Original subtitles

Canada -

the second largest country on Earth.

Famous for its epic wilderness.

From the Rocky Mountains...

..to the Great White North.

Breathtaking...

..rugged...

..and immense.

It's a rich and varied wonderland...

..which supports some of North America's most iconic species.

Theirs is a world of extremes.

Their life - at the mercy of the elements.

Every season brings new challenges.

It'll take strength...

..and tenacity.

Courage...

..and resilience.

Skill...

..and good fortune...

..just to make it through...

..a year in the wild.

Canada is over 40 times the size of the UK...

..with countless wild rivers...

..the largest tract of unbroken forest on Earth...

..hundreds of peaks taller than Ben Nevis...

..and more lakes than the rest of the world combined.

Canada is lodged between the USA and the Arctic.

And from the Pacific Ocean in the west to the Atlantic in the east

lies over 150,000 miles of coastline.

It's October on Newfoundland,

Canada's most easterly island.

There's a nip in the air,

and it won't be long before winter storms batter the land.

Animals here must fatten up

before the season takes a turn for the worst.

This year, there's a bumper crop of wild blueberries.

More than just a sweet treat,

they're a super food for the biggest black bears in North America.

Standing four feet at the shoulder,

and weighing up to 600 pounds,

this male must prepare for hibernation.

In a severe winter, he may not eat or drink for six months.

So, the sooner he builds up his fat reserves, the better.

Berries are good,

but meat would speed up the process...

..if he can catch it.

It's the caribou breeding season

and caribou bulls are busy rounding up females.

With food getting harder to find,

they could provide a vital meal for a hungry black bear.

There's nowhere on this barren plateau to launch an ambush from,

so, he charges in.

Black bears can hit speeds of 30 miles an hour.

But caribou have stamina.

Long legs and lithe bodies eat up the tundra...

..whilst the heavy black bear soon overheats.

He's burnt up valuable calories...

..and must now work hard to replace them.

Foraging for berries will become harder as autumn rolls on.

With the herd intact,

the bull follows the other caribou to safer grazing.

They can put the immediate danger behind them,

but there's a greater challenge looming.

Their food could soon be buried under several feet of snow.

To survive out here when winter comes,

the caribou will have to dig deep.

2,500 miles west of the Caribou,

nestled in the foothills of the Rocky Mountains,

lies a vast wilderness area

known as the Sheep River Valley.

Warm winds, called chinooks, keep the lower elevations snow-free.

Down here, things are hotting up amongst the bighorn sheep.

Just over a century ago, half a million sheep roamed the mountains.

Today, there's fewer than 12,000.

Ear tags help scientists monitor the remaining population.

It's breeding season,

and with less than a month to woo a ewe,

eager rams are popping up everywhere.

Each ewe is fertile for just 48 hours per year.

So, frustrated rams must trail after them,

waiting for the perfect moment.

Each female has several suitors.

So, when one comes into oestrous,

all hell breaks loose.

It's autumn in the Rocky Mountains of Canada,

and tension is building amongst the bighorn sheep.

It's the breeding season,

and with each ewe receptive for just two days a year,

rams are keen to mate.

But first, they must eliminate their rivals.

To determine who has the mating rights,

rams have to slug it out.

Charging head-on with enough power to crush a human skull...

..they don't stop

until there's a clear victor.

Today, an old experienced ram comes out on top...

..and turns his attentions to a ewe.

But he hasn't seen off all challengers yet.

A young pretender is at large.

He's big, muscular

and oozing confidence.

That can only mean one thing.

The fight is back on.

And the old ram drives his adversary back...

..but the younger ram won't submit.

Pound for pound, they're an equal match.

But with youth comes speed and stamina.

The young ram gets ahead...

..and claims the ewe in the blink of an eye.

The old male has no fight left in him.

He must admit defeat,

and try again another day.

As temperatures cool...

..and daylight hours shorten...

..Canada's trees undergo a miraculous metamorphosis.

The green pigment in their leaves breaks down...

..allowing new colours to shine through.

It's a dazzling, but short-lived, display...

..before forests go into lockdown.

Autumn is the season of transformation...

..and there are more profound changes on the way.

Nearly 10% of Canada is covered by fresh water.

Lakes, teeming with fish, provide food for many predators.

But when autumn tightens its grip,

they'll start to freeze solid...

..locking animals out of their favourite hunting grounds.

This American bald eagle returns here every year.

Good fishing makes it the perfect place to raise a chick.

This year's fledgling is almost fully-grown...

..but he still depends on his parents for food.

The free hand-outs can't last forever.

When this lake freezes-up...

..the family will be forced to split up

if they're to survive the winter.

But whilst there's still open water,

there are still opportunities.

There's more than one way to get a meal.

The male bald eagle is an experienced pirate.

Quick and agile enough to keep up with a gull.

The gull has only one option.

Better to drop the fish, than risk an encounter with inch-long talons.

At three months old,

this fledgling will soon need more fish than his parents can provide.

And with the big freeze just around the corner,

he will die, unless he learns how to hunt for himself.

Glaciers stripped most of Canada clean during the last Ice Age.

Even today, there's barely enough soil

for shallow-rooted conifers to cling onto.

Water tumbles off bare rock,

feeding a multitude of rivers,

which, in turn, feed lakes further downstream.

Some animals aren't just adapted to this watery world.

They control it.

Autumn is a busy time for a beaver family.

Trees must be harvested, for both food and building materials.

Tooth enamel, strengthened with iron, prevents dental disasters.

But the most important thing when felling trees

is knowing which way to run.

Branches are ferried across the pond,

which protects the beavers from land predators,

like bears and wolves.

To ensure there's always plenty of water,

they've built a dam.

It requires constant maintenance.

But the rewards are great.

The beavers get their own patch of flooded forest.

Youngsters help with the chores...

..whilst their parents take a break for some essential grooming.

Glands at the base of the tail secrete an oil,

which he spreads through his fur to keep it waterproof.

But if they're going to survive,

the beavers must also keep their house in order.

It will provide them with somewhere safe to eat and sleep when

winter comes.

To keep predators out, the only entrance is under water.

Daubing the walls with mud provides extra strength and insulation.

Soon the snow flurries will settle and the pond will freeze over.

The beavers must use the final days of autumn wisely.

The preparations they make now could mean the difference between

life and death when their pond is locked under five inches of ice.

The Rockies are North America's longest mountain range..,

..stretching from deep within the US, far into south-west Canada.

Snow coats the highest peaks for most of the year.

But now colder weather has reached the lower elevations.

In the Sheep River Valley, autumn's finally turned a corner.

For a pygmy owl, this is a good place to ambush other birds.

But steep cliffs keep the canyon below largely free

of land predators.

Chasing prey up here is just too dangerous, so bighorn sheep

come here for safety.

They were raised on these cliffs and are excellent climbers.

So, when they're tired of being pestered by randy rams, ewes

head for the canyon.

Slippery slopes slow the rams down,

giving ewes a welcome chance to catch a breath.

This older ram has already lost one battle, and is more

determined than ever to find a mate.

He finally tracks down an ewe in prime breeding condition.

But his younger rival is back...

..and he's up for another fight.

It's late autumn in the Rocky Mountains - the peak of the

bighorn sheep mating season.

One ewe has attracted a lot of rams, including a young, dark male.

An old pale ram has already lost one ewe to him, and doesn't want

to lose another.

With feelings running high, the ewe heads for the safety of the canyon.

Most rams quickly drop back, but the alpha pair press on over the cliff.

The young ram leads the chase...

..closely followed by his old adversary.

And suddenly the race to mate is over.

Under intense pressure, rams can lose their footing.

And 300 feet below, the lifeless body of a young, dark

male bears testament to the dangers of the breeding season.

The old ram's alive, but has lost his ewe...

..and now finds himself on the most perilous part of the cliff.

But he has age and experience to fall back on.

He spreads his cloven hooves and successfully finds purchase

on the shale.

He's made it to safety.

Now all he has to do is find his mate.

And finally he claims the right to father one of next year's lambs.

In the Sheep River Valley, the breeding season is nearly over.

The rams have done their job - now it's up to the ewes.

They'll give birth in six months' time, if they can survive the

long, cold, winter ahead.

Trees across Canada are ready for winter.

When the cost of maintaining a canopy starts to outweigh the

benefits, they shut off the circulation to their leaves,

saving what nutrients they have until spring.

In the forests of Ontario, just south of

Algonquin Provincial Park,

the autumn spectacle is already over.

What remains of the leaves will soon be buried by snow.

Autumn is a critical time for moose.

It's the last chance for a proper meal.

In winter, there's not enough food to sustain these 1,000 lb deer.

If they don't have enough fat, they'll quickly succumb to

starvation.

TURKEYS CALL

Wild turkeys have finished foraging for the day.

They get jittery an hour before sunset and make a beeline for

the tallest tree around.

This squirrel wasn't expecting guests.

But turkeys must get off the ground...

..or they could become dinner for coyotes.

JAUNTY ORCHESTRAL MUSIC PLAYS

The higher they get, the safer they feel.

But launching a 10 lb body in the air isn't easy.

Bigger birds need a bit of a run-up.

Dominant hens go first, keen to nab the premium perches.

Sturdy limbs close to the trunk provide a stable platform and

shelter from the wind.

The rest have to settle for the outer branches.

In winter, they'll huddle up to stay warm.

But, right now, not everyone's keen on sharing.

It's a delicate balancing act.

Once personal space issues are satisfied, the turkeys

settle down for a rest.

Elsewhere in the forest, other animals are just waking up.

A flying squirrel uses the cover of darkness to avoid birds of prey.

She spent the summer hiding nuts and seeds for lean times like these.

Her secret stockpiles are far apart.

Travelling between them wastes precious energy.

But she has that problem licked.

SQUIRREL SQUEAKS

Membranes between wrists and ankles let her glide.

She can clear 300 feet in a single jump...

..making long journeys much more energy-efficient.

SQUIRREL SNIFFS

With temperatures dropping, the less time she spends outside, the better.

So, once fully fed, she heads back to her nest...

..where she can use every calorie she has saved by gliding to

keep herself warm.

OWL HOOTS

More than halfway between the squirrel's forest and the

Arctic Circle lies Churchill, on the shores of the Hudson Bay.

Polar air is drawn through here by a weather system known as the

North American High.

It creates a sub-arctic climate, where snow stays on the

ground for over eight months a year.

By mid-November, the mercury has already dropped through the floor.

But it won't bottom out until it reaches minus 50 degrees Celsius

in just two-months' time.

Only the toughest animals can survive here.

Ptarmigans eke a meagre living,

eating the buds of the stunted willow.

But they're also food for other animals.

Arctic foxes will take ptarmigan.

But, luckily for the ptarmigan, the vole population is booming.

But the Arctic fox is not alone.

Red foxes are bigger, and powerful enough to kill her.

It's mid-November,

and on the western shore of Canada's Hudson Bay

relentless winds from the north have driven temperatures down to

below minus 30 Celsius.

This Arctic fox is well adapted to life out here.

Thick fur and a small body help her stay warm, to allow her to

save energy for hunting.

And this is prime vole-hunting territory.

But there's a problem.

A red fox wants in on the action.

Taller and heavier than the Arctic fox, it's more likely to

kill her than share this territory.

Using her keen sense of smell, she looks for the perfect spot...

..and listens for the faintest patter of feet under the snow.

It's all in the timing.

VOLE SQUEAKS

A single vole is a good mouthful...

..but the red fox wants more...

VOLE SQUEAKS ..and soon has another.

It's bad news for the Arctic fox.

Her rival won't leave here with so much food about.

With her belly full, the red fox stashes any surplus kills for later.

They'll stay nice and fresh under the snow.

The Arctic fox has lost her hunting ground,

and if she hangs around, she may lose her life.

Her only option is to move on.

There aren't many places with such rich pickings,

and she may be forced to scavenge.

Strange as it may seem, her fate may depend on an even bigger killer.

If she follows the polar bears, she can eat their leftovers once

they've eaten.

But polar bears are seal hunters, and seals don't come ashore

at this time of year.

At the end of every autumn, hundreds of bears gather around the

shores of the Hudson Bay and wait.

They can't hunt until the sea freezes over.

That means no seal meat for the Arctic fox either.

The bears are thin, restless and hungry.

A mouthful of snow is little comfort to a polar bear mum

with an adolescent cub.

They've not had a proper meal since the ice broke up in July,

and that's over four months ago.

They sniff the air, waiting for winter to come.

Until it does, all they can do is conserve what little energy

they have left.

Next time...winter is coming.

Canada is plunged into six months of freezing temperatures and

fierce storms.

For some, winter is a time of severe hardship.

For others, it brings food and even new life.

Subtitles by Red Bee Media