Original subtitles

♪ ♪

Narrator: The northern andes --

Towering mountains that straddle the equator.

Where bears reign supreme...

... And tiny, jewel-like hummingbirds

Dance in the thinnest of air.

On precipitous slopes, poison frogs piggyback their young.

The rarest monkeys stay one leap ahead of change...

... And life adapts to the dramatic forces

Still shaping these incredible mountains.

These are the tropical andes...

A land of infinite variety...

Unlike anywhere else on earth.

[♪ theme music ♪]

♪ ♪

Narrator: Born from volcanic fire,

The andes are the longest mountain chain on earth.

They snake more than 4,000 miles

Down the entire length of south america.

Their peaks soar to more than 20,000 feet.

Here, in the most northerly part of their range,

They sit firmly in the tropics.

This rare combination of altitude and latitude

Has created a rich -- and unique --

Variety of habitats and species...

... Some of which are seldom seen.

A mother spectacled bear.

♪ ♪

Her cubs were born in a den three months ago.

Now they are out for their first stroll in the páramo --

A high-altitude grassland.

At nearly 16,000 feet the air's so thin,

Most animals would be struggling to breathe.

Yet the cubs have energy to spare.

Spectacled bears are not in fact true bears,

Like polar bears and grizzlies...

They do, however, share a similar interest

In anything edible.

In the páramo, they feed mainly on bromeliads,

But occasionally also dig for food.

Spectacled bears are a type of short-faced bear

That crossed from north to south america,

Around two and a half million years ago.

Today, they are the only bears in south america,

And live only in the northern andes.

They spend much of their time high up in the trees,

Searching for tasty fruit and other edible plant parts.

Unlike their cousins -- the true bears --

Each individual boasts highly distinctive eye markings.

Also distinctive is their climbing ability...

Though getting down can often be harder than going up.

Traveling up and down the mountains

In a constant search for food,

Spectacled bears are always on the move...

Just like the mountains themselves.

♪ ♪

The andes mountains started rising

Around 25 million years ago...

... Becoming a massive range of fold mountains

Along south america's entire western edge.

The range rose rapidly, in a series

Of parallel mountain chains or cordillera.

In the northern andes,

This created a wide variety of different landscapes.

Dry forests grow on the lower coastal slopes,

Lush tropical cloud forests at altitude,

And -- above the treeline -- the grassy páramo.

Rising above it all -- huge volcanoes.

Mount chimborazo is the highest peak in ecuador,

At nearly 21,000 feet.

But its almost-constant cloud cover

Sees it only rarely touched by the sun.

Although chimborazo is currently inactive...

... This sleeping giant is surrounded

By other volcanoes that are very much awake...

... And very angry.

[volcano erupts]

Reventador is one of 200 active volcanoes in ecuador alone.

In the last 500 years it has erupted more than 25 times.

The many volcanoes of the northern andes are still rising,

Pushed upwards by huge tectonic forces,

Just like the mountains around them.

♪ ♪

As they rise, the mountains create new landscapes

For life to try its luck.

Tropical downpours have carved the volcanic slopes

Into exceptionally deep valleys.

The result is a collection of wildly diverse habitats...

Each evolving in its own extraordinary way.

♪ ♪

[buzz of hummingbird wings]

In the ecuadorian cloud forest,

This has led to a dazzling variety

Of one animal in particular...

The hummingbird.

Most hummingbirds depend on a single energy source: Nectar.

They have incredibly fast metabolisms

So need to refuel around every 10 minutes.

There are so many flowers in this cloud forest

That each hummingbird

Needs only a quarter of an acre to survive.

As the andes began to rise, the ancestors of these hummingbirds

Became cut off from one another.

Isolated in the steep valleys,

They evolved into hundreds of different species.

Some, like the marvelous spatule-tail,

Only live in one remote valley in peru.

A female has turned up, to judge a show.

The males are exceptional.

They have just four tail feathers,

Which they manipulate to dramatic effect.

These two are competing to impress the female.

They begin by elaborately wafting their tail feathers...

But this is only the start.

Soon the real dance-off begins.

The question is, has either of them done enough

To win the female's affections?

Sadly... Not this time.

♪ ♪

Each of the hummingbird species found in the tropical andes

Has carved out a tiny niche

That separates it from the surrounding world.

For creatures living higher up the mountains,

The isolation becomes extreme.

Hidden in the high montane forest of peru

Lives one of the rarest monkeys in the world.

Narrator: This is a yellow-tailed woolly monkey.

The species is critically endangered.

Seldom coming to ground, they have a tactile, prehensile tail

That acts like a fifth limb,

Easily supporting their entire body weight.

Luxurious fur offers protection

Against the cool days and chilly nights at up to 9,000 feet.

While they may look solitary,

This is actually an extended family, 14 strong...

... That travels, rests and feeds together.

Fruit is their mainstay.

When that's unavailable, they turn to the lichens

That grow on the branches of mature trees.

Together with other epiphytes -- like orchids and bromeliads --

They form tree-top gardens.

Easy pickings for the woolly monkeys.

Bromeliads are a delicacy for the monkeys.

They're related to pineapples,

But these can grow 65 feet above the ground.

Incredibly, they don't need soil.

Instead they trap all the water and nutrients they need

Between their leaves...

So the base is particularly fleshy and nutritious.

But this bounty may not be here forever...

These monkeys live in a narrow band of high-altitude forest...

A habitat that is being gradually destroyed

By encroaching farmland.

This, combined with a slow rate of reproduction...

... Means that today there may be as few as 250

Yellow-tailed woolly monkeys left in the wild.

But not every animal on these slopes is so hemmed in.

One in particular ranges from the mountain peaks...

... To the forests below.

The mother spectacled bear looks on

As her five-month-old cubs explore an inga tree.

♪ ♪

The tree's seed-pods hang high off the ground,

And are as tough as old leather,

But the seeds themselves are sweet, and rich in minerals.

Spectacled bears spend large parts of the day up a tree,

But the cubs are still a bit wobbly.

Mom is an old hand at climbing...

... And has perfect balance.

She picks the hard-to-reach pods...

... And rips open the packaging for her toddlers below.

Able to roam at all altitudes...

... The bears harvest seasonal food

Up the full height of these mountains...

... Making the most of every habitat.

♪ ♪

In the tropical andes, it's the mountains themselves

That produce the great diversity of life here.

They force moisture-laden air --

That's swept in from the oceans --

To rise abruptly.

As it cools, an almost-permanent shroud of mist

Hangs over the forest, more than 6,000 feet up.

This is the cloud forest.

The abundance of moisture

Has allowed evolution to go into overdrive.

Watered by almost 300 inches of rainfall a year,

The cloud forest is overflowing with plants and animals.

♪ ♪

Many of them are found nowhere else on earth.

And it's mainly thanks to the relentlessly wet conditions.

Hummingbirds use the rain to bathe.

Everything here has adapted to life in the clouds.

The result is a range of creatures

That are endemic to the region.

Among them, this rare caecilian --

A type of limbless amphibian

That exists only in the cloud forests of colombia and ecuador.

♪ ♪

While this abundance of water

May generate life in these mountains,

It is also wearing the mountains away.

The water cascades down the mountains,

Cutting through the hardest volcanic rock...

... Always finding the path of least resistance.

Much of the water passes through waterfalls

Like san raphael in ecuador.

Almost 500 feet high, it's a furious battleground

Between rising rock and falling water.

In the cloud forest, the precipitous terrain

Is as treacherous as it is enchanting.

♪ ♪

Dense vegetation crowds the forest floor,

Hiding the secrets within.

And yet sometimes a secret gets out.

Narrator: In the cloud forest of ecuador, as recently as 2013,

Scientists from the smithsonian institution

Made an amazing discovery:

A small mammal they never knew existed.

There are larger animals like it -- called olingos --

At lower altitudes.

But up at six and a half thousand feet,

The olinguito has evolved into a separate line.

It's so new to science, there is still much we don't know

About this elusive animal.

The olinguito lives on fruit,

And is distantly related to raccoons,

But the rest is a mystery.

Who knows what other living treasures

Are hidden among these high, tropical forests.

♪ ♪

As the isolation increases with altitude,

So too does the specialization required to live here.

The angel trumpet boasts foot-long flowers

That store their precious nectar

Deep within their colorful trumpets.

After all, there are thieves about.

The flower's thick wall is enough

To put off most would-be intruders...

Even though the nectar can clearly be smelled within.

Most animals can't reach the bottom

Of the deep well inside the trumpet...

But then the angel trumpet isn't waiting for just any animal.

It's waiting for a sword-billed hummingbird.

The swordbill's beak is the longest --

Relative to body length --

Of any bird,

Giving it access to the nectar stored deep within the flower.

While feeding, its head gets a dusting of pollen...

Which cross-fertilizes the next flower it visits.

It's a very special relationship,

Their fates as indivisible as a lock and its key.

But there are lock-pickers about.

This bird isn't called the flower piercer for nothing.

Gradually, it cuts through the flower's defenses,

Close to its precious nectaries.

Without offering anything in return,

It steals the sweet liquid, drop by drop.

Robbed of its nectar, the angel trumpet

Is now unlikely to attract a sword-billed hummingbird.

Its prospects for pollination are very slim indeed.

♪ ♪

The great height of the northern andes

Affects the two sides of the mountain range

In dramatically different ways.

While the soaring peaks

Provoke heavy rain on their eastern side,

The winds are wrung dry when they reach the west.

In this rain shadow, water is in scarce supply.

On the interior valleys of the western slopes,

Some trees must drop their leaves

To survive the driest seasons.

Even here, familiar faces still wander,

Making the most of all the different habitats

The mountains have to offer.

Now nearly a year old,

The cubs are still discovering the various treats

That trees can provide.

At the tips of an otherwise barren tree

Grow juicy bromeliads.

But the clay-oven nest of a hornero bird

With the eggs it likely contains

Is even more tempting...

... If only they could reach it.

Almost there.

♪ ♪

Success!

The layers of sun-baked mud spill their clutch of eggs.

It's precious protein... Too valuable to share.

Luckily there's enough to go around,

And the eggs make a valuable addition

To the cubs' already-varied diet.

No matter what the habitat,

It seems spectacled bears are the masters of finding food.

Of course, it helps when almost any food will do.

All the hornero can do is look on

As her treasured eggs become bear food.

Under their mother's guidance,

The cubs might move from forested foothills

To high peaks in a single day.

♪ ♪

These sheer limestone cliffs are dotted with bromeliads,

Each one fully exposed to the elements.

And yet, for one small animal...

They're the perfect place to raise one's young.

The maranon poison frog.

What little rainfall there is gathers

At the base of the bromeliad's stiff leaves...

Creating the perfect birthing pool

For these incredibly rare frogs.

This female is ready to lay...

... But it's the male who will guard the eggs.

After 14 days the tadpoles hatch, but now

They must leave the crowded confines of their bromeliad

And move to their own individual plants.

They're still dependent on dad.

One at a time -- the tadpoles shimmy onto his back.

They still can't breathe air,

So must rely on his moist skin to keep them alive.

Ironic perhaps, given that his skin

Is toxic enough to kill other animals.

One by one, he gives each youngster

A piggyback to a new home in a new bromeliad.

It's dangerous being out in the open like this.

Luckily, they don't have too far to travel...

But they do have a lot of possibilities to choose from.

Wherever they go, the new home must contain

A pool that is deep enough --

With sufficient mosquito larvae and algae --

To sustain each tadpole until it's a juvenile.

♪ ♪

High above the treeline

The diversity of plants and animals quickly thins.

But here, on the alpine moors of the páramo,

Grow the most amazing bromeliads of all.

These are puya raimondii, queen of the andes.

Found at over 13,000 feet,

It takes around a century of growth before they can flower.

Above a starburst of protective leaves,

Flower stalks rise 20 feet into the rarefied air.

Even up here, there's a hummingbird -- the hillstar --

To help pollinate it.

But so urgent is the need for pollination

That it also attracts sierra finches and other birds.

Having waited 100 years,

All the puyas in a group will flower at once

To attract as many birds as possible.

Then... They die.

Despite their long wait,

The millions of seeds they produce might not germinate...

Given how close they are to the icy breath of glaciers.

The cordillera blanca in peru

Is the highest glacier field in the tropics.

Here, almost 700 glaciers extend

Across nearly 300 square miles.

The meltwater trickles down

Through all the habitats of these northern tropical andes,

Making its way west to the pacific ocean...

And east into the amazon.

But climate change is causing the glaciers

To thaw faster than they grow.

At the current rate, they will be gone within 40 years.

♪ ♪

Narrator: High in the páramo grasslands,

A tiny hummingbird has made its home.

Rather than hovering like its lower altitude cousins...

... The hillstar conserves energy

By clinging to the chuquiragua flower

While it drinks its nectar.

This time, it's not just pollen

That the hummingbird taxis to the next flower.

Mites come too...

... Hitching a lift between sources of nectar

On which they too feed.

When the hillstar lands on another flower,

The mites disembark.

Weighing just a tenth of an ounce,

This tiny bird faces a daily battle with the elements.

♪ ♪

Páramo weather, with its chilly winds and intense sunshine,

Can go from spring to winter in a matter of hours.

Each night is a dice with death.

To survive the freezing night,

The hillstar drops its core temperature

Close to that of its surroundings

And enters a temporary state of nocturnal hibernation.

Just before dawn, it starts panting

To generate internal warmth.

But it's not out of the woods yet.

If the hillstar has chosen its roost carefully --

Protected from hard frost and facing east --

It gets an extra boost from the first warming rays of sun.

♪ ♪

Each morning it takes flight is a small triumph.

Most of the animals enclosed within this rocky fortress

Have become specialists,

Adapted to a narrow band of altitudes,

Whether it's the breathless heights of the páramo,

The dank world of the cloud forest,

Or the dry forests in the foothills.

One of the few to have mastered them all...

The ultimate generalist...

Is the spectacled bear.

♪ ♪

To the family of bears,

The berries are an easy source of nutrition.

Unlike some other food sources...

They don't bite back.

The curious bear cubs may have powerful claws...

But they're still learning their limits.

A boa constrictor...

Is a more dangerous challenge.

[hiss]

♪ ♪

The cubs test the water...

And find this food also bites back.

It seems some meals just aren't worth fighting for.

Soon, mom will leave her cubs to fend for themselves...

... To continue learning about

The huge diversity of plants and animals around them...

... As they explore the many habitats

Contained in these incredible mountains.

In the northern andes,

The contrast between the frozen peaks and the equatorial heat

Has created a world like no other.

For 25 million years,

The mountains here have inched higher and higher,

Bringing constant upheaval to the world around them.

These huge changes have given rise

To an extraordinary diversity...

... Of life in the clouds.