Nova (1974–…): Season 45, Episode 14 - First Face of America - full transcript

The remains of a 13,000-year-old skeleton of a prehistoric teenager are located in an underwater cave in Mexico.

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♪ ♪

NARRATOR:
Deep underground,

in a flooded
Mexican cave system,

divers make an amazing
discovery.

BETO NAVA:
The feeling is like one of those
outer space black holes

that sucks all your light.

ALEX ALVAREZ:
I see no reflection of my light.

The heart starts to beat
very hard.

NARRATOR:
At the bottom of a vast
sunken pit--

a forest of prehistoric bones.

♪ ♪



In their midst,
the skull of a girl.

♪ ♪

NAVA:
It's just incredible to see

another human in this
environment-- it's amazing.

DOMINIQUE RISSOLO:
He said you can't tell anyone

because we've never really seen
anything quite like this before.

♪ ♪

NARRATOR:
Who was she?

How did she die?

(birds squawking)

It's kind of a missing link
right?

And suddenly you are sitting
with that.

♪ ♪

NARRATOR:
The mystery of the girl
in the cave



leads scientists on a journey

into the world
of the very first humans

to arrive in the Americas.

Who were they?

How did they get here?

Finally, there are answers.

BLAINE SCHUBERT:
It's the most remarkable project

I'll probably ever work on.

NARRATOR:
They discover the way of life
of an Ice Age people.

JAMES ADOVASIO:
Rapidly moving big game hunters.

NARRATOR:
But it all begins
with the story of a girl

who lived 13,000 years ago.

VERA TIESLER:
Between 15 and 16 years of age.

♪ ♪

We know a lot more about
the early lives of the Americans

than we would ever have known
without her.

NARRATOR:
And what happened
on the day she died.

Fracture at death.

♪ ♪

(splashing)

NARRATOR:
Astonishing new finds

and a glimpse of the
"First Face of America."

♪ ♪

Right now on "NOVA."

♪ ♪

Major funding for "NOVA"
is provided by the following.

NARRATOR:
In a dark cave, deep underwater,

a cache of prehistoric bones,

Ice Age animals that walked the
earth thousands of years ago.

Among the ancient bones,

the skeleton of a girl,

one of the very first Americans.

Her skeleton is so complete,

it will allow scientists

to reconstruct her life
and death in amazing detail,

providing answers to questions
that have long puzzled them

about the peopling
of the Americas.

JIM CHATTERS:
In her death she left us
this incredible record

of the life of these
earliest people.

NARRATOR:
13,000 years after she died,

a young girl launches

an exciting archaeological
adventure,

finally unlocking
a great mystery:

how and when did humans
first enter the new world?

♪ ♪

(insects buzzing,
birds chirping)

NARRATOR:
In the remote jungles
of Yucatan in Mexico...

a team of cave divers,

intrigued by reports
of prehistoric bones,

is on its way to explore
a system of underground cenotes.

♪ ♪

It's a dangerous undertaking.

Beneath the surface
of the Yucatan Peninsula,

the cenotes are a vast network

of underground caves
and tunnels.

They stretch
for hundreds of miles

through the limestone bedrock
of the peninsula.

They were once dry.

But flooded at the end
of the last ice age

about 10,000 years ago.

♪ ♪

Only a fraction of the network
has been explored.

♪ ♪

The possibilities
of getting trapped,

lost, or running out of air...

(compressed air hissing)

are ever-present.

Over the years,
dozens of experienced divers

have drowned
in these flooded sinkholes.

♪ ♪

(indistinct chatter)

♪ ♪

Because they don't know
how big the cenote system is,

they've prepared carefully.

Their tanks have a special mix
of oxygen, nitrogen, and helium

that will allow them
to dive deep.

They also have rebreathers
that recycle their air,

extending their dive time.

Propelled by underwater
scooters,

they travel along submerged
tunnels for almost an hour.

In the first passages
of the cenote

they notice that guide wires
had been laid,

a sign that someone has explored
these tunnels before them.

♪ ♪

(water bubbling)

But before long, the lines end.

They are now
in a part of the cenote system

that is completely unknown.

♪ ♪

With no idea of what lies ahead,

they press on.

Suddenly the floor and walls
of the tunnel drop away.

NAVA:
At the end of this tunnel
we can see darkness.

And then everything was black.

ALVAREZ:
I was in front.

When I see no reflection
of my light,

it wasn't-- the heart starts
to beat very hard.

(heart beating rapidly)

NARRATOR:
They find themselves suspended
in a vast watery pit.

NAVA:
The feeling is like

we were faced with one of those
outer space black holes

that suck all your light.

ALVAREZ:
And then I am floating
in the dark.

You can't even see the floor,

you can't even see
the next wall.

NARRATOR:
The black hole, Hoyo Negro,

is so big,

the beams of their flashlights
cannot find its floor.

♪ ♪

Breathless with excitement,
they begin their descent.

♪ ♪

Finally, at a depth
of over a hundred feet,

their flashlights detect
the bottom

and reveal a treasure trove
of ancient bones

beyond their wildest dreams.

All of a sudden,
we start finding bones.

We see this huge pelvis.

And there was this beautiful
broken femur on top of a rock.

ALVAREZ:
Big, big bones,

we knew could be something
similar to an elephant.

♪ ♪

NARRATOR:
Here is the massive thigh bone
of an extinct elephant,

the skull of a cave bear,

a giant sloth.

The floor of the Hoyo
is littered

with over 20 skeletons of
long-extinct ice age species.

But the most amazing find
comes last.

Just as we thought
it couldn't get any better,

all of a sudden,
we go a little bit up.

♪ ♪

There's this human skull.

♪ ♪

It's amazing.

I mean this is the discovery

of our lifetime,

it's not going to get any better
than this.

NARRATOR:
The rest of the skeleton
is not far away.

A whole human skeleton
surrounded by the bones

of ice age megafauna

has never been found before.

♪ ♪

Who is it?

How did this person get here?

And when?

♪ ♪

(camera flash popping)

For many months
the divers explore the Hoyo,

taking bone samples and photos.

Finally,
they decide to send them

to the director
of subaquatic archaeology

at Mexico's National Institute
of Anthropology and History,

Pilar Luna.

(Pilar Luna Erreguerena
speaking Spanish)

(translated):
In 2009, Alejandro Alvarez
got in touch with me

about an extremely important
find

in a place called Hoyo Negro.

The news was very exciting

because I had always believed

that there is much
to be discovered

in this area
of the Yucatan Peninsula

about the past
and the first people

to populate the Americas.

♪ ♪

NARRATOR:
Pilar decided to send a CD
of the divers' photos

to the scientist who has studied

more ancient human remains
from the Americas

than any other-- Jim Chatters.

CHATTERS:
I said, "I've been looking
at your CD,

do you want to know
what you have?"

And she said, "Yes,
no one's been able to tell us."

And I said, "Well, you have
an adolescent female."

♪ ♪

And she said, "Would you like
to take over the study

of the human skeleton?"

To work with ancient humans
and extinct animals

at the same time, nobody's been
able to do that before.

♪ ♪

NARRATOR:
Knowing that the skeleton
they have found is a young girl,

the divers give her the name
of a mythological water nymph--

Naia.

NAVA:
You get a connection,

and you get more respect
if we have a name.

♪ ♪

And Naia was a kind
of water nymph.

It's a little bit related
to the spirits of the cave.

NARRATOR:
Jim must wait to examine
Naia's skeleton

until the divers retrieve her.

But from a few bone and tooth
fragments they bring him,

he can at least try to find out
how long ago she lived.

He hopes a radiocarbon
dating lab

will give him the dates
he needs.

It proves to be difficult.

To get radiocarbon dates,

it's necessary to extract
proteins such as collagen,

which contain carbon.

But her long sojourn under water

has destroyed all the collagen
in Naia's bones.

CHATTERS:
The problem we have
is in tropical environments

bone does not produce
good radio carbon dates.

The protein part of the bone
is dissolved away

by bacteria and
warm-warm weather.

And so what we're trying
is sort of second best,

which is the tooth enamel.

And tooth enamel, being
a very tight crystalline matrix,

has the best chance of having

a non-contaminated material
we can work with.

NARRATOR:
The key is to find
the radioactive isotope

carbon-14, present along
with other elements,

in the cells
of all living things.

The molecules of this form
of carbon are unstable,

slowly losing protons
to become nitrogen.

They do this at a steady rate
measured as a half-life,

the time it takes half
the carbon-14 to decay.

Once an organism dies,
the carbon-14 in its tissues

stops being replaced.

So its density in the tooth

relative to other
more stable elements

will give Jim a reading
on Naia's age.

♪ ♪

First of all, they dissolve
the tooth fragment...

Then heat the solution

until it becomes
gaseous carbon dioxide.

(bubbling)

Once frozen and purified,

the solution becomes
a fine carbon graphite powder.

♪ ♪

A mass spectrometer will then
be able to measure

the amount of carbon-14
in the powder,

if it's there
in the first place.

♪ ♪

At the end of the process,

the mass spectrometer
gets a carbon-14 reading

and compares it to a stable form
of carbon in the tooth.

That will give its age.

♪ ♪

CHATTERS:
Okay, so it's nearly
stabilizing now.

It's about two half-lives.

Yep.

NARRATOR:
At the end of the analysis,

the tooth proves to be
almost 13,000 years old.

CHATTERS:
It's really exciting.

Makes her one of the oldest
human skeletons yet found

in the Americas.

So, I couldn't be happier
about that result.

NARRATOR:
The radiocarbon date tells Jim
he is dealing with

a sensational find.

♪ ♪

Naia lived at the dawn
of human life in the Americas.

13,000 years ago,

the Americas were
the only habitable continents

that had not been settled
by our species.

♪ ♪

Since leaving Africa
some 80,000 years ago,

Homo sapiens had spread
through the Middle East,

Europe, Australia, and Asia

but had not yet reached
the New World.

When sea levels fell,
during the last ice age

to create a land bridge
between Siberia and Alaska,

they could finally enter
the Americas.

♪ ♪

Who were those first humans
to arrive in North America?

For a long time,

scientists believed that it was
the Clovis people.

Known principally by the
distinctive stone spear points

they left behind,

the Clovis people
have long been a mystery.

Who were they?

Were they the ancestors
of modern day Native Americans?

♪ ♪

Speculation about the Clovis
people began in the 1930s

when archaeologists
first discovered

their stone tools near Clovis
in New Mexico,

a site dating to around
13,000 years ago.

At that time,
the Bering Land Bridge

still connected
Siberia and Alaska.

When Clovis points
started showing up at sites

all over North
and Central America,

archaeologists decided
that the people who made them

must have been
the first Americans...

♪ ♪

Who used them to hunt bison

and ice age animals
like woolly mammoths.

JAMES ADOVASIO:
Because Clovis points
were widely distributed

in most of un-glaciated
North America

on down into Central
and parts of South America

the notion appeared
that the makers of those points

were the very first people
in the New World.

NARRATOR:
The Clovis people left their
stone tools in many sites,

but only a handful of bones.

So in 1968, when workers started
turning up Clovis points

at a site in Montana,

followed by the bones
of a 13,000-year-old child,

it was extremely exciting.

Called Anzick Child,
the one-year-old boy

had been buried

with a huge cache
of Clovis blades

and provided enough DNA
to be sequenced.

Here for the first time
was a link

between the Clovis technology
and an actual person.

♪ ♪

Would Naia also be revealed
as one of the Clovis people

as her age would seem
to suggest?

CHATTERS:
Naia and five other
mostly partial skeletons

are the only ones we know of

that are older than 12,000
years.

It's an extremely small club.

They are our window into
who those early people were.

NARRATOR:
Naia's skeleton promises to be
a treasure trove of information

about those first Americans.

Jim wastes no time
in going to Mexico

and organizing a dive
to bring her up.

But it won't be easy.

♪ ♪

(squawking)

♪ ♪

He knows that the bones
will be extremely fragile.

Susan Bird is the diver tasked
with picking up Naia's skull

and bringing her to the surface.

So, what I've got them set up as

is the best orientation
toward you.

They're designed that way
to have more room at this end

for your arms to come in.

NARRATOR:
Jim is nervous

as he and Susan rehearse
with plaster casts of the bones.

CHATTERS:
So, you'll slide your hand
under and support it that way.

All right.
Your strongest part
is here.

Your weakest points
are here and here

so we want to protect them.

Then just gently,
chin first...

release.

SUSAN BIRD:
On the day of the dive
there was so much tension,

so many people
on the verge of freaking out.

The stress level,
the tension was palpable.

(indistinct chatter)

♪ ♪

NARRATOR:
The entire operation
will be carefully documented,

photographed, and filmed.

♪ ♪

Underwater lights
have been set in the Hoyo

and almost half a mile
of cabling to power them.

People don't see that if you
go there, it's pitch black.

That's why it's call "Negro."

It's a 200 feet dome
and it's totally dark,

but with all of this technology
that we're bringing,

now we can finally see it,
it's amazing.

♪ ♪

MIKE MADDEN:
Hey Dominique,

tell me how much
slack you want.

♪ ♪

NARRATOR:
Leader of the underwater
camera crew Mike Madden

rehearses the divers
and photographers one last time.

You pick up the skull,

you come around here,

and you try to stay--
try to be at the level

of the table
and just set it in there, okay?
Okay.

Once you put her in the box,

she's in the box.

You do whatever you got to do,
you put the top on the box.

NARRATOR:
Finally, the moment arrives.

All right.

Let's rock and roll, man!

NAVA:
Good, let's do it!

♪ ♪

F55, coming
down.

♪ ♪

♪ ♪

(sighs)

NARRATOR:
As the divers set off carrying
the box for Naia's skull,

Jim is left to anxiously wait.

He feels a heavy burden
of responsibility.

Naia has lain for 13,000 years
at the bottom of Hoyo Negro.

In a few hours he'll know
if she makes it back out safely.

♪ ♪

(bubbling)

♪ ♪

NARRATOR:
Deep in the cenote system,

the divers are moving
through a world

they have only dimly seen
before.

♪ ♪

The huge underwater lights

reveal the full dimensions
of the Hoyo.

♪ ♪

As Susan approaches Naia's skull
with Beto and Alex behind her,

she too is nervous.

♪ ♪

After 13,000 years in the water,

the bone is brittle.

♪ ♪

It would be so easy
to let Naia's skull slip.

Finally, she has the skull
safely in her hands.

Naia is ready for her return
to the surface.

♪ ♪

It will take time.

The divers must make at least
three decompression stops

to avoid the bends.

♪ ♪

Finally, for the first time
in 13,000 years,

Naia emerges from the water

and into the light of day.

♪ ♪

(barely audible):
It's just... perfect...

♪ ♪

Gingerly, she is carried away
from the cenote.

A 4x4 is waiting to take her
across the province

to the labs

of the National Institute
of Anthropology and History

in Campeche, Mexico.

With conservator Diana Arano,

Jim lifts Naia's skull

onto the bed of a CT scanner.

It will give him
basic information

about the state of her bones.

♪ ♪

Ah, wow.

CHATTERS:
Her skull is in
very good condition.

She's fossilized to a degree,

which greatly
strengthens the bone.

So it's what I was thinking
I might see,

and it's even better
than I expected it to be.

So yeah, it's fantastic.

NARRATOR:
After the scan,

her skull is put in a tank
with chemicals

to protect it
from further exposure to air

after thousands of years
underwater.

♪ ♪

Meanwhile,
the rest of Naia's skeleton

is brought up bone by bone

for forensic analysis.

♪ ♪

♪ ♪

Finally, in Mexico City,

at the National Museum
of Anthropology,

Naia's skeleton is assembled.

♪ ♪

Jim and his colleague
Vera Tiesler examine it

for clues to her life.

TIESLER:
We have a set

of attributes in her skeleton
that tell us

that she was between
15 and 16 years of age.

Let's talk about the teeth,
for example.

The lower jaw,

basically her permanent
dentition is erupted

except for the third molars,
which are about to erupt.

She's past her growth spurt
but she's still in puberty,

she's still adolescent.

NARRATOR:
The third molars,
which haven't erupted yet,

are Naia's wisdom teeth,

so that's consistent
with an age of about 16.

CHATTERS:
Let's talk a little bit about

what's going on
with her pelvis here.

Well, if we take a look
at the sacrum,

the segments
are not fused yet

and some of them
are lacerated, they're open.

There are a lot of
indication for trauma.

She must have had
a childbirth, a pregnancy,

at an age where...
when her pelvis

was not prepared to hold
or, well, produce a child.

NARRATOR:
As more details
of her life emerge,

they start to provide clues

to what happened on that day
that Naia entered the cave.

♪ ♪

What was she looking for?

13,000 years ago,
the cenotes were dry.

It was the last ice age,

so much of the world's water
was locked up in glaciers.

Sea levels were lower.

So the system where
she was found was a vast cave.

But in the recesses of that cave
there was water.

(birds squawking)

CHATTERS:
The environment of the Yucatan
at the time of Naia's life

appears to have been very dry,
particularly seasonally dry.

The only way
you're going to get at water

is to find it inside the caves
during the dry season.

♪ ♪

So, she entered the cave almost
certainly looking for water.

NARRATOR:
Even if she knew the cave well,
she would have been wary.

She would have known that humans
were not the only things

that look for water in caves.

SCHUBERT:
I think it's common knowledge,

when you're a human
on the landscape

and you have predators...

That they use caves for denning.

Large scavengers
will use caves for denning.

Cats use them.

All across the world.

And so entering a cave
is a dangerous thing to do.

Naia would have had that
on her mind going into the cave

I'm sure.

♪ ♪

NARRATOR:
But Naia was tough;

that she was used to
extreme physical activity

is clear from the muscle
attachments on her bones.

CHATTERS:
We're learning
from the muscle developments

in her arms and legs

that she was constantly
on the move:

running, walking.

She has leg muscle development
more like a 35-year-old man

than she has
like a 16-year-old girl.

NARRATOR:
Naia's physique seems consistent
with the nomadic life

of a people always on the move
in search of food.

She was also no stranger
to violence.

♪ ♪

CHATTERS:
She'd been through a rough life.

She's got a fractured
left forearm;

this bone is definitely
not the right shape.

It's got a number of jogs to it,
its spiral fractured.

It's consistent
with being forcibly twisted

by another individual.

Like pulled.

Yeah, twisted and pulled,

which is what often causes these
in modern individuals.

So it's a sort of a...

what we might refer to
as an abuse fracture.

♪ ♪

NARRATOR:
Naia's abuse fracture
is no surprise to Jim.

He has studied around two dozen
of the oldest skeletons

found in the Americas.

Many of them bear the signs
of interpersonal violence--

like a 9,000-year-old skeleton
called Kennewick Man--

with trauma likely
from fighting.

♪ ♪

CHATTERS:
There are a lot of head injuries
in the front of the head.

♪ ♪

We have individuals
with spear wounds.

Kennewick Man, for example,

had a big spear point
healed in his pelvis.

So, we'll see a lot of violence
between the males,

but we also see some

of that violence transferred
over to the females.

♪ ♪

NARRATOR:
Jim is convinced that extreme
male aggression was common

in these ancient
hunter-gatherer populations.

As recent arrivals
in an unknown continent,

theirs was a dangerous
and precarious life.

Women died young,
often in childbirth,

and this may have intensified
male rivalry.

CHATTERS:
Females are dying
in their early 20s.

Males are dying
in their mid to late 30s.

And that's increasing
the competition for females

among the males because the
males are living a lot longer

there are more of them
in proportion to the females.

NARRATOR:
20 years ago,
when Jim started reconstructing

the physical features of these
very earliest Americans,

he noticed something perplexing.

Their facial structure
was different

from modern Native Americans.

Scientists have long assumed
that these earliest people

must be the ancestors
of today's Native Americans,

so he was surprised.

If we compare them
to modern Native Americans

they look quite different.

♪ ♪

And it's been a major question

that I've been struggling with
for 20 years.

Why do they look different
from each other?

NARRATOR:
Jim's first exposure
to this difference

was when he worked on
the 9,000-year-old skeleton

called Kennewick Man.

When he reconstructed the face,

it was clear Kennewick Man
looked very different

from a modern Native American.

And he was not the only one.

♪ ♪

Here's Kennewick Washington.

He's 9,500 years.

Spirit Cave from Nevada,
he's about 10,500.

A Horn Shelter male from Texas
close to 12,000 years old.

And here's Naia from Mexico

at 13,000.

And what's distinctive

about these early individuals,

they're much more ruggedly built
than modern people.

Heavy brows,
big muscle attachments.

Just generally much more massive
and much more projecting,

in their form.

NARRATOR:
By contrast,

modern Native American males
all have much smaller heads

and finer features.

CHATTERS:
You see the much smaller head,

the roundness
of the back of the skull.

Less prominent
muscle development in the face.

He's also got a longer face,

and if you hold him
in a similar position,

his face is tucked in.

It's not projecting anymore.

♪ ♪

NARRATOR:
What did Naia look like?

As Jim and sculptor
Tom McClelland set out

to anatomically reconstruct
her face,

the mystery of these very first
Americans deepens.

♪ ♪

Were these people ancestral
to today's Native Americans?

If so, how can these differences
be explained?

♪ ♪

CHATTERS:
Some folks have suggested
that they're different

because they come from
different parts of the world.

Perhaps some come from Europe.

Perhaps some come from Asia
earlier than the arrivals

that later became
Native Americans.

So, that's been a question
that needed to be answered.

NARRATOR:
Finally, answers are emerging

in the place
where those early humans

entered the western hemisphere
for the first time-- Alaska.

♪ ♪

In the Tanana Valley
of Central Alaska,

archaeologist Ben Potter
and his team

are discovering campsites
made by those early nomads

as they crossed over
from Siberia.

This is the heart
of the land bridge

that once connected Asia
and North America.

BEN POTTER:
People think of the
Bering Land Bridge

as a bridge that you
might fall off of,

when in reality it's a landmass

that stretching a thousand miles
or more north and south

that's connecting Asia
and North America.

It persisted for a long time.

NARRATOR:
This lost continent that,
for at least 20,000 years,

connected what is now
Siberia and Alaska

has been given a name--
Beringia.

It was cut off
from the rest of the Americas

by the ice sheets
covering northern Canada,

a vast territory of tundra,
mountains and grasslands.

For thousands of years,
this was the first home

of those very early immigrants
from Asia.

At campsites
in the Tanana Valley

some 14,000 years ago,
they hunted, fished,

and collected roots and berries
before moving on,

following the herds
that wandered Beringia.

POTTER:
We have evidence
that they're hunting mammoth,

possibly horse,

and later on they're definitely
subsisting on bison.

NARRATOR:
Theirs was a way of life
that left few traces,

but they did leave
some of their stone tools.

These have given Ben important
clues to who they were.

The tools are stored
at the museum

of the University of Alaska
at Fairbanks.

♪ ♪

POTTER:
What we see,

going back at least
20,000 years ago

in parts of northern China,
Mongolia, southern Siberia

is the emergence of
very sophisticated

stone tool technology

that we think partly allowed
them to expand northward.

And we see some of that
same material here in Beringia

in some of the very earliest
sites.

(beeping, clicking)

NARRATOR:
Their stone blades
and spear points tell the story

of an immigrant population

that had changed very little

since arriving from Siberia.

POTTER:
What we have here
is a representative collection

of some of the Beringian
material that we have.

Some of the earliest people
coming across

into this region
are making material

that are quite similar
to what we find in Asia.

So, microblade cores like this,
microblade technology.

Quite distinctive so,
we connect them really well

with the Asian antecessors.

NARRATOR:
But their tools
are completely different

from the distinctive
spear points found

in North America
south of the ice sheets--

the hallmark
of the Clovis culture.

POTTER:
If you compare
this Clovis point

to some of the points
that are being made up here,

they're quite distinct.

So, this has been
one of the problems

that we're trying
to grapple with

is how do we derive Clovis
from some of this

Beringian material,
which looks quite Asian.

NARRATOR:
What is the relation
between these Beringian Asians

and the Clovis people?

And where do Naia and
modern Native Americans fit in?

The answer would come from
Ben's most remarkable discovery;

(helicopter whirring)

On the banks of Alaska's
Upward Sun River,

the grave of two infants.

(camera clicks)

♪ ♪

Clearly loved, these children
had been carefully buried

with symbolic artifacts
and red ochre.

Dating revealed that they
were over 11,000 years old

making this one of the oldest
ceremonial burials

ever discovered in the Americas.

♪ ♪

Here at last was a window
on the belief system

of those first humans
in the new world.

Even more important
for the archaeologists,

the children provided enough
bone to retrieve their DNA.

Would their genes
allow scientists

to untangle the connections

between those first immigrants
to Beringia, the Clovis people,

Naia, and today's
Native Americans?

♪ ♪

Ben sent samples to Copenhagen,

to the Danish geneticist
who is one of the leaders

of the ancient genomics
revolution,

Eske Willerslev.

His research is providing
remarkable insights

into the early peopling
of the Americas.

ESKE WILLERSLEV:
Ancient genomics

have completely transformed
our ability to reconstruct

the biological history
of human beings,

including the biological history

of early peopling
of the Americas.

NARRATOR:
At his lab in the
Museum of Natural History,

Eske and his team extracted DNA
from the bones

of one of the Upward Sun
children.

Then, using massive
computer power

to piece together
the DNA data...

the team was able
to painstakingly reconstruct

the entire genome.

The results revealed
distinctive patterns

of DNA's chemical bases,
known as A, C, T, and G.

These so-called markers
can link a particular individual

to both ancestors
and living descendants.

Now Eske's team compared the
genome of the Upward Sun child

with other DNA results:

from the Anzick Child--
the only human remains

definitively identified
as Clovis;

from Naia's DNA,
studied by Jim and his team;

and from modern
Native Americans.

The results were momentous.

They showed that
the Upward Sun people,

known as Ancient Beringians,

provide links to the ancestors
of all Native Americans.

WILLERSLEV:
The Upward Sun sample
is extremely important

in the sense that it's the
oldest skeleton found in Alaska.

And when we did the genome
of Upward Sun

it became even more interesting

because it turns out to be basal
to all Native Americans.

♪ ♪

NARRATOR:
The genomic analyses
indicated the existence

of a single population

of ancient Asian hunters
in Beringia,

some 25,000 years ago,

who were the ancestors
of all Native Americans--

ancient and modern.

Educator Shane Doyle
views these results

from his perspective
as a member of the Crow tribe.

SHANE DOYLE:
What happened was the ancestors
of tribal people

all were able to come
to a confluence at the Bering

about 25,000 years or more ago.

And all these people
brought their own

genetic profiles with them.

They all had their own
skin color,

their own eye color,
their own size.

They have all their own
phenotypes.

And after they had
children together,

these ancient peoples,

they produced a new group
of people,

and that is who
American Indian people are.

NARRATOR:
For many years,

Shane has worked
to bridge the gap

between scientists and Native
American spiritual leaders.

(thunder rumbling)

He was instrumental
in bringing them together

for the reburial
of the Anzick Child in 2012.

(singing traditional song)

Eske's discoveries
are important to him

because they establish a clear
Native American identity.

DOYLE:
There's not Native American DNA

on the other side
of the Bering Strait.

Nowhere else in the world
is there Native American DNA

except for the Americas.

And so that was
one of the most profound things

that came from this study.

(wind whipping)

♪ ♪

NARRATOR:
So at last the story is clear.

Arriving in Beringia
from different parts of Asia,

about 15,000 years ago,

groups of those very first
Native Americans left

and began the long trek south,

exploring a land that no human
had ever seen before.

♪ ♪

Once south of the ice sheets,
these same people

developed a new way of making
stone tools and weapons--

(spear point sings)

the distinctive Clovis culture.

Their descendants
are today's Native Americans.

Naia's people were part of that
great southward migration.

♪ ♪

When Naia lived,

Jim believes her people
were recent arrivals in Yucatan.

A micro CT scan of her jaw
and her teeth reveals evidence

that they were not familiar
with their environment.

CHATTERS:
We're setting up
a micro CT scan

of Naia's mandible,
her lower jaw.

And the focus is on the teeth.

We want to look at
density variations in the teeth

to look at growth patterns.

NARRATOR:
Density variations are clues
to periods of malnourishment.

They soon become obvious in both
Naia's teeth and jaw bone.

Yeah, so you want to pick
right up...

Mm-hmm.
...there.

CHATTERS:
From the growth patterns
in her bones,

there is periodic growth
interruption.

That is one season every year

she doesn't get enough protein
to eat.

If her people were well adapted
to the place the lived,

they'd been there a long time,
they would've known

how to feed themselves protein
year round.

They don't-- they're new.

♪ ♪

NARRATOR:
Naia has already told scientists
so much about her people.

Her skeleton has one last piece
of information for them.

It's about the day she died.

This is the most indicative.

See the fracture of the bone
and the jagged character

of that fracture?

Jagged-edged breaks occur

in relatively fresh bone,
if not fresh bone.

Mm-hmm.

So that jagged fracture
is consistent

with fracture at death.

NARRATOR:
Jim has thought a lot
about that day--

the day she walked into the cave
13,000 years ago,

the last day of her life.

CHATTERS:
It's hard when
you know someone this well,

you get to learn their life
so much,

not to become attached to them
and have a sense of...

that's why it's hard
to tell her story.

NARRATOR:
What happened on that
fateful day?

♪ ♪

At some point she must've gone
deeper into the cave

in search of water.

The pit where she was found
is a long way

from the nearest entrance
to the cenote system.

♪ ♪

Deep in the system's recesses,

the Hoyo was dry

with a shallow pool of water
at its base.

I think, like the animals,
she got lost.

♪ ♪

NARRATOR:
How did she get lost?

Jim can only speculate.

CHATTERS:
She probably had a torch
to go in with

in order to see her way
around in the cave.

If she lost control of the fire,

lost her light...

♪ ♪

unlike the animals,
she can't scent-orient

to find her way out.

(sounds echoing)

NARRATOR:
She might have wandered
for hours,

perhaps even days.

♪ ♪

CHATTERS:
She's wandering in this cave
for quite a while,

and at some point,
she simply takes a fatal step.

♪ ♪

And the bottom
is no longer there.

♪ ♪

(splashing)

♪ ♪

NARRATOR:
Her pelvis was almost certainly
broken by the fall.

CHATTERS:
She fell a hundred feet

and there's a good chance
she struck something.

I don't think death took long,
if it were not immediate.

♪ ♪

NARRATOR:
Over the centuries
and millennia,

other animals fell into the pit
just like Naia did.

10,000 years ago the cave system
flooded as sea-levels rose,

preserving them all
in the anoxic environment

at the bottom of the Hoyo.

And there they lay

until divers discovered
the cenote,

a time capsule preserving
a unique record of ice age life

on this continent.

Scientists will be studying
this treasure trove of material

for many years to come.

♪ ♪

But it is Naia who has opened
a window on the world

of a mysterious people.

♪ ♪

CHATTERS:
Naia lived a very difficult life

but, in her death
she left us this

incredible record of the life
of these earliest people.

♪ ♪

NARRATOR:
Carefully reconstructed,

Naia has revealed to us
the first face of America.

♪ ♪

This "NOVA" program
is available on DVD.

"NOVA" is also available
for download on iTunes.

♪ ♪