DAVID ATTENBOROUGH:
In the far north of our planet
lie vast frozen lands...
...of snow-covered forests...
...and open tundra.
During the months to come,
they will be transformed
by the greatest
seasonal changes on Earth.
But now, in midwinter,
conditions are so hostile that
life seems all but impossible.
But...
...not so.
In this world of extremes,
animals must go to
extraordinary lengths to survive.
HOWLING
February, northern Canada.
The harsh winter
has brought together
an extended family of wolves.
But this is no ordinary pack.
There are 25 of them.
A super-pack,
one of the largest ever recorded.
They're ravenously hungry.
They may have walked over 150 miles
since they last had a meal.
But now, at last,
the lead male and female
have picked up a trail.
It's been left by the only
substantial prey there is here
at this time of year...
...bison.
GRUNTS
They're formidable animals,
not easy to att*ck.
The bulls are ten times
the size of a wolf.
And they have horns
with which they could
rip any attacker to pieces.
Gathered together and on guard,
they appear invulnerable.
The wolf pack's only chance...
...is to try and break up the group
and isolate one of them.
To do that,
they will have to work as a team
and try to start a stampede.
Even in thick snow,
bison can run at up to 35mph.
The lead female wolf
leads the chase.
A kick from a bison's hind leg
could shatter her jaws.
But the pack must feed,
and they take turns to att*ck.
YELPING
The bison head for cover.
The deep snow slows down
both att*cked...
...and attacker.
The herd splits into two.
But the wolves
are far from giving up.
Hours pass.
The thicker vegetation has turned
a straightforward chase...
...into a deadly form...
...of hide...
...and seek.
Discovered.
The lead female manages
to chase the smaller group
into the open.
GRUNTING AND YELPING
But here the bison are able
to close ranks once again.
The leading wolves wait for
the rest of the pack to catch up.
The super-pack is once
again at full strength.
Suddenly, two of the bison panic.
It's just what the wolves
have been waiting for.
One of the bison is tiring.
The lead female
gets a grip on its flanks.
The male joins her.
Together, they might be able
to bring it down.
The rest of the wolves
catch up and help.
After eight long, hard hours,
the hunt is coming to an end.
HOWLS
Victory is sounded to summon
the rest of the pack.
A single wolf
wouldn't stand a chance
of making such a k*ll by itself.
The only way they have
of surviving the winter
is as a super-pack.
HOWLING
These snow-covered forests
encircle the Arctic
from Scandinavia, through Russia,
to Alaska and the rest
of North America.
But close to the North Pole,
the winters are too long
and too cold
for even the hardiest of trees.
This is the tundra, and it stretches
all the way to the shores
of the Arctic Ocean.
Here, conditions are even more
extreme than in the forests.
During the two months
of winter darkness,
temperatures may fall
to minus 50 degrees Celsius.
The ground deep beneath the snow
has been frozen solid
since the last Ice Age.
There is no shelter of any kind.
Very few animals can survive here.
But this is one which does.
An arctic fox.
It has the warmest fur
of any mammal.
And it can survive
blizzards that may rage
for days on end.
It must nonetheless
eventually eat something.
But how is that something
to be found
when you're all by yourself
in this desolation?
Arctic foxes are wanderers.
And they can travel over 2,000
miles, from Norway to Canada,
in a constant search for food.
There might be something here.
A patch of grass,
kept clear of the snow
by the near-constant wind.
The slightest hint of scent
might indicate the presence of prey.
Less than a metre below the surface
may lie a hidden network of tunnels,
shown here using
a special filming burrow.
SQUEAKS
Tiny arctic lemmings.
With a carpet of edible moss beneath
and a thick blanket of snow above...
...the lemmings spend
their entire winter
hidden below the surface.
And here they breed.
SQUEAKS
For a hungry fox...
...a group of lemmings
could be a life-saving discovery...
...if it can catch one.
Lemming burrows may
extend for up to 15 metres.
Pinpointing the position
of one of the inhabitants...
...is not easy.
An acute sense
of hearing is essential.
SQUEAKS
And the arctic fox
has a special trick.
SQUEAKING
It doesn't always work first time.
And it does require dedication.
With less than 25 lemmings
per square mile of tundra...
...you have to persevere.
And at last,
one plump lemming.
The foxes' tenacity
and unique hunting skills
enable them to find prey
which few others could catch.
On the tundra's southern fringes,
winter is significantly less severe.
The slight increase
in annual sunlight
has enabled a stunted forest
to develop.
It's the northern edge of the
world's largest woodland...
...the boreal forest.
750 billion trees.
A quarter of all the trees on Earth.
And it encircles the globe.
These forests store
twice as much carbon
as a tropical forest,
and they play a crucial part
in regulating the climate
of the entire planet.
One of the most remote tracts
stands in the far east of Siberia.
It's cut off from the rest of
the world by towering peaks...
...and precipitous valleys.
And it is the last stronghold
of the world's rarest big cat.
The Amur leopard.
Hunting has brought it
close to extinction.
Only 120 are left in the wild.
And this is one of the very
few ever to be caught on film.
Each must patrol a territory
of over 100 square miles
to find enough to eat.
In the cold of March,
prey is at its most scarce.
But leopards are clever opportunists
and watch for clues.
CAWING
Crows.
They too are looking for food.
And their calls tell him
that they've found something.
CAWING
But he is not
the only predator here.
On one of the trees,
the marks of huge claws,
ten centimetres long.
They've been made
by a hunter twice his size...
...a Siberian tiger.
Fewer than 500 remain in the wild.
These two rare big cats
are sharing the same territory.
And fixed remote cameras
show that they even use
exactly the same trails.
But leopards know
they must be careful.
Siberian tigers are the
biggest of all the big cats,
and could k*ll a leopard...
...should they ever meet.
In winter,
many forest animals
rely on carrion for food.
CAWING
And that includes leopards.
But he can't let down his guard.
CAWS
The crows that led him here...
...may also have alerted the tiger.
GROWLS
The crows are disturbed.
Another mouthful might be risky.
CAWING
Survival sometimes
depends on knowing
when to leave.
Only a few choose
to take their chances here
in the depths of winter.
Elsewhere, vast swathes of
the forest remain eerily empty.
Above, there is
an otherworldly light show...
...the aurora borealis.
High in the sky,
electrically charged
solar particles from space
collide with the Earth's atmosphere
and create this ethereal display.
Meanwhile, in Canada, through
the six long months of winter,
life below ground
is biding its time.
The world's most northerly turtle...
...the painted turtle...
...seen here
in a special filming chamber.
They hatched last autumn
but have remained
in a state of suspended
animation ever since.
Their hearts have stopped b*ating...
...and only their brains
have remained active,
and even then, only very faintly.
Painted turtles wait underground
for this most important
of moments...
...the arrival of spring.
In April, the strengthening sunshine
triggers a miraculous
transformation.
The turtles' body temperature
rises just above freezing...
...and their hearts
start to b*at once more.
Slowly, they return to life.
Thanks to this extraordinary
adaptation, these young turtles
get a valuable head start
in spring...
...and are one of the first
to emerge, ready to take
full advantage of the forest's
renewed abundance.
In just a matter of weeks,
the vast northern forests
flush green.
For Siberia's big cats, each
spring could bring new hope.
Cubs.
Each of them
increases the chance that,
even at this very late stage,
both species might recover.
By June, the northern forests
are full of life.
But several thousands of miles
further north, in the tundra,
the spring thaw
is only just beginning.
When it does,
under 24-hour daylight,
its impact is even more extreme.
Five million square miles of snow
disappear in a matter of days.
Ten centimetres beneath
the surface of the ground,
a snow queen is waiting
to make her appearance.
A Lapland bumblebee.
She's barely alive.
All the other members of her colony
were k*lled by the cold.
She survived,
as bumblebee queens do,
thanks to her larger size,
her particularly thick fur,
and a natural antifreeze
that she has in her body.
As temperatures continue to rise,
she begins to thaw.
BUZZING
She vibrates her flight muscles,
which raises her body temperature
to over 30 degrees Celsius
in just six minutes.
There is no time to lose.
She must now create
an entire colony.
First, the queen must find
a drink of nectar
to regain her strength...
...travelling as much as
three miles a day
to find the flowers
from which to collect it.
She works tirelessly.
As well as high-energy nectar...
...there's pollen to be gathered.
Back underground, she uses the
pollen to build a waxy cocoon.
And in it,
she deposits the tiny eggs.
Had she laid them
directly on the frozen ground,
the cold would have k*lled them.
And now she warms them
by pulsating her body.
She has also constructed
a little pot
in which she stores nectar
to provide her with a drink
when she needs it.
For the next three weeks...
...this single mother
works around the clock,
gathering nectar
to top up her pot...
...and vibrating her body
to prevent her developing young
from freezing to death.
Eventually, a new generation of bees
starts to emerge.
She leads each young
worker to her honey pot
and encourages it to drink.
By the end of the following week,
the number in her little colony
has increased to eight.
Her timing has been perfect.
The tundra is now in full bloom.
And the bumblebee families
help to pollinate
the largest wild-flower
meadow on Earth.
But the summer here is one
of the shortest on the planet.
And all of the tundra's residents
are now racing to breed.
SCREECHES
Alaskan snowy owls have
a brood of six fluffy chicks
and only eight weeks
in which to raise them.
The parents provide them
with 30 lemmings a day...
...for the chicks will need
to triple their weight
before they reach independence.
Unusually for an owl,
snowies hunt by day.
And over the next two weeks,
they take full advantage of
the Arctic's continuous light.
But this morning, the female
returns to an empty nest.
Her chicks are nowhere to be seen.
They're hiding.
CHIRRUPING
They're so big, the whole group
might be spotted by predators,
so they have scattered
across the tundra.
But that makes feeding them
all much harder work.
SCREECHES
Over 600 meals later,
the parents' lab ours
are starting to pay off...
...as the chicks stretch
their newly developed wings.
Just a month is left
before winter returns.
SCREECHES
Two weeks more,
and their transformation
is almost complete.
The chicks' wings
might at last be able
to do more than just
lift them from the ground.
Getting there!
Keep going!
Airborne!
The youngsters are ready
for independence.
And the exhausted parents
can take a well-earned rest.
The tundra has come to life
once again.
But in the longer term,
its very foundations
are now at risk.
BIRDSONG
The ground itself is giving way.
RUMBLING AND CRACKING
In some places, it's dropped
by more than 60 metres.
Grasslands that once supported
thousands of different species
have become wastelands.
Arctic temperatures are rising
as a consequence of climate change.
The deep soil
which has been frozen solid
for thousands of years,
the permafrost,
is now thawing at a rate
never witnessed before.
Without the ice to bind it together,
the ground becomes unstable.
In Canada, thousands of
tonnes of the tundra
have collapsed in a matter of weeks.
And in Siberia,
huge scars are appearing.
By the end of the century,
an area of Arctic permafrost
one third of the size of Europe
could have thawed.
The warming of the tundra
is having a profound impact
on its wildlife.
For millennia, caribou
have made annual migrations.
Every summer,
driven by the seasonal
changes of the far north
and following
long-established pathways,
they have trekked
almost 400 miles north.
This herd alone in north-east
Alaska numbers over 200,000.
Their destination
is a vast wilderness
known as the Arctic
National Wildlife Refuge.
These summer pastures
provide rich grazing,
just what's needed
to raise newborn calves.
GRUNTS
This one, fattening up
on its mother's milk,
would normally double its weight
in just a few weeks.
But now grazing time
is being disrupted.
INSECTS BUZZ
In summer, the tundra
becomes waterlogged.
These are excellent
breeding conditions
for mosquitoes
and other biting insects.
But as the climate warms,
there are concerns
that insects will breed earlier
and eventually reach
plague proportions
just as the caribou need to feed.
INSECTS BUZZ
Individual animals could lose
a quarter of a pint of blood
a day to biting insects.
GRUNTING
So the caribou may
end their grazing early
and head for cooler,
mosquito-free pastures.
But to get to such places,
they will have to cross rivers
swollen by seasonal runoff.
For a young calf, a deep river
crossing is very dangerous.
He does what he can
to stay close to his mother.
But he doesn't have the strength
to resist the fast-moving current.
GRUNTS
GRUNTS
He is one of the lucky ones.
Reunited with his mother,
he can continue
on his journey with the herd.
GRUNTS
But other calves
are less fortunate...
...and must now
fend for themselves.
Some are too exhausted
to take another step.
But this is not a safe place
to take a rest.
Grizzly bears.
For the past few weeks,
there has been little food
for them on the tundra.
And this one is extremely hungry.
GRUNTING
He's looking for the weak and weary.
And he's found one...
...too tired to flee...
...and too weak to resist.
The herd's finally reached
the northern limits of its range.
These coastal pastures
bordering the Arctic Ocean
remain cool enough to provide relief
from the swarms of insects.
Mothers and calves
can finally feed in peace.
For now, this
immense herd is stable.
But in the long term,
its survival is now uncertain.
The seasonal extremes
of the far north
have always tested
its inhabitants to the limits.
But climate change
could present them
with one challenge too many.
Only if we can mitigate its effects
will the remarkable wildlife here
stand a chance of survival.
Filming in the extremes
of the far north...
...the team's greatest
challenge was to capture
the epic showdown between
super-packs of wolves
and bison in midwinter.
GRUNTING
The crew travelled to
Wood Buffalo National Park
in northern Canada,
a remote wilderness
the size of Switzerland.
To stand a chance
of filming this drama,
they must take to the skies.
Drawing on local knowledge,
pilot Matt Erhardt
helps to pinpoint
one of the last
free-roaming herds of bison
and the wolves that
specialise in hunting them.
Some of the wolves
have run forwards.
Just have all your kit
ready to go.
With a positive sighting,
it's time to mobilise the film crew.
Cameraman Jamie McPherson
has rigged the helicopter
with a gyrostabilised camera system,
enabling him to capture
rock-steady images
from a safe distance.
You'd think filming
from a helicopter's easy,
because you can just
fly around and film stuff.
But you've got to be
incredibly careful,
not influence the behaviour,
not scare the wolves or the bison.
There we go.
Yeah, that is them.
It's a big pack. Yeah.
They're really chilled out
with the helicopter.
Really encouraging.
But before Jamie can start filming,
the chopper must first drop
the accompanying ground crew.
Good luck. OK.
We got put down
in this vast open space,
and now we're going to
try and hike in and see
if we can get close to them,
or hopefully they'll
get close to us.
To intercept the pack, the team
must scramble into position.
But trudging through
knee-deep snow
is hard going.
HE BREATHES HEAVILY
Every time I catch up with
Justin, he just keeps on going.
He's a machine!
Yeah, go ahead, Matt.
OVER RADIO:
They're starting to head
a little bit towards
the north-west,
so they're starting to
move away from you.
Oh, g*dd*mn it!
The ground crew
will have to dig deep
if they're to film
the fleet-footed wolves.
Over the following week,
Jamie manages to track
the wolf pack
from the comfort
of the helicopter...
...while down on the ground,
Justin and Will are having
a tougher time of it.
Ohhh! It's really
incredibly awkward getting around.
Even lunch offers
little consolation.
It's frozen bread,
frozen Brie and frozen pickle.
And with no wolf activity
visible from the air,
Jamie is soon grounded.
Yeah, I'm just
looking for an update.
Great...
WIND HOWLS
The winter weather
takes a turn for the worse.
It's snowing, and it's at
a temperature where it could
potentially stick to the blades
and become really dangerous.
For the next few days, the crew
are forced to sit it out.
Finally, the skies clear.
But after nearly three weeks
on location,
there's precious little
filming time left.
We've got one last sh*t
to get what we're looking for.
And just hoping that it comes
together at the last minute.
There, there's the trail there,
so they're on the west side
of that trail there.
Soon enough, they find the bison,
along with wolves
who appear to be in hunting mode.
The spotter plane just found
the wolves with the bison,
so we're scrambling to get
there as quick as we can.
There's something about
being in the presence of prey
and predator on the ground
like this which is very special.
Justin is in prime position
to capture the showdown.
As a chase begins,
Jamie picks up the action
from the air.
It'd be amazing
if we could get round that. OK.
In a stop-start pursuit
lasting an entire day,
Jamie manages to record
the full jaw-dropping drama.
They've definitely got
that female.
I think they're going to
bring it down.
Perfect, Jim. We got it.
With the hunt nearly over,
the crew reposition Justin
once more.
HOWLING
We got on the ground
just in time to capture
from a really far distance
the last moments
of the bison's life.
There's a moment of confliction
between your loyalty
for each animal.
One is filled with a mixture of
both celebration for the wolves
but a sadness. Both exist
somehow simultaneously.
Bearing witness to this
rarely seen age-old battle
between predator and prey
leaves the crew
with an appreciation of
just how challenging life is
in the frozen extremes
of the far north.
Next time...
...we meet the scientists
and people...
...who are dedicating their lives
to understanding
the changes taking place...
...across our frozen planet.
Changes that'll impact
the lives of each...
...and every one of us.
01x05 - Frozen Lands
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David Attenborough narrates `Frozen Planet II', an exploration of the wildlife in some of the coldest regions found in the world.
David Attenborough narrates `Frozen Planet II', an exploration of the wildlife in some of the coldest regions found in the world.