Life in the Snow

These are our planet's winter wonderlands.

And the remarkable animals that call them home.

I'm Gordon Buchanan and, as a wildlife cameraman,

I've visited many of these unique and special places.

But the animals that live in places like this need to be resilient,

and many of them are specially adapted

to make the very most of these seasonal conditions.

I'm going to reveal the extraordinary animals

that don't just survive, but positively thrive, in the snow.

Oh, very, very cute!

Each has different and surprising tactics to face winter head-on.

From the polar bear mother,

who spends seven months without food and water

to give her babies the best start in life.

To the fox, who can catch food it can't even see.

And a seasonal specialist, the reindeer,

and a surprising secret behind that red nose.

Just how these animals make these places their own

are amongst the most incredible stories in the natural world.

I hope you've snuggled up nice and warm,

because it's time to meet the amazing animals

that spend their life in the snow.

Each year, up to one third of our planet is transformed by snow

into a sparkling world of wonder and white.

The animals who live here must adapt to this dazzling change.

How they rise to the challenge of living in the snow

is what sets each of them apart.

Our first animal is the world's largest land carnivore.

They face the coldest temperatures the Arctic has to offer.

But they seem to take it all in their stride.

The polar bear.

Most animals couldn't live this close to the North Pole.

But he appears to be revelling in it.

In fact, the bears roll in the snow when they want to cool down.

But how is it possible to get too hot in the Arctic?

The polar bear has the thickest fur of any bear.

But, it's the 11 centimetre fat layer beneath the skin

that makes all the difference.

It keeps in the heat like nothing else.

It works so well,

polar bears can swim for mile after mile in the freezing Arctic Sea.

To maintain this vital layer,

they need to eat as much fatty food as they can find.

The polar bears' staple diet is seal.

But they spend most of their time under the ice.

The bear can't afford a drawn-out game of hide and seek.

His sense of smell is 100 times better than ours.

Able to track a scent from 20 miles away.

A bear can smell a seal through a metre of snow.

A seal can be nearly 50% blubber.

He'll catch nearly one a week,

enough to keep his insulation in top condition.

At this time of year, female polar bears have a very different problem.

They have their cubs in the depths of the Arctic winter.

A polar bear simply can't give birth out on the Arctic ice -

with such small, vulnerable babies, it is way too cold.

Down to minus 50 Celsius.

So, for a pregnant mother living in such a cold and exposed place,

there's really only one place to be.

And that is underneath the snow.

It might sound counterintuitive,

but we can actually use snow to keep us warm.

Within this lump of snow is trapped air,

and trapped air makes a fantastic insulator.

So, when you're in a snow hole, or a snow den,

you could even get cosy.

And, when a polar bear is underneath the snow like this,

the temperature inside can be an incredible 30 degrees warmer

than the temperature outside.

And when she's hidden in a den like this,

that's when something truly remarkable happens.

Around the turn of the New Year, across the Arctic,

under three feet of snow and ice...

..female polar bears give birth.

Then in early spring, they emerge for the first time.

April in Svalbard.

Just the right moment to see this happen.

Aw!

Oh, very, very cute!

Both cubs combined aren't even as big as the mother's head.

At three months old,

this is their very first experience of the outside world.

During her time in the den, she loses half her body weight.

Her milk is 30% fat,

so her cubs grow fast.

Oh...

Wow.

Look at that!

They're already 20 times heavier than when they were born.

Just about big enough to take on their frozen world.

And it's all down to their mother's winter hidden beneath the snow.

Polar bears aren't the only animals to use this strategy.

Our very own common dormouse spends more than half of its life asleep.

Avoiding the winter altogether.

And the Arctic ground squirrel can let its body temperature drop

to 2.9 degrees below freezing.

It's the coldest any mammal can get.

Remarkably, it appears to change the chemistry of its body

to stop ice crystals forming.

Every few weeks, it has to feed,

so it shivers and shakes in its sleep

to raise its temperature just enough to wake up.

But bears are the most impressive hibernators of all.

Able to survive up to seven months without food or water.

There is no doubt about it.

Taking shelter beneath the snow is a really good strategy.

For a baby bear, for the first few months of its life,

the den is its world.

But sooner or later, mother bears and the cubs do need to emerge.

And getting the timing right is absolutely critical.

It's spring in North America.

And this young female black bear has just come out of her den.

In a normal year, she'd emerge to greet a brand-new spring.

But an unexpected cold front has blown in from the Arctic.

What's worse, she has three-month-old twin cubs with her.

This is her first ever litter.

She should be keeping them warm.

Instead, she gets up and leaves.

After half a year in hibernation, she's desperate for food.

Her cubs don't have the three layers of waterproof fur

all adults bears grow - they're defenceless in this weather.

Their instinctive survival strategy is to climb a tree.

But this only works for avoiding predators.

Up here, they're even more exposed to the cold.

At last, their mum returns.

But straightaway, she sets off again.

Walking in thick snow is almost impossible on little legs.

They struggle to keep up.

Hopefully, Mum has a plan to keep them warm and safe.

Overnight, temperatures drop to minus 12 degrees.

Dawn. The storm has passed.

But, what about the cubs?

Their mother led them to a sheltered spot

and kept them warm through the chill of the night with her own body heat.

Experience can make all the difference to living in the snow.

It's been a steep learning curve for this family, but they've made it.

Being ready and equipped for the cold is critical.

As I can show you.

This is a thermal camera.

It sees temperature as different colours.

Right now, I'm just wearing a thin top,

and it should show me losing body heat in red and white.

Now, as I stand here,

I can actually feel the cold nipping at my exposed skin.

On the thermal camera that will show as white hot.

So it's all about layering up.

It's about keeping that heat in, and we do that with insulation.

For any animal that lives in a snowy wilderness,

they've got to be able to take the cold in their stride.

And there is one very special animal that does that better than most.

The Arctic fox.

They live further north than any other member of the dog family.

And something extraordinary makes this possible.

In the warm days of summer, they look very different.

Then, every year, as the winter approaches,

they undergo a spellbinding transformation.

They grow a thick, snow-white winter coat.

I'm lucky to be able to see this up close,

with a fox that's been brought up by people.

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.

In winter, their fur becomes 200% thicker.

There's a longer, outer layer,

with hollow hairs that trap air to increase insulation.

And a dense undercoat provides even more warmth.

An Arctic fox won't even start feeling the cold

until it's minus 40 degrees.

And, they have other clever features that help them get through winter.

Their ears are round and tucked into their deep fur to reduce heat loss.

And, to prevent frostbite, their nose is short and stubby.

And a magnificent tail

means that when the Arctic weather is at its worst,

they can hunker down and use it as a blanket.

Being well-dressed for winter is an obvious advantage.

But to survive in a snowy landscape like this,

you have to be able to exploit every single opportunity to get food.

And foxes are experts at that.

They have incredible senses.

Particularly their hearing.

And, despite having these fairly small ears,

this fox will be able to detect its prey with pinpoint accuracy,

even when it's hidden underneath the snow.

But learning how to use this skill takes time.

Their preferred food are lemmings, small, Arctic rodents.

Many foxes won't make it through their first year

and that's mostly down to a lack of food.

Their sensitive hearing means they can detect

lemmings scurrying through tunnels in the snow.

But the fox also has to judge the depth of the snow.

And then...

..with this dramatic pounce,

he's trying to punch right through the snow

and catch the lemming underneath.

It isn't easy.

But practice makes perfect.

The fox's ability to track down prey using its hearing alone

is truly amazing.

Relying on your hearing in the snow can be a real challenge.

Have you ever noticed that when there's a blanket of snow,

the world seems a very silent place?

That is because the snow literally deadens the sound waves.

The snow stops the sound from bouncing and reflecting off things.

In my pocket I have a speaker,

and on this speaker, I have the sound of a vole.

To many creatures, voles means food.

SCRABBLING NOISE

See, if your dinner relies on you being able to detect these little

creatures that are scurrying about, beneath the grass, beneath the snow,

you'll see what the challenge is.

Pretty loud.

There's the vole.

I can barely hear it.

It's almost completely gone.

OK.

So I'm about a foot and a half above the speaker,

and I can just about hear it.

Thankfully, I don't rely on voles for food.

But, what if you had to listen out for this sound

from high above the snow?

That's the challenge faced by the great grey owl.

But this magnificent bird pinpoints sound so accurately,

it can launch a strike from the air.

So, how does it achieve this incredible feat?

The disc shaped feathers on its face collect the sound waves

and directs them to the ears on the side of its head.

It can work out exactly where the sound is coming from.

These skills come into their own when the owl takes to the wing.

Special edging on its feathers

mean that its flight is completely silent.

Nothing can hear it coming.

In the final moments,

it brings its talons into exact alignment

with the sound of the prey.

Catching a meal without ever seeing it.

Phenomenal.

But there is another way to find a vole under the snow,

and that's to go in after it.

Although the least weasel is several times larger than a vole,

its body is exactly the same width.

Once the weasel finds a hole,

it's an old-fashioned game of cat and mouse.

Although it doesn't always end in getting dinner.

Whatever the outcome,

at least the weasel is small enough to take shelter beneath the snow,

away from the worst of the weather.

But, what if you aren't able to get out of the cold?

Well, one animal has some surprising ways to cope.

Reindeer. There could not be another animal more closely associated

with snow and Christmas.

And, there could even be some truth in that famous red nose.

Reindeer live in the forests and tundra of the far north.

In winter, they dig through the snow to find food.

Out here, they're breathing in air

at temperatures down to minus 40 Celsius.

To stop it chilling their lungs,

they pass the air through chambers in their nose...

..where a network of blood vessels heat it up.

We can see this on the thermal camera.

Where they warm the air up, their noses really are red.

And, when they breathe out,

their noses take the precious body heat from their breath,

so it isn't lost to the atmosphere.

And it isn't the only thing

that makes reindeer so well-equipped for snow.

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.

So, why don't reindeer have the same issue?

The answer lies in their specially adapted feet.

Their four toes splay out to increase their surface area,

stopping them from sinking, and giving them traction.

This ability is one reason we domesticated the reindeer.

The Dolgan people of Siberia

use reindeer for their nomadic lifestyle,

literally moving house every week or so, with their help.

So clearly, I need to increase the surface area of my feet.

There we go. Adapted for walking in the snow.

Big surface area to stop me sinking through,

spikes to stop me slipping on the ice.

That is so much better.

It's easy. I can walk through the forests,

I'm not sinking down into my waist, I can go fast,

I can almost go silently.

Like I belong here.

Other animals also use this approach.

Polar bears have huge paws, 30 centimetres across.

And their pads are covered with tiny bumps to give extra grip.

And the snowshoe hare has long, fur-covered feet

to help it move effortlessly across the snow.

Yet, despite their special equipment,

even reindeer find sheet ice a little tricky.

But reindeer have something else that really sets them apart.

Their eyesight.

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,

is bouncing back up off the snow.

But reindeer, they see things differently.

Not only can they see in colour like I can,

they can also see in ultraviolet.

And that's vital.

Because some very important things show up in ultraviolet.

Tracks in the snow show up clearly,

helping reindeer find a path.

They can see the telltale scent marks of predators in the snow.

And most important of all, a staple part of their winter diet, lichen,

stands out like a beacon.

So, when deep snow covers the other plants they eat,

they can hone in on this extra food source.

No wonder reindeer are so closely associated with this time of year.

With these specialist skills, they can get through the deepest winter.

When temperatures plummet,

we start burning more calories, just to keep warm.

So, finding extra food can make all the difference.

In fact, it's vital.

But when your larder is frozen solid, you have to be resourceful.

The robin.

The gardener's colourful companion

relies on soft earth to pick out worms and grubs.

But a deep frost means the ground is frozen solid.

If only there were someone to dig it up.

Deep underground, in total darkness, where the frost can't reach,

moles are digging their tunnels.

And pushing up fresh, soft piles of earth.

For the robin redbreast, this is an opportunity.

It's a real lifeline.

And one that could continue for the whole winter.

When food is hard to find,

joining forces can help.

And one resourceful animal has worked out just how to do this.

Wolverines are the largest member of the weasel family.

In winter, most of their diet

is made up of the animals that haven't made it through

these testing times.

But, with the world covered by snow,

it could take hours to find this meal.

This is where the wolverine's resourcefulness comes in.

It has an airborne spotter.

Ravens.

One of the most intelligent birds in the world.

Although it's found a moose,

a raven isn't strong enough to dig it out of the snow.

So it calls out, attracting the wolverine's attention.

It will even lead its ally towards the food.

Wolverines are renowned for their strength.

But the meat is frozen solid.

Fortunately, there's an answer for that.

The wolverine is one of the only animals on the planet

whose teeth and jaws are specifically adapted

for eating frozen food.

They can cut through meat and bone as hard as concrete.

This is what the raven's been waiting for.

Newly revealed leftovers are their reward for finding food.

And there's one final clever strategy

in case times get really tough.

The wolverine will bury part of the meal,

storing it away in the freezer for later.

Two different species working together like this

is rare in the natural world.

But, when you live in one of the toughest places on Earth,

it can make sense to work as a team.

Musk ox are Arctic giants.

They live in family groups of around 20 in the northern tundra,

where they face some of the planet's most extreme weather.

When it comes to being prepared for the coldest part of 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 winter time they require less food.

Because finding that food can be a challenge.

In winter, the snow is covered with a thick layer of ice,

making it hard to get to the plants beneath.

So musk ox use their large front hooves like snow shovels.

And the neighbours are quick to spot an opportunity.

Ptarmigan, hardy Arctic birds that also feed on plants,

but can't break through the ice on their own.

Arctic hares join the winter feast too.

Soon, the musk ox have quite an entourage.

But finding food is just one of their problems.

Protecting their calves is perhaps the most important.

They're born just before the spring.

Everything is new to this calf.

But the snow is a particular challenge.

It'll need to get to grips with it soon.

There are predators here.

Arctic wolves.

They are big, strong, and live in packs.

The calves are vulnerable.

They must try to keep up.

The musk ox form a defensive ring, with the calves in the middle.

A wolf would be foolish to mess with this impenetrable wall of musk ox.

When it comes to living in the Arctic,

these animals are hard to beat.

LONE WOLF HOWLS

PACK HOWLS

Relying on hunting to get a meal is always a challenge.

So how do predators like wolves get through the toughest time of year?

Here in northern Norway, these wolves are habituated to people.

It's a rare opportunity

to get closer than would ever be possible with a fully wild pack.

Hello.

Look at the size of the paws.

You are a beaut.

Just stroking this wolf,

you could lose your hand in its coat.

And when I part the hair you can see that underneath there's 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.

Look how narrow the wolf is,

you look at the wolf face on, it's got this big head.

But its shoulders are quite narrow, and that's a physical adaptation

that helps him move around through deep snow.

So, no matter what physical characteristics you have,

clever hunting strategy is essential.

And in these bitterly cold conditions,

it helps to have friends.

Wolves live in tight-knit family groups.

There's a strict hierarchy.

Alpha males and females are in charge.

Every pack member knows their place.

The strong relationships between the wolves are critical

for getting through hard times.

It's February in Yellowstone National Park.

At this stage of winter, the elk are weak.

But elk are several times the size of a wolf.

They need to work together.

One wolf charges, making the elk run.

They can identify the weakest animal by the way it acts and moves.

One wolf cuts the elk away from the herd.

While two more come in from the sides.

A tactical manoeuvre that means the whole family will feed.

HOWLING

A wolf's ability to hunt as a team, as a pack,

that's really what helps guarantee its survival.

In Yellowstone,

the wolves have found a way to get through the harsh winter.

But, for other animals that live here,

there's another way to survive.

These bison are caught in the grip

of the worst winter for a generation.

The snow is too deep to break through.

And they need to eat.

But Yellowstone holds a secret.

This winter wonderland has a burning heart.

Formed on a giant volcano,

Yellowstone is peppered with thousands of hot springs

and spectacular spouting geysers.

The bison can take advantage of this,

but they need to move.

They're taking a big risk.

This journey could use all their remaining strength.

Some won't make it.

But even as night falls,

the bison push on.

The herd have reached an oasis.

The hot springs warm the air,

and melt the snow.

And there's grass here.

But this paradise is too good to be true.

Volcanic springs can contain toxic chemicals like arsenic.

Over time, this could make the bison ill.

But, right now, this is the lifeline they need.

Knowing every secret in the landscape

can make all the difference to surviving in the snow.

And some animals take using thermal springs to a whole new level.

In these heated pools,

Japanese macaques take refuge from the freezing winter temperatures.

The water is a steamy 41 degrees Celsius.

It's not just a chance to keep warm, though,

it's also an opportunity for the group to socialise.

But this spa is exclusive.

Only the elite of macaque society are permitted entry.

The rest are left on the sidelines to look for other distractions.

Even the less privileged monkeys are lucky,

compared to those animals that live in the coldest

and most extreme place on the planet.

On the day like this in the mountains,

the temperature is about minus 1, minus 2.

On a different day with a bit of wind chill,

you're talking about minus 20, minus 30.

But, if you want it colder than that,

if you want the coldest ever recorded temperature,

you have to go to Antarctica.

Recorded by satellite in 2010,

the temperature hit a mind-blowing minus 94.7 degrees Celsius.

The average temperature at the South Pole is minus 50 degrees.

Winds have been known to reach nearly 200mph.

Much of the land is surrounded by permanent sea ice.

Which means the animals that live here have developed some of the most

amazing survival strategies in the natural world.

Harsh as it is up top, in the water,

temperatures remain about minus 2 degrees all year round.

This eerily beautiful world

is where Weddell seals spend much of their lives.

They live closer to the South Pole than any other mammal.

Feeding on fish underneath the ice.

Surely this is a potential problem for an air breathing mammal?

Well, there are some natural holes,

cracks and openings in the constantly moving sea ice.

And that's where the seals' remarkable adaptations come in.

They can hold their breath for over an hour,

swimming far and wide in search of the next air hole.

They've also developed a kind of sonar.

Listening to the minute differences in the echoes

from this peculiar call, they can detect gaps in the ice.

But, most amazing of all is how they stop a hole from freezing over

in these sub-zero temperatures.

Weddell seals have large, strong, and protruding teeth.

They use them to rasp away at the ice.

It takes extraordinary effort,

but it keeps their precious breathing holes open.

Going to these lengths is the only way to survive

in extreme places like this.

Our final group of animals can face up to the elements

like no other -

the Antarctic penguins.

Under their skin, penguins have a thick layer of blubber

to keep them warm.

And it gives them that distinctive rotund shape.

To save time and energy, they take advantage of the ice to get about.

Even their waddle is energy efficient.

And, on top of all of this is their most fortifying of features -

feathers.

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

and underneath is an air void, full of these downy feathers.

This is an incredibly sophisticated form of insulation.

When it comes to a life in the snow,

the emperor penguin really does deserve its name.

They're able to live further south than any other penguin.

For three months each year,

the males remain out on the ice whilst their partners go fishing.

They face temperatures of minus 50

and winds that can exceed 100mph,

all to achieve one extraordinary thing.

In a place with no shelter, no materials to build a nest,

and where everything is frozen solid,

he is responsible for bringing up the next generation.

Balanced on his feet, the closest part of his body to the ice,

he's protecting his most precious possession,

an egg.

In a specially adapted pouch,

the egg is kept at 38 degrees above freezing.

But it's not just about keeping his egg warm and off the frozen ground.

To survive, the penguins must stick together.

They move in and out of formation

with the other expectant fathers to keep warm.

Then, one magical day,

the hard work pays off, and he receives the ultimate gift.

A brand-new baby penguin...

..to show off proudly when Mum returns home from fishing.

Whether a parent or a baby,

nature's winter wonderlands are demanding places to live.

Yet, as we've seen,

our animals are more than up to it.

They've come up with extraordinary ways to survive,

and even thrive.

For me, these animals are some of the most impressive on our planet.

They've overcome every challenge

to each lead a remarkable life in the snow.