New research published in the journal Science Advances has provided strong, independent evidence that human footprints discovered in New Mexico date back to the Last Glacial Maximum, reinforcing a controversial timeline that places humans in the Americas thousands of years earlier than previously accepted. A team of geologists and archaeologists analyzed ancient mud deposits from the same layers as the footprints, using a different dating method to address criticisms of the original 2021 discovery. This new chronological data strongly supports the conclusion that humans inhabited the area between 21,000 and 23,000 years ago, during the peak of the last ice age.

The scientific debate ignited in 2021 when researchers first dated the fossilized footprints found in the ancient lakebed of White Sands National Park. Their age estimate upended the long-standing “Clovis-first” theory, which posited that the first widespread human culture in North America, characterized by its distinctive stone tools, emerged around 13,000 years ago. Critics of the initial finding questioned the reliability of radiocarbon dating, a technique that measures the decay of the radioactive isotope Carbon-14 to determine the age of organic material. They argued that the aquatic plant seeds used for dating could have absorbed ancient carbon from the lake water, making them appear artificially old.

To test the original findings, a new research team led by Vance Holliday, a professor at the University of Arizona, returned to the site to analyze a different type of material from the same geologic layers or strata. Instead of seeds, they focused on dating the ancient mud that once surrounded the trackways. This mud, a mixture of sediment and organic matter from a marsh-like environment, provided an additional set of organic samples for radiocarbon dating, which two independent laboratories conducted. The results from the mud analysis produced a consistent age range of 20,700 to 22,400 years old, aligning almost perfectly with the original timeline derived from seeds and pollen.

With this latest study, the White Sands footprints are now supported by 55 separate radiocarbon dates from three different types of material analyzed by multiple research groups. While this wealth of evidence strengthens the case for an earlier human arrival, one question remains: the lack of stone tools or other artifacts at the site. Holliday suggests that the footprints likely represent people moving quickly through the area, such as hunter-gatherers who would have been careful not to abandon their essential and hard-to-replace tools. For now, the footprints themselves stand as the primary evidence, offering a remarkable and increasingly solid glimpse into human life in North America during the Ice Age.

References

• Cornell University. (2021, September 23). Earliest evidence of human activity found in the Americas. Phys.Org; Cornell University. https://phys.org/news/2021-09-earliest-evidence-human-americas.html
• Holliday, V. T., Windingstad, J. D., Bright, J., Phillips, B. G., Butler, J. B., Breslawski, R., & Bowman, J. E. (2025). Paleolake geochronology supports last glacial maximum (Lgm) age for human tracks at white sands, new mexico. Science Advances, 11(25), eadv4951. https://doi.org/10.1126/sciadv.adv4951
• University of Arizona. (2025, June 18). Earliest evidence of humans in the Americas confirmed. Phys.Org; University of Arizona. https://phys.org/news/2025-06-earliest-evidence-humans-americas.html