Original subtitles

For 270,000 years, our species, Homo sapiens,

lived in a world inhabited by other types of human.

We hunted and foraged for food,

alongside many of our human relatives.

But one by one, we out-survived them...

..and spread across the planet as small bands of nomads...

..until we'd reached almost every corner of the globe.

But a great landmass still evaded us.

The Americas.

As we entered this new world, we would face ferocious predators...

..and towering giants.

MAMMOTHS BELLOW

But how we took on these challenges...

..and the ways we began to tame nature

in our journey through the Americas...

..would set us on a path to how we live today.

It's a chapter of our story

that begins in one of the coldest and most dangerous times

humans have ever known.

At the height of the last Ice Age,

a time when sea levels were lower than today,

people were spreading from East Asia

into a place that no longer exists.

A vast land bridge called Beringia.

WIND HOWLS

And in this frozen north,

small groups of travellers dispersed ever eastward...

..and found themselves stepping into a new land.

If you were asked to conjure up in your mind

a world that was magical, that was pristine, that was primal,

you'd imagine something like this.

The northwest coast of America absolutely takes your breath away.

We don't exactly know when humans first arrived in North America...

..but many archaeologists believe

it was sometime around 20,000 years ago.

A time when this would have been a challenging place to live.

They were here at one of the coldest moments Homo sapiens had ever known.

And the landscape would have looked so different.

There would have been very few trees.

And, as far as the eye could see,

there would have been barren, icy rock.

They knew how to survive

in the barren lands of Beringia that they'd come from.

But their new environment was different in a few crucial ways.

The northern half of this continent

was covered in a vast, towering ice sheet.

From here in the northwest,

this wall of ice blocked routes into the deep interior...

..largely confining people to the ice-free land nearer the coast.

WAVES CRASH

All that's left from their time here

are footprints, stone tools, and animal bones.

Now, we know that they sometimes would have hunted seal,

they would have eaten fish,

they would have eaten seabirds if they could catch them.

GULLS CRY

Only tiny fragments of evidence remain...

SLIDE PROJECTOR CLICKS

..that hint at how they survived.

And whilst this northwest coast

offered them steady but limited sustenance,

the strip of land between the shore and the ice sheets

promised new opportunities to find food...

..but also hid unexpected new dangers.

Oof.

This is a now-extinct predator,

and it would have roamed these parts in the northwest

when the first people arrived in the Americas,

and they actually call it the short-faced bear.

And there is nothing short about this bear.

When it stood on its hind legs,

it would have been about 11, 12 feet tall.

That's about four metres.

And so it would have made the grizzly bear look...

..actually somewhat manageable.

And then look at these teeth, look at these canines.

The stuff that nightmares are made of.

And when it bumped into humans...

..it must have been absolutely terrifying.

And just like those humans,

these bears, too, would have been hungry.

But the early people of the northwest

did not run from the monsters that roamed this land.

Instead, it seems, they went on the offensive.

Signs of their bravery remain in caves along the Canadian coast.

Here, archaeologists sift through the muddy layers of time...

..to find out more about the risks these early people took to survive.

You know when people talk about archaeology?

Yes.

At the back of a cave, digging mud is...

..is... This is the hard stuff.

One thing that has been found

in a number of caves on the northwest coast

is, er... spear points in association with bear bones.

Yeah.

And these date as far back as 13,000 years. - Mm.

So is this one of these spear points?

This is a fragment of a spear point

that was found in a cave not too far from here.

Yeah.

We have uncovered a bone in the wall of this unit.

And it's, er, 20 centimetres below the surface.

And, er, so I'm going to pull it and we'll see if it moves.

All right.

And we don't know what species it is or what bit of bone it is?

Er, there's not enough here to know for sure.

Yeah.

But it is a pretty big mammal, for certain.

Oh, look at that.

- Oh, it's not ending. - THEY CHUCKLE

Just make sure it slides out.

Ah, it's a rib, isn't it? Is it?

It looks like a rib. - Yeah. - Yeah.

So that could be a bear rib.

It's probably most likely what it is, cos it's quite robust.

How amazing.

What age do you think it is?

Well, we have some other samples from above where this bone is.

Yeah.

And they're coming back, er, around 14,000 years old.

OK. So it's old.

So it could be the same age or older. - Yeah.

You know, one of the most wonderful things about archaeology

is that sometimes you uncover something

that hasn't seen the light of day in thousands of years.

And in this case, well, maybe 14,000 years.

Well, we're interested in where bears were hunted in the past.

And in the winter,

when there's... There's not as many resources around

and people are feeling a bit hungry,

knowing where there is a bear den is quite a valuable thing,

cos you can come up there and dispatch the bear.

You'll have a load of meat, fur, as well as bones.

One theory of how they hunted bears

would have meant getting perilously close.

Essentially, a hunter would go with a party to a cave,

smoke the bear out of the cave,

and entice that bear to attack a single hunter.

That hunter would be armed with a bracing spear.

A bear would come, er, to take the hunter up in a bear hug,

- which is a common thing that they do. - Yeah.

And the idea is a bear would take that hunter

and cru, er... essentially give him a good crushing.

The hunter, at the same time, would brace the spear on the ground

and aim it at the bear's heart.

- And so essentially the bear would take... - Oh...

..the hunter and the spear into the bear hug,

thereby spearing itself through the heart.

A successful bear hunt could have meant food through the winter.

But not every hunter survived.

This is the bone cast of the oldest adult

to have been found along this coast. They were born 10,000 years ago.

And this individual has been given a name - Shuka Kaa.

And there's so much we don't know about this person.

We don't know about their family life.

We don't know if they had children.

But the amazing thing about bones

is that they can tell a story if you know how to read them.

We know that this individual was a male.

We can tell that from various features,

like the squareness here of the chin,

like the back of the mandible,

like the angle here on the pelvis.

On a female, you would typically expect that angle to be much wider.

And it's kind of sad

because you can also tell quite a tragic story on the bones as well.

If you notice here -

that is a puncture wound,

and it fits quite well with the canine of a bear.

And so we think that this individual possibly met their demise

because they were hunting for bears.

The dangers early humans faced down in order to survive

are hard to imagine now.

But their precarious relationship with this unforgiving land

had begun to shift...

..thanks partly to a surprising form of help.

WOLVES CHATTER

By hunting in packs,

wolves can bring down prey far larger than themselves.

A person, especially on their own, would be highly vulnerable.

Good girl. Yeah.

It's unusual to have them all just around, hey?

OK, come on. Let's go.

Wolves are, and always have been, wild animals.

- Shelley, am I able to come a bit closer? - Yep.

I think the question is, how close?

It's funny, I can feel it in my shoulders.

My shoulders are a little bit tense.

But, given time, wolves are able to habituate to humans.

Hello.

WHISPERING: Hello.

From around 40,000 years ago, probably in Siberia,

before humans had even reached North America,

the threat they faced from wolves

began to transform into something different.

Now, we're not exactly sure of the details,

but it might have gone something like this.

Wolves would gather around human campsites.

Now, at first, maybe humans were terrified.

Maybe they thought that they wanted to eat them.

But actually, some of those wolves weren't interested in that at all -

they were looking for scraps.

And as they were doing that,

maybe they started fending off other predators

and protecting our combined territory.

And because of this, humans started tolerating

some of the least aggressive, some of the most docile of these.

Maybe they even started feeding them.

We were reshaping wolves into dogs...

..and began to use them...

..to guard our camps...

..hunt prey...

..and pull sleds.

Generation after generation,

we selected the most docile animals and reared their pups...

..driving the evolution of a cooperative behaviour

that suited our needs.

This marked a turning point for the human species.

Living with dogs helped us hunt for food and survive.

It gave us this much-needed edge over hunger,

but it also marked this profound and completely unprecedented shift

in our relationship with nature.

Because never before had any living thing,

whether plant or animal, been domesticated.

This was a complete first.

Unbeknownst to us, we were becoming curators of nature

and gaining more control over our own fate.

But powerful forces far beyond the control of any human

were about to open new gateways into the North American continent.

And as people answered the call of the interior,

far beyond the mountains and glaciers,

they would be forced to find entirely new ways to survive.

A fresh wave of human innovation would be triggered

around 15,000 years ago, when the climate began to warm.

The ice sheets and glaciers started to retreat.

And as they did, the last major barrier

blocking routes into the continent fell.

The first people to enter into the Americas

were coastal people in the northwest,

but it's likely that they eventually travelled

incredibly rapidly down south, all the way to Central America

and then carried on all the way to the tip of South America.

Because remember - they were coastal people.

It's likely that they were using some kind of seafaring method.

So, very early on,

some humans would have started to enter the continent

from along this sea route.

But when the ice sheets eventually started to retreat,

many new routes would have opened up.

More people started travelling into the interior of the country

and finding these completely new landscapes.

Some of the first humans to reach the interior

left traces here in New Mexico.

SLIDE PROJECTOR CLICKS

Fossilised footprints.

Left in the muddy shore of an ancient lake.

The people who made them

may have been part of one of the very earliest waves

of what was to become 10,000 years of human migration inland.

Where there is now desert, they saw rich grasslands.

The fossilised footprints of these continental pioneers

reveal what kind of a world they'd stepped into.

These are the footprints of an actual human being

who stood basically where I'm standing.

And we think she was a female.

And if you look closely at those footprints,

what you see is that, at times, the footprints,

they get broader and they slip a little in the mud.

SLIDE PROJECTOR CLICKS

And that's because

she was carrying a child.

Sometimes on this hip and sometimes on this hip.

Then at other times, she stopped and put the child down,

and you end up with two sets of footprints.

SLIDE PROJECTOR CLICKS

And she walked for at least a kilometre north,

and then heads back south.

I just can't think of anything more... more human

than a mother and a child walking together,

and a mother carrying her child.

And it's interesting, cos this whole journey

has been us tracing the footsteps of our ancient ancestors.

And in a moment like this, that's actually literal.

Archaeologists are finding more of these footprints,

left by a female or possibly an adolescent male carrying a child,

hidden beneath the hard, packed sand.

It's allowing us to piece together an ever more detailed snapshot

of what happened in the moments captured here.

Let's see if we can define the footprint a little bit.

Yeah.

It's always scary when you start these things.

You've got to...

..take them out.

There's a subtle difference between the soil in the print...

It's looser, it's a little damp, so it's going to smear a bit today,

but it will come out.

You see it so...

..so clearly.

OK. So how have you...? So you've just traced along the...?

I've just... I've literally just broken the surface

- with the dental pick. - Yeah.

And then this particular example

just brushes out with a little bit of encouragement.

Yeah.

And you can see the contrast between the white...

Yeah.

..and the fill in there. I'm removing the...

Wow.

..the sediment that's blown into the footprint.

So we think she was walking quite quickly, then?

Yeah, she's walking at about 1.6, something like, metres per second.

Wow.

And, and a comfortable, normal sort of walk is about 1.3 to 1.5.

So she, she's moving. And this surface is wet, it's slippy.

We do know that this was a mission.

They were on a mission.

They were moving quickly at speed, for whatever reason,

and the footprint, um, tells that story.

Why that person was hurrying might be explained by evidence nearby.

Other footprints, each one around two feet in diameter...

..left by mammoths.

And crisscrossing the footprints of the mother and child

are the tracks of a giant ground sloth.

Out in the open, with dangerous animals close by,

the mother was perhaps seeking safety for herself and her child.

This landscape would have been filled with mammoth and mastodon

and sabre-toothed cats - just huge animals.

They would have dwarfed us.

The mammoth alone would stand at about four metres high,

that's about 13 feet, at the shoulders,

and the mastodon were only slightly smaller.

For the humans here, this was their new world.

The early people of the plains

would have given these prehistoric mammals...

..a wide berth.

SLIDE PROJECTOR CLICKS

But they must have realised

that those animals also represented opportunity.

That these grazing giants could provide them with food...

..if they could find a way to bring them down.

We know they eventually found a way to do this

because they left a massive clue.

SLIDE PROJECTOR CLICKS

Skeletons of this megafauna.

Some clearly killed by humans.

Humans would have exploited some megafauna,

some large land animals on the coast,

but it was once they hit the interior

that they saw them on a scale like something else,

in terms of their sheer numbers, in terms of their diversity.

But how on earth could people hunt these giants?

BIRD CALLS

CRICKETS CHIRP

One animal still exists which gives us a sense

of just how difficult that would have been.

RUMBLING

HOOFBEATS RUMBLE

This beast can sprint at up to 40mph.

The male's horns are over two feet long.

And, 14,000 years ago,

these bison had an even bigger prehistoric relative

roaming these parts.

WHISPERING: Absolutely incredible, but they're also so...

..big. They're about one tonne in size.

And the giant bison, the one that's now extinct,

but would have been around back then,

was up to 50... 50% bigger.

HOOFBEATS RUMBLE, BISON SNORT

It's one of those things, I think -

today, you can romanticise the idea of these hunts

and you think about them as some kind of,

you know, adrenaline-filled adventure,

but it's harder to grasp that, actually, back then,

it would have been filled with fear and risk.

Only a powerful spear thrust could penetrate the giants' hides...

..so hunters needed to get close.

ALARM CALL

Many hunts ended in failure.

They needed a technology upgrade.

Up until this time,

the way spear points were attached to their shafts

was a serious weakness.

SLIDE PROJECTOR CLICKS

Spear points frequently broke on impact...

..until the design was altered.

A subtle shift at first glance,

but one that would change everything.

This is special.

So, it's about 18 centimetres long.

It's pretty sharp.

If we look at the shape,

it's long and narrow with the broadest point being quite low down.

Notice also this thinning here compared to the middle.

It's thought that the shape might help with the penetration of hide,

and it's thought that this might help

with reducing shattering on impact.

We call it a Clovis point,

because it was found near Clovis in New Mexico.

The narrow base of the Clovis points

allowed them to be slotted firmly into the spear shaft,

better absorbing the force of impact.

From archaeological finds,

we know this new design rapidly spread across the continent...

..and the technology continued to develop.

Within 500 years, these points had evolved

into more slender and sharper forms...

..able to penetrate deeper into prey...

..and archaeologists think these spear points

were delivered with such lethal force

because of another piece of technology...

..whose use was exploding.

So this is a replica spearhead,

and it's been hafted or attached on to a wooden shaft.

So, this would have been quite an effective weapon,

but this is where technology gets really interesting

because it's thought that one of the ways that they threw these spears

is with a spear thrower.

So you'd attach it to the top here,

and then you would effectively use it to...

..propel the spear forward.

At that velocity, you're more likely to pierce the hide of an animal.

And to me, it's...

It's especially interesting because what you get with this

is the ability for female hunters to be more effective,

because suddenly it's not just about strength, it's also about skill.

The new hunting technologies

allowed people to take down the largest animals in their world.

Humans had become the apex predator of the plains,

and now feasted on a glut of meat.

Our hunting prowess was shaping society here.

This is absolutely stunning.

It's one of the most striking spearheads I've ever seen.

It's... It's so well-crafted, and it shines,

and it looks like it was made of glass -

but actually, it's made of quartz,

so it's incredibly strong and it's sharp,

and yet it doesn't have any signs that it was actually ever used,

and that, along with the fact that it's so beautiful,

suggests that it was ceremonial.

Now, when you've got an everyday object

and it's made to look so... so beautiful, and so striking,

it implies that it had become a symbol.

We're not sure of what - perhaps of how important hunting was,

but perhaps of a cultural identity, perhaps of who they were.

Feasts began to bring different communities together...

..and cement social ties.

Sharing meat fostered cooperation.

Food was fuelling a culture.

In the midst of this abundance,

it must have felt as if it would go on forever.

But their world was changing.

The end of the Ice Age

that had gifted them this warm world of plenty

was now beginning to have an effect they could not have foreseen.

It's thought that melting ice at the poles disrupted ocean currents.

Temperatures in the northern hemisphere

rapidly cooled by several degrees.

Across North America,

the vegetation had begun to alter in unpredictable ways.

In some areas, trees and shrubs

began to replace grassland and tundra.

SLIDE PROJECTOR CLICKS

Woolly mammoths could not effectively chew or digest

these woodier plants...

..and as their environment transformed...

..the giant herbivores dwindled.

Over the space of just a few hundred years,

three-quarters of the large animal species in North America

became extinct, vanishing forever.

I imagine it must have been a shock for the early people here

to witness the megafauna disappearing,

because that's what they would have seen -

and they're such a part of your culture and your diet

and your lifestyle, and suddenly they're not.

That... That must have been quite difficult to comprehend.

Now, the main cause of the giant megafaunal extinction

is climate change, but it's likely that human hunting played a role,

that it was this final nail in the coffin -

and so, perhaps unknowingly, we humans tipped the balance of nature.

The once bountiful land of giants

had become a pile of bones.

All the hunting technology in the world

could do nothing to reverse this catastrophe.

The people here were plunged back to a time before the feasts.

With these animals gone, how would they now find enough food?

A clue lies in ancient holes carved in the rock.

People needed to branch out

and exploit every part of the food chain,

all the way through to something you probably don't think of as food -

and that's acorns.

Now, these are incredibly bitter because they're full of tannic acid,

and to get rid of some of that,

what they would do is they would firstly get rid of the shells,

and then they would grind the nuts up

with water in the hopes of getting rid of some of that bitterness.

And... honestly, acorns sound disgusting

and they taste disgusting.

They're still incredibly bitter -

and yet it's likely that the flour from these and the paste from these

were some of the earliest processed plant food.

We actually have some of the grinding stones

preserved in the archaeological record -

and if you look at all this, it seems so clever,

it seems so inventive,

and yet it's a lot of effort to go to

for what are essentially some really unpleasant calories.

If you were starving, no question you'd do this...

..and with the loss of the megafauna,

people's survival now hinged on smaller game

and foraging for plants.

But there had to be another way.

The solution people came up with in the Americas

would be found in tropical forests to the south.

This place, it has...

It has real challenges.

There are plants - so many of them look edible,

and yet some of them are definitely poisonous.

It requires a process of trial and error to find the actual food.

It was in a forest, archaeologists think in present-day Mexico,

that a momentous change took place -

and it began with the simplest of actions.

Every so often, someone would have come across a plant

that was safe to eat,

and would have sought out more of it.

An example of this is this grass called teosinte.

Now the seeds are incredibly small and hard,

but they can be ground up into an edible flour.

So, that same ingenuity that humans brought to acorns,

they were now bringing to this grass.

Where people found teosinte growing,

they encouraged it by weeding out other plants...

..and collected the seeds for food.

This may have continued for centuries...

..until one individual would have become the first person

in the Americas to do something completely original

with a teosinte seed.

There is something so magical about planting a seed, watering it,

and hoping that it sprouts

and becomes a tiny little delicate green shoot.

And there would have been somebody

who planted the very, very first seed...

..and they would have - they would have known

that it would require effort and care

and protection from herbivores

if it was to ever become something big enough

to feed their families with.

And anybody who's ever had an allotment, or a garden,

or a balcony knows how much care and commitment goes into it.

This was an idea whose time had come.

Because humans all over the planet started to plant seeds

and grow them for food...

..and it was an experiment that began to pay off.

Because across the world, the people who did this

were creating a more dependable way of feeding their families,

and so triggered a pivotal moment for our species.

In different places all over the Earth,

humans were inventing farming.

Probably first around 10,000 years ago,

in the Fertile Crescent of the Middle East,

where we domesticated wheat...

..then rice in China...

..sugar cane in present-day New Guinea.

Farming emerged independently

in separate locations across the globe...

..Central and South America among the first.

Here, people created what would become

one of the three most important staple crops

for feeding the world...

..because as the early farmers planted and harvested teosinte...

..they began to shape it into a new kind of plant.

Every so often, a genetic mutation would arise in teosinte

that would actually be quite beneficial for humans -

that would give rise to, say, larger seeds,

or more seeds, or sweeter seeds -

and, perhaps most important of all,

would get rid of the hard seed covering,

and humans started selecting for these better varieties,

and over thousands of years, they created something new,

that looked very different from teosinte -

because they created maize.

It was no longer a wild plant.

It was now a domesticated crop.

The invention of farming was to set in motion a change

that would go far beyond how we fed ourselves.

The clue is in that word, "plant" - to be put down in one place -

and just like the plants that they grew,

those early farmers would have had to have adopted

a very similar lifestyle.

Because you couldn't exactly keep moving

if you had to tend to your crops,

and so, for the very first time since the birth of Homo sapiens,

we were no longer a completely nomadic species.

More and more of us were quite literally putting down roots.

Farming supercharged our capacity to fuel human activity...

..and what emerged was extraordinary.

Here in South America,

there's a place where they began a new way of living

on an unprecedented scale.

The stepped pyramids of Caral were once lost under the desert sand.

Archaeologists are now uncovering a vast complex of structures.

And what made it possible to build these extraordinary edifices...

..were the fields of crops that surrounded them.

Caral became an immense hub for trading food.

It represented a new path humans could take

towards permanence and stability...

..but for our species to choose that path

was not a foregone conclusion.

I just can't help but think,

what would it have been like

for people visiting it for the first time back then?

Because they would have never seen a city before.

It must have been so alien to them.

It must have looked like a place from a different world.

This was a commitment to a static way of life -

and yet we don't consider how tumultuous

the process might have been,

how much social upheaval might have been involved -

because for those who chose to lead this life,

it must have come with a huge cultural shift,

because humans were becoming an urban species

for the very first time.

Humans across the planet stood at a fork in the road.

For almost 300,000 years,

we had survived as nomadic hunter-gatherers...

..but settled lives as farmers

promised a more reliable way to feed ourselves

and plan for the future.

The choice most of our species took

would bring dilemmas and dangers we could never have imagined.

In the final chapter of our Human story,

we begin to live together in ever larger numbers -

but open a Pandora's box...

..of death and chaos...

..as we seek ways to harness human knowledge

on our path to the modern world.

In this episode, we filmed at a place I'd long dreamt of visiting.

White Sands in New Mexico.

Underneath the surface of the desert are sets of fossilised footprints.

They've become the subject of some of the most ground-breaking

but also most hotly debated research in archaeology.

In 2018, the discovery of the double footprints,

possibly a mother and child,

revealed vivid details about who the early people here were...

..and what animals roamed alongside them.

When we first started seeing the human prints

walking alongside a mammoth print,

when I'd first seen it, I was like, "Uh, that's not possible,"

but it takes a while to understand what you see,

and then you go back and you start to understand them.

But the prints themselves were just the start -

because, in 2021, new research on their age

sent shock waves through the scientific world.

There's been a lot of ideas when people got to the Americas.

Some of the main theories is there's a large ice sheet

and people weren't really able to enter this area

until about 14,000 years ago, until that ice sheet melted.

When humans first arrived in North America,

an ice sheet covered the northern half of the continent.

If no humans had been able to penetrate the interior

until it had melted,

then the oldest the footprints could possibly be is around 14,000 years -

but the dating of the footprints

seemed to overturn that conventional view.

We put in a trench at the edge of the lakeshore

and we're finding prints

that were dated above and below the prints,

so we can see the soil chronology.

The footprints themselves can't be carbon dated -

but fossilised plant seeds

trapped in the mud near the footprints can be,

and carbon dating of seeds

in the layers above and below these footprints were explosive.

So, we don't know exactly how old they are,

but we're looking at the lake sediments,

and what we see is there's at least 11 different layers right now,

and those range from the top of the sediment to the bottom,

from 21,000 to 23,000 years old.

The dating research suggested the footprints

went as far back as 23,000 years ago.

If true, it would mean humans had set foot in North America

thousands of years earlier than many scientists had long believed.

So, at White Sands we see people here

before the last glacier maximum,

before there was these last ice sheets,

people were already here.

The very early dates are controversial.

Further research will be needed

to confirm how old the White Sands footprints truly are.

If they date to before the melting of the ice sheets,

did those pioneers travel around the ice?

Despite the debate,

the footprints remain one of the most important archaeological finds

of recent history,

with huge significance for the entire question

of when humans first set foot in the Americas.