Name: Humans May Have Lived in North America Earlier Than Thought
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Ancient human footprints in White Sands National Park reveal that humans first arrived in North America thousands of years earlier than previously thought.

Scattered seeds help reveal when ancient humans first left footprints in North America.

Humans May Have Lived in North America Earlier Than Thought

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Ancient human footprints in White Sands National Park reveal that humans first arrived in North America thousands of years earlier than previously thought.

Scattered seeds help reveal when ancient humans first left footprints in North America.

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Humans May Have Lived in North America Earlier Than ThoughtPublished: June 1, 2022KIRK JOHNSON: That is a human footprint.DAVID BUSTOS: Yeah, there’s a human print, right there.KIRK JOHNSON: Wow.DAVID BUSTOS: So, if you look…KIRK JOHNSON: That is amazing.DAVID BUSTOS: Here’s the heel, right here.KIRK JOHNSON: Scattered across the landscape are human footprints from thousands of years ago. Each track is the trace of an ancient person, the shape of their bare feet locked in the sediment.But how long ago were these people here?In order to date the prints, the team has dug a trench. It reveals layers of sediment deposited over thousands of years during different periods of the Ice Age. Stamped on these buried ancient surfaces are human prints. The deeper they go, the older they are. But just how old are they?KATHLEEN SPRINGER: I can put them both on.JEFF PIGATI: Okay, sure.KIRK JOHNSON: To help find the answer, David has been joined by geologists Kathleen Springer and Jeff Pigati, who is also an expert in radiocarbon dating.You’ve cut a cross section. What are you trying to see with the cross section?KATHLEEN SPRINGER: So, the footprints themselves are just an impression on a surface, so there’s nothing to date. It’s an inorganic thing. So, you have to find something organic that you can date above and below the footprints and get good dates on them, so that you can actually say, that footprint is between these two ages.KIRK JOHNSON: In this trench, Kathleen and Jeff have made a crucial find. Sandwiched in the layers above and below the footprints are scatterings of ancient seeds, precious organic material which the team can date.That way they can establish a window of time for when the footprints were made.KATHLEEN SPRINGER: There were actually plants growing on this, on the surface when, you know, these critters were walking around.KIRK JOHNSON: So, the same layers that have the tracks will have the seeds.KATHLEEN SPRINGER: Absolutely, above and below them, that way we can constrain in time.KIRK JOHNSON: So, your seeds are effectively little timepieces, right? Like little clocks or something, buried in there.JEFF PIGATI: They’re little capsules, yeah. And, basically, these things are really resistant to, to decay. And so they look like they were put down on the on the landscape just yesterday, but in fact, they might be tens and tens of thousands of years old.KIRK JOHNSON: At the U.S. Geological Survey lab, Jeff has been analyzing the seeds they found in the sediment layers at White Sands. He’s been using radiocarbon dating to calculate the age of the seeds and from that, the age of the footprints.It’s the moment of truth. After more than a year and a half, have Kathleen and Jeff managed to find out the age of the footprints?So, tell me, what were the dates of those footprints?KATHLEEN SPRINGER: We were able to document that humans were in White Sands National Park between 23,000 years ago and about 21,000 years ago.KIRK JOHNSON: Twenty-three-thousand years ago? That’s way older than there’s been good evidence for humans in North America.KATHLEEN SPRINGER: It’s about 10,000 years older than, sort of, the established, sort of, thought of when humans arrived in the Americas.KIRK JOHNSON: And you got tracks at more than one layer, which means that wasn’t just one group of people at one moment in time, but it was many groups of people over a lot of time.KATHLEEN SPRINGER: Two-thousand years.KIRK JOHNSON: I mean, 2,000 years itself is a long duration, but the fact that they were here 23,000 years ago…JEFF PIGATI: Yeah, crazy.KIRK JOHNSON: …blows my mind. I mean,…KATHLEEN SPRINGER: It blew our minds.If these dates are correct, that would make the White Sands footprints the earliest direct evidence of humans ever found in North America.

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Humans May Have Lived in North America Earlier Than Thought

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Human tracks may be earliest evidence of people in North America

Ice Age Footprints

Making North America

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Human tracks may be earliest evidence of people in North America

Ice Age Footprints

Making North America