When Vance Holliday accepted a research invite to New Mexico’s White Sands in 2012, he didn’t know he was stepping near what would become one of the most pivotal archaeological sites in the Americas. While examining trenches on the U.S. Army missile range, he had stood just 100 yards away from ancient human footprints buried beneath the gypsum dunes. When they were unearthed in 2019, these prints became the most indisputable evidence that humans thrived in North America during the Last Glacial Maximum — well before the Clovis culture, long considered the continent’s first known inhabitants.

As per a Science Advances report, a new radiocarbon analysis of ancient mud samples has again confirmed that the prints were made between 21,000 and 23,000 years ago. This study, undertaken by Holliday and doctoral student Jason Windingstad, bolsters contentious 2021 studies suggesting that the footprints are 10,000 years older than the previously accepted evidence from New Mexico’s Clovis site. Previous dating via seeds and pollen had been criticised as flawed, but with this third material — analysed in a separate lab — there is another level of reliability.

The footprints, preserved in sediment on ancient streambeds that flowed into Ice Age lakes, are surprisingly well-preserved, though many of them have been weathered away by wind erosion. Those who made the prints are thought to be hunter-gatherer humans, moving purposefully through the landscape, and who neither settled in any single location nor made any tools that have survived to this day. Holliday noted that the absence of artefacts didn’t discredit the findings, as groups would presumably have been careful about leaving valuable resources behind.

Windingstad, who has worked extensively in White Sands, remarked on the significance of seeing the tracks in person, acknowledging they challenge long-held narratives about early migration into the Americas. He emphasised that the new radiocarbon results are statistically consistent over 55 dates and three labs. “It goes against everything you’ve been trained,” he mentioned.

The results are so consistent that the evidence is hard to reject, Holliday noted. “It would take an awfully lot of serendipity to line that up by accident to the extent that we have it here,” he added. The White Sands footprints are not an anomaly anymore for those who study the peopling of the Americas — they’re a new cornerstone of understanding.