Nature (1982–…): Season 35, Episode 6 - Snowbound: Animals of Winter - full transcript
♪♪
I'm Gordon Buchanan,
a wildlife cameraman.
I've filmed in
some of the planet's
most extreme and
bitterly cold places.
Despite being so harsh,
these frozen
wonderlands are full of life,
with creatures that
somehow manage to survive
against all the odds.
I'll be meeting some of
these fearless animals,
from sociable wolves
to the enigmatic lynx
and cunning Arctic foxes.
That is the most sumptuous
animal I've ever seen.
These are creatures
that are specially adapted
and have evolved
to live in the snowiest,
coldest places on Earth.
How they're able to survive
the big freeze is extraordinary.
♪♪
♪♪
I'm in the Arctic.
It is incredibly beautiful,
but it is also incredibly cold.
Winter temperatures
here can drop to
as low as minus-50 degrees.
Yet for some creatures,
like these magnificent wolves,
they call this place home.
They live on top of the world
in one of the
earth's freezers...
the Arctic Circle.
I'm in Polar Park in Norway,
the most northerly
wildlife park in the world.
The wolves here have
grown up with humans around,
so they're used to people.
But I still need
to gain their trust
and have to remain
quiet and calm.
Despite the cold, I've had
to take hat and gloves off
or these guys
would be too tempted
to snatch them off.
Hello.
This magnificent
beast is treating me
like another wolf
and saying hello.
That's how they
greet each other...
With their mouths.
Wolves often nibble
on each other's faces.
It might look aggressive,
but it's a sign of affection.
The size of the paws.
You are a beaut!
Just stroking this wolf,
you can lose hand in its coat.
And when I part the hair,
you can see the underneath,
these fine, very soft
hairs that gives insulation,
and these longer, outer hairs
repel the snow and water.
His coat is perfect
for these conditions.
But like the domestic dog,
the foot pads, the
toe pads of the wolf
are completely naked.
And they spend
most of their lives
with those naked toe
pads and foot pads
in contact with the snow
and ice certainly in the winter.
So how do the wolves
stop that cold temperature
coming from the ground
up through their naked feet
into the rest of their body?
Well, they've got a very,
very clever solution to that.
Hot blood never
reaches a wolf's paws.
As it flows down the
leg, it's cooled down...
Almost like entering a fridge.
Only cold blood is
kept within the paws
so that all the warm blood
can remain within the body.
This clever adaptation
means that any heat loss
is kept to an absolute minimum.
On a thermal camera,
which shows body heat,
the upper part of the
wolf's legs are red,
showing them to be
warmer than its feet.
The wolf's coat looks blue.
That's because
his stunning thick fur
is preventing heat
loss from his body.
So no matter what physical
characteristics you have,
a clever hunting
strategy is essential.
And in these bitterly
cold conditions,
it helps to have friends.
A wolf's ability to hunt
as a team, as a pack...
That's really what helps
guarantee its survival.
Being part of a
strongly bonded pack
is invaluable in the
coldest part of winter.
In North America,
this pack have been
waiting until their prey is
at their most vulnerable.
The elk here are
weak with hunger
and in such deep snow,
they struggle to run very fast.
The wolves follow a
well-practiced formula.
They target a
straggler of the group.
Three members of the pack
work together to bring the elk down.
It's a brutal but
impressive hunting strategy.
Impeccable teamwork, along
with remarkable adaptations,
make wolves stand out
as supreme snow animals.
Not all snow animals live
in social groups like wolves.
In fact, one of the most
successful snow animals
is solitary
and lives most
of his life alone.
They can be
found in the very far
north of the Arctic...
The polar bear.
This male, like
every polar bear,
is almost completely
covered in fur.
But his secret to staying
warm in this frozen land
is actually inside
his large body.
He has a huge layer
of insulating fat...
About four inches thick.
It traps heat, keeping
him warm from the inside.
To maintain this fat, he relies
on his good hunting skills.
His prey is hidden
under the thick ice.
Luckily he has a secret
weapon to help him hunt...
An extraordinary sense of smell,
a hundred times
stronger than ours.
♪♪
He can detect a seal carcass
from around 20 miles away,
and under three foot of snow.
Success.
He will eat all the
fat of a seal first,
often leaving the actual meat.
This extreme fatty
diet would kill us,
but for the polar
bear, it's essential.
Indeed, they are one of the
fattest mammals on Earth.
Their incredible insulation
and intense sense of smell
make the polar bear
a master in the snow.
They're also built
to move around
effortlessly in this
snowy environment,
unlike me.
I am a perfect
example of an animal
that is not adapted
for walking about
a snowy environment like this.
I'm 12 stone, 12
and a half stone,
and all of my
weight is distributed
onto my feet... size
12... Big feet for a human,
but not big enough to stop me
from sinking down into the snow.
What I need to do is
increase that surface area...
Put on some snowshoes.
I suppose the secret to
moving around in deep snow
is to do it efficiently.
Here we go...
Adapted for walking in the snow.
That is so much better.
It's easy. I can walk
through the forest.
I'm not sinking
down in to my waist.
I can go fast.
I can almost go silently.
Like I belong here.
Polar bears have
built-in snowshoes.
Their paws are wide,
measuring up to 12 inches across.
This helps them to distribute
their weight evenly on thin ice.
Underneath their large
paws are small, soft bumps
to give them extra
grip on the ice.
As well as being superbly
adapted to the snow,
some bears have another
strategy to get through winter...
By sleeping through it.
This is the recently
vacated den of a brown bear.
The den would have been
dug back in the autumn,
'round about October time.
In the hardest of winters,
a brown bear will spend up
to seven months in its den,
not eating, not drinking,
just drifting in
and out of sleep,
waiting for the thaw.
A bear will make a den
which is just slightly
bigger than itself...
A snug fit.
Some dens are built in
rock crevices or hollow trees.
For others, like
this polar bear,
it can be simply a case
of digging a small hole
and then waiting
for the snow to fall,
providing an excellent,
insulating roof.
♪♪
This female polar
bear, filmed in captivity,
is in hibernation.
During this time, her heart
rate drops dramatically
and she doesn't
eat, drink, or urinate.
Amazingly, she's
able to recycle waste
into new protein
to maintain her muscles.
Although she survives
purely on fat reserves,
she can, remarkably,
give birth in hibernation.
Her body heat keeps
her babies warm.
They grow rapidly thanks
to her extremely fatty milk,
which is nearly 10 times
richer than human milk.
♪♪
I've spent much time
filming polar bears
and been lucky enough to
see tiny twin cubs emerge
from their winter den...
A truly wonderful sight.
Aww.
Aww, very, very cute.
They were very eager
to explore the big, wide world.
After being born in hibernation,
the family venture out when
the babies are strong enough
to survive outside
and ready to make the
trek to the spring sea ice.
Oh, wow.
Look at that.
It's a sight I
will never forget.
Many smaller
mammals also hibernate
to avoid the bitter winter,
but there is one which
does so with a unique twist...
The Arctic ground squirrel.
When the harsh weather begins,
the ground squirrel escapes
to an underground burrow
to hibernate.
Amazingly, the squirrel's
body temperature
drops to below freezing...
The lowest of any mammal.
His major organs shut down,
and he looks dead to the world.
Despite this, he's
able to stop himself
from actually freezing to death.
Every few weeks, the
squirrel begins to shake.
This shivering is enough to
raise his body temperature
back to up normal
for a few hours.
After this session of shivering,
he can safely cool back down,
ready for another
cycle of deep sleep.
For animals that
don't hibernate,
being well-insulated to
withstand severe
weather is essential.
For human beings in the
cold, we have to layer up.
I've got five layers
on. I've got gloves on.
We generate heat,
and we want to retain
that heat in sub-zero
temperatures.
And if I remove my glove,
it goes without saying
my hands start losing heat,
my hands start feeling cold,
and you can see the comparison
very clearly on
the thermal camera
between my cold hand
and my warm hand.
The fingers on my
cold hand are blue,
showing how much
heat they've already lost.
Animals are far more efficient
than us at retaining heat.
And there is one
animal which tops the lot.
The Arctic fox is superbly
kitted out for the winter.
To prepare for it,
he undergoes a
spectacular transformation.
His thin brown summer coat
changes into one
which is 200% thicker.
It's white, and it's
very, very fluffy.
Hello, you handsome,
handsome boy.
My word.
That is the most sumptuous coat
I have ever seen on any animal.
In fact, Arctic foxes
have the warmest coat
of all Arctic mammals.
And it's not just that fabulous
fur the fox has got.
They have incredible senses...
Particularly the hearing.
And despite having
these fairly small ears,
this fox will be able
to detect his prey
with pinpoint accuracy
even when it's hidden
underneath the snow.
In the depths of
the Canadian winter,
a young Arctic fox
is searching for food.
He's still a hunting novice.
It's not easy when
you can't see your prey.
With his acute senses,
he can hear a faint
sound under the snow.
Lemmings.
To catch one,
he uses a special
pouncing technique
known as mousing.
He has to judge
its exact distance
as well as the
depth of the snow.
To help them
find the right spot,
foxes actually
align their pounce
to the Earth's magnetic field...
An extraordinary skill.
But mousing isn't always easy,
especially for a beginner.
♪♪
Super senses are
crucial for animals
that live in such white
and snowy landscapes.
And I'm about to meet one
whose eyesight is legendary.
This exquisite-looking
cat is a lynx.
It's a cat that is especially
adapted to the snow.
Look at those eyes.
Lynx have incredible vision.
It was once believed that
lynx can see through walls.
And actually looking
into those eyes,
I find that quite
easy to believe.
Maybe that's
stretching it a bit,
but a lynx can spot a
mouse from 80 yards away.
And their night vision
is truly remarkable,
far better than ours.
At this time of year,
when the landscape
is dominated in snow,
you can see how easily
the lynx just disappears in it...
Matches these birch trees.
It's almost invisible.
That's all the lynx needs
is a little bit of something
to break up its outline.
In the wild, lynx are
incredibly difficult to glimpse.
They roam the remote forests
for hundreds of
miles in search of prey
and may never visit
the same patch twice.
With so few prey animals here,
life for this silent hunter
is particularly hard.
And in this harsh wilderness,
they're not the only hunters.
The great gray owl
waits and listens.
He's watching for prey.
He has excellent,
super-sensitive hearing.
He can even hear the
scuttling of voles or mice
beneath two foot of snow.
He glides silently, like a
king of acoustic stealth.
His wings absorb
any noise of flapping
so he can take his prey
by complete surprise.
To survive in a snowy landscape,
it helps to have a
secret advantage,
a trump card up your sleeve.
My next snow animal
has quite a surprising one.
Reindeer traditionally
pull sleighs
and have a popular reputation
for red, glowing noses.
But behind this folklore,
there is some
surprising truth...
An ingenious adaptation
which helps them
survive the extremes.
Their noses are
full of blood vessels.
These cool warm air
down as it leaves the body
and warms cold
air up as it comes in,
keeping the reindeer's brain
constantly warm and active.
So, as the thermal
camera proves,
reindeers' noses
are actually red.
It's not just the
nose of the reindeer
which is extraordinary.
How they view their
winter surroundings,
through those large,
characterful eyes,
is truly astonishing.
When it's bright
and sunny like this,
my eyes struggle to cope
with the amount of UV light
that's coming from the sun
and is bouncing
back up off the snow.
If I was to spend too long here,
I'd eventually damage my eyes.
I could become snow blind.
But reindeer,
they see things differently.
Not only can they
see in color like I can,
they can also
see in ultraviolet.
For us, it's difficult
to make out detail
when the landscape is so white.
But with UV vision,
a reindeer can see things
in much greater contrast.
They can see shapes
and detail that we can't.
The lichen on the
trees which they eat
or animal urine in the snow
becomes more prominent.
In such a white, snowy
world, it certainly helps
to have that extra insight.
Reindeer even have specially
designed, flexible hooves.
In the winter, their four toes
can spread out wide
to act like snowshoes.
This means they
can walk on bumpy ice
without slipping.
However, on smooth
ice they can sometimes
find their shoes
a little ill-suited.
♪♪
When it comes to surviving
against all the odds,
there is one snow animal
which has to endure one
of the most extreme
places on Earth.
From the top of the
world to the very bottom
is Antarctica,
the coldest, windiest, and
driest continent on the planet.
This desolate freezer is also
the chosen home of the penguin.
How do they survive in
minus-90 degrees Fahrenheit?
Well, penguins
are superbly built
to resist the extreme cold.
First of all,
their round, shapely
figure isn't by accident.
It provides them with
enough blubber to keep warm.
But how do penguins
manage to keep
their extremities like
wings and feet warm?
Well, their bodies
are cleverly adapted
so that the muscles
needed to move their feet
and wings are kept inside
their warm, round body.
Only tendons operate
within the actual limbs,
and these are far less
vulnerable to the cold.
But it doesn't stop there.
These ice specialists
have another clever
trick to keep warm.
To reduce the amount of body
touching the frozen ground,
they just lean
back on their heels,
picking their toes off the ice.
It can decrease their
heat loss by 15%.
Penguins may not be able to fly,
but they do have
a lot of feathers.
And it's thought that penguins
have more insulating feathers
than any other bird.
And I've got some here.
Just look at them.
These are from an
emperor penguin,
a species that has to endure
bitterly cold
Antarctic conditions.
And it is a masterpiece.
At the base, it's
incredibly downy and fluffy.
The quill part is stiff.
The end is slick.
This is the waterproof part.
And on the bird,
these feathers interlock.
The outside is waterproof.
It creates a waterproof seal.
Underneath is an air void
full of these downy feathers.
This is an incredibly
sophisticated
form of insulation.
Penguins are
understandably very protective
of their precious feathers.
So much so, that when
the males come together
to form their famous huddle,
they take extra-special
care not to damage them.
In the deepest part
of the Antarctic winter,
the male emperor penguins
are huddling together to
try and keep themselves,
and their eggs, warm.
The center of the
huddle is the hottest part.
It can even get too hot.
So the penguins
constantly move around,
changing their position.
But instead of pressing
into one another,
they are barely touching.
If they were squashed together,
the insulation from
their incredible feathers
would be compromised.
So they leave almost an inch gap
between each other
to protect their feathers.
This means that if
one penguin moves,
its neighbor has to
react and follow suit.
Just one penguin's step
creates a chain reaction,
sending a ripple of movement
throughout the huddle.
There is only one mammal
which is tough enough
to live this far south
in the Antarctic all year-round,
and that's the Weddell seal.
This incredible snow
animal spends much of its life
under the expanse
of the frozen sea ice.
The Antarctic Ocean
can drop to 28 degrees.
Weddell seals can only survive
about an hour under
the freezing water
before needing air.
They have to find a
natural crack in the ice
to create a breathing hole.
To do this, they have
a unique adaptation.
A sharp tool designed
especially for the job...
Large, very strong,
protruding teeth.
With these razor-sharp incisors,
a seal is able to
scrape away fresh ice
and keep the hole open.
♪♪
But these breathing holes
also serve another function.
The males attract
females to them
during the mating season.
One male can draw
up to 10 females,
so the holes are
hotly contested.
This Weddell seal male
is on the search for one.
It's not easy in the
gloom under the ice,
but it's thought
that seals may use
their acute hearing
and sense of touch through
their whiskers to help them.
His call can be heard
by other seals nearly
two miles away.
He's found a hole,
but another male
has beaten him to it.
Let battle commence.
The occupant is just
too strong for him.
For now, he'll just
have to move on
and hope his luck
will improve elsewhere.
♪♪
In the far northern
coast waters,
most birds have
migrated for the winter.
But one species of bird
braves the icy seas...
Eider ducks.
Hundreds of thousands of them.
This patch of water
is their last refuge.
These open pools
are kept free of ice
by strong currents underneath.
From here, the birds can
dive down into the water,
picking off mussels from
the depths of the sea.
Surrounded by ice,
the eiders' survival
depends on this
single, vulnerable oasis,
and conditions here
can change very fast.
In a smaller pool,
other eider ducks are
learning a bitter lesson.
An early winter storm
has caught them out,
and the ice is closing in.
The pool is shrinking, and
the ducks are perishing.
The larger pool has
a far greater chance
of staying open all
winter, and the ducks
will have avoided an
exhausting migration.
It's always a gamble,
but for these ducks,
one which should pay off.
As the winter progresses,
temperatures plummet
and snow can sometimes
fall for hours at a time.
Snow forms when water vapor
in the atmosphere
freezes into ice crystals.
The ice crystals
become snowflakes
as they fall to the ground,
each one intricate and unique.
Although snow appears white,
it's actually colorless
but reflects the
light from the sun.
Falling snow looks
beautiful to us,
but it can be deadly.
As the snow gets
deeper and deeper,
animals need to be even
more specialized to cope.
When it comes to being prepared
for the coldest
part of the winter,
these musk ox
certainly look ready.
That long, thick,
shaggy coat is so efficient
a musk ox only uses a small
amount of energy to keep warm.
They can even slow
down their metabolism
so that in the wintertime,
they require less food.
And to get to that food,
their front hooves are
bigger than their rear hooves
to dig down through
the deep snow
to get to the food.
And if the snow
is very, very deep,
they can use their big head
and massive neck muscles.
They can excavate the
snow to get right down there
to the vegetation beneath.
Musk ox look like an animal
that has been especially
designed for the cold.
These hairy,
prehistoric-looking creatures
have inhabited the Arctic
for thousands of years.
They roam on the Arctic
tundra in search of roots
and mosses that sustain them.
They live in herds
and can withstand
incredibly harsh Arctic winters.
In the American Rockies,
there's another snow animal
with a very similar
hardy physique... bison.
Yellowstone is a unique place.
A quirk of geology has created
thousands of
thermals and geysers.
But it's not for the feeble.
For half the year,
Yellowstone is frozen.
Temperatures can reach minus-50,
and the winter snow can
be more than 20 foot deep.
Just as well these bison
are built for the snow.
However, they are struggling
in what is the snowiest
winter here for a decade.
They're able to swing their
massive heads through the snow,
but this year it's so deep
they can't reach the
grass underneath.
A bison's amazing, thick coat
keeps it warm down
to about minus-22.
But the wind chill is now
pushing them to that limit.
They need to move.
That will take more energy.
It's a risk that they
will have to take.
The herd need to find
somewhere warmer to survive.
They follow an ancient route
where hot thermals have
kept the river running.
It should lead to a place
they can eat and rest.
It's a long, hard trek.
The bison have
to keep to moving.
They just can't afford to stop.
In such a tough landscape,
not every bison will survive.
The herd have finally
reached their destination.
It's an oasis.
Thermals have melted the
snow, and grass is abundant.
It's a huge relief.
The bison can fill their
empty stomachs at last.
But not all is rosy in paradise.
Due to the volcanic
waters and geysers,
the grass here is
laced with arsenic
which could, over time,
slowly poison the bison.
The herd know they
can't stay too long.
However for the moment,
it offers them a lifeline
from the unrelenting snow.
♪♪
Food can be incredibly hard
to find in a landscape like this.
The rivers and the lakes
are completely frozen.
The snow underfoot
is incredibly deep.
So animals have to use
every trick in the book,
every ounce of their
intelligence just to stay alive.
A family of otters
is making its way
to a river kept open thanks
to the underwater geysers.
Here, they can happily fish
for a much-needed dinner.
♪♪
However, they are not
alone in this snowy landscape.
They are being spied
on by a clever trickster...
A coyote.
He's been watching and
waiting as the otters dive for fish.
This otter doesn't want
to risk losing his dinner
and plans to hide his
catch under the ice.
Although the coyote
can't see the otter,
he can hear him moving
somewhere underneath him.
The otter emerges
but without the fish.
He's stashed it somewhere
under the ice, but where?
It's turned into a
game of hide-and-seek,
and the coyote
fancies his chances.
♪♪
A huge trout... what a prize.
In these conditions,
being cunning as well
as a little bit devious
can be the key to survival.
Beneath the blanket of snow
is another game
of hide-and-seek...
one which is a matter
of life and death.
This little vole is active
throughout the winter.
He travels along tiny corridors,
moving from pocket to pocket
of perfectly refrigerated food.
Snow is a great insulator,
so down here the temperature
never falls more than a
degree or so below freezing...
Warm enough for
the vole to thrive.
But he's not the
only one out here.
A least weasel is also about.
♪♪
He may look cute and friendly,
but he has a devious plan.
His body is exactly
the same width
as the vole's,
so there's nowhere the vole can
go that the weasel can't follow.
The weasel's long, slender shape
is perfect for
hunting in the tunnels,
but the worst possible
shape for staying warm.
So to solve this problem,
he has a solution...
Though not a good
one for the vole.
The weasel plucks the
fur from the vole's body
tuft by tuft.
Then, putting it all together,
he cleverly makes
a warm blanket.
A sad end for the vole,
but a warm, underground
bed for the cold-hearted weasel.
It's everyone for
themselves in this climate.
We've seen some
amazing strategies
for surviving the cold.
But there are other
creatures battling to stay alive,
things we don't even see.
Underneath the snow,
they are thousands of insects
having their own
battle with winter.
And bizarrely, for some of
them, their survival strategy
is being frozen alive.
♪♪
One of the most remarkable
is a small Arctic caterpillar
known as a woolly bear.
He spends his winter
curled up under a rock.
As the temperature drops,
he goes into a kind of coma,
his heart stops beating,
and his insides
completely freeze.
He remains frozen
like this for four months.
Then, when the
Arctic spring arrives,
he thaws out,
as if rising from the dead.
This furry little critter eats
as much as he possibly can
before the cold
closes in once again.
♪♪
And so it goes on.
Year after year,
he slows right down
and freezes solid to
survive winter after winter.
The feeding season
in the Arctic is so short,
it can take years
for the caterpillar
to complete its growth.
But eventually that time comes.
The caterpillar
frantically starts to weave
a beautiful silk cocoon.
Meanwhile, inside,
his body starts
to change into one that can fly.
Now, the oldest
caterpillar in the world
is ready to fulfill
his life's purpose.
He has just days to
find a partner and mate
so he can help create
the next generation
of wonderful woolly bears.
He may be tiny and hidden
away, but this little caterpillar
has one of the most
extraordinary ways
to survive the big freeze.
We've seen how some
remarkable animals
can adapt to their surroundings.
These are animals
that not only live,
but thrive, in some
of the coldest,
most inhospitable
places on Earth.
Whether it's their super senses,
their extraordinary
physical adaptations.
Or whether it's
just clever tactics,
these animals are a
thing of great wonder.
And for me, these animals
are not only the most
impressive creatures
on the planet,
they're some of
the most beautiful.
♪♪
♪♪
To learn more about what you've
seen on this "Nature" program,
♪♪
I'm Gordon Buchanan,
a wildlife cameraman.
I've filmed in
some of the planet's
most extreme and
bitterly cold places.
Despite being so harsh,
these frozen
wonderlands are full of life,
with creatures that
somehow manage to survive
against all the odds.
I'll be meeting some of
these fearless animals,
from sociable wolves
to the enigmatic lynx
and cunning Arctic foxes.
That is the most sumptuous
animal I've ever seen.
These are creatures
that are specially adapted
and have evolved
to live in the snowiest,
coldest places on Earth.
How they're able to survive
the big freeze is extraordinary.
♪♪
♪♪
I'm in the Arctic.
It is incredibly beautiful,
but it is also incredibly cold.
Winter temperatures
here can drop to
as low as minus-50 degrees.
Yet for some creatures,
like these magnificent wolves,
they call this place home.
They live on top of the world
in one of the
earth's freezers...
the Arctic Circle.
I'm in Polar Park in Norway,
the most northerly
wildlife park in the world.
The wolves here have
grown up with humans around,
so they're used to people.
But I still need
to gain their trust
and have to remain
quiet and calm.
Despite the cold, I've had
to take hat and gloves off
or these guys
would be too tempted
to snatch them off.
Hello.
This magnificent
beast is treating me
like another wolf
and saying hello.
That's how they
greet each other...
With their mouths.
Wolves often nibble
on each other's faces.
It might look aggressive,
but it's a sign of affection.
The size of the paws.
You are a beaut!
Just stroking this wolf,
you can lose hand in its coat.
And when I part the hair,
you can see the underneath,
these fine, very soft
hairs that gives insulation,
and these longer, outer hairs
repel the snow and water.
His coat is perfect
for these conditions.
But like the domestic dog,
the foot pads, the
toe pads of the wolf
are completely naked.
And they spend
most of their lives
with those naked toe
pads and foot pads
in contact with the snow
and ice certainly in the winter.
So how do the wolves
stop that cold temperature
coming from the ground
up through their naked feet
into the rest of their body?
Well, they've got a very,
very clever solution to that.
Hot blood never
reaches a wolf's paws.
As it flows down the
leg, it's cooled down...
Almost like entering a fridge.
Only cold blood is
kept within the paws
so that all the warm blood
can remain within the body.
This clever adaptation
means that any heat loss
is kept to an absolute minimum.
On a thermal camera,
which shows body heat,
the upper part of the
wolf's legs are red,
showing them to be
warmer than its feet.
The wolf's coat looks blue.
That's because
his stunning thick fur
is preventing heat
loss from his body.
So no matter what physical
characteristics you have,
a clever hunting
strategy is essential.
And in these bitterly
cold conditions,
it helps to have friends.
A wolf's ability to hunt
as a team, as a pack...
That's really what helps
guarantee its survival.
Being part of a
strongly bonded pack
is invaluable in the
coldest part of winter.
In North America,
this pack have been
waiting until their prey is
at their most vulnerable.
The elk here are
weak with hunger
and in such deep snow,
they struggle to run very fast.
The wolves follow a
well-practiced formula.
They target a
straggler of the group.
Three members of the pack
work together to bring the elk down.
It's a brutal but
impressive hunting strategy.
Impeccable teamwork, along
with remarkable adaptations,
make wolves stand out
as supreme snow animals.
Not all snow animals live
in social groups like wolves.
In fact, one of the most
successful snow animals
is solitary
and lives most
of his life alone.
They can be
found in the very far
north of the Arctic...
The polar bear.
This male, like
every polar bear,
is almost completely
covered in fur.
But his secret to staying
warm in this frozen land
is actually inside
his large body.
He has a huge layer
of insulating fat...
About four inches thick.
It traps heat, keeping
him warm from the inside.
To maintain this fat, he relies
on his good hunting skills.
His prey is hidden
under the thick ice.
Luckily he has a secret
weapon to help him hunt...
An extraordinary sense of smell,
a hundred times
stronger than ours.
♪♪
He can detect a seal carcass
from around 20 miles away,
and under three foot of snow.
Success.
He will eat all the
fat of a seal first,
often leaving the actual meat.
This extreme fatty
diet would kill us,
but for the polar
bear, it's essential.
Indeed, they are one of the
fattest mammals on Earth.
Their incredible insulation
and intense sense of smell
make the polar bear
a master in the snow.
They're also built
to move around
effortlessly in this
snowy environment,
unlike me.
I am a perfect
example of an animal
that is not adapted
for walking about
a snowy environment like this.
I'm 12 stone, 12
and a half stone,
and all of my
weight is distributed
onto my feet... size
12... Big feet for a human,
but not big enough to stop me
from sinking down into the snow.
What I need to do is
increase that surface area...
Put on some snowshoes.
I suppose the secret to
moving around in deep snow
is to do it efficiently.
Here we go...
Adapted for walking in the snow.
That is so much better.
It's easy. I can walk
through the forest.
I'm not sinking
down in to my waist.
I can go fast.
I can almost go silently.
Like I belong here.
Polar bears have
built-in snowshoes.
Their paws are wide,
measuring up to 12 inches across.
This helps them to distribute
their weight evenly on thin ice.
Underneath their large
paws are small, soft bumps
to give them extra
grip on the ice.
As well as being superbly
adapted to the snow,
some bears have another
strategy to get through winter...
By sleeping through it.
This is the recently
vacated den of a brown bear.
The den would have been
dug back in the autumn,
'round about October time.
In the hardest of winters,
a brown bear will spend up
to seven months in its den,
not eating, not drinking,
just drifting in
and out of sleep,
waiting for the thaw.
A bear will make a den
which is just slightly
bigger than itself...
A snug fit.
Some dens are built in
rock crevices or hollow trees.
For others, like
this polar bear,
it can be simply a case
of digging a small hole
and then waiting
for the snow to fall,
providing an excellent,
insulating roof.
♪♪
This female polar
bear, filmed in captivity,
is in hibernation.
During this time, her heart
rate drops dramatically
and she doesn't
eat, drink, or urinate.
Amazingly, she's
able to recycle waste
into new protein
to maintain her muscles.
Although she survives
purely on fat reserves,
she can, remarkably,
give birth in hibernation.
Her body heat keeps
her babies warm.
They grow rapidly thanks
to her extremely fatty milk,
which is nearly 10 times
richer than human milk.
♪♪
I've spent much time
filming polar bears
and been lucky enough to
see tiny twin cubs emerge
from their winter den...
A truly wonderful sight.
Aww.
Aww, very, very cute.
They were very eager
to explore the big, wide world.
After being born in hibernation,
the family venture out when
the babies are strong enough
to survive outside
and ready to make the
trek to the spring sea ice.
Oh, wow.
Look at that.
It's a sight I
will never forget.
Many smaller
mammals also hibernate
to avoid the bitter winter,
but there is one which
does so with a unique twist...
The Arctic ground squirrel.
When the harsh weather begins,
the ground squirrel escapes
to an underground burrow
to hibernate.
Amazingly, the squirrel's
body temperature
drops to below freezing...
The lowest of any mammal.
His major organs shut down,
and he looks dead to the world.
Despite this, he's
able to stop himself
from actually freezing to death.
Every few weeks, the
squirrel begins to shake.
This shivering is enough to
raise his body temperature
back to up normal
for a few hours.
After this session of shivering,
he can safely cool back down,
ready for another
cycle of deep sleep.
For animals that
don't hibernate,
being well-insulated to
withstand severe
weather is essential.
For human beings in the
cold, we have to layer up.
I've got five layers
on. I've got gloves on.
We generate heat,
and we want to retain
that heat in sub-zero
temperatures.
And if I remove my glove,
it goes without saying
my hands start losing heat,
my hands start feeling cold,
and you can see the comparison
very clearly on
the thermal camera
between my cold hand
and my warm hand.
The fingers on my
cold hand are blue,
showing how much
heat they've already lost.
Animals are far more efficient
than us at retaining heat.
And there is one
animal which tops the lot.
The Arctic fox is superbly
kitted out for the winter.
To prepare for it,
he undergoes a
spectacular transformation.
His thin brown summer coat
changes into one
which is 200% thicker.
It's white, and it's
very, very fluffy.
Hello, you handsome,
handsome boy.
My word.
That is the most sumptuous coat
I have ever seen on any animal.
In fact, Arctic foxes
have the warmest coat
of all Arctic mammals.
And it's not just that fabulous
fur the fox has got.
They have incredible senses...
Particularly the hearing.
And despite having
these fairly small ears,
this fox will be able
to detect his prey
with pinpoint accuracy
even when it's hidden
underneath the snow.
In the depths of
the Canadian winter,
a young Arctic fox
is searching for food.
He's still a hunting novice.
It's not easy when
you can't see your prey.
With his acute senses,
he can hear a faint
sound under the snow.
Lemmings.
To catch one,
he uses a special
pouncing technique
known as mousing.
He has to judge
its exact distance
as well as the
depth of the snow.
To help them
find the right spot,
foxes actually
align their pounce
to the Earth's magnetic field...
An extraordinary skill.
But mousing isn't always easy,
especially for a beginner.
♪♪
Super senses are
crucial for animals
that live in such white
and snowy landscapes.
And I'm about to meet one
whose eyesight is legendary.
This exquisite-looking
cat is a lynx.
It's a cat that is especially
adapted to the snow.
Look at those eyes.
Lynx have incredible vision.
It was once believed that
lynx can see through walls.
And actually looking
into those eyes,
I find that quite
easy to believe.
Maybe that's
stretching it a bit,
but a lynx can spot a
mouse from 80 yards away.
And their night vision
is truly remarkable,
far better than ours.
At this time of year,
when the landscape
is dominated in snow,
you can see how easily
the lynx just disappears in it...
Matches these birch trees.
It's almost invisible.
That's all the lynx needs
is a little bit of something
to break up its outline.
In the wild, lynx are
incredibly difficult to glimpse.
They roam the remote forests
for hundreds of
miles in search of prey
and may never visit
the same patch twice.
With so few prey animals here,
life for this silent hunter
is particularly hard.
And in this harsh wilderness,
they're not the only hunters.
The great gray owl
waits and listens.
He's watching for prey.
He has excellent,
super-sensitive hearing.
He can even hear the
scuttling of voles or mice
beneath two foot of snow.
He glides silently, like a
king of acoustic stealth.
His wings absorb
any noise of flapping
so he can take his prey
by complete surprise.
To survive in a snowy landscape,
it helps to have a
secret advantage,
a trump card up your sleeve.
My next snow animal
has quite a surprising one.
Reindeer traditionally
pull sleighs
and have a popular reputation
for red, glowing noses.
But behind this folklore,
there is some
surprising truth...
An ingenious adaptation
which helps them
survive the extremes.
Their noses are
full of blood vessels.
These cool warm air
down as it leaves the body
and warms cold
air up as it comes in,
keeping the reindeer's brain
constantly warm and active.
So, as the thermal
camera proves,
reindeers' noses
are actually red.
It's not just the
nose of the reindeer
which is extraordinary.
How they view their
winter surroundings,
through those large,
characterful eyes,
is truly astonishing.
When it's bright
and sunny like this,
my eyes struggle to cope
with the amount of UV light
that's coming from the sun
and is bouncing
back up off the snow.
If I was to spend too long here,
I'd eventually damage my eyes.
I could become snow blind.
But reindeer,
they see things differently.
Not only can they
see in color like I can,
they can also
see in ultraviolet.
For us, it's difficult
to make out detail
when the landscape is so white.
But with UV vision,
a reindeer can see things
in much greater contrast.
They can see shapes
and detail that we can't.
The lichen on the
trees which they eat
or animal urine in the snow
becomes more prominent.
In such a white, snowy
world, it certainly helps
to have that extra insight.
Reindeer even have specially
designed, flexible hooves.
In the winter, their four toes
can spread out wide
to act like snowshoes.
This means they
can walk on bumpy ice
without slipping.
However, on smooth
ice they can sometimes
find their shoes
a little ill-suited.
♪♪
When it comes to surviving
against all the odds,
there is one snow animal
which has to endure one
of the most extreme
places on Earth.
From the top of the
world to the very bottom
is Antarctica,
the coldest, windiest, and
driest continent on the planet.
This desolate freezer is also
the chosen home of the penguin.
How do they survive in
minus-90 degrees Fahrenheit?
Well, penguins
are superbly built
to resist the extreme cold.
First of all,
their round, shapely
figure isn't by accident.
It provides them with
enough blubber to keep warm.
But how do penguins
manage to keep
their extremities like
wings and feet warm?
Well, their bodies
are cleverly adapted
so that the muscles
needed to move their feet
and wings are kept inside
their warm, round body.
Only tendons operate
within the actual limbs,
and these are far less
vulnerable to the cold.
But it doesn't stop there.
These ice specialists
have another clever
trick to keep warm.
To reduce the amount of body
touching the frozen ground,
they just lean
back on their heels,
picking their toes off the ice.
It can decrease their
heat loss by 15%.
Penguins may not be able to fly,
but they do have
a lot of feathers.
And it's thought that penguins
have more insulating feathers
than any other bird.
And I've got some here.
Just look at them.
These are from an
emperor penguin,
a species that has to endure
bitterly cold
Antarctic conditions.
And it is a masterpiece.
At the base, it's
incredibly downy and fluffy.
The quill part is stiff.
The end is slick.
This is the waterproof part.
And on the bird,
these feathers interlock.
The outside is waterproof.
It creates a waterproof seal.
Underneath is an air void
full of these downy feathers.
This is an incredibly
sophisticated
form of insulation.
Penguins are
understandably very protective
of their precious feathers.
So much so, that when
the males come together
to form their famous huddle,
they take extra-special
care not to damage them.
In the deepest part
of the Antarctic winter,
the male emperor penguins
are huddling together to
try and keep themselves,
and their eggs, warm.
The center of the
huddle is the hottest part.
It can even get too hot.
So the penguins
constantly move around,
changing their position.
But instead of pressing
into one another,
they are barely touching.
If they were squashed together,
the insulation from
their incredible feathers
would be compromised.
So they leave almost an inch gap
between each other
to protect their feathers.
This means that if
one penguin moves,
its neighbor has to
react and follow suit.
Just one penguin's step
creates a chain reaction,
sending a ripple of movement
throughout the huddle.
There is only one mammal
which is tough enough
to live this far south
in the Antarctic all year-round,
and that's the Weddell seal.
This incredible snow
animal spends much of its life
under the expanse
of the frozen sea ice.
The Antarctic Ocean
can drop to 28 degrees.
Weddell seals can only survive
about an hour under
the freezing water
before needing air.
They have to find a
natural crack in the ice
to create a breathing hole.
To do this, they have
a unique adaptation.
A sharp tool designed
especially for the job...
Large, very strong,
protruding teeth.
With these razor-sharp incisors,
a seal is able to
scrape away fresh ice
and keep the hole open.
♪♪
But these breathing holes
also serve another function.
The males attract
females to them
during the mating season.
One male can draw
up to 10 females,
so the holes are
hotly contested.
This Weddell seal male
is on the search for one.
It's not easy in the
gloom under the ice,
but it's thought
that seals may use
their acute hearing
and sense of touch through
their whiskers to help them.
His call can be heard
by other seals nearly
two miles away.
He's found a hole,
but another male
has beaten him to it.
Let battle commence.
The occupant is just
too strong for him.
For now, he'll just
have to move on
and hope his luck
will improve elsewhere.
♪♪
In the far northern
coast waters,
most birds have
migrated for the winter.
But one species of bird
braves the icy seas...
Eider ducks.
Hundreds of thousands of them.
This patch of water
is their last refuge.
These open pools
are kept free of ice
by strong currents underneath.
From here, the birds can
dive down into the water,
picking off mussels from
the depths of the sea.
Surrounded by ice,
the eiders' survival
depends on this
single, vulnerable oasis,
and conditions here
can change very fast.
In a smaller pool,
other eider ducks are
learning a bitter lesson.
An early winter storm
has caught them out,
and the ice is closing in.
The pool is shrinking, and
the ducks are perishing.
The larger pool has
a far greater chance
of staying open all
winter, and the ducks
will have avoided an
exhausting migration.
It's always a gamble,
but for these ducks,
one which should pay off.
As the winter progresses,
temperatures plummet
and snow can sometimes
fall for hours at a time.
Snow forms when water vapor
in the atmosphere
freezes into ice crystals.
The ice crystals
become snowflakes
as they fall to the ground,
each one intricate and unique.
Although snow appears white,
it's actually colorless
but reflects the
light from the sun.
Falling snow looks
beautiful to us,
but it can be deadly.
As the snow gets
deeper and deeper,
animals need to be even
more specialized to cope.
When it comes to being prepared
for the coldest
part of the winter,
these musk ox
certainly look ready.
That long, thick,
shaggy coat is so efficient
a musk ox only uses a small
amount of energy to keep warm.
They can even slow
down their metabolism
so that in the wintertime,
they require less food.
And to get to that food,
their front hooves are
bigger than their rear hooves
to dig down through
the deep snow
to get to the food.
And if the snow
is very, very deep,
they can use their big head
and massive neck muscles.
They can excavate the
snow to get right down there
to the vegetation beneath.
Musk ox look like an animal
that has been especially
designed for the cold.
These hairy,
prehistoric-looking creatures
have inhabited the Arctic
for thousands of years.
They roam on the Arctic
tundra in search of roots
and mosses that sustain them.
They live in herds
and can withstand
incredibly harsh Arctic winters.
In the American Rockies,
there's another snow animal
with a very similar
hardy physique... bison.
Yellowstone is a unique place.
A quirk of geology has created
thousands of
thermals and geysers.
But it's not for the feeble.
For half the year,
Yellowstone is frozen.
Temperatures can reach minus-50,
and the winter snow can
be more than 20 foot deep.
Just as well these bison
are built for the snow.
However, they are struggling
in what is the snowiest
winter here for a decade.
They're able to swing their
massive heads through the snow,
but this year it's so deep
they can't reach the
grass underneath.
A bison's amazing, thick coat
keeps it warm down
to about minus-22.
But the wind chill is now
pushing them to that limit.
They need to move.
That will take more energy.
It's a risk that they
will have to take.
The herd need to find
somewhere warmer to survive.
They follow an ancient route
where hot thermals have
kept the river running.
It should lead to a place
they can eat and rest.
It's a long, hard trek.
The bison have
to keep to moving.
They just can't afford to stop.
In such a tough landscape,
not every bison will survive.
The herd have finally
reached their destination.
It's an oasis.
Thermals have melted the
snow, and grass is abundant.
It's a huge relief.
The bison can fill their
empty stomachs at last.
But not all is rosy in paradise.
Due to the volcanic
waters and geysers,
the grass here is
laced with arsenic
which could, over time,
slowly poison the bison.
The herd know they
can't stay too long.
However for the moment,
it offers them a lifeline
from the unrelenting snow.
♪♪
Food can be incredibly hard
to find in a landscape like this.
The rivers and the lakes
are completely frozen.
The snow underfoot
is incredibly deep.
So animals have to use
every trick in the book,
every ounce of their
intelligence just to stay alive.
A family of otters
is making its way
to a river kept open thanks
to the underwater geysers.
Here, they can happily fish
for a much-needed dinner.
♪♪
However, they are not
alone in this snowy landscape.
They are being spied
on by a clever trickster...
A coyote.
He's been watching and
waiting as the otters dive for fish.
This otter doesn't want
to risk losing his dinner
and plans to hide his
catch under the ice.
Although the coyote
can't see the otter,
he can hear him moving
somewhere underneath him.
The otter emerges
but without the fish.
He's stashed it somewhere
under the ice, but where?
It's turned into a
game of hide-and-seek,
and the coyote
fancies his chances.
♪♪
A huge trout... what a prize.
In these conditions,
being cunning as well
as a little bit devious
can be the key to survival.
Beneath the blanket of snow
is another game
of hide-and-seek...
one which is a matter
of life and death.
This little vole is active
throughout the winter.
He travels along tiny corridors,
moving from pocket to pocket
of perfectly refrigerated food.
Snow is a great insulator,
so down here the temperature
never falls more than a
degree or so below freezing...
Warm enough for
the vole to thrive.
But he's not the
only one out here.
A least weasel is also about.
♪♪
He may look cute and friendly,
but he has a devious plan.
His body is exactly
the same width
as the vole's,
so there's nowhere the vole can
go that the weasel can't follow.
The weasel's long, slender shape
is perfect for
hunting in the tunnels,
but the worst possible
shape for staying warm.
So to solve this problem,
he has a solution...
Though not a good
one for the vole.
The weasel plucks the
fur from the vole's body
tuft by tuft.
Then, putting it all together,
he cleverly makes
a warm blanket.
A sad end for the vole,
but a warm, underground
bed for the cold-hearted weasel.
It's everyone for
themselves in this climate.
We've seen some
amazing strategies
for surviving the cold.
But there are other
creatures battling to stay alive,
things we don't even see.
Underneath the snow,
they are thousands of insects
having their own
battle with winter.
And bizarrely, for some of
them, their survival strategy
is being frozen alive.
♪♪
One of the most remarkable
is a small Arctic caterpillar
known as a woolly bear.
He spends his winter
curled up under a rock.
As the temperature drops,
he goes into a kind of coma,
his heart stops beating,
and his insides
completely freeze.
He remains frozen
like this for four months.
Then, when the
Arctic spring arrives,
he thaws out,
as if rising from the dead.
This furry little critter eats
as much as he possibly can
before the cold
closes in once again.
♪♪
And so it goes on.
Year after year,
he slows right down
and freezes solid to
survive winter after winter.
The feeding season
in the Arctic is so short,
it can take years
for the caterpillar
to complete its growth.
But eventually that time comes.
The caterpillar
frantically starts to weave
a beautiful silk cocoon.
Meanwhile, inside,
his body starts
to change into one that can fly.
Now, the oldest
caterpillar in the world
is ready to fulfill
his life's purpose.
He has just days to
find a partner and mate
so he can help create
the next generation
of wonderful woolly bears.
He may be tiny and hidden
away, but this little caterpillar
has one of the most
extraordinary ways
to survive the big freeze.
We've seen how some
remarkable animals
can adapt to their surroundings.
These are animals
that not only live,
but thrive, in some
of the coldest,
most inhospitable
places on Earth.
Whether it's their super senses,
their extraordinary
physical adaptations.
Or whether it's
just clever tactics,
these animals are a
thing of great wonder.
And for me, these animals
are not only the most
impressive creatures
on the planet,
they're some of
the most beautiful.
♪♪
♪♪
To learn more about what you've
seen on this "Nature" program,
♪♪