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 canapÃ©.
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
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
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
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.