Original subtitles

Life in the rockies can be a real headache.

Too high, and you're out on a limb.

And the snow can be a bear.

But there's more to these mountains than altitude.

The rockies create the strange...

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control the flow...

And challenge everything...

(roaring)

in their shadow.

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welcome to the top of the world.

Colorado's rocky mountains

hold seven of the ten highest peaks in the lower 48.

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and more than 600 others rise above the tree line.

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this is where the rockies...

Reveal their rock.

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a pointed crown

ringed by green gems made of pine.

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and just below, around 8,000 feet elevation...

...Is where the rockies tuck away their fall leaves.

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it's a color-coded message.

A signal that says, 'come and get it.'

the last buffet of the year is ready.

And it's all-you-can-eat.

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these american robins have a hankering for hawthorn berries.

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a crucial last course before winter hits.

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roosting sites like this

can hold up to a quarter million birds.

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and this restaurant also has clientele

that insist on larger portions.

(grunt)

this diner ambles in without a reservation.

And no respect for the dress code.

(grunting)

black bears don't always sport a black coat.

(grunting)

here, out west, they can also be brown or blonde.

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this mom teaches her two young

about the best dish on the menu.

It's the start of a lifelong habit.

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nearby, a male climbs high for the berries.

Something he's been doing since he was a cub.

But he's not a cub anymore.

15 feet in the air,

this 300-pound giant tests just how far

the tiny hawthorn branches will bend.

90% of what a black bear eats is vegetarian.

It's fine fall dining until...

Overnight, the berries freeze.

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the first big winter storm.

And just like that,

a blanket of white takes out the fall colors.

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all that's left to eat is frozen food.

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but the very berry bistro remains open for business.

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now its fruits are more precious than ever.

(growling)

bear essentials.

(growling)

as winter sets in, it's a race to feed

and convert these carbs into fat.

He can eat 20,000 calories.

And gain five pounds in a single day.

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sooner or later

there's a little berry

that's one too many.

(roar)

(grunt)

finally, he must settle down for the winter.

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five months of hibernation eat away

up to 40% of a bear's body weight...

As winter buries the southern slopes of the rockies

under 50 feet or more of snow.

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the rockies stretch 3,000 miles from canada to new mexico.

It is the backbone of america.

But it's colorado that's known as the home of the rockies.

From rocky mountain national park,

just over 50 miles northwest of denver,

and down south to the great sand dunes

of the san luis valley that mountains shaped,

colorado is the u.S. State with the highest mean elevation.

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winter here has bite.

Some shelter in the trees.

Up in a pine, this white-tailed ptarmigan nibbles on needles.

It's an elusive bird

that will mess with the chilled winds of a rockies winter.

But this one has special abilities.

By mid-December, she transforms herself from this...

...To this.

She is an ice queen.

This camouflage is designed to keep her safe.

But there are some keen eyes up here.

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mountain lions are expert climbers.

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they don't have dens.

So a branch is as good a place to hang out as any.

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she gets the lay of the land.

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and sits like a coiled spring,

ready to launch an ambush attack on any passing prey.

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she is an expert in stealth...

Patience...

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...And death.

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by late fall,

the pickings in colorado's rocky mountains are slim.

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no catch for this mountain lion all morning.

It's time for plan b.

Her range can be as much as 200 square miles;

smaller than some males,

but still a lot to cover.

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she uses her terrain to hunt for a hefty feed.

If not a bighorn sheep, then a deer or elk.

But she has a backup plan.

She hits up a stash from a previous kill.

One of several she keeps handy.

When she first got this kill,

she ate as much as 10 pounds of it in a single day.

The rockies provided a well-chilled freezer

for storage,

but now, weeks later,

other birds and animals have had a go,

outside and in.

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what's left would barely feed a rodent.

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she has no choice but to move on.

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winter is mean and lean.

Up high, it's April before there's relief.

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soon after, each rocky mountain becomes a runaway bride.

They lift veils of white.

(singing) ave maria

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and send spring snowmelt running down the aisles.

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icy water flows all the way down to their cold feet.

For one creature here, the very sound of this flowing water

seems to trigger an impulse.

It's like a reflex action.

Even an audio recording of a running stream

can set a beaver a-building.

This big male starts with the small stuff.

But don't let that fool you.

He works about a 12-hour day,

beginning in the late afternoon.

Bit by bit, he builds his own mountain.

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beaver dams can be up to 10 feet high

and nearly 3,000 feet in length.

He's a clever engineer.

This is not just a pile of sticks,

but a complex latticework cemented with mud

and packed down to be near waterproof.

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in slow water, they build the dams straight;

in fast water, they curve them

to be stronger against the current.

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for beavers, this is all about safety.

He knows he's protected from predators when in the water.

A good dam enlarges his safety zone

and gives him access to more trees--

wood he needs for construction

and for food.

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beavers eat bark and the soft tissue under it,

up to four and a half pounds of it a day.

It's mostly cellulose, like glue for the gut,

that most mammals can't digest.

But beavers are brewers; living distilleries.

They have a sac between their small and large intestines

that ferments vegetation to make it digestible.

All that brewing in the belly takes time.

What he eats today won't come out the other end

for another 60 hours.

He cuts branches into manageable chunks

and selects some to store nearby.

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he is a provider and must think ahead.

His family will soon grow.

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he's the hard-working responsible cousin.

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then there's the other side of the family.

That cousin who's a little slow.

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no early riser here.

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porcupines are the sloths of the rodent world.

Just getting out of bed can be a chore.

They're nearly as big as a beaver but more pear-shaped.

And they don't have a great need for speed.

Breakfast is never that far way.

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porcupines also have the diet of a mulching machine.

They can munch on leaves or bare twigs.

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even pine needles.

Or forget the greens altogether and just eat the bark.

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then, the surprise.

Those long claws are the only hint

that this prickly character has a superpower,

one that takes it above and beyond

the realm of its beaver cousins.

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when it's time for porcupines to find a sweet dessert,

it's up, up and away.

Beneath the colorado rockies, they take to the trees.

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well, sure, it's only three feet up.

But porcupines are one of the only mammals here

that eat spring buds up off the ground.

They grab on with those claws and large pads.

The stiff hairs on their bellies also grip.

They're safest among the trees; the forest provides more cover

than can be found farther down the slopes.

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just below is where the rockies

create an entirely different world.

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anywhere else, the rockies' eastern foothills

would transition straight to flat grasslands.

But here in colorado's san luis valley

they drop into something else.

Sand.

Lots of it.

The highest sand dunes in north america.

The 30 square miles of this dune field

would look more at home by the beach or in the middle east.

In summer the sand can heat up to 150 degrees.

Too hot for most life.

Unless you come with your own set of stilts.

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the great sand dune tiger beetle lives here

and nowhere else on the planet.

He's elevated just enough from the scorching sand below.

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and built to dash and dart about the dunes

in search of insects.

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he's a bejeweled bedouin.

But that hasn't always been the case.

As a kid, he definitely went through a homely stage.

Nearby, a great sand dune tiger beetle

is still in its larval stage.

No long legs yet.

No dazzling green.

But don't underestimate this baby beetle.

It already knows how to dole out death.

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it digs a snug burrow.

A perfect cylinder.

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when it gets too hot, it'll cap it with a lid; but not yet.

First it wants to trap a victim.

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the larva anchors himself inside

with two protruding hooks...

Sits with just his eyes at the surface...

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and waits.

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then, when the time is right...

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at the foot of colorado's rockies,

the patience of the great sand dune tiger beetle larvae

finally pays off.

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fast food doesn't come much faster.

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it may stay here for a year,

taking down passing ants,

and preparing for a transition into beetlehood.

Unless, of course,

colorado's rockies make other plans.

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the rockies are responsible for these dunes,

but they also water them.

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that seasonal snowmelt from the slopes

makes it all the way to desert central.

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it's unpredictable and sudden.

Not so good for burrowing beetles.

The water swirls around the dunes,

then drains into the plains of the san luis valley.

No more mountain terrain here, just miles of open air...

...And the perfect racetrack

for america's fastest land animal.

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pronghorn have been clocked at almost 60 miles an hour.

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they have no collarbones,

allowing their legs to stretch forward an additional 20%.

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it's a sacrifice for speed

that's left them unable to jump;

but it's been worth the price.

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their ancestors probably had to run

from fast-moving prehistoric cats.

Out here they have slower,

but still formidable predators to worry about.

Coyotes keep close watch.

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the older pronghorns are vulnerable.

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so, too, the injured.

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males may have fearsome, nearly foot-long horns,

but canines usually attack from behind.

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no telling who would come out best in an ambush.

Too risky.

Strike one.

The coyote moves on.

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it's three weeks before newborn fawns

can keep up with the herd.

Until then, they have only one good line of defense: Mom.

Her bulging eyes give her

a near 360-degree field of vision.

She spots the interloper before he sees her.

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she hides her twins in some bushes...

And walks about 70 yards away...

...Within sight of the coyote.

She acts as a decoy.

But did she hide her young well enough?

The coyote knows the game.

But at the base of colorado's rockies,

it could take hours for him to find the hidden fawns.

And he's lost the element of surprise.

Strike two.

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about this time each year, a new option hits the menu.

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the rockies lead to a giant wetland

the size of 11,000 football fields.

Every spring, this basin becomes a super bowl.

(honking)

the players it attracts have some extraordinary moves.

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the monte vista wildlife refuge,

in the middle of the valley,

is a favorite migration rest stop for sandhill cranes.

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they trickle in at first.

(squawking)

(squawking)

then...

...A deluge.

These birds average four feet high,

with a wingspan of more than six feet.

(squawking)

more than 23,000 take over the valley.

It's something they've been doing for millions of years.

And why not?

This marsh has plenty to offer.

Freshwater and loads of seeds and insects to dine on.

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while they're here, they have some serious business to do.

To get this far, many of them bonded into survival groups--

gangs of unrelated cranes

that decided to fly, feed and roost together.

(squawking)

but now it's spring break from all that work.

And they're in the world's best pick-up joint.

Any single sandhill crane

that's between two and seven years old

is probably looking for a mate.

Problem is, how does one stand out in a crowd like this?

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the answer: Duke it out on the dance floor.

You just need some fancy footwork...

A flirty flap...

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...And the right flair.

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it's high-stakes choreography.

(squawking)

when you're picking a mate for life, you want to get it right.

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two lovers lock eyes and take center stage.

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it's a dance that dazzles the crowd.

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the aim is to get in sync with your partner.

No missteps.

(cooing)

it was meant to be.

You may kiss the bride.

(cooing)

(cooing)

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(cooing)

now bonded in the shadow of the rockies,

they're ready to continue north

where they'll work together to build a nest.

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soon, they'll have two eggs.

(squawking)

a month after that, chicks.

(squawking)

and in the fall, they'll pass back through

the san luis valley with the whole family.

And take in their bird's-eye view.

They're one of the few creatures

to get the full picture.

They see the rocky mountains from top to bottom.

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only one other animal in the rockies

comes close to reaching their heights.

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and it is the undisputed king of the mountain.

Safety for the bighorn sheep of colorado's rocky mountains

is about going where predators dare not roam.

These climbing kings have hooves that stick like glue.

And a confidence that has them scaling slopes

and scrambling over loose rock at up to 15 miles per hour.

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summer fills their alpine fields with much to munch on.

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they stack on the weight while they can.

But still spend a third of their day resting.

That's when they must turn rock beds...

Into day beds.

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they arrange themselves to face every direction.

Now they can see danger coming from up to a mile away.

Predators are out there.

Just down at the tree line,

the mountain lion hasn't gone far.

Nor the black bears.

And the bighorn can't stay up here all year round.

Soon they'll have no choice but to overlap territory

with their most fearsome foes.

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fall chills the peaks.

The herd moves lower and hides among the trees.

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they must contend with predators down here,

and now each other.

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the first snow triggers the rut...

...When males fight for females.

A large alpha male stands out; the heavyweight champ.

But rocky has challengers.

Stand back.

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30-pound horns collide at speeds of 20 miles per hour.

Backed by a 300-pound body.

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there's enough power here to crack a young skull.

But the older champ is well built for the battering.

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he has a fully formed double-layered skull

with enlarged sinuses

to cushion his brain from the blows.

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it's not nonstop boxing; more a match of endurance.

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each round may only be five hits across an hour.

But they might go at it for 25 rounds.

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the older male proves once again

that he's the king of the ring.

And he's not done.

He humiliates the loser with a show of dominance.

A soft kick, as he would give one of his cows.

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then an attempt to mount.

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the spurned male won't go far.

He still needs the safety of numbers

to protect him from predators.

He's just got to suck it up.

That's part of being raised up here in the rockies.

From the coldest snow to the hottest sand...

And all its altitudes and diverse terrains

seem to have one thing in common:

Tough love.

Animals out here face challenges daily.

But they keep coming back for more.

Because from these same peaks comes life.

Underwater...

In the trees...

And in open plains.

A rugged oasis

for those who know how to survive...

...In the shadow of the rockies.

(cranes squawking)