The Nazca lines are UNESCO-protected geoglyphs dating from between 100 BCE and 300 CE that depict humans, camelids, birds, orcas, felines, and snakes. There are a range of theories surrounding their purpose, including that the Nazca geoglyphs depict deities, are a form of irrigation, or are a calendar with astrological alignments, though it remains unclear.

Discovered about 100 years ago with the advancement of aerial technology, the geoglyphs are nearly impossible to decipher from the ground.

Researchers at Yamagata University in Japan developed and trained the AI-driven deep learning technology to spot the lines from satellite images.

DL, as the researchers explain, “is a particular kind of machine learning that achieves great power and flexibility in pattern analysis of images, speech, language, and more. In archaeology, DL is used in the analysis of the iconography, text, and writing of excavated objects.”

While the variability in design and limited subset posed a challenge with training the AI program, researchers were able to develop a new approach to detecting geoglyphs based on similarities to other known designs.

Four new geoglyphs were identified during this process. Of the four, they depict a human-like figure holding a club, a pair of legs or hands stretching more than 250 feet, a fish, and a bird. The new designs were subsequently verified during on-site visits.

“We could identify new geoglyph’s candidates approximately 21 times faster than with the naked eye alone,” said researchers. “The approach would be beneficial for the future of archaeology in a new paradigm of combining field survey and AI.”

Late last year, the team discovered 168 new geoglyphs using aerial photography and drone images.

Researchers from Yamagata University, in partnership with Peruvian archaeologists, conducted field surveys that yielded the latest find. The geoglyphs, which date between 100 BCE and 300 CE, depict humans, camelids, birds, orcas, felines, and snakes. Measuring less than thirty-three feet in diameter, they were created by removing black stones from the earth’s surface to expose the white sand beneath and were primarily distributed along ancient trails.

Scholars believe there are two types of geoglyphs—linear and relief types. Of the 168 recently identified geoglyphs, only five are linear, while the other 163 are reliefs.

Yamagata University, in collaboration with IBM’s T.J. Watson Research Centre, also plans to conduct an AI-based study on the distribution patterns of Nazca geoglyphs. The results will be used for geoglyph conservation activities.

This latest discovery adds to 190 previously identified geoglyphs between 2004 and 2018, which led to the establishment of an archaeological park in the Aja area by the Peruvian Ministry of Culture in 2017. While there are a range of theories that the Nazca geoglyphs depict deities, are a form of irrigation, and are a calendar with astrological alignments, the purpose of the Nazca geoglyphs is ultimately unclear.

Nazca society developed during the Early Intermediate Period from 200 BCE–600 CE. The Nazca developed from the preceding Paracas culture and settled in the valley of the Rio Grande de Nazca drainage and the Ica Valley. Their culture is characterized by its pre-fire slip polychrome pottery, which indicates a shift from their predecessor’s post-fire resin method.

The early Nazca civilization was comprised of local chiefdoms cantered around the pilgrimage site Cahuachi along the coast of the Central Andes. Cahuachi contained around 40 mounds topped with organic built structures, which would have been used for agriculture, water, and fertility rituals.

The feline carving is what’s known as a geoglyph, and it is the latest discovery among the group of drawings in in the Nazca Desert that are often called the Nazca Lines. Many of them were created around 2,000 years ago. According to Peru’s Ministry of Culture, the cat etching dates to 200 B.C.E.–100 B.C.E., making it the oldest known geoglyph unearthed at Nazca.

“The discovery shows, once again, the rich and varied cultural legacy of this site,” the ministry said in a statement.

The monumental depressions are dispersed over roughly 600 square miles of desert floor about 250 miles from Lima, the Peruvian capital. They site was discovered in the early 19th century by a Peruvian aerial surveyor who spotted mysterious markings on the Nazca plains that resembled animals. Images of a hummingbird, orca, and monkey were unearthed soon after. In 1994, UNESCO designated the Lines and Geoglyphs of Nasca and Palpa, a World Heritage Site site “that bears witness to the culture and magical-religious tradition and beliefs.”

The designs were believed to have been created when ancient Peruvians scraped off a dark and rocky layer of earth, which contrasts with lighter-colored sand underneath. In recent years, advances in drone technology, artificial intelligence, and satellite photography have led archaeologists to discover drawings with with increasing frequency. In 2019, a team of Japanese researchers from Yamagata University unearthed more than 140 geoglyphs at Nazca, including images of lamas, a two-headed snake, birds, and alpacas.

“It’s quite striking that we’re still finding new figures, but we also know that there are more to be found,” Johny Isla, director of the Nazca Lines conservation mission at the Ministry of Culture, told Euronews. He added, “In fact, there are new ones and we will continue to find more.”