There are thousands of aligned holes in Peru. Archaeologists now think they know who made them

A series of about 5,200 holes stretching nearly 1.5 kilometers across the Pisco Valley in the southern Peruvian Andes has baffled researchers for nearly a century. But a new look at the site, called Monte Sierpe, or “serpent mountain,” could help archaeologists decipher why ancient people built it hundreds of years ago.

The “strip of holes,” as it is informally known, first gained attention when National Geographic published aerial photos of the site in 1933.

But there is no written record relating to the training, leaving its purpose open to interpretation – and there has been plenty. Hypotheses on the use of the holes include purposes of defense, accounting, storage, gardening, water harvesting, and fog capture. Proponents of the ancient astronaut theory, which holds that aliens are real and shaped the first civilizations on Earth, have also suggested extraterrestrial connections.

Now, new drone footage and microbotanical analysis of pollen grains found in the holes lead researchers to suggest that the site first served as a bustling marketplace for a pre-Inca civilization and then as a method of accounting for the Incas, according to a study published Nov. 10 in the journal Antiquity.

“Why did ancient people make more than 5,000 holes in the foothills of southern Peru?” said study lead author Dr Jacob Bongers, a digital archaeologist at the University of Sydney and visiting researcher at the Australian Museum Research Institute. “We don’t know why they are here, but we have produced promising new data that provide important clues and support new theories about the site’s use.”

Go back in time

The scale of Monte Sierpe made it difficult to study, but drone technology has opened up a new perspective, said Charles Stanish, study co-author and professor in the University of South Florida’s department of anthropology.

Each hole is 3.3 to 6.6 feet (1 to 2 meters) wide and 1.6 to 3.3 feet (0.5 to 1 meter) deep. Photography taken by the drone shows them organized into about 60 distinct sections separated by empty spaces, Bongers said. His team was also able to identify patterns, for example a section of 12 rows alternating between seven and eight holes, suggesting that the organization is not random, he added.

Ancient pollen grains found inside the holes indicate the presence of crops such as corn, as well as wild plants including reeds and willows, traditionally used to make baskets, Bongers noted.

Crops and other goods may have been placed in these baskets or deposited in the holes, which could have been lined with plant material. It’s possible that structures were also built over or near the holes, Bongers said, but no evidence of any architecture remains.

The team believes that indigenous peoples of the pre-Inca Chincha kingdom of coastal and highland Peru may have come to exchange goods and barter using their own goods rather than their currency.

“Perhaps other important resources such as cotton, coca, corn and chili peppers would have been placed in the holes and traded,” Bongers said. “For example, a certain number of holes containing corn would have been equivalent to a certain number of holes containing another type of commodity, such as cotton or coca. »

The clear evidence provided by the pollen helps rule out many of the site’s other proposed uses, said Dr. Dennis Ogburn, an associate professor in the department of anthropology at the University of North Carolina at Charlotte. Ogburn was not involved in the new study.

“Monte Sierpe is a site that has truly been a mystery in Andean archaeology, and I am excited to see this research being conducted,” Ogburn wrote in an email.

Investigating a modified landscape

Dating of the holes suggests that the site was used between 600 and 700 years ago.

Although the team continues to conduct radiocarbon dating to determine a precise timeline, they believe it was built during Peru’s Late Intermediate Period, between 1000 and 1400 AD, consistent with the site’s use by the pre-Inca civilization.

Citrus pollen, introduced to the area during the colonial period between 1531 and 1825, suggests that the site was still in use after the fall of the Inca Empire in 1532, as the Spanish colonized Peru. It was probably ultimately abandoned “because the Spanish couldn’t find a way to incorporate the site into their economic expansion,” Bongers said.

It is possible that Monte Sierpe only comprised a few sections of holes as a barter market before being expanded under the Inca Empire.
Or it may have been completed before the arrival of the Incas. Regardless, the team believes the Incas used the site as a large-scale accounting tool.

“In a sense, Monte Sierpe could have been an ‘Excel spreadsheet’ for the Inca Empire,” Bongers said.

The segmented organization of Monte Sierpe reflects an Inca counting system involving knotted ropes called khipu. One such device, with 80 groups of cords, was recovered in Pisco Valley.

“The numbers tied on these strings show a complex set of arithmetic relationships, suggesting that this is a surviving record” of accounting operations that may have been used at Monte Sierpe, Bongers said.

Monte Sierpe was ideally located for bartering and accounting, near a pre-Hispanic road network and between two major Inca sites called Tambo Colorado and Lima La Vieja.

Bongers’ team members continue to study the khipus of Peru to test any potential numerical relationships between the design of Monte Sierpe and the Inca counting system. If there is a link, the flaws could come from the way the empire collected tribute, an early form of taxes, from local communities.

Since the market and accounting systems would have worked in two very different ways, and the connection between the holes and the Incan khipus is tenuous, more support is needed to be convincing, Ogburn said.

Preserve ancient heritage

As new research aims to unlock the secrets of Monte Sierpe, future discoveries could provide insight into a piece of history that has not been well preserved.

“The Andes are one of the few regions in the world where large-scale ancient societies developed, such as the Inca Empire, but there is no solid evidence for the existence of pre-Hispanic currencies or writing systems,” Bongers said.

Dr Christian Mader, head of a research group at the Center for Dependency and Slavery Studies at the University of Bonn in Germany, believes the paper is an important contribution to Andean archaeology, as well as the study of ancient economies. Although Mader was not involved in this research, his work focused on pre-Hispanic economies and trade.

“Their proposition that the site served as a marketplace during the Late Intermediate period and as a device for accounting for goods and tributes under the Inca Empire is interesting and compelling,” Mader wrote in an email. “And this article illustrates how much we still have to learn about indigenous economic mechanisms. »

Monte Sierpe presents a difficult puzzle to interpret, Bongers said, and part of the puzzle is presenting hypotheses, rather than arguments, that can be tested further to better understand local heritage.

“The stories we build about local cultural heritage have real impact,” Bongers said. “It is crucial to ensure these stories integrate Indigenous perspectives and archaeological evidence to accurately represent local heritage. »

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