Radiocarbon dating of ancient human footprints at White Sands National Park in New Mexico confirmed that humans were present in North America approximately 10,000 years earlier than previously believed. The footprints, dated to between 23,000 and 21,000 years old, provide evidence that humans occupied the area much earlier than the Clovis culture, which was long considered the oldest in North America.
Researchers initially dated the footprints using seeds and pollen, but critics argued these were unreliable markers. The new study relies on dating the ancient mud in which the footprints were found, providing a third method that supports the earlier findings. Three separate, independent labs conducted the dating, resulting in 55 consistent radiocarbon dates. The research was published in the scientific journal Science Advances.
"It's a remarkably consistent record. You get to the point where it's really hard to explain all this away," said Vance Holliday, a professor emeritus at the University of Arizona. "It would be serendipity in the extreme to have all these dates giving you a consistent picture that's in error," he added.
The research team returned to White Sands in 2022 and 2023 to examine the geology of the lake beds where the footprints were found. The footprints were excavated from the bed of ancient muddy streams that flowed into a lake. Millennia ago, White Sands was a series of lakes that eventually dried up. Wind erosion piled the gypsum into the dunes that define the area today. "The wind erosion destroyed part of the story, so that part is just gone," Holliday said, according to a press release published on EurekAlert. "The rest is buried under the world's biggest pile of gypsum sand."
Some of the footprints uncovered for the 2021 study were part of trackways that would have taken just a few seconds to walk, suggesting that early hunter-gatherers were moving quickly to other locations. The U.S. military uses portions of White Sands as a missile range, making research at White Sands National Park challenging. Much of the natural resources in the area are protected by the national park, but archaeological evidence has been destroyed due to changes in the environment and landscape over time.
The discovery of these older footprints has implications for understanding human migration to the Americas. The footprints provide evidence that human activity in the area occurred between 23,000 and 21,000 years ago, making them about 10,000 years older than remains found 90 years ago at a site near Clovis, New Mexico. The Clovis site gave its name to an artifact assemblage long understood by archaeologists to represent the earliest known culture in North America.
Despite the evidence, some experts remain skeptical about the early dates of the footprints, but the accumulated evidence is becoming increasingly convincing. The prevailing question among scientists is: if these footprints are evidence of the first North American culture, why are there no other signs of their presence? Holliday acknowledges that the new study doesn't address this question. "It's not logical to me that you're going to see a debris field," he said, according to EurekAlert. "These people live by their artifacts, and they were far away from where they can get replacement material. They're not just randomly dropping artifacts," he added.
Jason Windingstad, a doctoral candidate in environmental science, had worked at White Sands as a consulting geoarchaeologist before joining Holliday's study. "It's a strange feeling when you go out there and look at the footprints and see them in person," Windingstad said. "You realize that it basically contradicts everything that you've been taught about the peopling of North America."
The findings have sparked lively discussions in the scientific community. Scientists hope that continued research at White Sands will help unravel the mystery of ancient migration to the New World. Even though he was confident in the 2021 findings to begin with, Holliday is glad to have more data to support them. "I really had no doubt from the outset because the dating we had was already consistent," he said. "We have direct data from the field—and a lot of it now."
Written with the help of a news-analysis system.