Our Planet (2019) s02e01 Episode Script

[theme tune playing]
[David Attenborough]
Sixty thousand years ago,
humans left Africa for the first time.
Since then, we haven't stopped,
traveling to every corner of the Earth.
But our journey is just one of many.
At any given moment,
billions of animals are on the move.
[music becomes stirring]
And the health of our planet
depends on it.
[music abates]
[music fades, intensifies]
Migration is the most vital
survival strategy.
[music intensifies]
Whether to feed
to breed
[elephants roar]
or to find a new home.
And it's not without risk.
[music intensifies]
- [growls]
- [screeches]
[trills]
This series traces extraordinary journeys
in a world that is changing
faster than ever.
[rousing music playing]
And only now
are we beginning to understand
that all life on Earth
depends on the freedom to move.
[music intensifies]
[music ends]
[somber music fades in]
[wind howling]
Every year, this land in Botswana
is transformed.
These scars are the only sign
that it was covered by water
just three months ago.
[poignant music playing]
Then, rich and green.
Now, baked and barren.
This change drives animals
to move en masse.
[bellowing]
[dramatic tribal music playing]
Cape buffalo are marching
across the Kalahari Desert
towards the last remaining water.
Groups have come together
and formed a mega herd.
[grunting]
The largest in Africa.
[music continues]
[music abates]
All are making the same annual pilgrimage
to one remote marsh.
[chirping]
And others are relying on them to do so.
These lions are buffalo specialists.
And the mega herd's arrival
is the most important event of their year.
For weeks, they've been waiting
for the buffalo army.
Eyes fixed on every shape
crossing the horizon.
[menacing music playing]
[buffalo calls]
[growls softly]
[birds shrieking]
[insects buzzing]
[growls softly]
Finally.
[dramatic music playing]
[music abates]
[rasping, snorting]
The approaching horde
is a wall of horns and muscle.
But the lions must find a weakness.
And this could be it.
A lone bull.
He may be separate from the herd,
but he is four times heavier than a lion
and one of Africa's
most dangerous animals.
The pride must approach with care.
[buffalo snorting]
One by one, they casually walk towards him
as if uninterested in a hunt.
In fact, they're falling into position.
[menacing music playing]
- [lion growls]
- [buffalo snorts]
[buffalo snorting]
[music intensifies]
[lion roars]
The females take it in turns to attack
tiring the bull.
[dramatic tribal music playing]
Now, the heavier males join the fight.
[music intensifies]
[buffalo bellows]
[lions snarl]
[buffalo groans]
[music abates]
[buffalo bellowing]
[bellowing fades]
The pride has honed
their technique so well
that in just three minutes,
they have defeated
their most formidable opponent.
[stillness]
[music fades away]
The migration on which the lions depend
is one of millions driven by the seasons.
And they, in turn,
are a consequence of another journey.
[music reprises]
Our planet's year-long loop
around the sun.
As it travels,
it does so on a tilt
of 23 and a half degrees.
And it is this that creates our seasons.
[music intensifies]
To understand how,
keep your eye on the North Pole.
For half the year,
it's angled away from the sun,
bringing darkness and winter.
[music soars]
For the other half,
it swings towards the sun,
bringing longer days.
It's this annual cycle
that drives the greatest movements
of life on Earth.
And in the Northern Hemisphere,
this brings the year's biggest change.
Spring.
[music fades out, ends]
In late March, the days lengthen faster
than at any other time.
[poignant string music playing]
Sunlight increases,
quickly heating the land.
[thunder rumbles]
Triggering rainstorms.
The Northern Hemisphere
suddenly becomes warmer
and wetter.
Perfect for plants.
[music intensifies]
The land turns green.
[music fades away]
And one animal exploits the boom
in plant growth like no other.
- [chirping]
- [tiny footsteps]
A week ago,
this desert locust in Ethiopia
was a shy, solitary creature
that moved very little.
[dark playful music playing]
Not anymore.
When available food skyrockets,
locusts switch to swarm mode.
[music intensifies]
[chorus of chirping]
They start marching
and multiply ten times faster.
[strident string music playing]
As their numbers explode,
they strip the land bare.
So to find more and more food,
they must keep moving.
[music intensifies]
The swarm grows.
And grows.
[music intensifies]
Devouring every plant in its path.
But this is just the start.
On foot, they can only move so far.
[music ends abruptly]
To go further,
they must change form.
[soft squelching]
They grow wings.
[suspenseful music playing]
[music becomes uplifting]
Now, with an even larger appetite,
the entire army takes to the sky.
[music becomes dramatic]
They eat
and fly.
Eat
and fly.
[cacophonous buzzing]
They come together to form a super swarm,
200 billion strong.
The biggest seen in 70 years.
It consumes 400,000 tons of food
every single day.
So if the whole swarm is to feed,
it must move further and faster.
[music intensifies]
It travels 100 kilometers a day
across farmland and towns.
[music abates]
It sweeps across country after country
and most astonishing of all,
it even crosses the Red Sea.
It's the first time a swarm clears
the Himalayas and reaches Tibet.
[music intensifies]
Everywhere it goes,
it brings chaos.
It will keep moving
until the changing seasons bring drought.
For when their food finally disappears
so will they.
[music fades out abruptly]
[solemn drumbeat reverberates]
[metallic percussive sound reverberates]
In April, day length in the North
continues to rise.
[subdued expectant music playing
The increase in sunlight warms the oceans,
creating vast algal blooms
and a sudden abundance of food.
For one animal,
this is the moment to travel.
[music becomes suspenseful]
Midnight on a remote island
off British Columbia.
Underground
something stirs.
[whimsical music playing]
[chirruping]
This ancient murrelet chick
has only just hatched,
yet it's about to face
the toughest journey it will ever make.
She hasn't had her first meal
and urgently needs food.
[warbling]
Mum makes contact.
[chick chirruping]
[warbling]
Across the island,
hungry chicks emerge from their burrows
following their parents' calls.
But if they're expecting to eat now,
they're going to be disappointed.
[music intensifies]
This is the only seabird
that is fed exclusively at sea.
[music abates]
The chicks just need to get there.
[peeping]
They can't yet fly,
so their only way to the ocean
is on foot.
- [quirky dramatic music playing]
- [peeping]
[chicks peeping]
While waiting till nightfall makes sense
to avoid predators,
it's a little harder to see
where you're going.
[squeaks]
[soft thud]
And when you're barely bigger
than a golf ball,
anything can be an obstacle.
- [thuds]
- [music stops abruptly]
[chirps]
[music reprises]
[all chirping]
Their way may be blocked
by the lowest of logs
and the smallest of streams.
[peeping]
[music abates]
For some, the journey is over
before it has even begun.
[muffled cheeping]
[music reprises]
But not for this chick.
[optimistic music playing]
Finally, the beach.
And it's the last land
it will touch for two years.
[chirping]
To find Mother,
it calls into the darkness.
[gentle piano music playing]
[chirping]
[chick peeping]
Together again.
But the chick has still not eaten.
To reach the nearest food,
they paddle nonstop
for a remarkable 70 kilometers.
Here, Mother can finally dive
to collect
the chick's first meal of krill.
But this is just a pit stop.
The pair paddle
a further thousand kilometers.
It's a month-long migration
to the rich northern seas
where they can feast.
It's probably the longest journey made
by any newly hatched bird.
[music becomes rousing]
And because the oceans
are so productive in summer,
the murrelets can spend
virtually their entire lives at sea.
- [single piano key plays]
- [metallic percussive sound reverberates]
1600 kilometers northwest of Hawaii
lies a remote speck of land,
Laysan.
Home to one of the world's
largest seabirds.
[whimsical music playing]
The Laysan albatross.
[quacks, beak clacks]
This chick, six weeks old,
will become
a supreme long-distance traveler
[music becomes comical]
flying millions of kilometers
in its 60-year life.
Now, however, at four months old,
it's still flightless
and going nowhere.
[whimsical music playing]
Unlike the murrelet,
it depends on food being brought to it
by its parents.
But they could be fishing
up to 3,000 kilometers away.
So it may be waiting a while.
- [comical music playing]
- Through pouring rain
blasting winds
and baking heat.
[music intensifies]
[music ends]
Every bird crossing the horizon
brings hope.
- [shrieks]
- [expectant music playing]
An albatross.
But the wrong kind.
A black-footed.
[music intensifies]
Though she has almost certainly
brought food.
[clucking]
Starving, the Laysan chick tries its luck.
[shrieks]
- [squealing]
- [shrieks]
Clearly, for this mother,
it's family first.
[peeps, beak clacks]
[beak clacking]
[somber music playing]
But what looks like a lifeline
[peeping weakly]
could be a death sentence.
[peeping stops]
Across the island, chicks are dying.
[music becomes more somber]
There is now so much plastic in our oceans
that it reaches
even the most remote islands on Earth.
Carried here by the currents.
The parents mistake
small floating pieces for food
and bring it to their young,
accidentally killing them.
- [beak clacking]
- [music intensifies]
It's almost certain
that every chick on the island
has plastic in its stomach.
[cheeps softly]
Those that are fed too much
starve to death.
Laysan albatross
are in the greatest danger.
They consume more plastic
than any other seabird.
And it's getting worse each year.
[music becomes rousing]
[music abates]
At last, after nearly three weeks at sea
the chick's father returns.
[whimsical music playing]
[shrieking]
Having spent so long apart,
they need to renew their bond.
[chirping, beak clacking]
[chick peeping, beak clacking]
This could be the last meal
the chick is ever given.
And almost certainly contains plastic.
[tense poignant music playing]
[chick chirping]
[chick chirping]
[distant chirping]
Its father returns
to a life traveling the Pacific.
And the chick is left to its fate.
But it's not over for him yet.
[tense music playing]
Albatrosses normally throw up
hard-to-digest parts,
like squid beaks and bones.
Ejecting lighters and bottle caps,
however, is more of a challenge.
[music intensifies]
[music crescendos]
[cheeps, clacks beak]
But this chick
is a survivor.
- [whimsical French music playing]
- [cheeping]
And with that,
he is one step closer to takeoff.
In a few weeks, on the right wind,
he will finally be able
to make his big debut
as one of the greatest ocean travelers.
[music fades out]
The course of our tilted planet
through space
affects one place more than any other.
[disquieting classical music playing]
Summer in the North.
The Arctic now faces the sun
and is bathed in round-the-clock daylight,
melting an ocean covered in ice.
[music becomes rousing]
To survive in this shifting world,
life must move with it.
[snorts]
[music becomes menacing]
[music abates]
[growling]
This young polar bear's home
changes so much each year
that he can't keep to a limited territory.
Instead, he must roam
for thousands of kilometers
in search of seals.
[quirky string music playing]
But every summer,
as the ice begins to melt,
he must spend less time walking
and more time swimming.
[music becoming dramatic]
Now, for almost eight hours a day.
[snorting]
He can smell prey from 30 kilometers away.
[music abates]
So he knows
that this bearded seal is nearby.
[seal snorts]
[tense music playing]
[sniffing]
The seal is unaware of the danger.
[croaks softly]
And the bear needs to keep it that way.
[music intensifies]
[music continues]
[croaks]
[music becomes chaotic]
[music fades out]
[snorts]
The success rate
of hunting from the water is very low.
[gentle classical music playing]
[sniffing]
[music becomes suspenseful]
[music abates]
Maybe third time will be lucky.
[sniffs]
[music continues]
[music intensifies]
[music becomes chaotic]
[music fades out]
[stillness]
[subdued music playing]
This young bear has yet to master
the art of stalking from the sea.
But it's important that he does.
He may have to rely on it
more and more each year.
[yawns]
Our climate is warming.
[poignant music playing]
And nowhere is this
having a greater effect
than in the Arctic.
This year, the temperature climbs
to a staggering 38 degrees Celsius
melting sea ice faster than ever.
And one Arctic animal
is affected more than most.
[music continues]
To feed,
walrus need a combination
of a shallow seabed,
abundant clams,
and ice floes on which to rest.
[walrus rasping, snorting]
But there are now fewer places to do so.
[music abates]
Making each summer
more difficult than the last.
[music resumes]
Especially so for a new mother.
[calf chirping]
[mother rasps]
Three days ago, she had to leave the herd
to give birth on her own.
And since then,
she hasn't left her calf's side.
- [calf grunts]
- [mother growls]
Nursing mothers need
nearly twice as much food.
But they can't leave their calves alone
while they themselves feed.
So she must go in search of others
to help her care for her young.
A newborn walrus
is able to swim from day one.
But he's not yet strong enough
to travel far.
So, for his first journey,
he hitches a ride.
[music becomes whimsical]
With fewer ice floes each year,
they must swim further to find help.
And until then, his mother can't feed.
Even when they do find others,
the ice must be low enough
for the calf to climb out.
[rasps]
Too high.
[rasping]
[growling]
This looks just right.
But with suitable ice in short supply,
space is very limited.
- [attacker growls]
- [mother grunting]
[both snarling]
[roaring]
[snarling, roaring]
- It's not the welcome they needed.
- [calf softly grunting]
[poignant music playing]
Even when there's enough ice,
without anyone to help,
she is unable to feed
and must stay with her calf.
- [calf barks]
- [mother rasps]
Their search must go on.
The calf will depend on her
for the next three years.
Wherever she goes,
they will go together.
[music intensifies]
In the next decade, the summer sea ice
could disappear altogether.
If that happens,
even for the Arctic's
most seasoned travelers,
there may be nowhere left to go.
[music intensifies]
[music fades out]
In late June,
the North feels the full impact
of the Earth's tilt
and receives more daylight
than at any other time.
And, in one corner of the Pacific,
this creates the greatest opportunity
of the year.
[somber music playing]
For six months,
Alaska's Bering Sea
appears lifeless and empty.
Then, one day in June
all that changes.
Humpback whales arrive
after a month-long voyage
for the biggest event in their calendar.
Thousands of them.
[music becoming dramatic]
Across the Pacific,
other travelers are also on their way.
Sooty shearwaters
race to get there in time
flying 1,000 kilometers a day nonstop.
The occasion is so important,
they come from the other side
of the world.
At 65,000 kilometers,
it's the longest animal migration
on Earth.
[music intensifies]
A million of them join the whales.
All have come to feed.
[music intensifies]
It's one of the greatest gatherings
of life on Earth.
Here, five months ago,
there were just
seven hours of light a day.
Now, there are 17.
The change triggers an explosion
in the numbers of plankton and krill.
For the whales, it may be the only time
they feed in the entire year.
Over the summer,
each scoops up 900 tons of food.
They all have just 90 days
to eat as much as they can.
Soon, the days will shorten
and bring an end to the great feast.
Then, every one of them will return south.
The opportunities brought
by our tilted planet's journey
can be enormous yet fleeting.
[music abates]
After a month of long summer days,
temperatures in the North Pacific
are reaching their peak.
An ocean predator detects the change
and sets a new course.
[suspenseful music playing]
A tiger shark
on a thousand-kilometer odyssey
across the Pacific.
Guided by the Earth's magnetic field,
she swims in a straight line
towards her target
Laysan Island.
And she's not the only one.
[music intensifies]
This species makes some
of the longest journeys of all sharks.
And hunts a bigger range of animals
than any other.
Including even
birds.
[music abates]
The Laysan albatross chick hasn't eaten
since he was abandoned by his parents
two weeks ago.
[whimsical French music playing]
To find food,
he must now leave the island.
[chirping]
But the world's largest seabirds
need a lot of lift.
[music fades out]
That could come at any moment.
In July, the high ocean temperatures
generate tropical storms at sea
bringing wind to Laysan
and the young albatross
a ticket out of here.
[dramatic string music playing]
The breeze continues to build
until there's enough
to lift even an albatross.
And the black-footed chicks
are always first to go.
[music intensifies]
[chirping]
[music abruptly ends]
A chick's first flight
is never a long one.
[disquieting music playing]
And here, it's often their last.
[music becomes dramatic, fades out]
[chirping softly]
The tiger sharks have arrived.
[menacing music playing]
[music intensifies, abates]
[squawking]
And they are very effective.
[music reprises]
[music fades out]
For the young albatross,
it's not exactly encouraging.
- But it's now
- [quirky dramatic music playing]
or never.
If he reaches the open ocean,
he may not touch land again
for five years.
But there is no room for error.
[music intensifies]
Time to throw caution to the wind.
[music builds]
Time to fly.
[music crescendoes]
[music fades out]
[theme tune playing]
[music crescendoes]
[music ends]