A research team led by an assistant professor at the University of Maine in Orono has uncovered what are now the world's highest known Ice Age settlements.

Professor Kurt Rademaker reported the discovery in an article that appeared Thursday in the journal Science. The article describes settlements 4.5 km above sea level in the southern Peruvian Andes that were inhabited at least 12,000 years ago.

According to Rademaker, researchers have found artifacts, including stone tools, animal bones, food remnants and primitive artwork.

The location of the two sites is within 160 kilometers of the Pacific coast and roughly west of Lake Titicaca in southern Peru.

Rademaker said the tools found include scrapers for working animal hides and implements for cutting and butchering. The professor added, "A lot of the stone tools seem to be all about hunting and processing of animals."

Rademaker said he doubts people lived there year-round because the rainy season at that altitude brings rain, sleet and snow from December to March.

The art on the walls of the rock shelters includes red ochre pictographs of animals with some entire wall sections painted red.

Some experts think people need to make 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.