Excavations at Peru’s Huaca Prieta archaeological complex have uncovered evidence that habitation in the area stretches back to nearly 15,000 years ago. The site itself is home to a 7,800-year-old pyramid mound, with the area previously believed to have been inhabited for thousands of years. However, this new find is part of a growing body of evidence that humans had settled the Americas far earlier than scientists had originally thought.

These new findings were made when archaeologists decided to dig deeper under the pyramid: initially curious about the landform supporting the mound from underneath, the researchers dug down further than originally planned, and were surprised to find evidence of an earlier settlement. Hearth fires, stone tools, food remains, and other cultural objects were found, evidence of an otherwise sophisticated culture.

While no sophisticated items such as spearheads were found, chipped stone tools, fashioned for cutting, were uncovered. The remains of harvested avocado, chiles, mollusks, sharks, birds, and sea lions were found, meaning the inhabitants were well accustomed to a variety of food sources, indicating that they had formed established settlements, rather than simply being a nomadic group that was just passing through.

"This looks like people settling in," says Loren Davis, an archaeologist at Oregon State University. "As old as this is, you’re probably not looking at the first peoples on the landscape."

"These strings of events that we have uncovered demonstrate that these people had a remarkable capacity to utilise different types of food resources, which led to a larger society size and everything that goes along with it such as the emergence of bureaucracy and highly organised religion," explains James Adovasio, from Florida Atlantic University.

This find now adds Huaca Prieta to a growing list of archeological sites that illustrate that humans were present in the Americas long before the previously-assumed date of 13,000 years ago, when an ice-free corridor opened up in the Laurentian ice sheet to allow a southward migration. The current theory to explain this migration is that these populations came down the Pacific coast from Siberia, via present-day Alaska, but there is currently a lack of direct evidence that this specific route was used.