Some 2000 years ago in a desert in southern Perú, the ancient Nazca and Paracas peoples created massive designs in gravel and stone, depicting animals, humanlike figures, and plants in geoglyphs up to 90 meters long. Now, an artificial intelligence (AI) analysis of aerial photographs has helped identify 303 new glyphs in just 6 months, allowing researchers to know more about why ancient South Americans made them.
In the 20th century, researchers spent almost 100 years uncovering 430 geoglyphs. Scientists classified the drawings into larger, line-type glyphs, created by removing stones and gravel to reveal lighter colored earth beneath, and smaller, relief-type glyphs, drawn using surface stones of colored both white and black. The big line-type glyphs are easier to spot using photographs shot from the sky, whereas the relief-type glyphs, averaging only about 9 meters in size, are harder to see because of erosion and more subtle contrast with the desert terrain.
To find more glyphs, researchers led by archaeologist Masato Sakai of Yamagata University trained an AI program to identify relief-type glyphs in high-resolution drone images taken of the entire region. The program identified 1309 possible geoglyphs, and the team confirmed 303 of them with on-the-ground surveys, almost doubling the number of known geoglyphs of this type, the researchers report today in the Proceedings of the National Academy of Sciences.
Among the new glyphs, about 80% depicted humanoid figures, decapitated heads, and domesticated animals, particularly llamas (see image showing original photo and AI-identified humanoid glyph). Most relief-type drawings were found within viewing distance from foot trails, and researchers think the art communicated daily-life activities for viewing by small groups or individuals. In contrast, about 60% of line-type glyphs depict wild animals, such as birds, monkeys, and felines. The team suggests these were linked with ceremonial pathways and pilgrimage routes.
