WASHINGTON (AP) — Petrified footprints discovered in New Mexico indicate that early humans walked through North America about 23,000 years ago.
They were discovered in White Sands National Park’s lake bed.
The US Geological Survey scientists analysed seeds found in the footprints to estimate their age.
Researchers believe that at least some of them were made by children or teenagers during the last Ice Age, based on the size and shape of the footprints.
Science published the research Thursday.