Original subtitles

(gentle music)

- [Narrator] From the northern icescapes

of the Arctic Circle

to the southern most extremes of Antarctica,

winter prowls the Earth from top to bottom,

conjuring up scenes of wondrous beauty and stark severity.

Breathtaking in spectacle,

but often harsh environments to call home.

Those that do live here thrive here

through amazing adaptations and animal cunning.

It's survival of the fittest, the fastest and the fearless.

A cycle of life where being strong, smart, and shrewd,

can mean the difference between life and death.

Because in this extraordinary world of ice and snow,

only the most resilient and resourceful

will endure the wild winter.

(gentle music)

For the wild animals of Earth,

winter in the coldest regions of our planet

is a season like no other.

It is a multifaceted test of survival,

pushing the limits of an animal's

physical and cognitive abilities.

To succeed, they rely on

remarkable behaviours and adaptations

evolved in response to winter's challenges.

Whether they're built for the conditions,

or make the best of them,

mother nature's preppers and hoarders,

her ducks that know just where to land,

the ice age bovine that look out for each other,

and those that prefer to go it alone,

they use their size, their strength, and their sensitivity.

To pass this test

every creature must have a strategy for survival.

(tense music)

Antarctica, the coldest continent on the planet.

The polar night lasts six months

and days plunge to minus 60 degrees Celsius.

A frozen desert where winds can gust up to

300 kilometres an hour.

(penguins braying)

A colony of noisy emperor penguins

is bracing for this time of brutal beauty.

Winter is a critical time for them on the sea ice.

(wind howling)

No food and no shelter, they are totally exposed.

They must stay warm.

Their survival depends on it.

A male hunches his shoulders as he walks,

a posture that protects against the cold.

The way he moves is calculated and surprisingly clever.

The waddle may look unwieldy, but it's energy efficient.

Avoiding heat loss is always the priority.

(penguins braying)

While these penguins rock back and forth on their heels,

they're reducing contact with the icy ground.

A father penguin lends his feet to his chick,

warming the baby up on his insteps.

But it's as a community that this species excels.

In the ultimate act of cooperation, they form huddles,

choreographed groups that shuffle against the wind.

Those on the outside shield those on the inside,

and to share the shelter, the huddle constantly shifts,

allowing everyone a turn in the warm centre.

This admirable collective behaviour reduces heat loss

by up to 50%.

This is the emperor penguins' incredible solution

to surviving the bitter winter.

To ensure their collective survival,

they've turned the power of cooperation

into a successful strategy,

and it's made them one of the most resilient species

in what is arguably the harshest environment on Earth.

Beyond the extremes of the Antarctic Circle,

winter in the southern hemisphere is more forgiving

for the animal inhabitants,

though survival still requires a solid strategy.

To much of the world, Australia is not a place

associated with freezing temperatures.

Yet parts of this wide brown land can and do turn white.

(gentle music)

From June to October,

Australia's alpine region is a snowy wonderland.

(gentle music continues)

Mount Kosciuszko is the country's highest peak,

and has shifted from the fiery heat of summer

to regularly hitting temperatures

of five degrees below zero.

It's a landscape of incredible extremes

that challenge all that live here.

This common wombat is one of the only

large marsupial species that can handle life

above the snow line.

But as a concession to the cold,

the normally nocturnal animal has ventured out in daylight.

Even with no natural predators,

the wombat must be on alert for the red fox,

an introduced killer now considered a pest in these parts.

The Australian native needs to be ready to run.

(upbeat music)

The focus of today's trek is a hunt for food.

To save exerting himself, he halves his effort.

His back feet fit perfectly into the deep impressions made

by his front paws.

Saving energy is strategic,

for he needs all the strength he can muster

to survive the winter.

(upbeat music continues)

Wombats are herbivores

and primarily feed on grasses, roots and shrubs.

He'll graze for up to 10 hours a day.

His physical and behavioural adaptations

means he's well equipped to endure the conditions.

His sharp incisors sever the tough grasses he eats,

and when the ground becomes completely covered with snow,

powerful claws will cut through to unearth his meals.

(upbeat music continues)

And even though he sometimes looks a little out of step

with his surroundings, this wombat is at home in winter.

Its compact, barrel-shaped body does not sweat,

which makes wombats far more tolerant of the cold

than many other Australian marsupials.

His survival relies on spending long periods

in his warmly insulated underground burrow,

conserving energy until his next meal.

(gentle music)

The volcanic fields of Japan's Hell Valley region,

surrounded by rugged mountains, spectacular hot streams,

and the sound of serenity.

At first glance, Hell Valley may appear more heavenly,

especially to the resident snow monkeys.

These macaques don't have to contend with the polar nights

of further north,

having an ample 10 hours of winter daylight to find food.

But to get them through the months of sub-zero temperatures,

they've latched on to a unique way to warm up.

This mother and baby

know it's nicer in a warm bath than out.

(upbeat music)

The local thermal springs generally sit at a soothing

40 degrees Celsius.

(upbeat music continues)

Heated by volcanic activity,

and the ideal temperature for a snow monkey spa,

they'll lull about in the warming waters

for up to 10 hours a day, grooming, playing,

and as scientists have discovered, relieving stress.

(upbeat music continues)

The macaque have only been submerging themselves

since the 1960s,

when one curious monkey discovered the delights

of a steaming hot bath.

Now it's a regular occurrence

and a remarkable example of how

animals' winter survival strategies are always adapting

to suit their environment.

About 8,000 kilometres to the east of Hokkaido,

the thermal springs of Yellowstone National Park

also offer unique advantages to the animals

who winter in this region.

While most natural water sources are frozen over

at this time of year,

geothermal springs help to create areas of open water,

making it easier for birds like these mallard ducks

to filter food from the water

and feed on aquatic vegetation.

But the birds are not the only animals in Yellowstone

who need to eat to maintain strength and energy.

A bobcat leaves the relative warmth of its lair

in search of a meal.

Hunting in deep snow cover and cold weather

can be physically demanding,

but the bobcat has adapted to survive.

In winter, their coats become denser and longer,

providing extra insulation.

But despite its effectiveness for warmth, like most cats,

bobcats prefer not to get their coats wet.

And avoiding cold water

helps maintain their body temperature.

An important part of surviving the winter.

Relying on its acute hearing

to detect the faint sounds of mice beneath the snow,

it's believed the bobcat's tufted ears help to pinpoint

the direction and source.

Their strong hind legs allow them to pounce on prey

up to 3 1/2 metres away, with remarkable accuracy.

But success is never guaranteed in the wild.

(ducks quacking)

For Yellowstone's mallard ducks,

the thermally heated open waters have become

a pleasantly warm microclimate

where they gather in flocks to feed and socialise.

But in winter, hungry eyes are never far.

Bobcats are patient hunters.

(tense music)

Keeping low and moving silently through the snow,

the bobcat uses the natural terrain to cloak its approach.

Success hangs on the cat's ability to time its attack.

(tense music continues)

Not so lucky this time,

but these skills are being constantly refined.

As a cub, the bobcat learned how to stalk, hunt,

and kill prey, by observing its mother.

As well as other key predatory behaviours

such as the feline art of persistence and patience.

With the ducks oblivious,

the cat's judgement needs to be decisive.

(tense music continues)

Striking with precision, the bobcat targets the neck

to immobilise its prey quickly.

A successful kill,

immediately improving the bobcat's chances of survival,

at least for this winter.

Predators like bobcats expend a lot of energy

stalking and ambushing their prey.

Their methods of survival involve risk.

But other animals approach winter's challenges

in a more economical way, by scavenging.

Those animals that don't make it

through the cold dark winter

provide an easy food source for others,

like wolverines and ravens.

During extreme winters,

ravens' diet consists mainly of carrion.

Ravens rely on their keen eyesight

to spot a dead carcass from a distance,

which requires less energy and exertion than ambush hunting.

Often foraging in groups,

ravens share information about food sources

and cooperate during scavenging.

In the sub-zero temperatures,

the raven's meal stays fresh for much longer.

But this also means more time for competition

from other scavengers, especially from birds of prey.

Golden eagles are formidable predators of smaller animals

like hares and squirrels,

but in the lean winter months, they will scavenge.

And finding dead prey is a much easier option.

But winter is a competitive time,

even amongst your own species.

Another golden eagle has spied the carrion.

It's now a battle to determine dominance.

Older and more experienced eagles are typically territorial,

with the younger birds forced to wait at a distance

until the more powerful eagle has had its fill.

But ravens are intelligent and persistent birds

and do not relinquish their ready-made meal easily.

(tense music)

Social hierarchies in arctic animals can play a crucial role

in their survival during winter,

with younger, less experienced animals

learning valuable knowledge and survival skills.

(gentle music)

Most male polar bears lead solitary lives

hunting and sleeping.

But these two young boars have buddied up,

even if their interactions don't appear that friendly.

This is a play fight with a purpose,

as wrestling helps build up their strength and stamina.

Because even though they're apex predators,

they may need to defend themselves

against other polar bears,

usually during mating season,

or in year-round battles over food.

This hand-to-hand combat prepares them for the day

when they will fight for their lives.

With their sparring done,

it's important to regulate their body temperature again.

And resting properly is a survival skill young bears learn

in their formative years.

Like humans, they sleep up to eight hours a day.

A young male digs a shallow pit in the snow

and curls up inside.

Facing his body away from the bitter wind

is a deliberate move.

Even with the snow piling up around him, he's not cold.

The growing blanket of snow insulates.

The thicker it gets, the warmer he is.

And with a padded paw for a pillow,

the world's biggest bear is settled in for the night.

(wind howling)

(upbeat music)

Emerging from a den nearby is a mother bear

and her growing cubs.

She needs to find food for her offspring

who are almost two-years-old.

Soon they'll be able to leave the family

to stake their own territory.

But until then, she plays a crucial role

in teaching them how to navigate, find food,

and eventually become self-reliant individuals

able to survive the Arctic winter.

Setting a leisurely pace shows them how to conserve energy.

She's helping them get fit for future battles.

And disciplines them when they get out of hand.

Young cubs who will one day rein confidently

as rulers of the Arctic.

(uplifting music)

While much of the landmass of the polar north

is frozen during winter,

the temperature at the coast is mild in comparison,

thanks to the warm ocean currents of the Gulf Stream.

(uplifting music continues)

The sea water average is five degrees Celsius

at this time of year,

so it won't freeze, regardless of the ambient temperature.

And these waters are a critical wintering ground

for various bird species that migrate to this region

in order to survive.

Herons fly in from the European interior

and gather in the sheltered bays of Norway,

attracted by the abundant availability of food.

Purple sandpipers also arrive en masse,

spending their winter further north

than any other shorebird,

and they hastily consume as much as they possibly can

during the few hours of light each day.

For common eider ducks,

survival in the high Arctic during winter

is not something they have adapted to.

So between September and November,

they fly more than 1000 kilometres,

heading south from the glacial islands of Svalbard

to the warmer Norwegian coastlines.

Feeling at home in this archipelago,

eider ducks are a protected species.

The numbers throughout Europe

have been declining for decades,

with hunting, shipping disturbances and pollution

all playing a part.

Yet for these travellers,

their future is intrinsically linked to human settlements

at their overwintering destination.

The seas around their northern homelands are covered in ice,

cutting off their sources of food.

So their very survival depends on how well they feast

here in the Arctic Ocean.

The ducks are well adapted divers, foraging for starfish,

molluscs and sea urchins.

These dives can be up to 20 metres deep,

but they are not without danger,

as predators such as seals and sea lions will prey on them

as they descend.

Once near the sea floor,

they use their bills to prod and probe for food,

which is plentiful here,

bringing the eider ducks back year after year.

(gentle music)

Winter has blanketed the forests of Northern Europe.

The previously lush green landscape

transformed by snow and ice,

with many animals seeking shelter

under icy cold snow-laden tree canopies.

But this clan of European badgers

is not affected by the chill.

Their burrow, or set,

is the warm haven they call home each year.

This badger pokes out its nose

to test the outside temperature.

During winter, badgers do not hibernate,

instead entering a state of torpor, or dormancy,

a state they can drift in and out of.

The first priority of the day,

a visit to the clan's communal toilet.

Badgers are meticulous about hygiene.

Keeping the set mess-free is a courtesy to fellow badgers,

ensuring comfort during their winter seclusion.

Braving the wild weather

for anything longer than a toilet break

is something they do only when necessary,

like when they're hungry.

Having a highly adaptable diet is a huge advantage

when it comes to survival through winter.

Badgers will eat anything.

They are expert scavengers,

tearing into carrion with their powerful jaws and teeth,

allowing them to crush bones,

to access marrow and other nutrients.

(gentle music)

In the same forest, another animal has a different strategy

for surviving the winter.

(gentle music continues)

The red squirrel, when compared to the highly social badger,

is a loner.

They will readily leave the security of their nest

when food stocks run low.

(gentle music continues)

Throughout autumn, this squirrel has buried nuts, mushrooms,

and other goodies in the ground.

It can smell the food through the dense snow,

so has located the supplies quickly.

(gentle music continues)

Storage isn't a problem.

In their cheeks are pouches they use like shopping bags.

(gentle music continues)

The red squirrel, always on the go,

and always well prepared.

(gentle music continues)

When it comes to surviving

the long snowbound winters of Northern Europe,

forest animals of all kinds

have developed their own strategies, adaptations,

and instincts to see them through to summer.

But there is one other advantage they all share

that is critical.

The forests themselves.

The dense evergreen canopies of pine, spruce and fur

act as a natural barrier against cold winds.

They provide camouflage for animals

trying to avoid predators.

And they provide food.

One animal that is relentless in seeking out

what the forest has to offer is the wild boar,

scavenging wherever it can.

(boar grunting)

(uplifting music)

This herd is cutting a swathe

through the frozen forests of Belarus.

Wild boar have been treading the Earth

since before the Stone Age,

and once preferred conditions less extreme

than these biting sub-zero temperatures.

But the boar's instinct to endure is stronger

than winter's power to freeze them out.

They're supreme survivors,

having infiltrated every continent bar the Antarctic,

Slavic, Nordic and Canadian boar populations

have been adapting and advancing further north each decade,

trampling the snow and using their snouts to dig for food.

But this rooting behaviour upends saplings

and releases precious soil nutrients,

degrading the natural ecosystem

and threatening not only habitats,

but the existence of small animals, like the squirrel.

Ravenous boars gobble up acorns,

the mainstay of a squirrel's diet,

and also plough through the tree dweller's

winter food stores.

(boars snorting)

The wild boars make themselves at home and comfortable,

wherever they choose.

These two beasts are burrowing a cradle for themselves.

In a trench of mud and snow, they huddle together,

away from the wind and the worst of the season's weather.

When the elements ease,

they'll be ready to pillage another day.

Because in a contest for resources,

the wild boar always comes up a winner.

(gentle music)

In Yellowstone National Park,

the combination of moist air from the Pacific Ocean

and minus 25 degree mountain temperatures

have created blizzard conditions.

(tense music)

The park's thermal springs

coat the trees in steam, which freezes.

To survive here during winter, herbivores like elk and bison

have developed similar strategies.

They gather near the natural hot springs to warm themselves

and to drink and forage in areas that remain unfrozen.

But there is more than one survival strategy at play here.

Large hoofed mammals are wolves' preferred prey.

(wolf howling)

And with so many of them concentrated

around the warm springs,

a pack of hungry canines has taken a keen interest.

Steam rising from hydrothermal areas

has its own distinctive smell,

which helps mask the wolves' scent,

allowing them to get close to the unsuspecting bovine.

For a full grown healthy bison,

a lone wolf is of little threat.

Their true menace begins when they hunt together.

(wolves howling)

The valleys of Yellowstone attract elk herds during winter.

Searching for food, they migrate from high mountain terrain

to lower elevations.

(tense music)

And watching the elks from a distance,

the wolves scout the size and behaviour of the herd.

They will prey on the weak and vulnerable.

(wolf growls)

For elk, the risk of being attacked lessens

when they are part of a large group.

They depend on each other

for their increased odds of survival.

This bull's vigilance means he's able to draw

the wolves' attention away from the herd,

allowing them to escape.

Deep snow works in the bull's favour.

Confronting the wolves with his size and impressive antlers,

he aims to intimidate.

Finding refuge in a thermal stream

where the wolf's footing is less sure

has guaranteed this bull's survival,

and diverted attention away from his herd.

However, for the younger and weaker members of the herd,

the wolf pack is too fast and agile.

Using their instinctive hunting tactics,

they overcome the young elk.

To survive the winter,

wolves must hunt and elk must stick together.

(gentle music)

In Finland, the most forested country in Europe,

the woodlands glisten

as the Arctic Circle savours last light.

But the beauty of these pristine landscapes

belies their danger.

(gentle music continues)

For these deer, it's the riskiest time of the year.

(gentle music continues)

The grasses and mushrooms they enjoy

during the warmer months have disappeared

under layers of snow.

They congregate on mountain slopes and conifer stands.

The only places vegetation grows without sunlight.

As vegetarians, they have an amazing ability

to eat and digest foods other animals find unpalatable,

such as bark, lichen, and moss.

Though they are low-quality meals,

it's enough to sustain them during the lean season.

But predators are never far away.

The deer exposed in the higher altitudes

need to be on constant alert.

(tense music)

Hungry eyes are everywhere.

(tense music continues)

The deer's survival comes down to a callous game of chance.

Forming a gang for protection,

and relying on their sense of smell and sight,

deer are on the constant lookout for predators.

The herd must also work together

to combat the brutal weather.

Their mass of bodies form a wind break

as they buffer themselves against the blistering winds.

A sheltered location is crucial.

They settle beneath a line of trees,

where the canopy shields them from the constant snowfall.

(tense music continues)

And as darkness descends, they move as little as possible,

conserving energy to stay warm and slowing their metabolism,

which decreases their desire to eat.

These innate behaviours are strategic,

ploys that will help them survive the winter.

(wind howling)

(uplifting music)

In contrast to the great forests of Finland,

in the treeless expanse of Alaska's Arctic tundra,

a bonded pair of arctic foxes prepare a snow den.

This temporary accommodation is where they will hunker down

for up to two weeks at a time during winter.

When they're warm,

they are able to slow down their heart rate and metabolism,

saving energy so they don't have to eat as much or as often.

But they will eventually need to find food.

So leaving the safety of the snow den

is a gamble this one must take.

Their species survival relies on this combination

of nomadic and communal behaviours.

The fox is so familiar with the territory,

it knows exactly where it has food squirrelled away,

enjoying a quick bite to eat from his stockpile

and hiding it again for later.

In the meantime, his partner has ventured further afield.

She smelt an abandoned reindeer carcass

and risked the journey for a chance to eat.

Eating another animal's leftovers is an intelligent move

when temperatures are so low.

The effortless feed

conserves the fox's body heat and energy.

(uplifting music)

Having avoided any predators of their own,

the Arctic fox partners head back to their snow den.

(uplifting music continues)

The dog and his vixen curl into balls

to reduce their exposure to the freezing air,

minimising their heat loss.

Wrapped in the thermal protection of their thick tails,

they'll sleep to further conserve energy

until they need to hunt again.

From these two little foxes,

the lone predators that must hunt to live,

the animals that endure the polar environments

have adapted their behaviours to overcome

the worst weather imaginable and survive the wild winter.

(uplifting music)

(uplifting music continues)