WASHINGTON (AP) — Fossilized footprints discovered in New Mexico indicate that early humans were walking across North America around 23,000 years ago.
The footprints were found in a dry lake bed in White Sands National Park.
Scientists at the U.S. Geological Survey analyzed seeds stuck in the footprints to determine their approximate age.
Based on the size of the footprints, researchers believe that at least some were made by children and teenagers who lived during the last ice age.
The research was published Thursday in the journal Science.