Science  /  Discovery

North America's Oldest Known Footprints Point to Earlier Human Arrival to the Continent

New dating methods have added more evidence that these fossils date to 23,000 years ago, pushing back migration to the Americas by thousands of years.

When picking up a tired toddler on a long walk, or hunting and confronting a giant sloth, the humans walking the wetlands around a shrinking lake were simply going about their lives in prehistoric North America. They could never have imagined that their everyday acts would create an incredible, enduring tableau for us to ponder thousands of years later. Their fossilized ancient footprints found at White Sands National Park humanize them, revealing the actions of their lives in ways that static bones and stone tools cannot.

Footprints can’t tell us who these prehistoric humans were. Yet a new study suggests something very surprising about this group. They were living in what’s now New Mexico likely during the Ice Age some 23,000 years ago—thousands of years earlier than the ancestors of modern Native Americans are generally believed to have arrived on the continent.

The authors of a study published Thursday in Science put the footprints into the spotlight back in 2021 by publishing research that dated ancient seeds, found in layers with the prints, to 21,000 to 23,000 years ago. Now, in an attempt to corroborate those controversial dates, the researchers’ new study has employed two additional dating methods. They have dated tree pollen from Ice Age conifers and quartz grains in sediment. Both lines independently confirm the earlier date range, according to the authors, a conclusion that raises fascinating questions about who these humans were, where they came from and what happened to them.

Even after thousands of years, the striking array of footprints found in New Mexico’s White Sands National Park evokes a strong human connection between those who view them and those who made them. “The incredible stories they tell us could never be told with artifacts or fossil bones alone,” says study co-author Kathleen Springer, a geologist with the U.S. Geological Survey (USGS).

One set of prints appears to have been made by a woman and a toddler who intermittently walked on its own and then was picked up and carried. At some places the child’s little prints disappear even as the woman’s broaden in the mud under the burden of the youngster’s extra weight.