This undated photo made available by the National Park Service in September 2021 shows fossilized human fossilized footprints at the White Sands National Park in New Mexico.

Fossilized footprints discovered in New Mexico indicate that early humans were walking across North America around 23,000 years ago, researchers reported Thursday.

The first footprints were found in a dry lake bed in White Sands National Park in 2009.

Based on various evidence — including stone tools, fossil bones and genetic analysis — other researchers have offered a range of possible dates for human arrival in the Americas, from 13,000 to 26,000 years ago or more.

He and others found more in the park over the years.

Earlier excavations in White Sands National Park have uncovered fossilized tracks left by a saber-toothed cat, dire wolf, Columbian mammoth and other ice age animals.

The tracks at White Sands were laid down along the shore of an ancient brackish lake that once filled the valley where the park’s famous dunes now stand.

The footprints were layered around — and in one case below — seeds that were buried in place between 21,000 and 22,800 years ago, suggesting two millennia of human habitation along the ice age lake some 10,000 years before the Clovis people.

The research team has since linked what was found in the ground to a clear climate signal: a well-documented warming period about 23,300 years ago that would have caused the lake to shrink, creating new places “for all these people (and animals) to pad around in wet sand,” Springer said.