South America. ||||| NEW YORK (AP) — The air was thin, the nights were cold, the sun could easily burn the skin. But about 12,000 years ago, small groups of hunter-gatherers found a home very high up in the Peruvian Andes. 
 
 This undated image provided by journal Science shows excavations at Cuncaicha rock shelter in the Peruvian Andes. Stone tools and other artifacts have revealed the presence of hunter-gatherers at about... (Associated Press) 
 
 This undated image provided by journal Science shows a campsite in Pucuncho Basin. Stone tools and other artifacts have revealed the presence of hunter-gatherers at about 14,700 feet above sea level,... (Associated Press) 
 
 This undated image provided by journal Science shows Sonia Zarriollo during an excavation at Cuncaicha rock shelter in the Peruvian Andes. Stone tools and other artifacts have revealed the presence of... (Associated Press) 
 
 This undated image provided by journal Science shows Kurt Rademaker and Sonia Zarrillo during excavations at Cuncaicha rock shelter in the Peruvian Andes. Stone tools and other artifacts have revealed... (Associated Press) 
 
 Now, their stone tools and other artifacts have revealed their presence at about 14,700 feet above sea level, about as high as the Matterhorn and much higher than Machu Picchu. They lived there nearly 1,000 years earlier than any other known human habitation anywhere above even 13,000 feet, researchers report. 
 
 Among the bogs, wetlands and grasslands of the treeless plateau, the ancient people found plentiful deer and wild ancestors of llamas and alpacas to hunt for food and clothing between 12,000 and 12,500 years ago. There were rock shelters to live in, and deposits of obsidian for making stone tools. While the plants weren't edible, some contained combustible resin and made for "really nice warm fires," says researcher Kurt Rademaker. 
 
 "I can't say why people first went there," said Rademaker, an author of a report released Thursday by Science. "But once they did go there, there were plenty of reasons to stay." 
 
 Rademaker is a researcher at the University of Tuebingen in Germany and a visiting assistant professor at the University of Maine in Orono. He led a research team that uncovered two sites of high-altitude Andes settlement in southern Peru, within about 100 miles of the Pacific coast and roughly west of Lake Titicaca. 
 
 Both sites included workshops for making stone tools. Hundreds of tools were found there, including scrapers that were evidently used to make clothing from hides. Sharpened points were probably used for spears. Bone and shell beads, used for adornment, were also recovered. 
 
 Rademaker said he doubts people lived there year-round, noting the rainy season from December to March. 
 
 "You're cold," he said. "You're being rained on and snowed on and sleeted on all day long. It makes for misery." 
 
 John Rick, an archaeologist at Stanford University who didn't participate in the study, called the work "a major advance." 
 
 He said he had found an Andean site at about the same elevation that appeared to be about as old, but its age could not be as confidently established as in the new work. So the new study provides the first solid data showing extensive human settlement in the Andes that high and that long ago, he said. 
 
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 Online: Journal Science: http://www.sciencemag.org 
 
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 Malcolm Ritter can be followed at http://www.twitter.com/malcolmritter
– Archaeologists who found ancient settlements high up in the Peruvian Andes were surprised to learn that humans were there between 12,000 and 13,000 years ago. At nearly 3 miles above sea level, that makes them the "world's highest known Ice Age settlements," in the words of Reuters. It also means that humans got to these sites in the Pucuncho Basin about 2,000 years earlier than thought, reports National Geographic. Researchers found tools and animal bones in the rock alcoves, along with artwork on the walls and soot on the ceiling from fires. "What this tells us is that hunter-gatherers were capable of colonizing a very extreme environment, the high Andes, despite the challenges at the end of the Ice Age," says an archaeologist from Germany's University of Tübingen who led the study published in Science. One theory is that these first inhabitants braved the cold temperatures and thin air because of the abundance of llamas and alpacas for hunting. They also would have found deposits of obsidian to make their stone tools, reports AP. (In another archaeological find, researchers discovered a missing sphinx head inside a Greece tomb.)