Eden: Untamed Planet

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

...feasting on the abundance

of fleeting summers...

to make it through relentless winters.

ROARING

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

...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

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

But bears patrol the coast

in search of something other than food.

ROARS

His cowboy swagger

denotes a dominant male...

all 700 pounds of him.

OTHER BEARS BARKING

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

But a mother with yearling cubs

is in no mood to mate.

ROARS

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

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

GROWLING

With this overeager male safely out of reach...

the young family can make the most...

SNIFFING

GROWLS SOFTLY

...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

...as a vast injection of protein...

turns the waters a milky white...

with herring spawn.

SEABIRDS SQUAWKING

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

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

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

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.