Planet Earth (2006) s01e06 Episode Script

1
Both poles of our planet
are covered with ice.
They're the largest and most
demanding wildernesses of all.
Nowhere else on Earth
is seasonal change so extreme.
It causes the ice to advance
and retreat every year,
and all life here
is governed by that.
When the first polar explorers
headed south,
giant cathedrals of ice marked
their entry into uncharted territory.
Passing the towering spires, they must've
wondered what unearthly sights lay in store.
As they battled on, the ice
became increasingly dominant,
but nothing could have prepared them for
the ice world that finally loomed into view.
Terra incognita — the unknown land.
At the southernmost extreme of our
planet, the continent of Antarctica
is as large
as the United States of America.
90% of all the world's ice
is found here.
This frozen world is largely deserted
until the start of spring.
Adelie penguins
in a hurry.
The clock is ticking.
Instead of waiting for the summer melt, the
new arrivals hasten south over the frozen sea.
They have come here to breed, but
polar summers are so short
they must be in position
before the thaw starts.
As the sea ice retreats,
life can journey farther south.
Antarctic waters are so rich, that visitors
come from far and wide to harvest them.
Vast numbers of chinstrap penguins
come ashore to breed.
No bird will lay their eggs
directly onto ice,
so bare rock is a vital commodity.
The best patches are worth the climb.
The clifftops are soon
stained pink
with the droppings of tens of
thousands of nesting penguins.
Only in a land almost entirely covered in
ice, could bare rock be reckoned an oasis.
Some will travel into the heart
of the continent to find it.
These are "noon attacks", the exposed
peaks of vast mountain ranges
buried in ice over a mile deep.
The eerie silence here
is only broken in spring.
The snow petrels have arrived
and are courting.
Antarctic petrels now join the most
southerly bird colony on Earth.
The birds have flown inland
for over 300 hundred miles
to reach this breeding site.
Once their eggs have hatched,
they'll be forced repeatedly to
make the 600 mile round trip
to gather food in the ocean.
First though, valuable nesting places
must be defended from property thieves.
After laying their eggs, the petrels
take time out to clean their plumage.
The south polar skua
is a formidable opportunist.
But the skuas have not chanced
upon the petrels —
they've been waiting for them.
These birds do not need to go
to the ocean for their food.
The skuas can survive further south
than any other predator
by exploiting the petrels'
desperate need for bare rock.
Even at the height of summer, less than
3% of Antarctica is free of ice
and nearly all of that
exposed rock is found in one place —
the Antarctic Peninsula.
It's long arm extends further north
than the rest of the continent,
so spring arrives here first.
The thaw unlocks sheltered bays
that provide refuge from the relentless
battering of the southern ocean.
In the depths something stirs —
Humpback whales.
They have travelled over 5,000 miles
to reach these waters.
The whales are harvesting krill,
shrimp like creatures that begin to
swarm here as soon as the ice retreats.
Diving into the heart of the swarm,
teams of whales spiral around
each other in close coordination.
Now they turn and blasting air from their
blowholes and ascend towards their prey.
The krill becomes concentrated as the
spiralling net of bubbles draws inwards.
The team of whales work 'round the clock,
for the bloom is short lived.
Summer is already fading and the whales
will soon be forced north as winter returns.
The sun's influence diminishes
and the ocean starts to freeze.
The greatest seasonal change
on our planet is underway.
The ice grows at an extraordinary rate
advancing two and a half miles a day.
In a matter of weeks the continent
effectively doubles in size.
Life flees from Antarctica
but one creature is just arriving.
Every winter, Emperor penguins leave
the comfort of their ocean home
and begin a remarkable journey.
They head towards their breeding grounds
almost a hundred miles inland.
Eventually, the emperor penguins reach
the place where they were hatched,
an area sheltered by icebergs
trapped in the frozen ocean.
Here, they will raise
the next generation,
but first, each must find a mate.
Males begin to serenade,
and if a female replies,
they pair up, posing like statues.
New couples quickly form
a strong bond
they seem oblivious
to the noisy crowd around them.
To cement their relationship,
the male steps out with his female.
The brief courtship complete,
there isn't a moment to loose.
With so much pressure to perform,
any male would struggle to stay on top.
Several weeks later and it seems
that most couplings were successful,
but producing the egg
has taken it's toll.
The females no longer have
the energy to incubate.
The male takes over.
It's still -20 degrees centigrade,
so the transfer must be done quickly
or else the egg will freeze.
With no bare rock to nest on, the male
tucks the egg into a special pouch
where he can keep it warm.
It requires an extraordinary
piece of teamwork.
Driven by hunger, the exhausted females
now return to the ocean on their own,
repeating the epic journey they made
with the males only a month before.
Now the sun barely appears
above the horizon.
As the day shortens, it's warmth
is withdrawn from the continent.
With the females gone, the colony
undergoes a strange transformation.
The males shuffle into groups, their
eggs still tucked away above their feet.
They lock together in tightly packed
huddles as they struggle to keep warm.
Speeding up the action reveals how these
huddles constantly shift and change
as each penguin works it's way
towards the warmer interior.
Crammed into this scrum, the birds are
remarkably good natured, but they have to be.
If the huddle breaks even for a moment,
precious heat escapes.
It's imperative they reform
as quickly as possible,
for only by as acting as one can the males
withstand the elements, and protect their eggs.
But their greatest test lies ahead.
As winter advances, frequent blizzards
drive the temperature down.
It's now 60 degrees below zero.
The birds
at the edge of the huddle
bear the brunt of the
100 mile an hour winds
and so provide shelter to those
taking their turn in the middle.
Abandoned by the sun, the males
are left alone with their eggs
to face the coldest darkest
winter on Earth.
At the northern extreme
of our planet,
the sun rises for the first time in months,
illuminating a very different ice world.
Unlike Antarctica, the Arctic is
a vast frozen sea surrounded by land.
Here, winter is coming to an end,
but this bleak wilderness
remains locked in ice.
Eider ducks break the silence.
They have stayed here
braving the northern winter,
instead of flying south
to warmer climes.
Flocks 40,000 strong
sweep across the frozen wastes.
They all have the same goal —
a "polinear" — a permanent hole
in the sea ice
kept open throughout the winter
by strong ocean currents.
This unusual duck pond
provides an overnight sanctuary,
and when day breaks,
a rare chance to feed.
Just 10 meters beneath the ice, the sea
floor is carpeted with dense mussel beds.
These can only be reached
during a brief lull in the currents.
The ducks must quickly prise the mussels
free before the tide starts to turn.
The window of opportunity is short.
As the current begins to build,
it's up up and away.
These permanent holes in the ice
provide seafood throughout winter.
The diners attract others.
In the Arctic, any breach in the
icy barrier can be a lifeline.
Musk oxen create their own.
These giants have the strength
to smash through the frozen crust
to graze on the vegetation below.
These ice-breakers create an opening
for other over winterers.
Flocks of ptarmigan make unusual
grazing companions for the musk oxen,
whose entourage grows
throughout the day.
This odd assembly of vegetarians
doesn't go unnoticed.
An arctic fox.
The musk oxen have
recently given birth.
For the fox,
it's a chance to scavenge
but half a ton of mad hairy cow
is not to be trifled with.
The calves are born well
before the spring melt,
giving them a head start
when summer finally arrives.
It must get to grips
with it's new ice world,
benign one minute,
life threatening the next.
Even in spring,
winds chill to the bone.
The calf must stay close to it's mother to
avoid getting lost in the sudden blizzard.
Arctic wolves.
In the white-out, the threat
is almost impossible to detect,
but the musk oxen instinctively
retreat to higher ground.
Forming a defensive ring
around their calves,
the adults present a barricade
that few hunters could breach,
but the wolves need not
risk injury today.
A calf has been left behind
in the panic.
With each passing day, the sun
climbs higher in the sky
and it's rays strike the Arctic
more directly.
It's spring and new life stirs.
The polar bear cubs emerge from
the den in which they were born.
Their mother stretches her legs
after 5 months under the snow.
They're just two months old
and instinctively follow her lead.
A steep slope makes
the best site for a den,
but it's a tricky place
to take your first steps.
It may look like fun, but this
is serious training for the task ahead.
There's no food on the slopes,
and the family will need to
head out across the frozen sea,
before the mother's milk runs dry.
Two weeks later, they're ready.
Out on the sea ice,
the female can hunt for seals,
but it will take all her mothering
skills to keep her cubs safe
in this dangerous world of ice.
The annual melt has begun.
This is a challenging time
for the bear family.
1 out of every 2 cubs do not survive
their first year out on the ice.
As the sun's influence increases,
the sea ice seems to take on
a life of it's own.
Glacial melt waters pour
from the land,
mingling with the sea
and speeding up the thaw.
The seascape is in constant flux, as broken
ice is moved on by winds and currents.
The ice is becoming too weak
to support a male polar bear.
He attempts to spread his weight,
but the ice that has supported him
all winter is rapidly disintegrating.
Each year as the climate warms,
the Arctic holds less ice.
This is a disaster for polar bears.
Without it's solid platform, they can't hunt
the seals they need in order to survive.
This may be a glimpse
of the unstable future
faced by this magnificent creature.
As the ice disappears,
seabirds return to the high Arctic.
Little auks arrive in their millions.
In some ways, these birds
are the penguins of the north.
The seek bare rock on which
to lay their eggs
and they look rather
like penguins too.
Unlike Antarctica, the Arctic can be
reached by land based predators,
which is why little auks have kept
the ability to fly.
They use scree slopes
to protect their eggs,
burrowing up to a meter
beneath the rocks.
At the height of summer,
the sun never sets,
but just skims the horizon
before rising again.
Migrants return to the Arctic
from far and wide.
They've come to make the most
of the brief flush of food
and to produce their young.
Sandhill cranes have travelled
all the way from New Mexico.
Their chicks join the growing band
of youngsters exploring the tundra.
For a few months each year, the Arctic
becomes the land of the midnight sun
and 24 hours of daylight allow
animals to feed around the clock.
The arctic fox finally has enough
food to raise her large family.
If you choose to nest in the open,
you must be prepared for a fight.
Arctic skuas will see off any
trespassers even large vegetarians.
The male polar bear's ice world
has finally vanished beneath him.
While the female is still kept
on land by her dependent cubs,
the male can take to the sea
in search of food.
Ducking and diving,
he hopes to ambush seals
resting on the remaining
fragments of ice.
In these new surroundings, he is
a surprisingly adept swimmer.
Once an extremely rare sight,
polar bears have recently been seen
over 60 miles from the shore.
There is now no turning back
for this bear.
He's forced to head out
into deeper water.
His giant front paws help him
to fight the ocean currents.
He seems at home in the sea,
but he cannot swim indefinitely.
He will drown if he doesn't find land
somewhere in this vast ocean.
Walruses are now gathering
on low lying islands.
They gave birth on sea ice,
but with this platform now gone,
they need a new place to haul out
and nurse their young.
After several days at sea, the
male bear finally makes landfall,
drawn by pungent smells
emanating from the island.
By the end of summer,
the bear has lost half his weight.
With the ice long gone, he is
forced onto land in search of food.
There will be no easy meals
on this island.
Walruses are the largest seals in the
world. They weight over a ton
and are armed with tusks
a meter long.
Exhausted from his swim,
the bear must regain his strength.
The next day,
a sea fog shrouds the island.
The walruses sense
that they're in danger.
Using the fog as cover,
the bear approaches the herd.
The adults close ranks around their young,
presenting a wall of blubber and hide.
He tests the barrier,
but it stands firm.
It appears that the world's largest
land carnivore has met his match.
There must be a chink
in the armor somewhere.
Not here.
This female walrus is shielding
her pup, if can just prise her off.
The bears claws and teeth
can't penetrate her thick hide.
With the herd retreating to water,
the bear must move quickly.
Having failed with one,
he heads straight for another.
The chance of his first meal
in months is slipping away.
He seems increasingly desperate.
It's now or never.
He must avoid the stabbing tusks
if he's to win.
The flailing walrus
is immensely powerful
and drags the bear away
from the shallows
towards the safety of the herd.
It slips from his grasp.
Only at the height of summer, when
bears are on the verge of starvation,
will they risk attacking
such dangerous prey.
It was a gamble
that this bear took, and lost.
The stab wounds he received
from the walrus
are so severe
that he can barely walk.
The walruses are calm again,
seemingly aware
that the injured bear
no longer poses a threat
to them or their young.
Unable to feed,
this bear will not survive.
If the global climate
continues to warm,
and the Arctic ice
melts sooner each year,
it's certain that more bears
will share this fate.
At the southern end
of our planet,
fiery ribbons are illuminating
the winter skies.
The "Aurora Australis".
This light brings no warmth to the
male penguins who are still huddling,
defying the coldest conditions
on the planet.
Their ordeal is drawing to a close.
30 days after it last set, the sun
rises once more on Antarctica.
Their appalling trials
have all been for this.
Each father has just one meal
left inside him.
He's been saving it all winter.
This single feeding will sustain
the chicks for a few more days,
but the males have not eaten
for nearly 4 months.
If they do not eat soon,
they and their chicks will die.
But there is hope on the horizon.
The females are returning,
and their bellies are full with fish.
As they approach, waves of excitement
ripple through the huddle.
Each female calls to her mate, and he,
recognizing her song, trumpets back.
Reunited, at last.
The mother feeds her chick
for the first time.
She's keen to start parenting,
but the father needs persuading
to surrender the chick
he's been caring for all winter.
He must now put his chick at risk.
In these temperatures,
it could freeze in seconds.
The male will have to let go.
Eventually, the transfer
to the mother is safely made.
The chicks grow quickly
on a diet of fish and squid.
Soon, they're keen to explore,
but always with mother in tow.
This chick is less fortunate.
It's mother has not returned
to claim it.
Another orphan is searching
for a new family,
but this female already has
a chick of her own.
Some orphans receive too much
mothering from penguins
whose own chicks
have not survived.
The urge to parent is so strong,
that they will compete with one
another to adopt any chick they find.
Many of these squabbles
will end in tragedy,
as the poor chick
is trampled to death.
Those chicks that do have parents,
quickly learn survival skills.
Even in spring, they must
huddle together for warmth,
just as their fathers did
in the depths of winter.
A group of chicks has got lost
in the blizzard.
Cold and disorientated,
they search for the colony.
It will not be long before the
storm claims it's first victims.
By early summer, the chicks are
surprisingly well developed,
and now look ready
to take on the world.
Those that survived their first year,
have the best possible start in life,
thanks to the extraordinary hardships
endured by their parents —
parents who battled with the
Antarctic winter, and won.
In the Arctic, the 2 polar bear cubs
are now independent of their mother
and they briefly reunite
where their home ranges overlap.
Their time together will be fleeting.
Most of their lives
are now spent alone,
wandering the vast tracts
of frozen ocean.
Following their mother has prepared
them for life at the pole,
an ever changing land ruled by ice.
Whether they are ready
for the bigger changes
that have begun to shape
the ice worlds of our planet
remains to be seen.