Nova (1974–…): Season 31, Episode 16 - America's Stone Age Explorers - full transcript

More than 2,000 years ago, the thriving city of Petra rose up in the bone-dry desert of what is now Jordan. An oasis of culture and abundance, the city was built by wealthy merchants who carved spectacular temple-tombs into its cliffs, raised a monumental Great Temple and devised an ingenious system that channeled water to vineyards, bathhouses, fountains and pools. But following a catastrophic earthquake and a slump in its desert trade routes, Petra's unique culture faded and was lost to most of the world for nearly 1,000 years. Now, in a daring experiment, an archaeologist and sculptors team up to carve an iconic temple-tomb to find out how the ancient people of Petra built their city of stone.

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The ancestors of modern humans
originated in Africa

at least 150,000 years ago.

By 40,000 years ago,
they had radiated out of Africa

and were occupying most
of Europe, Asia and Australia.

But half the earth
humans had yet to explore.

How people first came to America

remains one of the greatest
mysteries of our past.

Archaeologists have been looking
for the earliest

for a long time...

It's been a Holy Grail for them.

Who was first?

The whole question

of the peopling of the Americas

is a huge piece
of the total human experience.

That's just a question
we can't leave unanswered.

Who were these
earliest explorers?

Where did they come from?

How did they make this epic
journey to the New World?

The first clue to the mystery
was found in a dried-up lake

in Clovis, New Mexico.

Here, in 1933,

archaeologists uncovered a stone
tool made by human hands,

an ancient spearhead.

It became known
as the "Clovis point."

Alongside the Clovis point was
the skeleton of a mammoth

which, evidently, the spearpoint
had been used to kill.

Later, scientists were able
to date the bones,

establishing the age of the
spearhead as 13,500 years old.

It made the Clovis point
the oldest human artifact

ever found in America.

Archaeologists have
now discovered

thousands of Clovis spearpoints
across much of the continent.

There's Clovis
in every one of the 48 states

in the United States,
Mexico, Belize, Costa Rica...

In all kinds of environments.

So many spearpoints spreading
widely across the continent

suggested a rapid expansion
of a weapon

crucial to the lives

of the earliest
Stone Age American explorers.

The Clovis point was the
fundamental basis for survival

in Ice Age America.

Clovis points arguably represent
the state of the art

in hunting weapons on earth
at the time

and are probably capable
of taking down

just about any animal on
the late-Pleistocene landscape.

In an age defined by its
most valuable resource... stone...

The Clovis spearpoint

a great technological

transforming rock
into a killing machine.

It's a very distinctive
type of artifact.

As you can see here,

it has a flake that's been
taken out of the base,

and there's also a flake on the
other side removed from the base

and these are called flutes.

And beyond that, the projectile
point is flaked on both sides.

You see it's worked here
and it's worked on this side,

which is what we call

The bifacial design
transforms a rough stone

into a projectile
with a serrated sharp edge.

The fluting,
some archaeologists speculate,

allows Clovis hunters
to rapidly load

and reload the deadly blades
onto spear shafts.

And when you throw this
at an animal,

this goes in
and sticks in the animal,

and this comes back out
so you can put a new one on it

and start hunting again.

There have been some experiments
carried out by archaeologists,

using replicas of Clovis points
and other stone tools,

in which they were used

to penetrate the hides
of modern elephants,

elephants which had
already deceased.

And it's found
in all these cases

that they actually are
very efficient weapons

and could potentially
kill mammoth

where you'd get them into
the soft, vulnerable underbelly

and then quickly back away.

Testimony to the deadliness
of the Clovis spearpoint

is that in a dozen cases,

they were discovered in the
remains of butchered mammoths.

This led scientists to connect
the spearpoint

to a catastrophe that befell
these Stone Age giants.

For around 13,500 years ago,

all the mega fauna
in the Americas went extinct...

The mammoths,
the giant armadillo,

the giant sloth,
the short-faced bear...

All disappeared
within a few hundred years.

But who were these
big-game hunters

with their Stone Age
weapons of mass destruction?

Where did they come from?

When archaeologists looked
for an answer,

they found an important clue

in the climate
of the ancient world.

Between 24,000 and 13,000 years
ago was the last great Ice Age.

Huge swaths of the northern
hemisphere lay frozen under ice.

These giant ice sheets locked up
vast quantities of water

causing sea levels to drop
far lower than they are today.

When you've got
that much ice on land,

what happens is,
is that it draws, essentially,

water out of the oceans.

So with that much ice on land,

sea levels worldwide
are lowered.

By lowering sea levels,

you expose the continental shelf
between Siberia and Alaska,

and that made it possible for
people to walk to the Americas.

Asia and North America were
essentially one great continent

joined by a land bridge
more than a thousand miles wide.

But although it was possible
to walk from Siberia to Alaska,

giant ice sheets barred entrance
to the rest of the continent.

Then, as the climate warmed
at the end of the Ice Age,

the glaciers receded,
opening up an ice-free corridor

through the center
of the continent.

For the first time, it seemed,

the door was open to the virgin
landscape of the New World.

As that corridor opens up,

that's just about the time when
Clovis appears in the lower 48.

So, it all seemed to work out
very, very beautifully

in terms of the timing of
getting these New World peoples

from Asia into the Americas.

The timing of the land bridge,
the ice-free corridor

and the Clovis dates
all seemed to fit together

in a simple, elegant theory.

13,500 years ago,
Clovis people...

Big-game hunters from Asia,

armed with their lethal
Clovis spearpoint...

Walked across the land bridge
to the Americas,

followed the ice-free corridor
down into the lower continent

and spread across the land,
killing all the great beasts.

As Ice Age glaciers melted,
the seas rose,

submerging the land bridge.

The descendants of the Clovis
people... the Native Americans...

Remained isolated until their
first contact with Columbus.

The theory became known
as "Clovis First."

It was written
into the textbooks

and taught for the better part
of a century.

The Clovis spearpoint became
the icon of the first Americans.

Clovis First was
such a powerful story

that for years,
few archaeologists looked back

beyond 13,500 years ago.

But then, a few did.

Jim Adovasio has spent
the past 30 years excavating

at Meadowcroft,

a prehistoric site
near Pittsburgh, Pennsylvania.

The deeper he dug, the further
back he descended in time.

On these surfaces
that you see before us,

we have signs of repeated visits
by Native Americans

to this site.

These discolorations
literally represent

a moment frozen in time.

Each tag marks ancient fire pits
that can be carbon dated,

creating a cross section
of who lived here and when,

stretching back 13,500 years.

Just below the surface
I'm standing on

is where the conventional
Clovis First model says

that the earliest material
should stop, basically...

That there ought not to be
anything beneath it,

no matter
how much deeper we dug.

But then, Adovasio did
go deeper,

below 13,500 years,
to a time in the Americas

when no trace of humans
should exist,

according to
the Clovis First theory.

He was astounded
by what he found.

The artifacts simply continued,

and we recovered
blades like this

all the way down to 16,000 B.C.

When he published his findings,
he was immediately attacked.

The majority of
the archaeological community

was acutely skeptical,

and they invented
all kinds of reasons

why these dates
couldn't possibly be right.

Some claimed that
nearby coal deposits

had contaminated
Adovasio's samples.

But he was known to be
a meticulous excavator.

a few other archaeologists

began to report evidence

the Clovis First theory

and they, too, were attacked.

The best way in the world

to get beaten up professionally

is to claim you have
a pre-Clovis site.

When you dig deeper than Clovis,

a lot of people do not report it
because they're worried

about the reaction
of their colleagues.

I've been accused
of planting artifacts.

People will reject
radiocarbon dates,

and just simply because there's
not supposed to be any people

here at those times,

and it just goes on
and on and on.

Even faced with evidence
to the contrary,

Clovis First supporters
refused to accept

that people could have arrived

in America earlier
than 13,500 years ago.

For, as they pointed out,

although it was possible
to walk across the land bridge

into present-day Alaska,

ice sheets blocked entry
to the rest of the continent

until at least that time.

As they put it,

if people were coming
to the New World before then,

how could they get past the ice?

Some archaeologists began
to defy the dogma

and search for
an alternative route...

Down the coast of Alaska.

Well, when I was a student,

we learned that the entire
northwest coast of North America

was covered by glacial ice

all the way out
to the continental shelf.

So really there was
no opportunity

for, uh, plants or animals
or much less humans

to exist along that coastline
during the last Ice Age.

Today Jim Dixon and Tim Heaton

are finding evidence
of abundant plants and animals

at a time
when the northwest coast

was thought to be
a lifeless, frozen wasteland.

We just cleaned up
this caribou antler

I want you to take a look at.

Here along the coast,

the glaciers destroyed most
traces of the Ice Age world.

But Heaton and Dixon

have investigated
a rare, undisturbed site

deep underground
in an ancient bear cave.

The cave floor
is excavated inch by inch

from dated layers of soil

going back tens
of thousands of years.


I think it's a bone fragment.

This excavation has uncovered
a record of caribou, fox

and bear bones
dating back 50,000 years.

What this suggests
is that bears survived

the entire last period
of glaciation,

and if bears
could have survived here,

it's certainly clear
that humans could have also.

We now realize that
those early portrayals

of this massive
continental glacier

all the way out to the ocean,
really is... is not accurate.

And that by,
oh, 14,000 to 16,000 years ago,

this ice had
retreated sufficiently

to create habitat
for plants and animals

and ice-free areas that, uh,
could have been used by humans.

Abundant vegetation,
temperate coastal climate

and bear survival
are all evidence

of a possible Ice Age route
to the Americas

along the Alaska coast by sea.

But still no evidence

that humans had actually made
the voyage down the coast.

Then another surprise from deep
in the southern hemisphere

at a place called Monte Verde.

This site of
human habitation in Chile

40 miles from the Pacific coast

was claimed to date back earlier
than Clovis.

In 1997, a group of highly
regarded archaeologists

went to examine the evidence
with their own eyes.

They saw weapons, tools
and other objects... the result

of two decades of excavation.

After intensely scrutinizing
the dating,

they confirmed the artifacts
were older than Clovis

by over a thousand years.

It wasn't until Monte Verde that
we saw the first unambiguous,

unquestionable evidence
of people here before Clovis.

It allowed us to think

that perhaps the initial
peopling of the New World

was beyond 12,000,
13,000 years ago

and allowed us to look further.

But even as more archaeologists
allowed themselves

to consider that Clovis
might not have been first...

the pillars
of the Clovis First theory

could not be completely toppled.

Clovis First remained
the entrenched answer

to the question
of the peopling of the Americas.

And so it could have stayed
until a remarkable discovery.

Doug Wallace takes
a different approach

to the mystery of
the first Americans.

Instead of archaeology,

he's using DNA to reveal traces
of ancient migrations.

Stored in his lab are DNA
samples of indigenous people

collected from all corners
of the globe.

DNA is the molecule
of our genetic endowment

expressed in a code
of four letters

representing four different
chemical bases.

Every cell in these samples
contains DNA.

But Wallace studies
a specific kind of DNA,

not from the nucleus,

which is a random mix of genes
from both parents,

but from the mitochondria...

The cell's energy factories
outside the nucleus.

This kind of DNA is inherited
only from the mother

and is passed intact
from generation to generation

as lineages diverge.

But at a steady
and predictable rate,

tiny mutations creep
like spelling mistakes

into specific stretches of DNA.

The amount of genetic variation
between any two lineages

can reveal how far back in time
they shared a common ancestor.

So what we've been able to do
using genetic variation

and comparing
the genetic variation

of aboriginal populations

from all the major continents
of the world,

we've literally been able
to reconstruct the history

of migration.

When Wallace
and his team analyzed

the mitochondrial DNA
of Native Americans,

they found four
distinctive lineages

that he labeled A, B, C and D.

All four turned out to share
common ancestors back in Siberia

and northeast Asia.

So far these findings
were consistent

with the Clovis First theory...

That the first Americans
came from Asia.

But when Wallace calculated
how long ago the Asian

and Native American DNA
diverged, he was shocked.

He repeated his work,
as did other labs.

The results were consistent.

Three of the four main ancestral
groups... A, C and D...

Diverged from
their Asian forebears

at least 20,000 years ago.

And even more striking,

the first Americans
didn't all come at once,

but in at least three waves
of migration.

All of the papers
that had been published

have come to
a very similar conclusion...

That the first migration
was in the order

of 20,000 to 30,000 years ago.

The DNA results made the Clovis
First theory even more unlikely.

Together with the evidence
from Monte Verde, Meadowcroft

and other sites, it now seemed
as if Clovis people

could not be
the first Americans.

The Pacific coast route offered
a possible alternative

to the Bering land bridge
and the ice-free corridor.

And the DNA suggested
that humans

had been coming to America
in waves,

and far earlier
than ever imagined.

Only one last pillar
of the epic Clovis First theory

was still standing.

The artifact that inspired
the theory...

The icon of Stone Age America...
The Clovis spearpoint itself.

Where did it come from?

Archaeologist Dennis Stanford

decided to search
for its origins

along the route
from Asia to America.

But as he worked back
from Alaska to Siberia,

the trail went cold.

The weapons and tools he found
in Asia were quite different.

After looking
at the collections,

we were disappointed

that we didn't find
what we thought we would find,

and I was surprised to find

that the technologies
were so much different.

The Clovis spearpoint
is a single stone,

Or shaped on both sides...

With a flute, or groove,
at its base.

The spearpoints in Asia

are made from lots
of small, razorlike flints

called microblades,
embedded in a bone handle.

Microblade technology
is making a projectile point

or a knife blade out of bone

and then cutting a slot in it

and then putting the microblades
in the slot,

and that's a totally different
philosophy entirely

than using the bifacial
projectile point.

As you can see here, it's just
a total different mindset.

Now there was a real puzzle.

The DNA says the earliest
Americans are from Asia,

yet the Clovis point
is nowhere to be found in Asia.

It was a puzzle
not only for Stanford,

but also his colleague
Bruce Bradley.

Bradley is an anthropologist
and a skilled flint knapper...

An expert at crafting
stone tools.

One day, while making
a Clovis point,

he had a moment of inspiration.

He remembered a popular
science book he had seen

when he was a student.

It showed pictures
of ancient spearheads

made by the Solutreans...

People who lived
in Ice Age France and Spain.

Their spearpoints
resembled Clovis points.

It seemed unbelievable,

but Stanford and Bradley
posed the question:

Could the Clovis point

and some of the earliest
Americans be from Europe?

I was going through
the old arguments,

"Yeah, well,
Solutreans' 5,000 years
older than Clovis

and you've got
the Atlantic Ocean
out there,

so I wasn't convinced

that we really ought
to push forward on it.

I remember it a little
bit differently.

You said, "Are you
out of your mind?"

Despite the unlikelihood
of the connection,

Stanford and Bradley decided
to pursue the idea.

Bradley thought
an important clue might lie

in the specific technique

in making Clovis points.

And you can see how this,
starting from this side,

went and took off
this whole other side.

This is what we call an
overshot, or outrepassé, flake...

A very intentional process.

Overshot flaking
was an unusual technique

that left behind a distinctive
byproduct... big flakes...

At ancient Clovis stone
working sites.

Bradley wondered if traces of
this technique might show up

in southwestern France,

where the Solutreans
had lived 20,000 years ago.

When he went there
to investigate,

one thing soon became clear...

The Solutreans
were a remarkable people.

The Solutreans were responsible

for much of the great
Stone Age art of Europe

and were the forefathers
of the artists

who painted the Sistine Chapel
of the Ice Age...

The caves of Lascaux.

They did a lot of carving

in bone and in antler
and in ivory.

Uh, they fashioned
spear throwers.

They painted on cave walls.

They had a fairly complex means

of expressing themselves
through their art.

Could these remarkable
Stone Age Europeans

have brought the Clovis
spearpoint to the Americas?

Bradley's research took him
to the local museum

in the town
of Les Eyzies, France.

What he saw

were hundreds of what looked
very much like Clovis points.

What we're seeing here

is only the finished objects,

only the things
that museum people thought

were really good for display.

It doesn't always show you
how things were made.

To connect the Solutreans
and Clovis,

he needed to find out if
they produced their spearheads

using the same
big-flake technique.

So what we do is we go back

to the collections
of the broken materials,

which is probably 99%
of what there is here,

and in that we're seeing
the various ways

that the Solutrean
were making the things,

not just the finished objects.

And so it's the pieces
that are hidden away

that are going to tell us
the most.

And there, in the drawers,
were big flakes...

A clear sign that the Solutreans
had made their spearheads

in an identical technique
to that of Clovis.

This is a good example here

that shows a kind of flaking

that... where the flake
is struck from one side...

and went across the surface,
removed some of the other side.

And these pieces show it
over and over and over again.

I mean, just about
any piece you pick up

shows this
very special technique.

I just knew there had to be
some kind of a connection.

Clovis and Solutrean spearpoints
not only look alike,

they are made
the same unusual way.

To Stanford and Bradley,
this was a powerful clue

that prehistoric explorers
had come from Europe

and brought with them
the technology

that transformed
Stone Age America...

The Clovis spearpoint.

It was an outrageous idea,
with a few big problems.

The Solutreans' culture ended in
Europe around 18,000 years ago,

and the Clovis point
would not arrive in America

for another 5,000 years.

If the Solutreans brought
the Clovis point to America,

where had they been?

Stanford and Bradley needed
to find some artifact

in the Americas
to bridge the time gap.

They scoured Clovis sites
across the continent,

places where other
archaeologists had been digging

for years.

Then, from a site called Cactus
Hill in Virginia, a possibility:

a point that resembled
the Solutrean style,

and it dated far earlier
than the Clovis.

Here we have a projectile point
from a feature that dates

right at 15,900 years
or 16,000 years ago,

which is clearly
right in the middle

between Clovis and Solutrean,

and what's really exciting
about it

is that the technology here
is very similar to Solutrean.

In fact, it's closer
to Solutrean than Clovis,

but you can see that
it's in a progression

between Solutrean and Clovis.

So you have Solutrean,
Cactus Hill and Clovis.

For Stanford and Bradley,

the Cactus Hill point bridged
the 5,000-year gap,

connecting Solutreans in France
and Clovis in America.

But their fledgling theory
now confronted

another massive problem
almost 3,000 miles wide...

The Atlantic Ocean.

At the time of the Solutreans,

ice sheets stretched down
as far as southern France,

where winter temperatures were
50 degrees colder than today.

Unlike the more temperate
Pacific coast,

the Atlantic would,
at times, have been thick

with icebergs and blizzards.

There are 5,000 kilometers

of open North Atlantic Ice Age
conditions to be crossed,

there are icebergs floating
around in the Bay of Biscay

and it's a polar desert.

Could the Solutreans,
a Stone Age people,

have made such a voyage?

Stanford flew to a place

where he thought he might find
the answer...

Barrow, Alaska,
on the edge of the continent

at the northernmost tip
of the United States.

Here he hopes the native people
of Alaska, the Inupiat,

might reveal how,
thousands of years ago,

the Solutreans could have made
an epic trans-Atlantic journey.

Today, the Inupiat survive

of minus 35 degrees.

For warm waterproof clothing,

traditionalists prefer
caribou skin and sinew,

the same materials available
to their Stone Age ancestors.

And for food on their seasonal
hunting trips,

the Inupiat turn to
an age-old resource... the sea.

The sea has been our garden.

We don't have any grow...
growing things.

There's nothing growing up here,

so we depend on the sea
for our livelihood,

and most of our hunting is based
on sea-mammal hunting.

We have the great whales, polar
bears, walrus, seals and fish.

Even with warm clothing
and food,

could the Solutreans
have made boats capable

of crossing thousands of miles
of treacherous, icy water?

Today, traditional Inupiat build
umiaks... whaling boats...

Using sealskin
and caribou sinew,

stretched on wood frames
and waterproofed with oil

applied directly
from seal blubber.

These same techniques
and materials

would have been available
to prehistoric people.

Boats like these can...
could have made the journey

that we're hypothesizing
for Solutrean people quite well.

I was noticing
on the distance signs

here in the middle of town,

they say it's about
1,500 miles to Greenland,

and we know that,

Eskimo peoples moved that
distance from here to there

several times.

In Arctic seas filled
with pack ice...

Conditions similar
to the Ice Age Atlantic...

The boats pass the test,

as the Inupiat paddle
from ice floe to ice floe.

Well, it certainly
is exactly the way

I think the Solutrean guys
were dealing with the ice edge,

because you can get in and off
of the ice real rapidly

and... and if the weather gets
a little... little nasty,

then you just pull up
off the... out of the water

and onto the ice.

For Stanford and Bradley,

this ability to travel great
distances in Arctic conditions

suggested how the Solutreans
could have made

their epic journey
during the Ice Age.

They had now gathered
a broad range of evidence.

Physical similarities

between the Solutrean
and Clovis spearpoints,

a similar technique
used to make them,

and the Cactus Hill point

connecting Solutrean
and Clovis in time...

all added up to a radical
and provocative theory...

That the Solutreans invented
the Clovis point technology,

and Ice Age Europeans

were amongst America's
earliest explorers.

the theory was attacked.

The close resemblance of
the spearpoints was not enough.

If you're careful
in your selection,

you can always find one
or two things that look alike.

I'm not looking
for one or two things,

I'm looking for lots of things.

The artwork, the antler
spear-throwers... where are they?

Did they get left behind?

There's no reason
why they shouldn't be there,

but we don't see it.

Can one spearpoint bridge
a 5,000-year gap?

Although Cactus Hill...

It's radiocarbon date
and artifact...

Have been used to bridge the gap

between the Solutrean
and Clovis,

in reality it will take
a lot of sites,

a lot of radiocarbon dates

and a large assemblage
of artifacts

to make that connection.

And although the Solutreans
may have been capable

of making a cross-Atlantic

there's little archaeological
evidence that they did.

There is absolutely no evidence

of deep-sea fishing.

There's absolutely no evidence,
for that matter, of boats.

But Stanford argues that
crucial evidence is missing,

submerged under 300 feet
of water,

as rising sea levels inundated
the Solutrean coastline

at the end of the Ice Age.

The debate raged on,

with arguments for and against
the Solutrean theory.

Then came evidence
that again seemed

like it might end
the battle... DNA.

It was the latest report from
colleagues of Doug Wallace,

who were investigating
early human migrations.

They were puzzling over
mitochondrial DNA samples

from a Native American tribe
called the Ojibwa.

When we studied the
mitochondrial DNA of the Ojibwa,

we found, as we had anticipated,

the four primary lineages:
A, B, C and D.

But there was about a quarter
of the mitochondrial DNAs

that was not A, B, C and D.

There was a fifth source of DNA
of mysterious origin.

They called it X and,
unlike A, B, C and D,

they couldn't find it anywhere
in Siberia or eastern Asia.

But it was similar
to an uncommon lineage

in European populations today.

At first, they thought
it must be the result

of interracial breeding
within the last 500 years,

sometime after Columbus.

We naturally assumed

that perhaps there had been
European recent mixture

with the Ojibwa tribe

and that some European women had
married into the Ojibwa tribe

and contributed their
mitochondrial DNAs.

But that assumption
proved wrong.

When they looked at the amount
of variation in the X lineage,

it pointed to an origin
long before Columbus...

In fact, to at least
15,000 years ago.

It appeared to be evidence
of Ice Age Europeans in America.

Well, what it says is that
a mitochondrial lineage

that is predominantly found
in Europe

somehow got to the Great Lakes
region of the Americas

14,000 to 15,000 years ago.

Could X be genetic evidence
of the Solutreans in America?

Further investigation raised
another possibility.

The ancient X lineage
may have existed in Siberia

but died out, though not before
coming over to America

with ancient migrations.

And so the DNA data itself
cannot distinguish

between those two alternatives.

It could be either
from Europe or from Siberia

of a population
that is now lost.

So X could have reached
the Americas through Asia,

or across the Atlantic
directly from Europe.

The DNA could not provide
a storybook ending.

The hypothesis that Clovis may
derive from... from Solutrean...

It's going to be... it's going
to take years to sort that out.

That's not the most
important thing right now.

The very fact that that
hypothesis is being articulated

forces us to think
in... in much broader terms

about the problem
of the peopling of the Americas.

With Clovis First in ruins

and the Solutrean theory
still hotly contested,

now archaeologists must pull
together their discoveries

into an all-encompassing
new theory

of the peopling of the Americas.

And central to that quest is
the origin of the Clovis point.

Although the technology needed

to produce a Clovis point

was found among other cultures
during the Ice Age,

the actual Clovis point itself
is unique to the Americas,

suggesting that it was invented
here in the New World.

Perhaps the Clovis spearpoint
was not brought

by big-game hunters from Asia

or seafaring Solutreans
from Europe.

Could the Clovis point be the
first great American invention?

A prime place for investigating
Clovis culture in America

is the Gault site
in central Texas.

Unlike its hot, arid

Gault is a shady,
parklike oasis.

Michael Collins,
from the University of Texas,

started excavating at Gault
in 1998.

As you can see,

the Gault site is
really a special place.

It's well watered,
got lush vegetation,

an abundance of resources...
Both plant and animal.

It's an ideal place for people
who are hunters and gatherers.

Gault is the best
of both worlds.

Nearby is a parched plateau
for hunting game,

while down in a cool,
stream-fed valley are pecans,

walnuts and berries.

And not far from the stream bed
is a natural resource

so crucial to the survival
of prehistoric people

that it defines the whole age...

We're at an outcropping here,

a rich outcropping
of cretaceous chert.

This was the choice material

for making stone tools
for at least 13,000 years.

It's pretty good stuff
when you break it open.

It, uh...

You see how it breaks?

You get nice flakes of it
out of there.

To a Stone Age craftsman,
this particular rock

was perfect for fashioning
stone tools

and may have drawn people
for hundreds of miles.

To date, nearly half a million
Clovis artifacts

have been found at Gault,

but curiously,
very few are spearpoints.

The Clovis spearpoint is

the... sort of the icon
of Clovis culture.

But what we see
at the Gault site is

we only have
about 30 projectile points,

mostly broken and worn out
and discarded Clovis points

in comparison to the several
thousand other tools.

What can explain
the lack of spearpoints

at one of Stone Age America's
premier stone quarries?

And why would big-game hunters
need any other tools

beside the spearpoint?

At the Texas Archaeological
Research Lab,

Marilyn Shoberg examines
the Clovis tools

under a microscope.

By studying the scratches
on the tool,

she hopes to discover
its function.

The last hand to use this tool
did so some 13,000 years ago.

Very fine striations

that are running parallel
to the edge of the blade...

And these striations,
all parallel to the edge,

indicate that it was used

primarily in
a longitudinal motion...

Sort of slicing,
as in slicing grass.

To test her idea,

Collins and his colleagues
created replica tools

made from the same Gault stone
and used them at the site.

In cutting just this
little bit of grass here,

I've already developed
a bright sheen

right along the edge,

and under the microscope,
that'll be a very bright polish

built up on that edge,
and it'll have striations in it

going this way
because of my cutting motion.

Under the microscope,

the replica tool has
the same sheen and pattern

as the Clovis tool.

Perhaps Clovis people
were cutting grass or reeds

for baskets, bedding
or thatched roofs for shelter.

Shoberg examines other types
of tools found at the site.

Deep troughed grooves,

characteristic of contact
with bone.

A spearpoint used for hunting.

All along the edge
of this artifact, there's polish

that's characteristic of contact
with a soft material like meat.

A knife used for slicing food.

This is the hide punch.

A punch or awl
for sewing tailored clothing.

This little blade fragment was
used to engrave or incise bone.

Small pieces of limestone
have been discovered at Gault

etched with mysterious
geometric patterns...

Among the only examples
of Ice Age art in America.

Art, tailored clothes, baskets
and thatched roofs for shelter

all contradict
the old Clovis First image

of nomadic mammoth murderers.

And although the remains of
a mammoth were found at Gault,

Collins and colleagues
have found

far more bones of turtles, birds
and small mammals.

This menu suggests more variety

than a big-game hunter's diet
of woolly mammoth and bison.

What emerges from the totality
of all of that information is

these people were generalized
hunters and gatherers;

they were living on
a variety of animals;

staying in one place
for quite a while

and not simply pursuing
large game

as their primary way of life.

There's even evidence of trade
networks between Clovis people

at different sites
across the continent.

It's not uncommon to find
Clovis points

hundreds of miles from
the source of the original rock.

And different bands
of Clovis people

probably traded
more than just tools.

They may have been exchanging
potential spouses.

Although we tend
to think sometimes

of hunter-gatherers as being
fairly simple in adaptation,

it's actually
a pretty complicated world

in which they live.

There have to be
social mechanisms in place

that allow you to
sort of share information

and relate to surrounding groups
in some systematic way

and to be
on good enough terms with them

that you're able
to sort of exchange mates,

and therefore genetic viability,

across an otherwise sort
of sparsely populated landscape.

A clue that Clovis people

had intimate knowledge
of the landscape

lies, once again,
with the Clovis point.

Many have been found in caches...

Bundles of spearpoints
hidden away for later use

by Clovis hunters.

David Kilby has traveled
the United States

and studied all of the nearly
two dozen known caches.

This strategy of caching

intimate familiarity
with the landscape

and, uh... sort
of a complex understanding

of the distribution of different
resources around the landscape.

The fact that they're putting
tools and raw material

in specific places
on the landscape

and leaving them behind

suggests that they knew
with some confidence

where they were going to be
in the future.

Caching, trade and travel
must have involved

patterns of seasonal migration

developed over dozens
of generations.

This emerging picture
of the Clovis lifestyle

contradicts the old image
of Clovis as a single people...

Nomadic big-game hunters

sweeping rapidly across
the continent

with their lethal spear,
wiping out all the great beasts.

The long-standing notion

of the rapid spread... the
archaeologically rapid spread...

Of Clovis across the continent
has been taken to mean

the spread of a people
across the continent.

An alternative to that might be
that the spread of Clovis

is actually the expansion
of a technology

across existing populations...
A little bit analogous

to the fact you can go
anywhere in the world

and find people driving
John Deere tractors.

Technology can spread
across different languages,

different cultures
quite readily.

Perhaps this is the birth
of an intriguing new theory

for the peopling of America.

The first Stone Age explorers
arrive on this continent

more than 20,000 years ago...

Much earlier than scientists
ever imagined.

They come from Asia,
and maybe even Europe,

by land and by sea.

Tenuously at first,
these different groups spread

across the virgin land,
and over thousands of years,

they develop an intimate
knowledge of the New World.

Around 13,500 years ago,
a stone weapon is invented

so powerful,
so crucial to survival

that it spreads swiftly across

all the people of the Americas.

With this new technology
they take root,

proliferate and prosper.

Clovis is the first great
invention of the New World

and the icon of the peoples

who may rightfully be called
the first Americans.