01x07 - When the Continents Collided

[bunniefuu]

[NBC chime]

NARRATOR: The story
of life on Earth...

[roars]

...has been marked by a series

of catastrophic
extinction events.

Natural disasters, which have
threatened to wipe out

many of the creatures
that call our planet home.

But after each brush with death,

life has come back
even stronger.

[majestic music]

One such event occurred
two and half million years ago,

in the Americas.

Up until then, North and South
America had been separated

by ocean.

[trumpeting]

But then, the seabed rose up,

and a land bridge formed.

[snarling]

♪

For the first time,

animals and plants from these
two completely different worlds

would face off.

[squawks]

Many were driven to extinction.

- [growling]
- [screeching]

But for others,
it was a whole new beginning.

- [trumpeting]
- [screeching]

[growling]

[trumpeting]

[majestic music]

[low grunting]

It changed life
in the Americas forever.

[theme music]

[wind gusts howl]

[reverent music]

NARRATOR: Long after the time
of the dinosaurs,

and more than two million years

before modern humans
walk the earth,

the world is becoming
drier and cooler.

In Central America,

the climate shift is extreme.

A punishing drought has gripped
these lands for six months.

♪

To survive here,

it takes a special
kind of animal.

[snuffling]

Like these majestic
Gomphotheres.

[low, rumbling grunts]

Descended from
ancient elephant species

that originally migrated
out of Africa,

these creatures have made
North America their home.

[trumpeting]

Today, they are celebrating.

[trumpeting]

A little female calf,
only hours old.

[trumpeting]

Her mom is the 40-year-old
matriarch.

She is the leader of this herd.

[trumpeting]

[grunting]

She doesn’t have the strength

to join the celebration.

♪

[trumpeting]

Exhausted after giving birth,

she looks for a place
to be alone.

[screeching]

As matriarch, she is key

to the whole herd’s survival,

so it is not surprising
her behavior

is starting to make
them anxious.

Something extremely rare
has happened.

[high-pitched trumpeting]

[gentle music]

The matriarch
has given birth to a twin.

♪

[trumpeting]

Brother and sister meet.

It is a moment of pure joy.

[high-pitched trumpeting]

The entire herd
is elated with the arrival

of its newest members.

[herd trumpeting]

[tense music]

When night comes,
the mood changes.

Despite an exhausting day,

it is the new mom
who bravely stands guard

while the rest
of the herd sleeps.

As an experienced matriarch,

one of her duties
is to keep the others safe.

♪

And it’s a good thing,

because tonight,
there is danger,

lurking in the darkness.

[snarling growls]

Smilodon.

Ruthless sabretooth cats,

as big as jaguars.

♪

They've picked up the scent
of the new calves.

♪

[tense music builds]

At three and a half tons,

these adult Gomphotheres are too
big for Smilodon to take down.

[snarling]

But with a surprise attack...

they could separate
one of the calves,

and go in for the k*ll.

[clattering]

[birds cawing]

[trumpeting]

[snarling]

Well, it’s no longer a surprise.

[roars]

Changing tactics,
they go straight for the herd.

[dramatic music]

- [trumpeting]
- [snarling]

If they cause enough chaos,

one of the babies
will be exposed.

[high-pitched trumpeting]

- [roaring]
- [trumpeting]

Led by the matriarch,
the adults hold the line...

for now.

But the sabretooths
have got all night.

- [roaring]
- [trumpeting]

It’s rare for twin
calves to both survive

their first year
in this harsh land.

But can they even survive
their first night?

[roaring]

[tense music]

NARRATOR: The moon sets
over Central America,

two and a half
million years ago.

♪

It is a land gripped
by a severe drought.

[snarling]

During the night,

a herd of American elephants

have been targeted
by sabretooth predators,

drawn by the smell
of newborn twin calves.

[high-pitched trumpeting]

[trumpeting]

[snarling]

[gentle music]

NARRATOR: In the morning light,

the matriarch
triumphantly reveals

all the members
of her herd survived.

[gentle music]

Most importantly,
her two babies.

♪

They didn’t go unscathed.

Both the little male,

and his mother were injured.

But there’s no time to rest.

The drought makes
our matriarch’s top priority

to find water for the herd.

[dramatic music]

She knows a place
where her own mother

took her, decades ago.

It might seem dry,
but if you know where to look,

there are underground springs.

[suspenseful music]

There's barely a trickle.

[low grunting]

She is distressed.

Her home range has failed her,

and she has failed her herd.

She must find water.

[reverent music]

It is all down to the very land
she is standing on.

Before now,

the continents
of North and South America

were completely separate
land masses.

♪

But continental drift
has been pushing them

on a collision course
over millions of years.

Now, they are almost touching.

♪

Ocean currents are rerouting,

and the climate
in Central America

is getting steadily drier.

[wind gusts howl]

As the dry seasons get longer,

reliable water sources
disappear,

and animals suffer.

These Gomphotheres can normally
survive for days without water.

But with two calves to feed,

this new mother needs
to find a solution, fast.

[high-pitched trumpeting]

Another mother
in the herd has already

lost her calf to this drought.

[babies trumpeting]

Staying here, with no water,

would mean certain death
for her two babies.

[trumpeting]

But then, our matriarch
feels something

in the ground.

Through thick pads on her feet,

she can sense vibrations.

From experience,
she knows what this is.

Distant thunderstorms.

[joyful music]

The promise of rain pushes
her to take a huge risk.

[trumpeting]

[thud, echoes]

[low grunting]

[majestic music]

She decides to leave
her ancestral lands,

and lead her herd south.

These American elephants can
walk over 100 miles in a day,

but they are traveling
into the unknown.

The lands to the south
are even more inhospitable

than their home territory.

♪

Even the creatures they meet
will be alien to them.

The gamble she’s taking
could be disastrous

for her new babies,
and for the whole herd.

[high-pitched trumpeting]

[trumpeting]

[reverent music]

NARRATOR: The matriarch
of a herd of Gomphotheres

has decided to migrate
in search of water.

Desperate, she is leading
her herd further south

than any American elephants
have ever been.

And so far,
it is only getting drier.

[suspenseful music]

When the matriarch’s young son
wanders away from the herd,

he encounters something
he’s never seen before.

- [grunting]
- [trumpeting]

[braying]

An armored Glyptotherium.

Definitely not a creature
from around here.

In fact,
he’s from another world...

the island continent
of South America.

[trumpets]

[whimsical music]

Somehow, he’s crossed
into the north.

[grunting]

[braying]

He doesn’t smell dangerous.

[trumpeting]

Maybe this odd-looking animal

could be a playmate.

[trumpeting]

[high-pitched trumpeting]

[screeching]

[low trumpeting]

The mother who lost her own baby

comes to the rescue.

[baby screeching]

[dramatic music]

[braying]

[low trumpeting]

It’s nice to be part of a herd.

[trumpeting]

The little one is a bit bruised,

but his instincts were right.

The herd has nothing to fear
from these strangers.

[whimsical music]

[braying]

Although, the Glyptotherium
aren’t used

to creatures powerful enough
to turn them on their backs.

[braying]

For them, this new,
dry world is proving tough.

[dramatic music]

The desperate herd
is also struggling.

They haven’t drunk now for days.

But our matriarch
is sticking with her plan,

so she steps up the pace.

[bird screeching]

They persevere for days.

♪

Perhaps this was a mistake.

For the new calves,
the pace is punishing,

but something
even worse is happening.

[low grunting]

Their mother’s wound
is badly infected,

and she is growing weaker
with every step.

♪

She made the decision
to take them south,

but now, exhaustion
and her infected wound

are making it impossible
for this matriarch to lead.

She can barely walk.

[solemn music]

She knows her time has come.

[herd trumpeting]

Her herd try to help
their leader back to her feet.

♪

But she's reached the end
of her journey.

[trumpeting]

And her death could
mean the death of her twins.

[herd trumpeting]

♪

NARRATOR: The next morning,
the herd has no leader.

But then, something
remarkable happens.

The mother who lost
her own calf still has milk.

[poignant music]

[grunting]

[high-pitched trumpeting]

She is now the new matriarch.

And following in the footsteps
of her predecessor,

she starts to lead
the herd south again.

♪

Finally, rolling clouds
on the horizon.

It looks like our old
matriarch was right.

Her legacy will be
the herd’s survival.

♪

There’s the smell
of water in the air.

But it's not like any water
they've smelled before.

[majestic music]

It's the ocean.

This is where the Atlantic
meets the Pacific.

For the last 50 million years,

this would have been the end
of their journey.

Now, as the American
continents collide,

there is the promise of a
whole new land on the horizon.

[waves splashing]

But the journey there will test
this herd to its limits.

[dramatic music]

NARRATOR:
After an epic migration

the new matriarch
has brought her herd

to the southern most tip
of North America.

Before them lies South America

a continent
that has been isolated

for the last 50 million years.

In between stretches miles
of shallow sea,

crisscrossed with sand banks

and deep channels
in all directions,

Here, they face an ocean
for the first time.

[Gomphotheres grunting]

The new environment
makes the herd nervous.

For the innocent calves,
it's a fun day at the beach.

[Gomphotheres squeaking
and grunting]

Their new leader can tell
the water isn't drinkable.

[Gomphothere growling]

Then, she picks up
the unmistakable scent

of lush vegetation floating
on a southerly breeze.

Ahead, lies the island continent
of South America.

Except, it's no longer
an island.

2.5 million years ago,

continental drift is pushing
it so close to North America

that a series of new islands
are forming a strip of land.

To find fresh water,

all the matriarch has
to do is follow her nose.

So, she continues
the journey south.

But she is unaware
the land bridge they are on

only exists at low tide.

[dramatic music]

Now, the tide is coming in.

The herd is trapped,
surrounded by water.

[Gomphotheres groaning]

Gomphotheres are
naturally good swimmers,

but fighting tides and
unpredictable currents

is much harder
than crossing a river.

They all struggle
to stay together.

The little female calf
is pulled by the tide.

[calf crying]

The new matriarch
can do nothing to help her.

[Gomphotheres crying]

[Gomphotheres groaning]

NARRATOR:
Exhausted and disoriented,

they find themselves
on a new continent:

South America.

But at what cost?

[Gomphothere trumpeting]

A miracle arrives
on the high tide.

It’s his sister!

In her young life
she’s overcome so much already.,

And now she’s even managed
to survive the rough sea.

[Gomphotheres trumpeting]

Finally, a new world.

This part of South America is
less affected by the drought,

with plenty of fresh water
and dense vegetation.

Yet, for the herd
and their matriarch,

nothing is familiar here.

New scents hang in the air.

There are strange
varieties of fruits.

Even the birdsongs
are new to their ears.

Here, they are the aliens

and they have no idea
who they’ll encounter.

[animal growling]

This ancient land has been
isolated for so long,

[bird squawking]

it has had plenty of time

to evolve
its own terrifying predators.

NARRATOR:
The herd of gomphotheres

have made the impossible journey
across the tidal isthmus

that connects North
and South America.

Everything is new to them.

These are
the sights and sounds

of a completely
unfamiliar world.

[birds trilling]

[animals growling]

Almost immediately, a strange
call echoes around them.

It comes from
an enormous creature.

Luckily, he’s only
interested in the fruit.

A Giant sloth.

One of the wonders
of South America

two and a half
million years ago.

Even bigger
than the gomphotheres,

they evolved during
the continent’s

50 million years of isolation.

The matriarch leads them
deeper into this new world.

Her role is to protect
the herd

but she has no idea
who’ll they'll meet next.

For now, there is
no sign of predators.

A herd of toxodons.

Thousands of these one-ton
beasts graze these plains.

And with so much
vegetation around,

they have no problem sharing.

So far, South America
seems like paradise.

[bird trilling]

Suddenly, a piercing call sends
the toxodons into a panic.

[birds squawking]

South America’s Terror Bird.

These seven-foot
super-predators

can run at over


They start
to flush out the weak.

[Gomphothere trumpeting]

Until, they spot
unexpected visitors.

[bird squawking]

[Gomphothere groaning]

Our matriarch knows
it’s time for her to step up.

[Gomphothere trumpeting]

The birds assess
these new creatures.

They have never seen
an elephant of any kind before.

But, in this land,
everything is prey to them.

[Gomphothere grunting]

[bird squawking]

They select their target.

[Gomphothere trumpeting]

[bird squawking]

[Gomphothere trumpeting louder]

[bird squawking]

[bird crying]

[bones snapping]

[bird squawking]

Not today.

Our new matriarch secured her
place as leader of the herd.

And stamped her mark
on this new continent.

They’ve finally made it.

In a land where no predators
can threaten the adults,

the gomphotheres'
future looks bright.

But this is only the beginning.

More species are moving south

and it is not
just the herbivores

discovering this new continent.

Predators from the north
have also made the crossing

and are about to change
this land forever.

[growling]

NARRATOR: Over the course
of hundreds

of thousands of years,

the movement of the continents

continue to push North and
South America closer together.

A new permanent land
bridge grows

at what will
one day be Panama.

Thousands of species
of plant and animal

move both north and south.

It is one of the largest
rapid mixings of plant

and animal species
in Earth’s history.

And as these vastly
different species collide,

they forge a new future
for the Americas.

One million years later,

life in South America has
gone through a seismic shift.

During the great
Clash of Species,

many went extinct.

But out of the melting pot,
new ones have evolved.

Now, at the top
of the food chain,

sits the giant
South American sabretooth.

Four times the weight
of the sabretooths

that crossed
over from the North,

this is one of the largest
cats that ever lived.

The gomphotheres
are also thriving.

Tens of thousands now
roam these grassy plains.

And a large herd of
gomphotheres is perfect

for a hungry sabretooth.

[sabretooth growling]

[Gomphothere trumpeting]

Unlike his Northern cousins,

this predator hunts alone

and is easily large enough to
take down a gomphothere calf.

[Gomphothere trumpeting]

[frantic music]

[Gomphothere trumpeting]

[sabretooth growling]

[gomphothere grunting]

A bull gomphothere.

[gomphothere growling]

Pumped full of testosterone,

the little guy
is part of a herd.

[animals growling]

And even apex predators
know when to run from a fight.

[gomphothere trumpeting]

[gomphothere trumpeting]

From their origins in Africa,

the elephant family have now
claimed a fifth continent

as their home.

A million years after
the Americas unite,

there's been
an expl*si*n in biodiversity.

The continent will go on

to support 32 different
types of mammals

that weigh over a ton.

It’s the greatest
diversity of mega-mammals

in Earth’s history.

The impact of the joining
of the Americas

can still be seen today.

NARRATOR: But more recently, it
is humans that have kickstarted

an even bigger clash of species.

After some 110 million years
of separation,

the arrival of Columbus marked
a new continental collision.

Living things from
Africa and Eurasia

met with those
of the Americas.

Everything from
livestock and insects

to vegetables and viruses

moved both ways
across the Atlantic.

The consequences of our
re-connecting the continents

have been profound:

Some species'
populations are exploding,

while others' go extinct.

Humans have
impacted the environment

in countless ways,

but the way our activities
are now mixing species

on a global scale

is perhaps our biggest legacy

to the future shape
of life on Earth.