Original subtitles

NARRATOR: In Southeast Alaska,

where the coastal mountains meet the Pacific,

lies the Alexander Archipelago,

a remote island chain...

running for almost 300 miles

along the Alaskan Panhandle.

Defended by ramparts of rock and ice to the east...

with 3,000 miles of ocean to the west...

this frozen frontier

is one of the last great wildernesses

of North America.

This is part of the largest temperate rainforest

on Earth...

and a stronghold for the country's

highest diversity of megafauna...

BELLOWING

NARRATOR: ...feasting on the abundance

of fleeting summers...

to make it through relentless winters.

ROARING

NARRATOR: Both big...

and small...

live here in perfect balance.

Their worlds connected

in surprising

and intricate ways...

that allow each of them...

to thrive.

There are still places on Earth that remain pristine.

Where wildlife flourishes.

These are the last regions that could be called...

Eden.

For six months of the year,

North America's icy mountain realm

is gripped by winter.

With the arrival of spring,

life stirs once more...

BEAR GROWLS

NARRATOR: ...as the world's

largest population

of grizzly bears

emerge from hibernation.

A mother with hungry cubs must hurry

to make the most of brief times of plenty

in this unspoiled, untamed land.

In spring, the best feeding opportunities

can be found where it's milder...

along the coast.

Telltale footprints signal the arrival...

of newly-emerged grizzly bear families.

After six months of hibernation,

this female and her cubs

are in need of a protein hit.

Twice a day, low tide exposes a seafood smorgasbord.

A fresh fish looks tasty...

but defensive spines

mean it's probably best avoided.

Betrayed by their squirts,

the real prize is the butter clam.

Surprisingly delicate paw-work

prevents the clam digging deeper.

Now, add brute force...

GRUNTING

NARRATOR: Et voila! A clam canapé.

But when you smell a clam...

and can't find it...

it can be frustrating.

But if you copy mum's technique...

it should work.

Or you could just use your teeth...

but there may be some shell in that.

SEABIRDS SQUAWKING

NARRATOR: But bears patrol the coast

in search of something other than food.

ROARS

NARRATOR: His cowboy swagger

denotes a dominant male...

all 700 pounds of him.

OTHER BEARS BARKING

NARRATOR: And he's keen to kick off the breeding season.

But a mother with yearling cubs

is in no mood to mate.

ROARS

NARRATOR: A grizzly can hit a top speed

of around 35 miles an hour.

Males may kill cubs

to bring a female into season.

But all that muscle mass...

BEARS GROWLING

NARRATOR: ...makes it hard to keep up the pace.

GROWLING

NARRATOR: With this overeager male safely out of reach...

the young family can make the most...

SNIFFING

GROWLS SOFTLY

NARRATOR: ...of this Eden's other

spring feeding ground...

sedge grass meadows.

While the succulent shoots provide few calories,

they'll tide a hungry bear over.

Even the cubs are happy to eat their greens.

But they still prefer mum's milk.

She'll nurse them for nearly two years...

all the while teaching them the dangers

and rewards

that come with this bountiful Eden.

Triggered by spring sunshine...

the first boom in productivity...

takes place offshore...

SEABIRDS SQUAWKING

NARRATOR: ...as a vast injection of protein...

turns the waters a milky white...

with herring spawn.

SEABIRDS SQUAWKING

NARRATOR: Hundreds of millions of fish

gather in the shallows to breed.

Each hen fish releasing 20,000 eggs.

For resident Steller's sea lions,

it's the first great feeding opportunity of the year.

Flying 9,000 miles,

one of the longest bird migrations,

tens of thousands of red knots

arrive from South America...

to take advantage of a feast...

that's also the cue for marine megafauna.

It's one of the greatest gatherings of whales

on the planet.

45-foot-long gray whales.

Mothers with newborn calves

have navigated 6,000 miles

from Baja, Mexico.

The longest seasonal journey of any mammal.

But it's worth it.

In vast mouthfuls of fatty roe and krill,

each consumes more than a ton a day.

And so, the smallest creatures here...

sustain the biggest...

enabling gray whale calves

to put on a third of their adult body weight

before their autumn return to the south.

In spring, life also stirs

in this pristine forest that crowds the shoreline.

Covering 17 million acres,

roughly the size of West Virginia,

it's part of the largest tract

of temperate rainforest on Earth.

Bathed in 100 inches of rain a year...

each 700-year-old spruce

may carry 500 pounds

of moisture-loving lichen, mosses,

and ferns on its branches.

It's one of the last places in North America...

where prey...

and predators

exist in equilibrium.

SCREECHES

NARRATOR: Early migrants, like rufous hummingbirds, arrive.

The climate here is perfect

for sap-rich trees to grow.

So it's worth a 4,000-mile journey.

They refuel on the sugary resin

before pairing up to breed

in this most northerly

of all hummingbird habitats.

Yet life here is built

on superficial foundations.

In some places,

ice fields only retreated

in the last 200 years.

So, the soil is still shallow

and nutrient-poor.

But this Eden has an answer:

it's intricate connections between species...

as revealed under the magical display

of the aurora borealis.

Flying squirrels emerge from their tree hollows

in search of a mate.

With spring in the air,

this young male sniffs the breeze.

From a neighboring tree

drifts the heady aroma

of a receptive female.

He eagerly sets off to track her down.

For a flying squirrel...

gliding is the perfect way

to get around this 100-foot-high canopy.

CHIRPING

NARRATOR: In a matter of seconds,

the scent source has been located.

She's just come into season...

but she's playing hard to get.

He'll have to prove he's a worthy partner.

If he can't keep up, he's not worth the effort.

CHIRPING

NARRATOR: But just when it looks

like a match made in heaven...

she decides that he's failed to make the grade.

Yet the intoxicating scent of female

is still in the air.

He must find this femme fatale.

The lower he gets, the more enticing it becomes.

Desperately digging,

this confused lothario

thinks he's found the mother of all mates.

But his consolation prize is

a white truffle.

The furtive fungus emits an odor

that mimics female pheromones.

The truffle tricks him into solving

the biggest problem for this mineral-starved forest.

When a squirrel carries a prize truffle

to the treetops...

its spores

are dispersed far and wide.

As they germinate,

they help form a vast underground web

of fungal filaments...

effectively extending the range of tree roots...

enabling them

to extract enough nutrients

to allow these great forests

to flourish.

BIRDS SINGING

BIRD CAWING LOUDLY

NARRATOR: By early summer,

long hours of daylight...

promote a flush of growth...

across the archipelago's coastal meadows.

But for grizzly bear families...

high-calorie food is scarce...

and aggressive males must be avoided.

So some head inland...

to secluded rivers

in the heart of the forest.

This young mother has just the one cub.

His siblings may have been taken by a male.

But she has led him to a place where he will be safe...

and females gather to feed in peace.

SEABIRDS SQUAWKING

NARRATOR: Most are related,

and all have young to feed.

But for now, they must wait.

Downstream...

along Alaska's 7,000-mile seaboard...

half a billion Pacific salmon.

Among the largest concentrations in the world.

After four years of fattening up at sea,

some may swim 2,000 miles upstream...

before spawning in the very upriver pool

in which they were born.

A rich reward for the eager bears.

Unfortunately, for this young mother and cub...

all the prime fishing spots are taken...

by the older, more experienced females.

So she leads her cub upstream,

away from the competition.

But there's a reason

they have this place to themselves...

Rapids.

CUB HOWLS

CUB HOWLS

NARRATOR: For the cub, it's a brutal baptism.

WHIMPERING

GROWLING

NARRATOR: But the inexperienced mother

coaxes him straight back in...

MOTHER ROARS

CUB HOWLS

NARRATOR: Her desperation to feed

overrides her urge to protect her cub.

But fortune favors the brave!

CUB GROWLS SOFTLY

Finally, the ravenous cub

gets a first taste of salmon.

Over the next five months that the salmon will run,

grizzly bears will eat up to 100 pounds a day.

That's over 50,000 calories.

And this cub will have the rest of the summer

to master the art of fishing.

Got it!

It's not just the bears that benefit

from this mass migration.

To avoid a catch from being stolen,

the woods offer private dining.

FLIES BUZZING

NARRATOR: With the fatty head preferred to everything else...

leftovers litter the forest floor.

From half a mile away...

fishy fumes are picked up...

by the sensitive antennae...

of an inch-long

indispensable insect...

the burying beetle.

This male has two things in mind...

fresh meat...

and a mate.

Battles establish breeding rights.

They're brief...

but brutal.

Then, living up to their name...

the new couple proceeds to dig the salmon a grave.

In the safety of their cozy crypt...

the fresh corpse provides a feast

for a newly-hatched brood

of larvae.

And there will be plenty of surplus fish

to fertilize the surrounding soil.

In a soccer field-sized area,

there can be as much as three tons

rotting underground.

Known as 'fish trees',

spruces grow three times faster

along these rivers.

It's possibly the largest transfer of nutrients

between water and land

anywhere on Earth.

Because of the salmon,

the entire forest prospers.

SQUAWKING

NARRATOR: It's autumn.

The long days and short months of summer

brought with them great riches.

But now, animals that can depart

will soon be journeying south.

MOOSE BELLOWS

NARRATOR: Yet for some,

this is the time to secure

your bloodline.

MOOSE BELLOWING

BELLOWING

BELLOWING

NARRATOR: Crowned by antlers

spanning six feet or more...

and weighing around 40 pounds...

a 1,500-pound moose

proclaims dominion over his realm.

BELLOWING

NARRATOR: This antler-free female...

and the five or so others in his harem...

will stick around as long

as he's the best bull on offer.

Younger males go head-to-head,

honing their combat skills.

Though without the impressive headgear

and imposing physique,

they only have a 10% chance of mating.

But one male is willing to try his luck.

At five years old, he's almost fully grown.

But he'll never be

a mighty moose.

To win over a female...

he needs a different game plan.

From a discrete distance,

he closely observes what it takes

to be main moose.

The females are in season for less than two days.

But the dominant male has a mood-enhancing move...

that guarantees romance.

He scrapes a shallow pit...

and urinates into it.

It contains potent pheromones

that bring females into season.

They find the aroma so intoxicating,

they can't resist a roll.

Ah! So that's how it's done.

GROANING

NARRATOR: Anointing himself in the musky pee...

this young pretender seizes his chance.

With the help of the alpha's aroma...

he gets the come-on he's been dreaming of.

Under the nose of the moose monarch...

she leads the cheeky youngster off to mate...

proving that the smartest moose

isn't always the one with the biggest antlers.

BIRD SQUAWKING

NARRATOR: As autumn gives way to winter...

temperatures plummet

to minus 4 degrees Fahrenheit.

While most rivers are now locked in ice...

WIND HOWLING

NARRATOR: ...the Chilkat continues to flow

throughout November.

BIRDS SQUAWKING

NARRATOR: Heated to 45 degrees

by thermal springs...

it supports one of Alaska's last salmon runs...

offering one final feeding bonanza...

for America's national bird...

the bald eagle.

Over 4,000 stop off here

in the largest gathering on Earth...

to fuel up on salmon

ahead of their migration south.

For a young eagle,

this is the first true test of survival.

SQUAWKING

NARRATOR: Every catch is ferociously contested

by adults much bigger than him.

SQUAWKING

NARRATOR: But to make the journey ahead,

he needs to bulk up.

To avoid serious injury,

disputes are settled

by locking needle-sharp

two-inch-long talons.

SQUAWKING

NARRATOR: He moves in on the unguarded carcass...

only for it to be snatched away.

At dusk, eagles retreat

to the safety of the treetops.

They may have one of the most acute daytime eyesights

in the animal kingdom...

but in the dark, they're virtually blind.

On the ground, they could easily be ambushed

by nocturnal predators,

like a coyote.

But night may also offer

an opportunity to feed.

Under the safety of darkness,

a mother grizzly leads her two cubs

to the river's edge.

Brown bears have a membrane in the back of their eyes

that reflects light within the lens...

giving them excellent night vision.

BOTH ROARING

NARRATOR: While the cubs amuse themselves...

ROARING

NARRATOR: ...mum gets on with the serious business of fishing.

GROWLING

GROWLING

BEAR GROWLS

NARRATOR: With the coast clear...

the daring youngster

makes his move...

profiting on the leftovers.

While almost three quarters of fledglings die

in their first year...

SCREECHING

NARRATOR: ...this wily eagle has found a way

to gain the strength he needs

to escape the Alaskan winter.

These late salmon runs are vital

to grizzly bears

right across Northern America.

As temperatures drop to minus 20 degrees Fahrenheit...

icicles adorn their fur.

So they are known here by the First Nations

as 'Ice Bears.'

Every salmon increases the chance of surviving

the long winter hibernation.

But across Southeast Alaska,

the predictability of the salmon run

has been thrown into doubt.

The damming of rivers,

logging, pollution,

and climate change...

could mean this entire habitat

is at risk.

On this fragile planet,

home to nearly eight billion people,

the threat to remaining wilderness

grows ever greater.

But if we take steps to keep our world safe...

enriched by natural wonders...

its exquisite symmetry...

kept in balance

by intricate relationships...

these last frontiers

BELLOWING

NARRATOR: ...will remain...

SCREECHING

NARRATOR: ...forever Eden.

NARRATOR: The Eden team

spent a year braving

the freezing conditions

of Southeast Alaska...

in one of the most remote and pristine wildernesses

left in North America.

With new technologies,

they were able to reveal the hidden lives

of its exceptional wildlife.

From the miniscule...

to its mighty megafauna.

But the team's biggest challenge

was to capture the intimate story of bear families

on their quest to find food

along Alaska's coastline.

In spring,

camera operator Luke Barnett

set sail for Admiralty Island

in the Alexander Archipelago...

accompanied by bear expert

Bjorn Dihle...

and their timing is impeccable.

Just arrived at our filming location,

and there's a mother with two cubs on the beach.

Bjorn recognizes her, says she's 26 years old.

It's so amazing to see them day one.

NARRATOR: In this remote wilderness,

the crew will have to be entirely self-sufficient.

Setting up camp in bear country,

rule number one

is to cache any food high up in a tree

away from sensitive noses

and erect an electric fence

to deter any surprise visitors.

So right now it's on and it emits, uh...

a small jolt every second.

It's really not that bad.

Um, that was more me just being a wimp than anything else.

But it scares the heck out of bears.

NARRATOR: The team heads for the coastal meadows,

where mothers with cubs

gather to feed each spring.

BJORN: Coming around the corner.

LUKE: Bjorn's normally the strong, silent type

and he's talking a lot on this trip,

and that's just so...

we don't surprise any bears who think

another bear's come around

the corner and they charge us.

NARRATOR: It quickly becomes clear

that this is far from a peaceful scene.

One thing I have noticed about the bears

is they spend a lot of their time

looking quite anxious

and they're always looking about for other bears,

especially the females, and the males are always looking to

antagonize other males.

NARRATOR: Newly emerged from hibernation,

the 700-pound male grizzlies

are ravenous, eager to mate...

ROARS

NARRATOR: ...and highly territorial.

It's incredibly daunting.

Having filmed predators all around the world,

I've only ever approached them in a vehicle before,

so you've got that armor around you,

this is the biggest land predator here.

And it can move at speeds of up to 35 miles an hour,

and the only thing I have to stop them, essentially,

is some kind of bear spray,

and quite scary at times.

NARRATOR: Respecting bears

and learning to read their behavior

can avoid conflict.

Now we got a big male bear

about 30 meters away from us that's been looking at

anything that moves as a potential competitor

or a potential mate.

NARRATOR: Bjorn tells Luke to face the bear,

stand his ground.

NARRATOR: And talks to it calmly.

BJORN: You're okay, you're okay.

Um... if he keeps us here, we're gonna have some issues.

NARRATOR: After a tense standoff...

the male grizzly finally moves away.

RELIEVED SIGH

NARRATOR: Over the next few weeks,

the team's perseverance is rewarded

with intimate encounters

from a young mother with cubs.

LUKE: So, these bears are getting pretty close now,

which is a great sign for the filming,

but the mother's probably due to come into season

any moment now and that'll bring the males in,

so everything could change and those cubs

could be in for a little bit of a shock.

NARRATOR: It doesn't take long for Luke's concerns

to become a reality.

A huge and scarred male grizzly approaches.

LUKE: This big bear has got a big cut on its head,

it's been fighting, potentially a very angry bear.

Everything's fine when I look through the viewfinder,

so I'll just carry on doing that for a little bit.

NARRATOR: While still on the lookout for amorous males,

mum takes the cubs to the beach

for a day of clamming.

LUKE: That was pretty intense, when mother and cubs came down,

and they were so close,

and they started huffing a little bit.

I can't tell how far away she is from the viewfinder,

but I knew when I took the lens as wide as it would go

and there was still a very big bear in frame

that she was pretty close.

NARRATOR: While a protective mother with cubs

can pose a threat,

as time passes,

the team gain her trust.

BJORN: We've been watching this female for the last eight days

and I've known her for 12 years,

and we don't approach her,

we let her kind of do what she wants to do.

NARRATOR: But it may take Luke a little longer

to be completely at ease.

LUKE: We had to hold our position,

but it was a little bit nerve-racking.

It was great to have Bjorn with me

because he was talking to the bears,

just telling them what we were doing,

and half the time I thought he was talking to me,

to calm down, but he was talking to the bears.

Then they chilled out completely

and got the mother digging out a clam in full frame,

and the cubs have learned that behavior as well,

so that was amazing to see.

That intimate moment,

that's gonna stick with me.

NARRATOR: The grizzly bear's fearsome reputation

has contributed to their persecution.

BJORN: In Southeast Alaska,

about 2,000 brown bears

get shot by sports hunters

every year.

And it's like

less than one person will die

from a brown bear every year.

NARRATOR: While Luke maintains a healthy respect

for these formidable predators,

he has also experienced a gentler side.

This place is pretty special, it's a sanctuary for the bears.

And it's really lovely to be able to come somewhere

where they're not hunted

and they just go about their lives,

and we get to see them do that.

NARRATOR: As long as Admiralty Island

remains protected

and the wilderness of the Alexander Archipelago

can be preserved...

this will remain

the greatest stronghold for brown bears

on Earth.