蜜芽传媒

Scientists say they have found evidence that humans arrived in North America more than 20,000 years ago - about 5,000 years earlier than previously thought.

The new finding is based on a study of footprints found in White Sands National Park in New Mexico which has just been published in the journal 'Science'.

The previous theory was that ice sheets had prevented human migration to the region during the ice age.

Kathleen Springer is a Research Geologist who was part of the team that did the age-dating at the site.

"We were able to find seed layers above and below these track ways which wonderfully bracketed them in time and documented
human occupation in this part of White Sands National Park for 2,000 years between 21 and 23,000 years ago."

(Photo: Some of the footprints studied. Credit: NPS)