Original subtitles

First, our ancestors walked upright.

They became scavengers and toolmakers.

They learnt to work together as a family.

Now, the final step on the journey to us.

Southern England, almost half a million years ago.

Three brothers - hunters, on the brink of a kill...

...and the defining moment in the story of you and me.

I'm travelling back in time.

With science, we can build a picture of our past...

...and bring our dead ancestors to life.

Join me on a journey through our human story.

These people are heidelbergensis,

and their foe, the giant elk, Megaloceros.

It's wounded and can't escape, and the brothers split up to surround it.

The beast's three-metre antlers are deadly weapons.

The youngest is signalled to deal the fatal blow.

It's a cruel twist.

Though the men's hunt is over,

the younger brother is desperately injured.

By evening, the young man is delirious,

and his family distraught.

They use wild herbs to stop his bleeding and fight infection.

The eldest attempts to comfort him, but he is beginning to fit.

These men and women have brains almost as big as ours,

and they'll use all their skill and love

to try to keep their brother alive.

Though this is nearly half a million years ago,

these people appear to behave just like us.

(ANGUISHED CRIES)

But twelve hours later,

we can see the one thing that makes them and us so very different.

And the clue to what that thing is lies with him.

It's the younger brother.

He's died in the night and his family have left him.

For us, to simply let him sit where he died seems unthinkable,

and yet, for these people, it's unthinkable not to.

And that's because, for all their success in overcoming their physical environment,

they're trapped in another environment - that of their own minds.

Unlike you and me, these people can only see the world around them as it is.

They can't do what we take for granted,

and picture worlds of a different kind -

in this case, a world beyond death.

We none of us know for sure if such a world might exist,

but we can all at least entertain the notion!

It's one reason

why we commemorate our loved ones with some sort of ceremony.

But these people can't. They're just too literal-minded.

That's why he lies here.

It's not that his companions didn't like him - they loved him.

It's just that he's gone and that's an end of it.

There's no evidence heidelbergensis ever made the leap

to see the world as we do.

They lack the final ingredient

in the cocktail that makes you and me unique - imagination.

This is the story of how these creatures found that imagination

and became us.

It's the story of the most incredible natural experiment of all time...

...and the catalyst is the weather.

It's 500,000 years ago.

Heidelbergensis are spread throughout Europe and Africa.

But nature will split the population in two,

and expose the Europeans and the Africans to two incredible extremes.

To the north, an ice age...

...to the south, a devastating drought.

The people will struggle to survive for hundreds of thousands of years,

and we'll join them again when evolution has turned them

into two separate species.

But in their struggle to adapt and survive,

only one will emerge with the gift of a modern human mind.

It's now 140,000 years ago,

and the Europe of heidelbergensis is long gone.

It's a frozen wasteland from Scandinavia to Spain...

...and through the ice age,

heidelbergensis has evolved into a new people -

Neanderthals.

These are hunters returning home.

They're empty-handed after three days of trekking.

It's only the beginning of September,

but winter has come early.

Whilst they've been away, the bad weather has closed in.

Their home valley is under thick snow.

It's bad news, especially for the leader.

By mid-morning, they've reached home, and tensions are running high.

(MAN) Mooskee. Mufad.

Moofi-bee shi shi boosh.

Any day now, the leader's partner is due to give birth.

It will be her first child.

Mooshti ee bee shi shi boosh.

With snow on the ground, it's vital the clan move on,

but the journey would be suicide for a new mother and baby.

The leader must decide whether to move and risk his unborn child,

or stay and risk the future of them all.

Ratcharm bom.

Rad dunk shay shee shaw!

Be stadt all!

He's decided to lead the men on one final hunt,

a last chance to avoid the treacherous journey south

for his partner.

Pleez ee gloo!

Ee gloo! Lay chershay da lon!

Chershay da lon!

The temperature here is above freezing for only a few months a year.

It regularly falls as low as minus 30.

Without modern equipment, you and I would be lucky to survive a night.

So how are these people adapted to cope in such a hostile world?

Well, one answer lies with their bodies.

They're shorter than you and me, rarely over five and a half feet...

...and they've evolved a trait

characteristic of all animals that live in cold places -

short limbs and extremities that help keep valuable heat in.

They've another adaptation that helps them survive.

It comes into its own when they're hard at work.

It's their noses. They are broad and bigger than ours,

and we think they're designed not to help keep them warm,

but to cool them down.

In these surroundings, that might seem odd,

but the last thing a Neanderthal wants to do is overheat and sweat...

...because sweat would simply freeze.

And it's not just their bodies which makes these people so tough.

The weather has also changed their minds.

(THEY YELL)

Neanderthals seem capable of shrugging off incredible extremes...

...things that you and I might find unbearable.

Neanderthal's ice age way of life has made them unimaginably tough.

An X-ray would reveal a catalogue of fractures from head to toe,

like the body of a rodeo rider.

Welcome to the original school of hard knocks -

a place not for thinking but for doing.

But the hunters need more than toughness.

What they need now is luck.

The men have reached the edge of their known hunting grounds.

They've walked for three days...

...and found nothing.

The leader has failed.

Mah!

Will akee!

- Zjud bosh ee ee op. - Ee ee op.

Ee bee om.

(COUGHS)

(DISTANT TRUMPETING ROAR)

Chershay!

It's a herd of mammoth,

and an opportunity too good to be missed.

(TRUMPETING ROAR)

At over five tonnes, a mammoth is an incredible adversary,

but the hunters have a plan.

The head of the valley

narrows to a steep ravine - the perfect place for an ambush.

(COUGHS)

(TRUMPETING ROAR)

The leader's cough has blown the hunters' cover.

The men now have the added problem of a fast-moving target.

But their luck has changed.

It's more than the men could have hoped for,

and when the rest of the herd has left her,

the hunters will move in for the kill.

The hunt has been a triumph. Now the group have food enough

until long after the birth of the new arrival.

So where do we stand in the journey towards you and me?

Have the Neanderthals begun to see the world as we do?

Well, watching their lives, there's a lot about the way they are

that's just like us - their pleasure at being reunited,

their contentment at being warm and well fed...

(WHEEZES AND CHOKES)

...perhaps even their amusement at someone else's misfortune!

If you think that means that we share a sense of humour,

try telling them a joke, like the one about the mammoth

who couldn't sleep and asked his doctor for TRUNK-quillizers!

OK, it's not very funny, but around here it wouldn't even raise a groan.

Neanderthals simply wouldn't understand it.

For a start, it's about a mammoth that can talk,

and in the real world, you just don't get talking animals.

What you need, of course, to create a talking mammoth, is imagination.

And whilst these people can plan an ambush,

or anticipate the birth of a new baby,

flights of fancy, imaginative thinking like you or I can do,

are simply beyond them.

Neanderthal's ice age life doesn't need imagination.

Being strong and tough is enough.

So how have the other contenders in our human story fared?

What has happened to heidelbergensis in the south?

In Africa, thousands of arid years

have turned vast tracts of the continent to near desert...

...and the tall, strong heidelbergensis into this.

These are people physically like us.

They are taller and slimmer than the Neanderthals -

a good shape to cope with the heat -

and they a have dark skin to help keep them safe in the sun.

But whereas the Neanderthals are getting by in their tough world,

these people are not.

Unlike in an ice age, no amount of being tough or single-minded

can help in a devastating drought.

In these conditions, there is only one thing to do...

...die.

And that is what this family is doing.

They have been driven to the very edge of their world,

and they can run no further.

They are amongst the last of their kind.

It is 140,000 years ago,

and these people are on the brink of extinction.

Yet something extraordinary is happening, even to this dying breed.

When a species is close to extinction,

it's a situation where only the most inventive and resourceful

are likely to survive.

As numbers fall, so the fitness of the population rises.

If evolution is a process of natural selection,

then this is natural selection with the gas turned high.

Here in Africa, that intense natural selection

means only a very special group of people are still alive.

They're survivors who have developed a unique ability,

an ability that will make them us.

This strange buried object will reveal the secret to what that is.

Something has happened inside the minds of the few remaining people

to make them different to any other creature.

Just how different, we can see from this.

This beautiful object is an ostrich egg...

...but whereas it once contained a yolk, it now contains water.

This is hugely significant,

because it shows an ability so far missing in our human story -

the ability to think ahead, to go beyond the here and now,

what we call imagination.

To bury this, you need the imagination to see

that an egg can be used to hold water...

...and the foresight to know that one day you might come back this way

and need to drink.

Imagination is an insurance policy against the problems of the future.

With it, the tiny population of humans in Africa can hold on,

until, one day, as it always does, the weather once again changes.

Around 110,000 years ago,

the great ice age begins to thaw and water returns to Africa.

By this time, there are as few humans left alive

as there are orang-utans in your era,

yet we know from studying our genes

that we all are descended from this tiny band of survivors.

Let's take one last leap in time to 30,000 years ago,

to witness the final part of our human story.

Saved from the brink of extinction,

the imaginations of our ancestors have taken flight.

They've created sophisticated language

to share their new ideas with each other,

and they're spreading across the globe.

Wherever they go, they're leaving signs of their complex world...

...like this man is doing now.

Who knows what these images mean to him? We can only guess.

They're the world inside his head...

made real.

In a way, what they mean doesn't matter.

But the fact they're here at all,

that someone painted something

which only existed in their mind's eye,

is proof that these people are different

from every other creature in the whole history of life.

They are not simply living in caves,

but in an imagined world of their own making.

Since our story began, our ancestors, like all animals,

have lived within the confines of the world around them.

But now, after seven million years of evolution,

these people, us, have at last stepped outside the rules of life.

And of course, back in Europe, as we began to spread,

we came into contact with the other inhabitants -

those original cavemen, the Neanderthals.

For all their skill and toughness,

Neanderthal are no match for the imaginative newcomers.

Her kind has been one of the most successful species in human history,

but gradually, they'll be squeezed out.

In evolution, you don't have to fail to become extinct,

just succeed a little less often.

It's 30,000 years ago,

and soon there'll be only one species of two-legged ape

left on the planet.

(BABY GURGLES)

And this is where our story ends...

...for if I were to take this baby girl home

and bring her up as my own daughter,

she'd be physically and mentally indistinguishable from my own children.

Even though the human race has yet to invent the wheel,

discover writing or travel to the moon,

it's now just a question of time.