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Support your local PBS station.
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KIRK JOHNSON: White Sands
National Park, New Mexico...
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A vast, open desert that
holds clues to a lost past.
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DAVID BUSTOS:
At White Sands,
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all good stories sort of
begin with a Bigfoot.
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JOHNSON: Footprints dating all
the way back to the last Ice Age.
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All these circular things
are fossil footprints.
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JOHNSON:
That's amazing.
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♪
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JOHNSON:
Mammoths over 13 feet tall.
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[mammoth grunting]
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Dire wolves, camels,
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and enormous ground sloths
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that roamed North America
thousands of years ago.
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White Sands has so many hidden treasures.
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There's all these trackways here,
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it's just such an incredible discovery.
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♪
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JOHNSON:
Alongside them,
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something even more astounding.
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That is a human footprint.
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Yeah, so there's
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a human footprint right there.
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[laughing]:
Wow.
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JOHNSON:
Ancient human journeys
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printed on the landscape.
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When you make tracks in sand,
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they just blow away.
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When you make tracks in a place like this,
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where the chemistry is just right,
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the tracks can last forever.
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[voiceover]: Now a team
of experts is investigating
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how these remarkable tracks
could shed new light
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on life in the Ice Age.
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MATTHEW BENNETT:
There's a double trail.
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Somebody going this way,
and somebody going that way.
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JOHNSON:
Wow, that is really incredible.
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[voiceover]:
How long ago were they made?
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KATHLEEN SPRINGER:
That's amazing.
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MAN: Yeah.
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SPRINGER: The Ice Age
megafauna went extinct
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about 11,500 years ago.
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So they're at least that old.
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How much older than that
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is really anyone's guess at this point.
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JOHNSON: Could they
provide new information about
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early peoples of the Americas?
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It really does put our feet prints
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firmly into the past here
in North America.
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KIM CHARLIE:
Here's our proof.
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Footprints, footprints of our ancestors.
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♪
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JOHNSON: Can the secrets
of these ancient footprints
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help answer the questions
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when and how did humans first
arrive in North America?
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♪
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"Ice Age Footprints"...
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right now on "NOVA."
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♪
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JOHNSON:
The dazzling dunes of
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White Sands National Park.
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Sand as bright as fresh snow.
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♪
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But hidden within this landscape
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are traces of an ancient story
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dating all the way back
to the last Ice Age.
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When we search for evidence of life
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in the ice ages in North America,
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we find things like the bones of mammoths
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or maybe even hearth stones
or spear points
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from the people that used to live here,
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and very rarely we find
the remains of those humans.
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But the story is still so incomplete,
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there's so much more
information we need to find.
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♪
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JOHNSON: That's why
the discovery of footprints
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here at White Sands is so significant.
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Could they help answer
some of the greatest mysteries
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of the Ice Age?
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♪
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The precise location of this site
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is a secret.
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These dunes cover
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nearly 300 square miles...
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with some rising over 50 feet.
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I'm driving through
these snow-white dunes.
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It's kind of a surreal landscape.
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Once we get through the dunes,
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we'll be out in the great ancient lakebed,
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and it's absolutely covered with tracks.
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[voiceover]:
I'm Kirk Johnson.
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As a paleontologist,
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I've spent most of my career
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studying the remains of ancient life.
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But footprints can tell
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really detailed stories about the past.
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♪
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30 minutes later,
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we've reached our destination:
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a huge dried-up lakebed.
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As the wind scours this remote area,
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new prints are being revealed,
and old ones disappear.
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It seems like such an improbable place
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to even look for tracks.
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[voiceover]:
Joining me is David Bustos.
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He's leading the team of scientists
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investigating the footprints.
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BUSTOS: You look out
and it's just bleak desert,
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and who would think that there's
all these trackways here?
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JOHNSON [voiceover]: As
my eyes adjust to the brightness,
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round patterns start to appear.
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So there's one there... Yes.
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And there and there,
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and there and there, there...
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BUSTOS:
Yeah.
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Oh, yeah. Those are amazing.
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Uh-huh.
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♪
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[voiceover]: The mysterious
shapes are over five feet apart,
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and nearly two feet across.
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These are the fossilized tracks
of an Ice Age giant...
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a Columbian mammoth.
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It died more than 10,000 years ago,
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but its footprints remain.
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♪
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[mammoth trumpeting]
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The tracks are preserved in various ways.
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Sometimes the wind fills them
with different textured sand,
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leaving ghostly impressions,
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while others dry into hard casts
which are exposed
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when the softer ground
around them erodes away.
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One of the things that
really stand out at White Sands
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is just thousands and thousands
of footprints preserved.
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In this area, we'll see trackways
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that go for ten miles in one direction
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and two or three miles
in another direction.
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You know, there might be
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over 100,000 prints
throughout this large area.
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Do...
it's okay to walk on them?
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We can walk near them and around them,
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as long as we don't
disturb the surface below
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or add more sediment in.
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JOHNSON [voiceover]:
We need to be careful not to
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step on the fragile prints...
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and the team tries to only
visit the trackway areas
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when the ground is dry,
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and hard enough to support their weight.
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The surface is always changing.
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We are seeing more erosion.
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Every year, more and more prints
are becoming visible.
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JOHNSON [voiceover]: And along
with the many mammoth prints here,
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we soon spot traces of another
large creature.
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BUSTOS:
They're very common,
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they'll sort of look like an S shape...
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Yep. You'll see them connecting
to each other.
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There's one here, right?
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Yep. There's another one
coming through...
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I think as well, right there.
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JOHNSON [voiceover]:
Twice the size of a human foot,
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and with giant, curved claws,
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these are the prints of
a massive ground sloth,
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a beast more than double
the weight of a grizzly bear,
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that walked this land
thousands of years ago.
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[sloth panting]
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So that's sort of how the story
of White Sands began.
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People, they've seen these
incredible footprints,
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and they thought that it was Bigfoot.
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[chuckling]:
Bigfoot with three weird claws.
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Yes.
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JOHNSON [voiceover]: Then we
discover something even more special.
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That is a human footprint.
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Yeah, so there's... there's a
human footprint right there.
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[laughing]:
Wow.
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Yeah, so if you look...
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That is amazing.
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Here's the heel.
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Okay. Right here.
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JOHNSON [voiceover]:
Scattered across the landscape
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are human footprints
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from thousands of years ago.
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Each track is the
trace of an ancient person,
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the shape of their bare feet
locked in the sediment.
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Look at this, this is amazing here.
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This actually looks like
a human print right in there.
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♪
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JOHNSON [voiceover]: Could
these extraordinary human footprints
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help answer two big questions:
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when did people first set foot
in North America?
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And did their arrival contribute to
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the disappearance of
giant Ice Age animals?
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20,000 years ago,
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Earth was in the grip of an ice age.
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The climate was colder,
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vast ice sheets covered
much of North America...
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and White Sands was not a desert,
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but a huge lake... Lake Otero.
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♪
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The lakeshore surrounding it
teemed with life.
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Giant ground sloths wielding big claws
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shared this wetland with mammoths
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weighing up to ten tons.
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Alongside them,
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packs of dire wolves hunting for a kill,
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and hardy North American camels.
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These Ice Age giants disappeared
from the fossil record
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over 10,000 years ago.
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So the human footprints here
are probably at least that old.
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♪
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But they could be much older.
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What can they reveal
about the deep history
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of humans on this continent,
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00:10:00,047 --> 00:10:03,879
and how they met the challenges
of life in the Ice Age?
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00:10:07,192 --> 00:10:09,401
♪
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00:10:09,436 --> 00:10:11,024
To find out,
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00:10:11,058 --> 00:10:13,992
David has assembled a team of scientists
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00:10:14,027 --> 00:10:15,787
to uncover the tracks' hidden secrets.
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00:10:17,237 --> 00:10:18,963
BENNETT:
I'm confident in it now,
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00:10:18,997 --> 00:10:20,792
that that's mammoth, and
it links to your one in the,
220
00:10:20,827 --> 00:10:23,450
um, that you've got
in cross section there.
221
00:10:23,484 --> 00:10:24,416
Cross section over there? Okay. Yeah.
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JOHNSON:
One of them is Matthew Bennett,
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00:10:28,697 --> 00:10:31,907
a forensic footprint expert from England.
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00:10:31,941 --> 00:10:34,944
♪
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On the eastern side of the ancient lake,
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00:10:37,913 --> 00:10:39,466
close to the restricted area of
227
00:10:39,500 --> 00:10:42,020
the White Sands Missile Range,
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00:10:42,055 --> 00:10:45,783
Matthew is excavating a remarkable set
229
00:10:45,817 --> 00:10:48,233
of human footprints.
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JOHNSON:
Hey, Matthew,
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how's it going?
232
00:10:50,270 --> 00:10:51,823
It's going well.
233
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These are amazing. They are.
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Are these...
so, are these
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00:10:57,070 --> 00:10:58,934
just the ones you've exposed
this afternoon, then?
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00:10:58,968 --> 00:11:00,901
Yep, there's a double trail.
237
00:11:00,936 --> 00:11:05,768
Um, somebody going this way,
and somebody going that way.
238
00:11:05,803 --> 00:11:07,736
How far do they go off in that direction?
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00:11:07,770 --> 00:11:08,875
So, in that direction,
240
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about three-quarters of a mile,
241
00:11:10,808 --> 00:11:13,051
something like that, and then they go to
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00:11:13,086 --> 00:11:15,157
the boundary fence on the missile range
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00:11:15,191 --> 00:11:17,849
and an unknown distance
into the missile range.
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♪
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JOHNSON: How common
is it to have a track this long?
246
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BENNETT:
Okay, so I've looked at tracks
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00:11:24,822 --> 00:11:27,445
all around the world,
and this, to my knowledge,
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00:11:27,479 --> 00:11:30,828
is the longest human trackway
anywhere in the world.
249
00:11:30,862 --> 00:11:33,106
JOHNSON:
Oh, that's amazing.
250
00:11:33,140 --> 00:11:34,901
Could it be the same person
going away and coming back?
251
00:11:34,935 --> 00:11:37,144
Absolutely.
They're the same size.
252
00:11:37,179 --> 00:11:38,007
It's actually quite a small individual.
253
00:11:38,042 --> 00:11:40,113
It could be a woman,
254
00:11:40,147 --> 00:11:43,530
but could be a male adolescent equally.
255
00:11:43,564 --> 00:11:45,221
The size is...
256
00:11:45,256 --> 00:11:46,982
Looks like a size five
or something. Yeah.
257
00:11:47,016 --> 00:11:48,742
But the tracks are very big.
258
00:11:48,777 --> 00:11:51,020
There's sort of 30% of the track,
259
00:11:51,055 --> 00:11:52,919
maybe more is pure slippage.
260
00:11:55,576 --> 00:11:57,820
It's very wet and slippery conditions
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00:11:57,855 --> 00:12:00,443
as the individual has been moving.
262
00:12:00,478 --> 00:12:06,242
JOHNSON [voiceover]: Some
are clearly defined imprints,
263
00:12:06,277 --> 00:12:10,005
but many are stretched out and distorted,
264
00:12:10,039 --> 00:12:13,180
an indication that
the walker was moving fast,
265
00:12:13,215 --> 00:12:15,079
and slipping on wet, muddy ground.
266
00:12:17,322 --> 00:12:19,911
Some prints are bent out of shape,
267
00:12:19,946 --> 00:12:23,190
from a foot sliding sideways,
268
00:12:23,225 --> 00:12:24,329
which could mean
269
00:12:24,364 --> 00:12:26,884
the person was carrying
something on their journey.
270
00:12:28,437 --> 00:12:31,923
BENNETT:
They were also carrying a child.
271
00:12:31,958 --> 00:12:33,545
Oh, they're carrying a child as well?
272
00:12:33,580 --> 00:12:35,237
They're carrying a child.
273
00:12:35,271 --> 00:12:36,445
How do you know that
they're carrying a child?
274
00:12:36,479 --> 00:12:39,793
BENNETT: Along the
trackway, there are very small,
275
00:12:39,828 --> 00:12:41,588
tiny little children's prints.
276
00:12:41,622 --> 00:12:45,903
They sort of face the direction of travel.
277
00:12:45,937 --> 00:12:47,870
So if you imagine you were
carrying a child on your hip
278
00:12:47,905 --> 00:12:49,907
and you wanted to readjust, you...
279
00:12:49,941 --> 00:12:51,218
you put it down... Right.
280
00:12:51,253 --> 00:12:52,461
...and then you readjust,
281
00:12:52,495 --> 00:12:55,913
and there's a few small child prints,
282
00:12:55,947 --> 00:12:57,846
pick the child up again and carry on.
283
00:12:59,917 --> 00:13:01,539
Just over to here...
284
00:13:01,573 --> 00:13:03,921
JOHNSON [voiceover]: A little
farther along the same trackway,
285
00:13:03,955 --> 00:13:08,028
Matthew discovers a twist in the story.
286
00:13:08,063 --> 00:13:11,135
The travelers were not alone.
287
00:13:11,169 --> 00:13:13,309
What's this unusual set of tracks?
288
00:13:13,344 --> 00:13:17,382
So there are a series of sloth tracks here
289
00:13:17,417 --> 00:13:19,488
entering from, from...
290
00:13:19,522 --> 00:13:20,834
to the left there...
So this is the first one.
291
00:13:20,869 --> 00:13:23,009
And then it comes out over here.
292
00:13:23,043 --> 00:13:24,286
That's really the amazing one,
293
00:13:24,320 --> 00:13:26,184
you can see the claws
of the sloth so clearly.
294
00:13:26,219 --> 00:13:27,220
BENNETT:
You can, yeah.
295
00:13:27,254 --> 00:13:29,222
It's a beautiful, a beautiful track.
296
00:13:29,256 --> 00:13:30,637
They're not large tracks. Yeah.
297
00:13:30,671 --> 00:13:33,916
So it's a relatively small sloth.
298
00:13:33,951 --> 00:13:36,919
Bear-size, I would have suggested.
299
00:13:39,094 --> 00:13:41,096
JOHNSON [voiceover]:
Was this sloth here
300
00:13:41,130 --> 00:13:43,857
at the same time as the humans?
301
00:13:43,892 --> 00:13:46,170
The sloth's footprints are right on top of
302
00:13:46,204 --> 00:13:48,586
the outbound human track.
303
00:13:48,620 --> 00:13:51,106
Which means this animal must have arrived
304
00:13:51,140 --> 00:13:56,283
after the travelers first passed by.
305
00:13:56,318 --> 00:13:59,459
Where do they actually
step on the human track?
306
00:13:59,493 --> 00:14:01,012
So... Is it this one?
307
00:14:01,047 --> 00:14:02,669
It's actually just over there.
308
00:14:02,703 --> 00:14:04,291
There's an example where they,
309
00:14:04,326 --> 00:14:06,086
they cut across the human track.
310
00:14:11,989 --> 00:14:14,681
But the sloth did something quite cool.
311
00:14:14,715 --> 00:14:18,512
It seems to have gone from
all fours up onto its hind legs.
312
00:14:18,547 --> 00:14:22,137
It's done a little dance around...
313
00:14:22,171 --> 00:14:24,277
And then it goes off that way.
314
00:14:27,728 --> 00:14:30,421
So it crawls in kind of like sloth-like,
315
00:14:30,455 --> 00:14:31,940
and then as it gets here,
316
00:14:31,974 --> 00:14:33,217
it kind of pivots around and up
317
00:14:33,251 --> 00:14:34,252
and looks, looks...
318
00:14:34,287 --> 00:14:35,978
Looks, scents the air, and off.
319
00:14:36,013 --> 00:14:36,979
...and pivots
320
00:14:37,014 --> 00:14:37,980
and then heads off that way.
321
00:14:38,015 --> 00:14:39,050
That's correct.
322
00:14:39,085 --> 00:14:40,465
A little sloth dance.
323
00:14:40,500 --> 00:14:41,225
Yeah, that's exactly what it is.
324
00:14:44,297 --> 00:14:46,126
JOHNSON [voiceover]:
Matthew thinks the sloth
325
00:14:46,161 --> 00:14:50,234
noticed the human tracks and reacted.
326
00:14:50,268 --> 00:14:53,237
Either the sloth's either
visually responding to the track
327
00:14:53,271 --> 00:14:55,618
or it smells something.
328
00:14:55,653 --> 00:14:58,035
My instinct is smell.
329
00:14:58,069 --> 00:15:01,003
It basically reared up to scent
the air a little bit more
330
00:15:01,038 --> 00:15:05,042
and then decided to, to disappear off.
331
00:15:05,076 --> 00:15:08,148
They're not here at the same time,
332
00:15:08,183 --> 00:15:10,737
but within a few minutes,
hours of each other,
333
00:15:10,771 --> 00:15:12,256
they're here.
334
00:15:12,290 --> 00:15:14,983
[chuckling]:
That's a phenomenal thing.
335
00:15:15,017 --> 00:15:18,193
Some small person having a stroll
336
00:15:18,227 --> 00:15:20,298
on a landscape full of
giant ground sloths.
337
00:15:23,094 --> 00:15:25,510
[voiceover]:
The tracks at White Sands show
338
00:15:25,545 --> 00:15:30,377
just how close humans here
came to Ice Age animals.
339
00:15:30,412 --> 00:15:32,621
Imagine what it must have been like
340
00:15:32,655 --> 00:15:35,451
to meet one of these
enormous beasts in the flesh.
341
00:15:35,486 --> 00:15:37,212
[sloth groaning]
342
00:15:40,180 --> 00:15:42,769
♪
343
00:15:42,803 --> 00:15:45,254
You can get a sense of
these Ice Age encounters
344
00:15:45,289 --> 00:15:48,775
at La Brea Tar Pits in Los Angeles.
345
00:15:48,809 --> 00:15:53,573
Here, animals that wandered
into tar deposits were trapped,
346
00:15:53,607 --> 00:15:55,092
and their bones were preserved.
347
00:15:57,370 --> 00:16:00,338
In the last century,
experts have unearthed
348
00:16:00,373 --> 00:16:03,721
more than a million fossils here.
349
00:16:03,755 --> 00:16:05,136
EMILY LINDSEY:
Hey.
350
00:16:05,171 --> 00:16:05,792
Hey Emily, how are you doing?
351
00:16:05,826 --> 00:16:07,173
Good, how are you?
352
00:16:07,207 --> 00:16:08,208
Nice to see you again. Good to see you.
353
00:16:08,243 --> 00:16:09,347
Welcome to the Tar Pits. Thanks.
354
00:16:09,382 --> 00:16:11,246
Oh, here's our sloth, huh? Yeah.
355
00:16:11,280 --> 00:16:14,145
This thing is amazing, so massive.
356
00:16:14,180 --> 00:16:16,596
It's majestic.
357
00:16:16,630 --> 00:16:19,461
JOHNSON [voiceover]: Curator Emily Lindsey
works with fossils of the giant beasts
358
00:16:19,495 --> 00:16:23,810
that lived in North America
during the last Ice Age.
359
00:16:23,844 --> 00:16:25,674
So how much do you think this guy weighed?
360
00:16:25,708 --> 00:16:27,193
Probably more than a ton.
361
00:16:27,227 --> 00:16:28,608
And when people talk about sloths,
362
00:16:28,642 --> 00:16:30,575
they talk about how they move so slowly,
363
00:16:30,610 --> 00:16:32,508
would this guy have moved slowly?
364
00:16:32,543 --> 00:16:33,751
You know, it wouldn't have been like,
365
00:16:33,785 --> 00:16:35,511
a runner... Yeah.
366
00:16:35,546 --> 00:16:39,515
...but it wouldn't have been
so slow as the modern sloths
367
00:16:39,550 --> 00:16:42,449
that are really only adapted
for living in trees.
368
00:16:42,484 --> 00:16:45,280
What would an animal like this eat?
369
00:16:45,314 --> 00:16:47,420
So they were mostly herbivores,
370
00:16:47,454 --> 00:16:48,766
and it looks like they
were eating a lot of
371
00:16:48,800 --> 00:16:50,319
kind of desert shrubs
372
00:16:50,354 --> 00:16:52,390
that would have
been prevalent in the area.
373
00:16:54,530 --> 00:16:56,567
Sloths are part of this
very strange group of animals
374
00:16:56,601 --> 00:16:59,328
called Xenarthrans,
and it includes the sloths,
375
00:16:59,363 --> 00:17:01,261
the armadillos,
376
00:17:01,296 --> 00:17:03,608
and the anteaters.
377
00:17:03,643 --> 00:17:04,782
And like armadillos, some species
378
00:17:04,816 --> 00:17:08,061
produced bony armor, only in this case,
379
00:17:08,096 --> 00:17:09,269
it's in the form of these
380
00:17:09,304 --> 00:17:11,444
small sort of pebble-like bones
381
00:17:11,478 --> 00:17:14,688
that were embedded inside its skin.
382
00:17:14,723 --> 00:17:16,104
Oh, that's why I love sloths so much.
383
00:17:16,138 --> 00:17:17,139
[laughing]:
They're so cool,
384
00:17:17,174 --> 00:17:18,347
they're such amazing animals.
385
00:17:18,382 --> 00:17:20,211
Yeah, they're one of the weirdest animals,
386
00:17:20,246 --> 00:17:22,455
and it's a piece of ecology
387
00:17:22,489 --> 00:17:25,458
that has just completely gone from earth.
388
00:17:25,492 --> 00:17:27,494
[indistinct chatter]
389
00:17:27,529 --> 00:17:29,462
JOHNSON [voiceover]:
Nearby, I've spotted another
390
00:17:29,496 --> 00:17:33,328
lost species whose tracks
we see at White Sands.
391
00:17:33,362 --> 00:17:35,847
This is an amazing beast, isn't it?
392
00:17:35,882 --> 00:17:38,229
Yeah, the Columbian mammoth.
393
00:17:38,264 --> 00:17:39,610
JOHNSON [voiceover]:
From fossil evidence,
394
00:17:39,644 --> 00:17:41,784
we know that mammoths
arrived in North America
395
00:17:41,819 --> 00:17:46,513
around 1.8 million years ago.
396
00:17:46,548 --> 00:17:49,309
When you stand beneath the
skeletons of these huge animals,
397
00:17:49,344 --> 00:17:52,795
you can't help but wonder,
398
00:17:52,830 --> 00:17:56,558
why did they go extinct
less than 13,000 years ago?
399
00:17:58,870 --> 00:18:02,322
Was it because of a change in climate?
400
00:18:02,357 --> 00:18:04,635
Or human influence?
401
00:18:04,669 --> 00:18:08,811
Or a combination of the two?
402
00:18:08,846 --> 00:18:10,572
LINDSEY: It seems to have
been a really rapid event.
403
00:18:10,606 --> 00:18:12,401
As we we're coming out of the Ice Age,
404
00:18:12,436 --> 00:18:13,851
we're going through all
these big climate upheavals,
405
00:18:13,885 --> 00:18:16,612
so we need to know how much overlap
406
00:18:16,647 --> 00:18:20,478
there actually was
between when humans arrived
407
00:18:20,513 --> 00:18:23,550
and when the last animals disappeared
408
00:18:23,585 --> 00:18:26,243
in order to know what role
humans might have played
409
00:18:26,277 --> 00:18:27,865
in that extinction.
410
00:18:27,899 --> 00:18:32,835
♪
411
00:18:35,390 --> 00:18:37,150
JOHNSON [voiceover]:
The footprints at White Sands
412
00:18:37,185 --> 00:18:40,291
might be the oldest human prints
ever found in North America.
413
00:18:43,605 --> 00:18:47,367
They could shed new light on
the lives of Indigenous peoples
414
00:18:47,402 --> 00:18:50,267
and their long history on this continent.
415
00:18:50,301 --> 00:18:53,166
It's, it's just so amazing
to see these tracks...
416
00:18:53,201 --> 00:18:53,822
There's another one crossing there.
417
00:18:53,856 --> 00:18:55,410
Yeah.
418
00:18:55,444 --> 00:18:57,860
JOHNSON [voiceover]:
Today, I'm visiting
419
00:18:57,895 --> 00:19:01,278
the U.S. Army's
White Sands missile range,
420
00:19:01,312 --> 00:19:03,245
just across the boundary
from the national park.
421
00:19:05,730 --> 00:19:07,663
Here there are more animal prints,
422
00:19:07,698 --> 00:19:09,734
including those of a mammoth,
423
00:19:09,769 --> 00:19:14,705
and this magnificent trackway
of a ground sloth,
424
00:19:14,739 --> 00:19:17,190
crossed by the footprints
of an ancient camel.
425
00:19:20,435 --> 00:19:24,301
Can you imagine this whole area
426
00:19:24,335 --> 00:19:26,579
with all these animals here?
427
00:19:26,613 --> 00:19:28,857
Would have been amazing, huh? [sighing]:
Oh.
428
00:19:28,891 --> 00:19:30,721
Mammoths, sloths, cats, dogs. Yeah.
429
00:19:30,755 --> 00:19:31,963
Right? Yes.
430
00:19:31,998 --> 00:19:33,586
I always say we need
to build a time machine.
431
00:19:33,620 --> 00:19:34,552
[laughter]
432
00:19:36,934 --> 00:19:38,798
JOHNSON [voiceover]:
Joining me are Joe Watkins,
433
00:19:38,832 --> 00:19:40,386
an archaeologist and member of
434
00:19:40,420 --> 00:19:42,905
the Choctaw Nation of Oklahoma,
435
00:19:42,940 --> 00:19:47,910
and Kim Charlie from the
Pueblo of Acoma in New Mexico.
436
00:19:47,945 --> 00:19:51,397
They want to
see the prints for themselves,
437
00:19:51,431 --> 00:19:52,812
and learn more about
438
00:19:52,846 --> 00:19:57,817
the people who once walked
across this landscape.
439
00:19:57,851 --> 00:20:00,578
We have this tie where us Native Americans
440
00:20:00,613 --> 00:20:02,822
have been here for a very long time.
441
00:20:02,856 --> 00:20:07,033
And I believe that, you know,
I really believe that.
442
00:20:07,067 --> 00:20:08,931
And that ties back into, you know,
443
00:20:08,966 --> 00:20:11,037
our migration stories where
444
00:20:11,071 --> 00:20:14,627
we evolved somewhere, but we don't
445
00:20:14,661 --> 00:20:16,525
specifically know where.
446
00:20:16,560 --> 00:20:17,595
These are stories that
447
00:20:17,630 --> 00:20:20,978
we believe in our hearts as tribes,
448
00:20:21,012 --> 00:20:26,397
pueblos, you know, that we take,
that we hold sacred to us.
449
00:20:26,432 --> 00:20:28,675
So when we come back to these areas
450
00:20:28,710 --> 00:20:31,333
and we find evidence of footprints
451
00:20:31,368 --> 00:20:35,372
of our thousands of great ancestors,
452
00:20:35,406 --> 00:20:38,409
you know, we just kind of, like,
it's amazing.
453
00:20:38,444 --> 00:20:39,859
So we did exist here.
454
00:20:39,893 --> 00:20:42,655
The tribes talk about going way back.
455
00:20:42,689 --> 00:20:45,382
We all talk about
having been here forever.
456
00:20:45,416 --> 00:20:47,004
We've never been anywhere else.
457
00:20:47,038 --> 00:20:49,869
We have the evidence, it really does
458
00:20:49,903 --> 00:20:51,974
put our feet prints
459
00:20:52,009 --> 00:20:54,874
firmly into the past here
in North America.
460
00:20:54,908 --> 00:20:58,395
These are our relatives.
461
00:20:58,429 --> 00:21:00,776
We've been here since time immemorial
462
00:21:00,811 --> 00:21:02,364
and hopefully we'll continue on.
463
00:21:05,747 --> 00:21:06,679
JOHNSON [voiceover]:
When Europeans arrived
464
00:21:06,713 --> 00:21:09,406
on this continent, they began a pattern of
465
00:21:09,440 --> 00:21:10,959
ignoring the rights and stories
466
00:21:10,993 --> 00:21:14,859
of Indigenous peoples.
467
00:21:14,894 --> 00:21:20,865
With the colonization in the 14, 1500s,
468
00:21:20,900 --> 00:21:23,592
a lot of tribal histories
have either been lost
469
00:21:23,627 --> 00:21:27,562
or have been pushed back
or have been tossed aside.
470
00:21:27,596 --> 00:21:30,427
This was once our land, you know.
471
00:21:30,461 --> 00:21:32,912
Mother Earth
was our mother... Mm-hmm.
472
00:21:32,946 --> 00:21:34,948
...and we're
the descendants of her.
473
00:21:34,983 --> 00:21:38,469
And we're the people
that try to take care of it,
474
00:21:38,504 --> 00:21:42,024
but you've got the Western people
475
00:21:42,059 --> 00:21:46,615
have come in and just
taken over areas where,
476
00:21:46,650 --> 00:21:47,927
you know, they have no respect.
477
00:21:47,961 --> 00:21:50,136
Please understand that
478
00:21:50,170 --> 00:21:52,794
we Native Americans were here first.
479
00:21:52,828 --> 00:21:55,762
It's kind of an awful thing
480
00:21:55,797 --> 00:21:59,732
where we've been put on
little reservations.
481
00:21:59,766 --> 00:22:03,839
You know, where we once had
the freedom to roam.
482
00:22:03,874 --> 00:22:06,739
♪
483
00:22:06,773 --> 00:22:07,636
JOHNSON [voiceover]:
European-Americans not only
484
00:22:07,671 --> 00:22:10,950
took control of Indigenous territories,
485
00:22:10,984 --> 00:22:12,607
but some also spread
486
00:22:12,641 --> 00:22:14,471
misleading narratives
about Indigenous people.
487
00:22:15,748 --> 00:22:17,370
[indistinct chatter]
488
00:22:17,405 --> 00:22:18,785
♪
489
00:22:18,820 --> 00:22:20,546
WATKINS: There's pretty
much always been a conflict
490
00:22:20,580 --> 00:22:22,893
between archaeologists
and American Indians.
491
00:22:22,927 --> 00:22:25,413
In many ways,
492
00:22:25,447 --> 00:22:28,070
archaeologists have taken over.
493
00:22:28,105 --> 00:22:31,419
They've sort of colonized
American Indian history,
494
00:22:31,453 --> 00:22:35,146
and they felt that they, they're the ones
495
00:22:35,181 --> 00:22:37,632
who tell the true story of the past.
496
00:22:37,666 --> 00:22:41,083
So there's been that conflict between
497
00:22:41,118 --> 00:22:43,016
whose story is the true history.
498
00:22:43,051 --> 00:22:45,087
Archaeologists also
499
00:22:45,122 --> 00:22:48,021
came out to archaeological sites,
500
00:22:48,056 --> 00:22:49,747
started excavating,
501
00:22:49,782 --> 00:22:52,992
took the materials,
took them back to museums,
502
00:22:53,026 --> 00:22:54,856
and tribal people never saw them again.
503
00:22:54,890 --> 00:22:57,824
♪
504
00:22:57,859 --> 00:22:59,412
JOHNSON:
Over the centuries,
505
00:22:59,447 --> 00:23:01,656
some white scholars used archaeology
506
00:23:01,690 --> 00:23:04,762
as a way to dismiss
Indigenous people's accounts
507
00:23:04,797 --> 00:23:09,629
and ancestral connections to the land.
508
00:23:09,664 --> 00:23:13,564
It really wasn't until 40 years ago
509
00:23:13,599 --> 00:23:16,740
that Indians had a say in
who was excavating
510
00:23:16,774 --> 00:23:19,432
and what happened with the
results of those excavations.
511
00:23:19,467 --> 00:23:23,609
♪
512
00:23:23,643 --> 00:23:24,920
JOHNSON:
Here at White Sands,
513
00:23:24,955 --> 00:23:27,889
the scientists are consulting
with local tribes
514
00:23:27,923 --> 00:23:31,513
and pueblos to study and record
these important prints.
515
00:23:33,550 --> 00:23:38,658
They hope to solve one of
the biggest mysteries of all:
516
00:23:38,693 --> 00:23:42,455
when did humans first arrive
in North America?
517
00:23:47,253 --> 00:23:51,602
Fossil records show that by
at least 100,000 years ago,
518
00:23:51,637 --> 00:23:54,571
modern humans... Homo sapiens...
519
00:23:54,605 --> 00:23:58,540
began spreading
from Africa across the planet.
520
00:23:58,575 --> 00:24:00,887
The Americas were surrounded by ocean
521
00:24:00,922 --> 00:24:03,234
and out of reach.
522
00:24:03,269 --> 00:24:07,791
But during the last Ice Age,
massive ice sheets formed
523
00:24:07,825 --> 00:24:11,657
and sea levels dropped by over 400 feet,
524
00:24:11,691 --> 00:24:16,006
exposing land between Siberia and Alaska.
525
00:24:16,040 --> 00:24:17,835
Many scientists agree
526
00:24:17,870 --> 00:24:21,598
that this is how humans
got to North America.
527
00:24:21,632 --> 00:24:25,740
But when exactly did they first arrive?
528
00:24:25,774 --> 00:24:29,985
Throughout the 20th century,
many archaeologists
529
00:24:30,020 --> 00:24:33,679
thought the answer lay in
these stone projectile points
530
00:24:33,713 --> 00:24:35,715
found all across North America.
531
00:24:38,718 --> 00:24:40,927
They were made by people from
what became known as
532
00:24:40,962 --> 00:24:44,172
the Clovis culture.
533
00:24:44,206 --> 00:24:45,829
WATKINS:
I have a replica
534
00:24:45,863 --> 00:24:49,142
Clovis point with me.
535
00:24:49,177 --> 00:24:50,730
They look about like this.
536
00:24:50,765 --> 00:24:52,525
Some are larger, some are smaller.
537
00:24:52,560 --> 00:24:55,114
There's a very characteristic flake
538
00:24:55,148 --> 00:24:57,254
that's taken out of the base
539
00:24:57,288 --> 00:24:58,635
up to the middle of the point.
540
00:25:00,706 --> 00:25:02,259
JOHNSON:
The oldest known Clovis points
541
00:25:02,293 --> 00:25:03,985
are about 13,000 years old.
542
00:25:06,125 --> 00:25:08,921
And for a long time, many archaeologists
543
00:25:08,955 --> 00:25:10,612
thought that humans
arrived in North America
544
00:25:10,647 --> 00:25:14,789
no earlier than that.
545
00:25:14,823 --> 00:25:16,825
So these Clovis points have been found
546
00:25:16,860 --> 00:25:18,655
all across North America,
547
00:25:18,689 --> 00:25:21,934
from the Atlantic coast on the east,
548
00:25:21,968 --> 00:25:24,350
all the way out into the, the west coast.
549
00:25:24,384 --> 00:25:28,872
So with this, such a broad
geographical span of material,
550
00:25:28,906 --> 00:25:31,150
it's why most archaeologists thought
551
00:25:31,184 --> 00:25:34,187
that Clovis was the
first archaeological culture
552
00:25:34,222 --> 00:25:35,706
in North America.
553
00:25:35,741 --> 00:25:38,364
JOHNSON [voiceover]:
More recently,
554
00:25:38,398 --> 00:25:41,332
this view has been challenged
by the excavation of
555
00:25:41,367 --> 00:25:44,163
older sites, with stone artifacts
556
00:25:44,197 --> 00:25:46,268
that suggest humans lived in North America
557
00:25:46,303 --> 00:25:47,269
at least 2,000 years
558
00:25:47,304 --> 00:25:50,721
before the Clovis culture.
559
00:25:50,756 --> 00:25:53,690
♪
560
00:25:53,724 --> 00:25:56,002
There are some archaeological sites...
561
00:25:56,037 --> 00:25:58,764
one in Florida, one in Texas...
562
00:25:58,798 --> 00:26:04,286
that date about 15,000, 15,200 years ago.
563
00:26:04,321 --> 00:26:07,738
So those are currently
the oldest dates we have
564
00:26:07,773 --> 00:26:10,051
for the early peopling of the New World.
565
00:26:10,085 --> 00:26:13,848
♪
566
00:26:13,882 --> 00:26:16,057
JOHNSON: But now the
discoveries at White Sands
567
00:26:16,091 --> 00:26:19,336
may support even earlier dates,
568
00:26:19,370 --> 00:26:22,891
and could shed new light on
569
00:26:22,926 --> 00:26:26,377
how people came to North America.
570
00:26:29,311 --> 00:26:33,937
About 20,000 years ago was
the peak of the last Ice Age,
571
00:26:33,971 --> 00:26:37,078
the Last Glacial Maximum.
572
00:26:37,112 --> 00:26:42,221
Gigantic ice sheets blocked
the route into North America.
573
00:26:42,255 --> 00:26:45,983
But there's geological evidence
that as the climate warmed,
574
00:26:46,018 --> 00:26:50,712
an ice-free corridor opened up.
575
00:26:50,747 --> 00:26:53,094
Was this how humans reached
the rest of the continent?
576
00:26:55,924 --> 00:26:58,962
So one thing about the ice-free corridor,
577
00:26:58,996 --> 00:27:00,757
it didn't really open up
578
00:27:00,791 --> 00:27:04,208
until 13, 14,000 years ago.
579
00:27:04,243 --> 00:27:05,969
So if it wasn't open,
580
00:27:06,003 --> 00:27:09,351
it wasn't likely that anyone
could have come that way
581
00:27:09,386 --> 00:27:11,388
and come in to North America.
582
00:27:13,804 --> 00:27:19,120
JOHNSON: If the tracks at White
Sands pre-date the ice-free corridor,
583
00:27:19,154 --> 00:27:20,915
they will add more weight
584
00:27:20,949 --> 00:27:23,814
to the idea that humans
arrived here earlier
585
00:27:23,849 --> 00:27:28,129
than many archaeologists
previously thought.
586
00:27:29,371 --> 00:27:31,719
♪
587
00:27:31,753 --> 00:27:34,825
Searching for clues,
588
00:27:34,860 --> 00:27:37,897
David Bustos is studying some
other remarkable human prints.
589
00:27:37,932 --> 00:27:39,416
I don't know if you can see right here,
590
00:27:39,450 --> 00:27:41,073
this might be more of a child.
591
00:27:41,107 --> 00:27:45,974
It's about, maybe, four,
four inches or so across.
592
00:27:46,009 --> 00:27:48,045
And it's right next to an adult print.
593
00:27:48,080 --> 00:27:49,288
You don't normally think of, you know,
594
00:27:49,322 --> 00:27:52,809
taking your child all the way
across the country or so,
595
00:27:52,843 --> 00:27:54,707
unless you're, um, if you're hunting,
596
00:27:54,742 --> 00:27:55,570
you might leave the child back at home,
597
00:27:55,604 --> 00:27:57,158
but we see the children everywhere,
598
00:27:57,192 --> 00:27:59,954
so they're part of the scene
or part of the landscape.
599
00:27:59,988 --> 00:28:01,749
♪
600
00:28:01,783 --> 00:28:05,407
JOHNSON: The footprints
tell stories of Ice Age life.
601
00:28:05,442 --> 00:28:07,720
But how long ago were these people here?
602
00:28:07,755 --> 00:28:09,860
♪
603
00:28:09,895 --> 00:28:11,448
In order to date the prints,
604
00:28:11,482 --> 00:28:13,484
the team has dug a trench.
605
00:28:16,177 --> 00:28:18,006
[rocks rumbling]
606
00:28:18,041 --> 00:28:20,008
It reveals layers of sediment,
607
00:28:20,043 --> 00:28:22,286
deposited over many years,
608
00:28:22,321 --> 00:28:24,806
along the shore of this ancient lake.
609
00:28:27,084 --> 00:28:31,054
Stamped on these buried
surfaces are human prints,
610
00:28:31,088 --> 00:28:34,505
and the further down they are,
the older they are.
611
00:28:35,472 --> 00:28:38,993
But just how old are they?
612
00:28:39,027 --> 00:28:40,339
I can put them both on.
613
00:28:40,373 --> 00:28:42,272
Okay, sure.
614
00:28:42,306 --> 00:28:45,137
JOHNSON: To help find the
answer, David has been joined
615
00:28:45,171 --> 00:28:49,486
by geologists Kathleen Springer
and Jeff Pigati,
616
00:28:49,520 --> 00:28:52,075
who is also an expert in
radiocarbon dating.
617
00:28:52,109 --> 00:28:55,837
♪
618
00:28:55,872 --> 00:28:57,494
You've cut a cross section...
what are you trying to see
619
00:28:57,528 --> 00:28:59,807
with the cross section? SPRINGER:
So the footprints themselves
620
00:28:59,841 --> 00:29:01,084
are just an impression on a surface,
621
00:29:01,118 --> 00:29:02,499
there's nothing to date.
622
00:29:02,533 --> 00:29:05,019
It's an inorganic thing, you
have to find something organic
623
00:29:05,053 --> 00:29:08,850
that you can date above
and below the footprints,
624
00:29:08,885 --> 00:29:10,196
and get good dates on them,
625
00:29:10,231 --> 00:29:11,370
so that you can actually say,
626
00:29:11,404 --> 00:29:15,029
"That footprint is between
these two ages."
627
00:29:15,063 --> 00:29:19,136
JOHNSON [voiceover]: In this trench,
Kathleen and Jeff have made a crucial find.
628
00:29:19,171 --> 00:29:22,208
♪
629
00:29:22,243 --> 00:29:26,454
Sandwiched in the layers
above and below the footprints
630
00:29:26,488 --> 00:29:30,009
are scatterings of ancient seeds,
631
00:29:30,044 --> 00:29:33,875
precious organic material
which the team can date.
632
00:29:33,910 --> 00:29:36,291
That way they can establish
a window of time,
633
00:29:36,326 --> 00:29:38,880
for when the prints were made.
634
00:29:41,124 --> 00:29:43,920
There were actually
plants growing on this,
635
00:29:43,954 --> 00:29:46,025
on the surface when, you know,
636
00:29:46,060 --> 00:29:47,613
these critters were walking around.
637
00:29:47,647 --> 00:29:49,546
So the same layers that have
the tracks will have the seeds.
638
00:29:49,580 --> 00:29:50,616
Absolutely,
above and below them. Yeah.
639
00:29:50,650 --> 00:29:51,997
Yes, so above and below them,
640
00:29:52,031 --> 00:29:55,138
that way we can constrain in time.
641
00:29:55,172 --> 00:29:58,831
So your seeds are effectively
little timepieces, right?
642
00:29:58,866 --> 00:30:00,246
They're like little clocks
or something buried in the...
643
00:30:00,281 --> 00:30:02,455
They're little capsules, yeah.
644
00:30:02,490 --> 00:30:03,940
And basically the, the...
645
00:30:03,974 --> 00:30:08,047
these things are really
resistant to, to decay.
646
00:30:08,082 --> 00:30:10,498
And so they look like
they were put down on the,
647
00:30:10,532 --> 00:30:12,845
on the landscape just yesterday,
but, in fact,
648
00:30:12,880 --> 00:30:14,502
they might be tens and, you know,
649
00:30:14,536 --> 00:30:15,952
tens of thousands of years old.
650
00:30:18,230 --> 00:30:20,335
JOHNSON [voiceover]: Jeff will take
the seeds back to his lab in Denver,
651
00:30:20,370 --> 00:30:23,097
and use radiocarbon dating
to find out how old they are.
652
00:30:23,131 --> 00:30:25,996
♪
653
00:30:26,031 --> 00:30:28,378
JOHNSON: When I talk to you in
six months' time,
654
00:30:28,412 --> 00:30:29,897
either you have what you expect,
655
00:30:29,931 --> 00:30:32,589
PIGATI: Mm-hm. which
is around 12,000 years,
656
00:30:32,623 --> 00:30:35,074
or you have humans
here earlier than you expect,
657
00:30:35,109 --> 00:30:37,559
or mammoths are here later
than you expect.
658
00:30:37,594 --> 00:30:39,044
PIGATI: Something's going to
be pretty cool either way, right?
659
00:30:39,078 --> 00:30:40,597
So it seems like you're going to get
660
00:30:40,631 --> 00:30:43,358
a really interesting result no
matter what the result is here.
661
00:30:43,393 --> 00:30:45,429
PIGATI: It is a win-win,
no question about it. Yeah.
662
00:30:45,464 --> 00:30:47,017
That's a rare thing in paleontology.
663
00:30:47,052 --> 00:30:48,018
PIGATI:
It's kind of nice. Yeah.
664
00:30:48,053 --> 00:30:49,468
JOHNSON: Dying to hear
what you find out.
665
00:30:49,502 --> 00:30:50,641
Yeah. Yeah, us too, us too.
666
00:30:53,437 --> 00:30:57,303
JOHNSON [voiceover]: The trackways
at White Sands are constantly changing...
667
00:30:57,338 --> 00:31:00,962
as the wind erodes away the
surface to reveal new prints,
668
00:31:00,997 --> 00:31:04,517
it's also turning existing ones to dust.
669
00:31:06,347 --> 00:31:08,073
BUSTOS: It's great because
we can see the prints,
670
00:31:08,107 --> 00:31:10,144
but then they are rapidly blowing away.
671
00:31:10,178 --> 00:31:13,181
So we want to capture the data
before it's gone.
672
00:31:13,216 --> 00:31:15,287
Some of these really soft ones like this,
673
00:31:15,321 --> 00:31:19,222
once they're exposed, in
a few months they'll be gone.
674
00:31:19,256 --> 00:31:21,224
Some type of, you know,
priceless data is, is being...
675
00:31:21,258 --> 00:31:23,157
is right here, is being lost.
676
00:31:23,191 --> 00:31:25,262
It's the surface,
we're losing the surface,
677
00:31:25,297 --> 00:31:26,539
and these are where all the prints are.
678
00:31:26,574 --> 00:31:32,338
♪
679
00:31:32,373 --> 00:31:37,102
JOHNSON: To record this precious
evidence before the wind blows it away,
680
00:31:37,136 --> 00:31:39,656
the team is mapping the site
using aerial imagery.
681
00:31:42,417 --> 00:31:45,455
BUSTOS: One of the main
reasons is to fly over the area
682
00:31:45,489 --> 00:31:46,387
and then get an elevation model
683
00:31:46,421 --> 00:31:49,045
so we can see where these prints are.
684
00:31:49,079 --> 00:31:51,219
And then we're gonna re-fly it again,
685
00:31:51,254 --> 00:31:53,497
and so with that we'll be able to look at
686
00:31:53,532 --> 00:31:56,017
from this year to next year
687
00:31:56,052 --> 00:31:57,122
we'll see how much erosion's happening,
688
00:31:57,156 --> 00:31:58,226
so we can see how fast
689
00:31:58,261 --> 00:32:00,056
the prints are moving and going away.
690
00:32:03,576 --> 00:32:08,719
JOHNSON: One question they
hope to answer using digital imaging
691
00:32:08,754 --> 00:32:11,343
is whether the people here were
hunting the giant animals.
692
00:32:14,380 --> 00:32:19,316
David shows me an intriguing set
of tracks that may hold clues.
693
00:32:19,351 --> 00:32:21,249
Dave, what kind of image is this?
694
00:32:21,284 --> 00:32:23,113
BUSTOS:
It's a photogrammetry.
695
00:32:23,148 --> 00:32:24,770
You know, so basically overlapping photos.
696
00:32:24,804 --> 00:32:26,392
I think in this image,
697
00:32:26,427 --> 00:32:28,222
there might have been
400 or 500 different images
698
00:32:28,256 --> 00:32:31,432
and they're all stitched together.
699
00:32:31,466 --> 00:32:33,606
You can, you know,
tip the images upside down,
700
00:32:33,641 --> 00:32:35,263
see it in different directions.
701
00:32:36,575 --> 00:32:38,680
So this image right here
702
00:32:38,715 --> 00:32:40,579
is actually a giant ground sloth.
703
00:32:40,613 --> 00:32:42,305
It's walking along.
704
00:32:42,339 --> 00:32:45,722
These are hind and fore feet,
so when they weave in and out,
705
00:32:45,756 --> 00:32:46,619
what you see is a hind foot,
706
00:32:46,654 --> 00:32:47,206
and then the forefoot comes in front
707
00:32:47,241 --> 00:32:49,312
with the very long claw.
708
00:32:49,346 --> 00:32:51,245
And then right here, it changes.
709
00:32:51,279 --> 00:32:52,694
So it stands up, actually.
710
00:32:54,800 --> 00:32:57,389
JOHNSON [voiceover]: What
caused this sudden change in behavior?
711
00:32:57,423 --> 00:32:59,805
David has a theory.
712
00:32:59,839 --> 00:33:03,395
BUSTOS: If you look close,
you'll see a set of human tracks,
713
00:33:03,429 --> 00:33:06,329
And what's really exciting,
we took measurements.
714
00:33:06,363 --> 00:33:08,124
You can see they're running
toward the sloth.
715
00:33:08,158 --> 00:33:09,677
If you're in the field,
716
00:33:09,711 --> 00:33:11,196
you'd actually see where they're
almost toe to toe, you know,
717
00:33:11,230 --> 00:33:12,749
almost chest to chest, it looks like.
718
00:33:12,783 --> 00:33:14,578
I don't know if they're throwing a spear
719
00:33:14,613 --> 00:33:17,236
or what they're doing, but they
come right up to each other.
720
00:33:17,271 --> 00:33:18,617
The sloth's spinning around
and making, like,
721
00:33:18,651 --> 00:33:20,101
it looks like a sweeping motion.
722
00:33:20,136 --> 00:33:21,723
Actually, there's claw marks
on the ground.
723
00:33:24,140 --> 00:33:26,107
There's another set of human prints
724
00:33:26,142 --> 00:33:29,007
sort of running up along this direction.
725
00:33:31,147 --> 00:33:32,320
JOHNSON [voiceover]:
David believes these trackways
726
00:33:32,355 --> 00:33:36,014
are evidence that humans
were actually hunting sloths.
727
00:33:38,706 --> 00:33:40,328
[sloth grunts]
728
00:33:40,363 --> 00:33:43,469
But what was it like to take
on such big animals?
729
00:33:43,504 --> 00:33:45,264
[sloth growls]
730
00:33:45,299 --> 00:33:48,164
La Brea Museum curator Emily Lindsey
731
00:33:48,198 --> 00:33:50,097
has investigated how humans hunted them.
732
00:33:51,684 --> 00:33:54,618
So these are our collections
733
00:33:54,653 --> 00:33:57,069
where we keep all of the fossils
that have been excavated
734
00:33:57,104 --> 00:33:58,864
over the last hundred years.
735
00:33:58,898 --> 00:34:00,486
There's millions of fossils here.
736
00:34:00,521 --> 00:34:03,075
Yeah, there are literally
millions of fossils here.
737
00:34:03,110 --> 00:34:05,422
And here are some of our sloth claws.
738
00:34:05,457 --> 00:34:06,527
JOHNSON:
Oh man, look at those things,
739
00:34:06,561 --> 00:34:09,116
these are serious claws.
740
00:34:09,150 --> 00:34:11,463
What did they use the claws for?
741
00:34:11,497 --> 00:34:14,535
Some paleontologists
think they might have used them
742
00:34:14,569 --> 00:34:16,399
to dig roots out of the ground.
743
00:34:16,433 --> 00:34:17,296
They've found burrows
744
00:34:17,331 --> 00:34:20,299
that they think these guys dug there,
745
00:34:20,334 --> 00:34:23,268
where there's actually
scratch marks on the wall
746
00:34:23,302 --> 00:34:24,476
that line up with the the hands
of giant sloths.
747
00:34:24,510 --> 00:34:26,202
But, of course,
748
00:34:26,236 --> 00:34:29,308
they would have been really
useful for defense, as well.
749
00:34:29,343 --> 00:34:31,310
JOHNSON [voiceover]: But
despite their fearsome appearance,
750
00:34:31,345 --> 00:34:34,555
archaeological evidence shows
that ground sloths
751
00:34:34,589 --> 00:34:36,591
might have been on the menu
752
00:34:36,626 --> 00:34:38,145
for hungry humans.
753
00:34:40,354 --> 00:34:41,424
LINDSEY: You know,
we have a couple of sites
754
00:34:41,458 --> 00:34:44,358
that have been found where it
looks pretty clear
755
00:34:44,392 --> 00:34:46,774
that humans were, if not hunting,
756
00:34:46,808 --> 00:34:48,396
at least butchering giant ground sloths.
757
00:34:49,708 --> 00:34:52,366
We've got stone tools
758
00:34:52,400 --> 00:34:53,712
and we've got cut marks on the bones.
759
00:34:53,746 --> 00:34:56,715
Although we have many more sites
760
00:34:56,749 --> 00:34:58,648
that show humans hunting
761
00:34:58,682 --> 00:35:01,444
and eating things like mammoths
and horses and camels
762
00:35:01,478 --> 00:35:03,411
than we do of giant sloths.
763
00:35:03,446 --> 00:35:06,138
So, they may have been a food
source of last resort.
764
00:35:06,173 --> 00:35:08,175
Maybe bison tastes better, or...
765
00:35:08,209 --> 00:35:10,729
Yeah, given the types of plants
766
00:35:10,763 --> 00:35:12,696
that we find in the sloth dung.
767
00:35:12,731 --> 00:35:14,388
You know, desert plants
768
00:35:14,422 --> 00:35:16,390
that tend to have a lot of
chemicals in them.
769
00:35:16,424 --> 00:35:17,460
They might not have tasted very good.
770
00:35:17,494 --> 00:35:19,255
Huh, interesting.
771
00:35:19,289 --> 00:35:20,877
So what kind of techniques
were humans using
772
00:35:20,911 --> 00:35:22,844
to hunt and kill these animals?
773
00:35:22,879 --> 00:35:24,812
LINDSEY:
They had spears, but, of course,
774
00:35:24,846 --> 00:35:26,262
the most important tool that humans had
775
00:35:26,296 --> 00:35:28,816
were their big brains
and their social groups
776
00:35:28,850 --> 00:35:31,405
and ability to communicate. Hm.
777
00:35:31,439 --> 00:35:32,854
♪
778
00:35:32,889 --> 00:35:35,305
JOHNSON [voiceover]:
Teamwork and planning,
779
00:35:35,340 --> 00:35:39,551
these were the keys to bringing
down huge Ice Age beasts.
780
00:35:39,585 --> 00:35:41,553
♪
781
00:35:41,587 --> 00:35:45,177
But once the animal was dead,
782
00:35:45,212 --> 00:35:47,283
what did people do with all that meat?
783
00:35:47,317 --> 00:35:50,182
♪
784
00:35:50,217 --> 00:35:51,666
One of the challenges you have, if you're,
785
00:35:51,701 --> 00:35:52,943
if you're living in this environment,
786
00:35:52,978 --> 00:35:55,877
or hunting in this environment,
is how do you get your meat
787
00:35:55,912 --> 00:35:57,914
from where you kill the animal
to where you camp?
788
00:35:57,948 --> 00:36:01,400
♪
789
00:36:01,435 --> 00:36:03,747
JOHNSON:
Dan Odess is an expert
790
00:36:03,782 --> 00:36:06,543
in prehistoric archaeology.
791
00:36:06,578 --> 00:36:10,444
He searches for evidence to show
how humans might have dealt
792
00:36:10,478 --> 00:36:12,791
with the animals they killed.
793
00:36:12,825 --> 00:36:15,966
And alongside the footprints,
794
00:36:16,001 --> 00:36:19,591
he shows me
a very different kind of track.
795
00:36:19,625 --> 00:36:21,731
DAN ODESS: We have
these, these really interesting
796
00:36:21,765 --> 00:36:24,285
linear structures.
797
00:36:24,320 --> 00:36:26,218
There are four of them.
798
00:36:26,253 --> 00:36:29,773
You can see here one, two, three, four.
799
00:36:29,808 --> 00:36:34,261
JOHNSON: What could have caused
these strange marks in the sand?
800
00:36:34,295 --> 00:36:35,400
ODESS:
We were kind of wondering
801
00:36:35,434 --> 00:36:38,368
initially, could this be
a product of animal behavior
802
00:36:38,403 --> 00:36:39,887
rather than human behavior?
803
00:36:39,921 --> 00:36:41,337
But, interestingly,
804
00:36:41,371 --> 00:36:42,855
one of the things we see
805
00:36:42,890 --> 00:36:44,374
and you can see it very clearly
in this one,
806
00:36:44,409 --> 00:36:48,240
we've got people walking along behind it.
807
00:36:48,275 --> 00:36:51,416
JOHNSON: Dan believes this is
important archaeological evidence
808
00:36:51,450 --> 00:36:53,832
of human engineering.
809
00:36:53,866 --> 00:36:55,765
They're, they're drag lines.
810
00:36:55,799 --> 00:36:57,836
So impressions left in the mud
811
00:36:57,870 --> 00:36:59,700
as somebody probably pulled
812
00:36:59,734 --> 00:37:01,495
a pole or poles. Okay.
813
00:37:01,529 --> 00:37:05,533
With presumably meat
or something else on them.
814
00:37:05,568 --> 00:37:07,017
JOHNSON: And that's a typical
way to move meat around?
815
00:37:07,052 --> 00:37:07,880
I think this is the first time
816
00:37:07,915 --> 00:37:10,538
it's been described for the Ice Age.
817
00:37:13,610 --> 00:37:14,853
JOHNSON [voiceover]:
The team thinks these tracks
818
00:37:14,887 --> 00:37:17,752
could be the earliest known
evidence of an ancient device
819
00:37:17,787 --> 00:37:22,999
used to carry heavy loads,
such as large amounts of meat.
820
00:37:24,794 --> 00:37:27,003
ODESS: Instead of dragging
the carcass back to the camp,
821
00:37:27,037 --> 00:37:30,317
they would strap it onto
a couple of poles,
822
00:37:30,351 --> 00:37:32,008
and not one, or two poles.
823
00:37:32,042 --> 00:37:33,734
At this point, we're not sure whether
824
00:37:33,768 --> 00:37:35,425
they're dragging a single pole
825
00:37:35,460 --> 00:37:39,084
or whether they're using
two poles hitched together.
826
00:37:39,118 --> 00:37:42,018
JOHNSON [off-camera]: Huh, so like a
primitive wheelbarrow, basically, right?
827
00:37:42,052 --> 00:37:43,675
ODESS: So far we, we
don't have any reason to think
828
00:37:43,709 --> 00:37:45,746
they had a wheel. Right.
829
00:37:45,780 --> 00:37:46,919
Well, wheelbarrow with
no wheel, how about that?
830
00:37:46,954 --> 00:37:48,438
Yeah, right, right.
[chuckles]
831
00:37:48,473 --> 00:37:49,681
A barrow! Right, there you go.
832
00:37:49,715 --> 00:37:50,544
Let's just call it
a barrow. A barrow.
833
00:37:50,578 --> 00:37:52,994
♪
834
00:37:53,029 --> 00:37:55,721
JOHNSON [voiceover]: But what
could the device have looked like?
835
00:37:57,930 --> 00:38:00,312
[birds flapping wings, squawking]
836
00:38:00,347 --> 00:38:04,799
60 miles from the trackways
is Elephant Butte Lake.
837
00:38:04,834 --> 00:38:06,732
Experts think White Sands
838
00:38:06,767 --> 00:38:10,564
had a similar environment
during parts of the Ice Age.
839
00:38:10,598 --> 00:38:13,360
Archaeologist Joe Watkins
840
00:38:13,394 --> 00:38:15,638
has come here to conduct an experiment.
841
00:38:18,710 --> 00:38:20,953
Joining him are fellow
archaeologists Carol Ellick,
842
00:38:20,988 --> 00:38:23,749
CAROL ELLICK: I'll start
with the lashing on this corner,
843
00:38:23,784 --> 00:38:25,613
all right? Yup.
844
00:38:25,648 --> 00:38:30,653
JOHNSON: And Edward Jolie,
of Lakota and Muscogee descent,
845
00:38:30,687 --> 00:38:34,622
and a citizen of the
Muscogee Nation of Oklahoma.
846
00:38:34,657 --> 00:38:36,624
EDWARD JOLIE: Is this
going to be sufficiently stout,
847
00:38:36,659 --> 00:38:38,626
or should we cut a thicker one?
848
00:38:38,661 --> 00:38:40,490
ELLICK: I think that's
pretty tiny, Ed.
849
00:38:40,525 --> 00:38:42,389
JOLIE:
It is.
850
00:38:42,423 --> 00:38:45,357
JOHNSON: The team
wants to carry out experiments
851
00:38:45,392 --> 00:38:48,118
to try to reproduce the tracks
at White Sands.
852
00:38:48,153 --> 00:38:50,742
♪
853
00:38:50,776 --> 00:38:53,848
They're building two simple structures
854
00:38:53,883 --> 00:38:55,850
to see if one of them might leave
855
00:38:55,885 --> 00:39:00,130
similar drag marks to those
found in the desert.
856
00:39:00,165 --> 00:39:01,718
Ed, if you want to
857
00:39:01,753 --> 00:39:04,100
lash the end pieces together. JOLIE: Okay.
858
00:39:06,067 --> 00:39:08,691
I'll grab the important piece.
859
00:39:08,725 --> 00:39:11,694
JOHNSON: The first design
is an A-frame structure,
860
00:39:11,728 --> 00:39:14,800
based on a traditional device
used by Indigenous peoples
861
00:39:14,835 --> 00:39:17,665
called a travois.
862
00:39:17,700 --> 00:39:19,840
They're attaching 40-pound weights
863
00:39:19,874 --> 00:39:22,118
to represent a hunk of meat.
864
00:39:22,152 --> 00:39:23,706
I think that's the 40 pounds.
865
00:39:23,740 --> 00:39:26,053
This feels, like, more than
40 pounds, is this...?
866
00:39:26,087 --> 00:39:28,607
Honestly, that's 40 pounds.
867
00:39:28,642 --> 00:39:31,955
Two 15-pound weights,
plus two 5-pound weights.
868
00:39:31,990 --> 00:39:34,717
[chuckling]
869
00:39:34,751 --> 00:39:36,512
That's...
870
00:39:36,546 --> 00:39:38,410
We might have some structural issues.
871
00:39:38,445 --> 00:39:40,101
[laughter] I don't remember my daughter
872
00:39:40,136 --> 00:39:41,793
ever weighing this much! [laughs]
873
00:39:43,588 --> 00:39:46,038
JOHNSON: Carol is
going to pull each design.
874
00:39:46,073 --> 00:39:47,695
Walking barefoot, like the people
875
00:39:47,730 --> 00:39:50,940
who created the prints at White Sands.
876
00:39:50,974 --> 00:39:52,459
It feels pretty stable.
877
00:39:52,493 --> 00:39:53,391
ELLICK:
It looks pretty stable. It feels,
878
00:39:53,425 --> 00:39:54,875
from my end, it feels pretty good too.
879
00:39:57,809 --> 00:39:59,120
ELLICK: I was going to
follow the edge of the water,
880
00:39:59,155 --> 00:40:00,743
is that what you were thinking?
881
00:40:00,777 --> 00:40:01,744
WATKINS:
I think that's a good way.
882
00:40:01,778 --> 00:40:03,573
Okay. Okay.
883
00:40:03,608 --> 00:40:06,887
[grunts] Whoa, getting started.
884
00:40:06,921 --> 00:40:08,923
JOHNSON: Carol leaves
behind clear footprints
885
00:40:08,958 --> 00:40:10,546
and drag marks in the mud.
886
00:40:12,030 --> 00:40:15,723
♪
887
00:40:15,758 --> 00:40:18,243
WATKINS: Look at that.
JOLIE: Yeah, that's great.
888
00:40:18,277 --> 00:40:21,902
WATKINS: The footprints
are both on one side.
889
00:40:21,936 --> 00:40:23,524
I would have thought
there would have been footprints
890
00:40:23,559 --> 00:40:26,769
on either side and that the drag line,
891
00:40:26,803 --> 00:40:29,668
would have been
between the two. JOLIE: Mm-hm.
892
00:40:29,703 --> 00:40:32,050
And it appears to me, as well,
that what we're seeing
893
00:40:32,084 --> 00:40:34,811
is that the footprints
are the side opposite
894
00:40:34,846 --> 00:40:36,606
the weight imbalance on the travois.
895
00:40:36,641 --> 00:40:39,989
WATKINS: Either that or the
fact that there are two sticks
896
00:40:40,023 --> 00:40:43,130
is having an impact
on the way it's moving.
897
00:40:43,164 --> 00:40:44,545
JOLIE:
Looks great.
898
00:40:47,030 --> 00:40:50,689
JOHNSON: They record
the marks for further study.
899
00:40:50,724 --> 00:40:52,242
WATKINS: Let's get
one up by that footprint
900
00:40:52,277 --> 00:40:56,074
where the mud has pushed over to, okay?
901
00:40:57,903 --> 00:40:59,767
That's a good start.
902
00:40:59,802 --> 00:41:01,735
♪
903
00:41:01,769 --> 00:41:04,634
JOHNSON: Next, they
try the second design...
904
00:41:04,669 --> 00:41:07,672
a single pole with the same
weight attached.
905
00:41:07,706 --> 00:41:08,880
WATKINS: Do you want me to come up
a little bit?
906
00:41:08,914 --> 00:41:10,088
ELLICK:
Pull it forward a little bit.
907
00:41:12,815 --> 00:41:14,195
So... Put that end down.
908
00:41:14,230 --> 00:41:16,094
JOLIE: Come up parallel to this one.
909
00:41:16,128 --> 00:41:18,614
ELLICK:
All right, all right.
910
00:41:18,648 --> 00:41:21,996
[stick dragging]
911
00:41:22,031 --> 00:41:25,103
♪
912
00:41:28,865 --> 00:41:34,181
JOHNSON: This creates a single
drag line with a regular wobble pattern.
913
00:41:34,215 --> 00:41:36,563
That feels quite different pulling it
914
00:41:36,597 --> 00:41:40,118
on the single pole
rather than the double travois.
915
00:41:40,152 --> 00:41:43,259
WATKINS: So it definitely
is wobbling back and forth
916
00:41:43,293 --> 00:41:46,745
much more than the one with
the two-pole travois.
917
00:41:46,780 --> 00:41:48,195
Standing and staring at them
both in parallel,
918
00:41:48,229 --> 00:41:50,059
it's really drawn into stark relief
919
00:41:50,093 --> 00:41:51,819
Yeah. how different they are.
920
00:41:51,854 --> 00:41:54,028
It's a bit of a surprise,
actually. [shutter clicks]
921
00:41:54,063 --> 00:41:56,652
♪
922
00:41:56,686 --> 00:41:59,655
JOHNSON: But which
design makes a pattern closest
923
00:41:59,689 --> 00:42:02,830
to the tracks found at White Sands?
924
00:42:02,865 --> 00:42:05,902
WATKINS: My impressions
are that the straighter lines
925
00:42:05,937 --> 00:42:09,078
at White Sands pretty much equate with
926
00:42:09,112 --> 00:42:12,288
the straighter lines
we're getting with the travois.
927
00:42:12,322 --> 00:42:15,256
That's definitely not saying
that's the only way
928
00:42:15,291 --> 00:42:17,051
they could have had those straight lines.
929
00:42:17,086 --> 00:42:20,986
But just based on this initial experiment,
930
00:42:21,021 --> 00:42:25,128
I would be more inclined
to go with the double pole.
931
00:42:27,027 --> 00:42:30,789
JOHNSON: This experiment
suggests how Ice Age humans
932
00:42:30,824 --> 00:42:34,966
might have transported meat
or other heavy objects.
933
00:42:35,000 --> 00:42:37,865
But how long ago were they walking along
934
00:42:37,900 --> 00:42:40,212
the ancient lakeside at White Sands?
935
00:42:42,421 --> 00:42:44,769
♪
936
00:42:44,803 --> 00:42:47,634
It was time to visit Denver to catch up
937
00:42:47,668 --> 00:42:49,739
with Jeff Pigati and Kathleen Springer.
938
00:42:49,774 --> 00:42:51,983
PIGATI: Yeah, right at the top of the
sequence there.
939
00:42:52,017 --> 00:42:53,950
So that one has a stem attached.
940
00:42:53,985 --> 00:42:54,951
Still has a stem attached?
941
00:42:54,986 --> 00:42:56,332
Yeah.
That's awesome.
942
00:42:56,366 --> 00:42:57,851
We'll go through there. Yeah.
943
00:42:57,885 --> 00:43:00,716
JOHNSON: At the U.S.
Geological Survey Lab,
944
00:43:00,750 --> 00:43:02,925
Jeff has been analyzing
the seeds they found
945
00:43:02,959 --> 00:43:04,789
in the sediment layers at White Sands.
946
00:43:04,823 --> 00:43:06,307
♪
947
00:43:06,342 --> 00:43:07,999
He's been using radiocarbon dating
948
00:43:08,033 --> 00:43:12,244
to calculate the age of
the seeds, and from that,
949
00:43:12,279 --> 00:43:14,177
the age of the footprints.
950
00:43:16,283 --> 00:43:17,905
PIGATI:
This is the carbon extraction
951
00:43:17,940 --> 00:43:19,424
and graphitization system.
952
00:43:19,458 --> 00:43:21,357
And, basically, what we do here
is take a seed.
953
00:43:21,391 --> 00:43:24,429
We combust it in oxygen.
954
00:43:24,463 --> 00:43:26,155
We turn the carbon that's in the seed
955
00:43:26,189 --> 00:43:28,778
into carbon dioxide.
956
00:43:28,813 --> 00:43:30,021
We get rid of everything
else that's in the seed...
957
00:43:30,055 --> 00:43:31,125
water and other other contaminant gases
958
00:43:31,160 --> 00:43:32,126
that we don't want...
959
00:43:32,161 --> 00:43:34,888
and we end up with pure CO2.
960
00:43:34,922 --> 00:43:37,649
♪
961
00:43:37,684 --> 00:43:39,789
And we basically take that carbon dioxide,
962
00:43:39,824 --> 00:43:42,205
convert it to graphite,
963
00:43:42,240 --> 00:43:46,727
and that's what we actually
send out to the AMS lab.
964
00:43:46,762 --> 00:43:48,660
So you turn the seed into a gas
and then back into a solid.
965
00:43:48,695 --> 00:43:50,317
That's exactly right,
we start with a solid,
966
00:43:50,351 --> 00:43:52,353
we turn it into a gas, clean it up,
967
00:43:52,388 --> 00:43:55,046
and then end up with a
pure graphite pellet at the end.
968
00:43:55,080 --> 00:43:56,841
In these little targets, right here.
969
00:43:56,875 --> 00:43:58,359
That's a tiny little
thing. Exactly.
970
00:43:58,394 --> 00:44:00,258
It's about the size of a pencil
lead, they're very small.
971
00:44:00,292 --> 00:44:01,259
And they're sealed into this thing?
972
00:44:01,293 --> 00:44:02,743
That's right, exactly.
973
00:44:02,778 --> 00:44:04,434
I see this little
closed chamber. Yeah.
974
00:44:04,469 --> 00:44:06,747
JOHNSON [voiceover]:
The precious graphite pellets
975
00:44:06,782 --> 00:44:11,407
are then sent to a mass
spectrometry lab to be analyzed.
976
00:44:11,441 --> 00:44:12,857
So what happens at the
mass spectrometry lab?
977
00:44:12,891 --> 00:44:14,755
Yeah, so that's where they
measure the ratios
978
00:44:14,790 --> 00:44:16,757
of the various
carbon isotopes. Uh-huh.
979
00:44:16,792 --> 00:44:18,483
And those are the data that we get back,
980
00:44:18,517 --> 00:44:20,071
and we use those to calculate the age.
981
00:44:20,105 --> 00:44:22,038
♪
982
00:44:22,073 --> 00:44:25,352
JOHNSON [voiceover]:
It's the moment of truth.
983
00:44:25,386 --> 00:44:27,216
After more than a year and a half,
984
00:44:27,250 --> 00:44:29,701
have Kathleen and Jeff managed to find out
985
00:44:29,736 --> 00:44:31,254
the age of the footprints?
986
00:44:34,119 --> 00:44:38,330
So tell me, what were the
dates of those footprints?
987
00:44:38,365 --> 00:44:41,126
We were able to document that humans
988
00:44:41,161 --> 00:44:42,852
were in White Sands National Park
989
00:44:42,887 --> 00:44:45,096
between 23,000 years ago,
990
00:44:45,130 --> 00:44:47,201
and about 21,000 years ago,
991
00:44:47,236 --> 00:44:49,479
JOHNSON:
23,000 years ago?
992
00:44:49,514 --> 00:44:52,344
That's way older than there's
been good evidence
993
00:44:52,379 --> 00:44:53,483
for humans in North America.
994
00:44:53,518 --> 00:44:55,831
It's about 10,000 years older
995
00:44:55,865 --> 00:44:57,798
than sort of the established, sort of,
996
00:44:57,833 --> 00:45:01,319
thought of when humans arrived
in the Americas.
997
00:45:01,353 --> 00:45:03,977
JOHNSON: And you got tracks at more
than one layer,
998
00:45:04,011 --> 00:45:06,117
which means that
wasn't just one group of people
999
00:45:06,151 --> 00:45:08,050
at one moment in time. No.
1000
00:45:08,084 --> 00:45:11,156
That it was many groups
of people over a lot of time.
1001
00:45:11,191 --> 00:45:12,917
SPRINGER:
2,000 years.
1002
00:45:12,951 --> 00:45:15,022
I mean, 2,000 years itself
1003
00:45:15,057 --> 00:45:16,990
is a long duration. It is.
1004
00:45:17,024 --> 00:45:18,370
But the fact that they were here
1005
00:45:18,405 --> 00:45:21,132
23,000 thousand years
ago... Yeah, crazy, huh?
1006
00:45:21,166 --> 00:45:22,443
JOHNSON: Blows my mind,
I mean...
1007
00:45:22,478 --> 00:45:24,307
SPRINGER:
It blew our mind! [laughs]
1008
00:45:24,342 --> 00:45:27,345
That's like 10,000 years before Clovis.
1009
00:45:27,379 --> 00:45:29,174
SPRINGER:
Yes.
1010
00:45:29,209 --> 00:45:31,245
that's like the entire length
of human civilization
1011
00:45:31,280 --> 00:45:32,868
before Clovis.
1012
00:45:32,902 --> 00:45:34,283
SPRINGER:
Yeah, go figure.
1013
00:45:34,317 --> 00:45:36,147
This is not a subtle result.
1014
00:45:36,181 --> 00:45:37,942
♪
1015
00:45:37,976 --> 00:45:40,323
[voiceover]:
If these dates are correct,
1016
00:45:40,358 --> 00:45:42,567
that would make the White Sands footprints
1017
00:45:42,601 --> 00:45:44,983
the earliest direct evidence of humans
1018
00:45:45,018 --> 00:45:48,090
ever found in North America.
1019
00:45:48,124 --> 00:45:49,781
PIGATI: This is the Last Glacial Maximum.
1020
00:45:49,816 --> 00:45:52,370
This is when the ice sheets
were at their maximum,
1021
00:45:52,404 --> 00:45:53,923
and it's been thought that those
ice sheets
1022
00:45:53,958 --> 00:45:56,305
blocked people from coming down
into North America.
1023
00:45:56,339 --> 00:45:58,100
And what we found was that the people
1024
00:45:58,134 --> 00:46:00,067
were already here at that time.
1025
00:46:00,102 --> 00:46:01,034
JOHNSON: So you couldn't be blocked
from getting here
1026
00:46:01,068 --> 00:46:02,518
if you're already here.
1027
00:46:02,552 --> 00:46:03,830
SPRINGER:
That's right. If you're already here.
1028
00:46:03,864 --> 00:46:04,554
JOHNSON: And if you've been here
for a couple thousand years?
1029
00:46:04,589 --> 00:46:05,728
SPRINGER: Right. Yeah.
1030
00:46:05,763 --> 00:46:07,454
JOHNSON: What did you think when
you saw the results?
1031
00:46:08,904 --> 00:46:10,353
Holy...
1032
00:46:10,388 --> 00:46:12,114
[laughter]
1033
00:46:12,148 --> 00:46:13,425
It was pretty much like that. I mean...
1034
00:46:13,460 --> 00:46:15,565
There was words that were spoken
1035
00:46:15,600 --> 00:46:17,567
that were emphatic words.
Wow. Just wow, yeah.
1036
00:46:17,602 --> 00:46:22,331
♪
1037
00:46:22,365 --> 00:46:25,334
JOHNSON [voiceover]: But some
experts question these results.
1038
00:46:25,368 --> 00:46:26,611
They're troubled by the lack
1039
00:46:26,645 --> 00:46:28,544
of additional archaeological evidence
1040
00:46:28,578 --> 00:46:30,028
of this ancient population.
1041
00:46:32,410 --> 00:46:36,172
Others say the dating method
could be flawed
1042
00:46:36,207 --> 00:46:39,382
arguing that the sediment layers
may have been disturbed.
1043
00:46:39,417 --> 00:46:42,316
Or the seeds may have absorbed
older carbon
1044
00:46:42,351 --> 00:46:44,387
from surrounding groundwater,
1045
00:46:44,422 --> 00:46:46,458
which could skew the carbon dating.
1046
00:46:48,667 --> 00:46:50,911
This is an extraordinary discovery.
1047
00:46:50,946 --> 00:46:52,326
How confident are you
1048
00:46:52,361 --> 00:46:55,329
in the quality of the dates
that you've achieved?
1049
00:46:55,364 --> 00:46:57,953
We're very confident...
these, these ages,
1050
00:46:57,987 --> 00:46:59,989
we were able to reproduce them
extremely well.
1051
00:47:00,024 --> 00:47:03,061
They maintain what we call
stratigraphic order.
1052
00:47:03,096 --> 00:47:04,960
Basically, the oldest at the
bottom, youngest on the top.
1053
00:47:04,994 --> 00:47:06,133
And even though some of these samples
1054
00:47:06,168 --> 00:47:08,860
were only separated by a
centimeter or two of sediment,
1055
00:47:08,895 --> 00:47:11,483
they still maintain that order,
and that's one of the,
1056
00:47:11,518 --> 00:47:12,657
one of the, one of the key
things that we wanted to see.
1057
00:47:12,691 --> 00:47:14,210
And so it's not just what
we see in the lab,
1058
00:47:14,245 --> 00:47:16,488
but it's also what we see
in the field taken together
1059
00:47:16,523 --> 00:47:18,007
is really what makes this powerful.
1060
00:47:18,042 --> 00:47:20,561
JOHNSON: This is a huge discovery,
how do you feel?
1061
00:47:20,596 --> 00:47:21,942
[laughs]
Exhausted!
1062
00:47:21,977 --> 00:47:24,048
[laughing]
1063
00:47:24,082 --> 00:47:27,120
♪
1064
00:47:27,154 --> 00:47:28,949
JOHNSON [voiceover]:
If the results are correct,
1065
00:47:28,984 --> 00:47:31,158
then these prints could have
been left behind
1066
00:47:31,193 --> 00:47:34,058
by some of the earliest known Americans.
1067
00:47:35,956 --> 00:47:39,477
Back at White Sands,
I was curious to find out
1068
00:47:39,511 --> 00:47:43,964
what Kim Charlie and Joe Watkins
make of the discovery.
1069
00:47:43,999 --> 00:47:47,623
So now that there are
dates of 23,000 years ago
1070
00:47:47,657 --> 00:47:51,454
with Native American footprints,
how does that make you feel?
1071
00:47:51,489 --> 00:47:53,422
WATKINS:
It's just amazing.
1072
00:47:53,456 --> 00:47:56,632
We talk about having always been here,
1073
00:47:56,666 --> 00:47:59,221
it's just remarkable to put
that much of a movement
1074
00:47:59,255 --> 00:48:00,256
further back in time.
1075
00:48:00,291 --> 00:48:02,465
So now we've added another
1076
00:48:02,500 --> 00:48:04,329
6,000 to 8,000 years
1077
00:48:04,364 --> 00:48:06,918
to what archaeologists have told us was
1078
00:48:06,953 --> 00:48:09,507
the time depth of our history.
1079
00:48:09,541 --> 00:48:13,338
And so this keeps putting
that history back in the news,
1080
00:48:13,373 --> 00:48:15,547
keeps telling people, "Well, yeah,
1081
00:48:15,582 --> 00:48:19,586
you've been here 500 years,
we've been here for 20,000."
1082
00:48:19,620 --> 00:48:22,106
Here's our proof, you know?
1083
00:48:22,140 --> 00:48:26,455
Footprints, footprints of our ancestors.
1084
00:48:26,489 --> 00:48:29,320
You know, that goes to show, we were here.
1085
00:48:29,354 --> 00:48:32,426
We were here on this earth
a very long time ago.
1086
00:48:32,461 --> 00:48:36,120
♪
1087
00:48:36,154 --> 00:48:39,709
JOHNSON: But if humans
were here 23,000 years ago,
1088
00:48:39,744 --> 00:48:42,057
how did they get here?
1089
00:48:44,231 --> 00:48:46,440
At that time,
1090
00:48:46,475 --> 00:48:51,135
the corridor between
the ice sheets did not exist.
1091
00:48:51,169 --> 00:48:53,689
So humans might have followed
the Pacific shoreline,
1092
00:48:53,723 --> 00:48:56,381
possibly by boat,
1093
00:48:56,416 --> 00:48:58,521
a route known as the
"kelp highway."
1094
00:49:01,731 --> 00:49:04,079
But how exactly
they would have made it here
1095
00:49:04,113 --> 00:49:07,047
during the Ice Age is still unknown.
1096
00:49:09,739 --> 00:49:12,294
JOHNSON: These footprints tell us
that people were here
1097
00:49:12,328 --> 00:49:14,434
during the Last Glacial Maximum.
1098
00:49:14,468 --> 00:49:16,263
So how, how do you think they got here?
1099
00:49:16,298 --> 00:49:21,268
WATKINS: I think probably the
coastal highway is the best bet.
1100
00:49:21,303 --> 00:49:23,615
Many old sites are going to be
submerged under water now.
1101
00:49:23,650 --> 00:49:25,790
So I, I think that's where
we need to look.
1102
00:49:25,824 --> 00:49:28,517
♪
1103
00:49:28,551 --> 00:49:30,036
JOHNSON [voiceover]:
Whatever the answer,
1104
00:49:30,070 --> 00:49:32,107
there's no doubt that these
astonishing discoveries
1105
00:49:32,141 --> 00:49:35,041
are another step forward
1106
00:49:35,075 --> 00:49:38,251
in scientists' understanding
of human history.
1107
00:49:38,285 --> 00:49:41,668
And perhaps they could also
shed new light on humans' role
1108
00:49:41,702 --> 00:49:44,360
in the extinction of Ice Age animals.
1109
00:49:46,431 --> 00:49:48,606
So where does this leave us?
1110
00:49:48,640 --> 00:49:51,781
For many years, we thought that
the Ice Age animals went extinct
1111
00:49:51,816 --> 00:49:54,474
about the same time that people
got to North America.
1112
00:49:54,508 --> 00:49:58,029
Now this site is telling us
something very different.
1113
00:49:58,064 --> 00:50:00,238
Basically what we're seeing is
that humans were here
1114
00:50:00,273 --> 00:50:03,759
more than 10,000 years before
the extinction of the animals.
1115
00:50:03,793 --> 00:50:06,348
So the question of was the
extinction caused by climate,
1116
00:50:06,382 --> 00:50:08,729
or people, or both,
1117
00:50:08,764 --> 00:50:12,250
has just become a much more
complex problem to solve.
1118
00:50:12,285 --> 00:50:14,666
♪
1119
00:50:14,701 --> 00:50:18,049
One theory is that when humans
arrived on this continent,
1120
00:50:18,084 --> 00:50:19,671
their numbers were too small
1121
00:50:19,706 --> 00:50:24,711
to make a big impact on the wildlife.
1122
00:50:24,745 --> 00:50:28,059
But at some point, populations increased,
1123
00:50:28,094 --> 00:50:31,580
and they developed
better hunting techniques.
1124
00:50:31,614 --> 00:50:34,721
Was this what eventually spelled
the end for the animals?
1125
00:50:36,792 --> 00:50:38,449
People have always thought it was either
1126
00:50:38,483 --> 00:50:40,106
climate or people that caused
1127
00:50:40,140 --> 00:50:42,349
the extinction of the Ice Age megafauna.
1128
00:50:42,384 --> 00:50:43,799
What do you think?
1129
00:50:43,833 --> 00:50:47,251
You know, I...
we really don't know yet.
1130
00:50:47,285 --> 00:50:49,598
But what we do see, you know,
without a reasonable doubt,
1131
00:50:49,632 --> 00:50:51,531
is that, you know, around 12,000 years,
1132
00:50:51,565 --> 00:50:53,395
the area starts to dry out,
1133
00:50:53,429 --> 00:50:56,156
the lake dries up and then the dunes form.
1134
00:50:56,191 --> 00:50:58,158
So climate change might have
been influencing that as well.
1135
00:50:58,193 --> 00:50:59,642
Maybe someday we'll, we'll find out.
1136
00:50:59,677 --> 00:51:01,748
We might not ever learn.
1137
00:51:01,782 --> 00:51:04,647
But, but you know, the
exciting thing about White Sands
1138
00:51:04,682 --> 00:51:06,753
is there's thousands of prints to study.
1139
00:51:06,787 --> 00:51:08,858
So, you know, the secret
might be locked there
1140
00:51:08,893 --> 00:51:09,859
somewhere in the sand.
1141
00:51:09,894 --> 00:51:13,553
♪
1142
00:51:13,587 --> 00:51:14,899
JOHNSON:
The unique preservation
1143
00:51:14,933 --> 00:51:19,731
of these ancient footprints
could yield more clues
1144
00:51:19,766 --> 00:51:23,528
about the lives of Ice Age Americans.
1145
00:51:23,563 --> 00:51:27,118
SPRINGER: We're very
excited because it's, it's kind of
1146
00:51:27,153 --> 00:51:28,499
the tip of the iceberg, you know?
1147
00:51:28,533 --> 00:51:29,707
White Sands is still there.
1148
00:51:29,741 --> 00:51:31,226
Those tracks are still there.
1149
00:51:31,260 --> 00:51:34,298
They're eroding out every day,
every minute.
1150
00:51:34,332 --> 00:51:37,611
And we get the opportunity to go
back and, and to learn more.
1151
00:51:37,646 --> 00:51:38,578
JOHNSON:
So the research goes on, then.
1152
00:51:38,612 --> 00:51:40,476
Yeah, it goes on, sure.
1153
00:51:40,511 --> 00:51:41,615
PIGATI: Yeah, this is just the
beginning, that's exactly right.
1154
00:51:41,650 --> 00:51:43,824
It's a tremendous opportunity.
1155
00:51:43,859 --> 00:51:46,620
It... it's opening up
the world of archaeology
1156
00:51:46,655 --> 00:51:48,415
way beyond where it's been.
1157
00:51:48,450 --> 00:51:51,591
It's going to give a new
generation of archaeologists
1158
00:51:51,625 --> 00:51:54,180
something more to shoot for,
1159
00:51:54,214 --> 00:51:56,251
to see whether we can go back
1160
00:51:56,285 --> 00:51:58,494
any farther than 23,000 years,
1161
00:51:58,529 --> 00:52:03,223
or whether this, in and of
itself, is the threshold.
1162
00:52:03,258 --> 00:52:11,335
♪
1163
00:52:13,716 --> 00:52:19,722
♪
1164
00:53:14,052 --> 00:53:18,264
♪
89292
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