Researchers have found two sites in the southern Peruvian Andes that served as shelter and home for ancient people in South America 12,800 years ago.

The sites, which were described in the journal Science on Oct. 24, are located about 14,700 feet above sea level in Pucuncho Basin in Peru and to date are hailed as the highest human settlements during the Ice Age that have been found.

The site called Pucuncho is 14,300 feet above sea level while the Cuncaicha rock shelter is at 14,700 feet and likely served as a base camp.

The discovery offers evidence that ancient people lived at very high altitudes 12,800 years ago and that people started to move to high elevation sites just 2,000 years after first arriving in the continent.

It also challenged previous beliefs regarding the length of time it took humans to evolve and adapt to living in high altitudes.

"Either they genetically adapted really, really fast - within 2,000 years - to be able to settle this area, or genetic adaptation isn't necessary at all," said study author Kurt Rademaker, an archeologist from the University of Maine.

The archeologists who excavated the sites found stone tools including "fishtail" arrowheads, bones of hunted animals, ceramics and other artifacts that provided evidence the sites served as a human dwelling. Researchers also found art works on the walls of the rocky shelters such as pictographs of animals.

Remains of starchy plants and tubers had also been found and these were probably brought by the area's dwellers known as Paleoindians from lower elevations for consumption as these would not have grown in the high-altitude place naturally.

Living at such high altitude had its challenges. Solar radiation in such a high place is strong, temperatures averaged 37 degrees Fahrenheit and oxygen is less than 60 percent than at sea level but the researchers pointed out several possible reasons why the Paleoindians chose to live in what seemed to be an extreme environment.

The location would have provided its settlers with the basic necessities for survival including food, shelter and water. Paleoindian hunters were also likely drawn to the higher altitudes because of the llama-like animals such as the vicuña and guanaco that they hunted and ate.

"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," the researchers reported.

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