[ Birds calling ] ♪ [ Man speaking native language ] Narrator: Patagonia's forests are magical places.

Here, age-old relationships between animals, people, and trees still survive.

These bonds are needed like never before... ...as these ancient forests face unprecedented threats.

♪ At the ends of the Earth is a land of extremes... ...home to spectacular wildlife.

For centuries, people and animals have battled for supremacy.

But now enemies are becoming allies.

Together, they face new challenges... ...in a rapidly changing world.

You are at the mercy of the elements.

Narrator: This is the story of what it takes to survive... ...on the edge of the world.

♪ [ Birds calling ] Patagonia's forests are filled with fascinating wildlife and jaw-dropping vistas... ...unlike anywhere else on Earth.

We're on a journey of discovery through Patagonia's wild woodlands... ...from its northern rainforests to the tip of South America, where the trees have to tough out long, freezing winters.

Forests filled with a host of miraculous creatures... ...many found nowhere else on Earth.

♪ Today, though, these ancient woodlands are under siege, sometimes from surprising threats.

♪ ♪ These are araucarias, Patagonia's most iconic trees.

♪ Because of their intricate branching, they're also known as "monkey puzzles."

Found only in southern South America, they were once far more common.

They're hanging on in a few remote spots, peppered along the slopes of Patagonia's volcanoes in both Chile and Argentina.

♪ Reaching up to 160 feet, these giants are survivors from the Jurassic era more than 145 million years ago.

Distinct spiny leaves evolved as a defense against hungry long-necked dinosaurs.

♪ But today's visitors are less destructive... [ Birds squawking ] ...though they do raise a racket.

[ Squawking continues ] Austral parakeets -- the southernmost species of parrot on Earth.

♪ A restless bunch, they flit from tree to tree in flocks of up to 15 birds.

♪ When they find a good feeding spot, numbers can swell to over 100.

♪ Their preferred way to fatten up for the winter?

Gorging on monkey puzzle pine nuts.

In return, the birds spread the seeds far and wide.

But the parakeets aren't the only ones here for the harvest.

♪ The Mapuche -- indigenous people who have lived here for almost 3,000 years.

They rely on these seeds for food... ...grinding them into flour to make bread.

♪ The Mapuches' unique bond with the trees was almost broken.

For hundreds of years, European colonizers stole their land and forests, stripping them for lumber.

And the devastation continued through the 1990s.

♪ Petrona Pellao watched as homes were torched and many of her relatives fled to neighboring countries.

But she remained to defend her community and the trees.

[ Pellao speaking native language ] ♪ Narrator: In recent decades, the Mapuche battled with loggers and the government, demanding legal protection for the trees.

And they won.

Today, these once besieged monkey puzzle forests are protected by law across Patagonia, to the relief of parrots and humans alike.

But while these giants may yet survive for more millennia... ...one of Patagonia's tiniest creatures could really use a helping hand.

♪ ♪ Narrator: The wild forests of Patagonia... ♪ ...a vast region straddling southern Chile and Argentina.

North to south, it's over 1,000 miles, more than 200 miles longer than California.

And its mountain spine is blanketed by distinct forest kingdoms.

In the north, nestled in a narrow strip between the mountains and the warm waters of the Pacific is the Valdivian rainforest.

Bordered by ice caps, oceans, and deserts, it has been cut off from the outside world for millions of years.

♪ This is the forest that time forgot... ...home to tiny, magical creatures... ♪ ...many found nowhere else on Earth.

♪ Only 13 inches high, say hello to the world's smallest deer... ...the southern pudu.

♪ This miniature mom has her fawn in tow.

They'll stay close for up to a year.

♪ But pudus aren't the only tiny marvels here.

[ Insects chirping ] ♪ This elusive speedster is the monito del monte.

It's a marsupial, raising its young in pouches like koalas and kangaroos.

The monito is the only creature in South America to truly hibernate.

Remarkably, it's lived here virtually unchanged for 60 million years.

♪ Biologist Roberto Nespolo studies animal metabolism.

He first encountered one of these puzzling little creatures at the start of his career.

The monito's ability to survive the winter fascinated him, and he made it his life's work to figure out exactly how they pull it off.

Solve the mystery, and it might just help us to better understand our own metabolism.

♪ Roberto quickly discovered that monitos really know how to pack on the pounds.

[ Nespolo speaking Spanish ] Narrator: Like all monitos, this tiny critter is nocturnal.

To learn its secrets, Roberto and his team leave out baited cage traps overnight.

[ Insects chirping ] This little guy just couldn't resist a free meal.

Now he's ready to be weighed and measured.

[ Nespolo speaking Spanish ] ♪ Narrator: Hibernation has enabled monitos to survive the winters here.

[ Nespolo speaking Spanish ] ♪ Narrator: The truth is the monito's future is looking bleak.

Their forest home is being cut down to make way for farmland.

[ Nespolo speaking Spanish ] ♪ Narrator: But Roberto remains optimistic.

♪ ♪ Just as the monito has Roberto fighting for its protection... ...other creatures also have champions going the extra mile.

♪ ♪ Narrator: Summer in the magnificent ancient Valdivian rainforest.

[ Birds calling ] [ Tapping ] Everyone's making the most of the good weather.

Magellanic woodpeckers... ♪ ...they're South America's largest woodpecker, up to a foot and a half tall.

♪ Dad sports a scarlet hood... ...while mom's feathers are all black.

♪ They're kept busy by their growing chick.

He's beginning to get his own red crest, but his face still has some black feathers.

He has a way to go.

♪ Magellanic woodpecker couples are monogamous, defending their territory and sharing parenting duties for over two years.

The family depends on old-growth forest with plenty of rotting wood teeming with juicy insects and grubs.

♪ ♪ The hungry chick gives it a shot.

Right idea... ...wrong wood.

It's not rotten enough.

♪ Dad shows him how it's done... ...displaying his well-honed technique as he digs out grubs.

♪ ♪ The chick's got a lot to learn before he can fend for himself.

♪ While woodpeckers stand out among the trees, the Valdivian rainforest is a sanctuary for an extraordinary number of smaller, less obvious species... ...many still undiscovered... ♪ ...which attracts intrepid scientists like Isaí Madriz.

Isaí explores extreme environments, searching for some of the Earth's least loved creatures... ...bugs.

♪ His passion began in college when he first looked at one through a microscope.

Madriz: I started seeing how beautiful they were.

A bug could be as beautiful as any mammal you might like.

Narrator: His mission to track down new species has led him to Alerce Andino National Park in Chile.

Madriz: This forest is special because it's considered a biodiversity hotspot.

If you're looking for insects, this is the place to be.

Narrator: Today, Isaí is on the hunt for a bug he's never captured before... ...a primitive crane fly.

It's lived here for millions of years.

Like the monito, it's virtually unchanged since the time of the dinosaurs.

Being nocturnal, the crane fly is tricky to find and even trickier to catch.

Isaí uses a light trap.

A small light bulb on top attracts the night-flying insects, and a fan sucks them in.

♪ ♪ The next morning, he checks the trap, hoping to find a new friend.

Very careful so I don't damage the legs.

Wow.

So beautiful.

Narrator: Isaí has finally caught one of these incredibly rare insects.

Madriz: What makes this species of primitive crane fly that we're after special is it's the largest species of that entire family.

♪ Narrator: Some would assume it's simply a pest, but every creature here in the forest has a part to play.

♪ Isaí sees the crane flies as the forest's cleaning crew.

Their larvae chew up dead trees, helping them to rot and stopping them from damming up the rivers.

He believes these tiny insects may support the whole rainforest.

Madriz: This could have a huge impact in the biodiversity that you see in rivers in this part of the world.

Narrator: Species that play vital roles in the forest are worth seeking out and saving.

Madriz: All the evidence that I am finding doing my fieldwork leads to conservation.

If you don't know what's out there, you cannot preserve those species.

If it's been around for millions of years, that means they're hugely important for this ecosystem.

We just don't know about it yet.

Narrator: Isaí isn't the only one hunting for extraordinary creatures.

Further south, a man is on a mission to see one of Patagonia's most elusive predators.

♪ ♪ Narrator: The vast and magical Valdivian rainforest is home to many fascinating creatures... ...like this peculiar pocket-sized predator -- the kodkod.

♪ They may look cute, but kodkods are ruthless killers... ...often preying on poultry... ...which puts them on the locals' hit list.

Kodkods are now threatened with extinction.

♪ One man has become their defender -- Fernando Vidal.

♪ He's given up his life as a pilot, devoting himself to looking after captured and injured kodkods.

It all started when he was 12 years old and he tried to persuade neighbors not to kill a kodkod raiding their chicken coop.

Little did he know their futures would become so entwined.

♪ Surprisingly little is known about these wild cats.

[ Vidal speaking Spanish ] ♪ Narrator: To try and understand them, Fernando wants to observe kodkods behaving naturally, without fear of persecution.

He's had a tip-off that some cats have been spotted 400 miles to the south in Laguna San Rafael National Park.

♪ He's got five days to try to find them.

But it won't be easy.

Kodkods are so elusive, some call them "the ghosts of the forest."

♪ [ Vidal speaking Spanish ] ♪ Fernando spends the next four days combing the forest for tracks and signs, trying to stay optimistic.

But the tiny cats always seem one step ahead.

♪ ♪ It's Fernando's fifth and final day... ...his last chance to see a kodkod here.

♪ After searching all day, he finds evidence that he's getting close.

[ Vidal speaking Spanish ] ♪ As the evening approaches and hope begins to fade... ♪ ♪ ...it's the rarest of the rare -- a melanistic, or black, kodkod.

♪ ♪ This is almost certainly the first time a melanistic kodkod has been filmed in the wild.

[ Vidal speaking Spanish ] ♪ ♪ Narrator: Though it was just a glimpse, seeing a wild kodkod unafraid of humans gives Fernando hope for the future of these little cats.

♪ ♪ 30 miles to the south, Patagonia's forests are preparing for winter... ...and life for one of its most endangered creatures is about to change... forever.

♪ ♪ Narrator: Though summer's nearly over in Patagonia's mountain forests, temperatures are still pushing 90 degrees Fahrenheit.

[ Bird screeches ] Young pumas are getting older and bolder... ♪ ...honing their climbing skills.

♪ ♪ But their claws are no defense against the season's greatest threat.

♪ [ Thunder rumbles ] The forests are tinder dry.

All it takes... [ Thunder crashes ] ...is a spark.

[ Thunder crashes ] ♪ Devastating fires are all too common in Patagonia's drier forests.

Though lightning starts a few of them, more than 90% are caused by humans, either accidentally or to clear land for grazing.

♪ Every year, tens of thousands of acres of forest are turned to ash.

Fires are even a problem in the colder regions of Patagonia.

At the far end of the continent, majestic southern beech forests stretch for nearly 700 miles down towards the Antarctic.

♪ [ Horses neighing ] ♪ Autumn's here, so deciduous trees prepare for winter... ...drawing back nutrients from their leaves.

The result?

A stunning blanket of color rivaling any tree-scape on Earth.

♪ But this magical display doesn't last long.

[ Wind whistling ] ♪ The first snows of winter have arrived.

For ranger Daniel Velasquez Romero, it's a special time of year.

He used to be a commercial sheep rancher, but his love of nature has led him to a new calling... ...rounding up a very different kind of creature... ...the incredibly rare south Andean deer, the huemul.

Their short legs and stocky build are perfectly adapted for life in upland forests.

♪ Daniel uses radio-tracking collars to follow them over the rough terrain.

They're necessary for their survival.

Poaching and habitat loss have driven huemul to the brink of extinction.

Fewer than 1,500 remain -- just 1% of their former population -- making them one of the rarest mammals on the planet.

At the start of winter, Daniel fits the young huemuls with their first radio-tracking collars.

He's joined by colleague and wildlife veterinarian Cristian Saucedo.

They've both dedicated their lives to a project that is transforming Patagonia.

♪ In a groundbreaking partnership, the governments of Chile and Argentina have teamed up with the charity Tompkins Conservation.

Their mission?

To rewild vast areas of former farmland.

Cristian is in charge of the project, hoping to save the huemul.

[ Saucedo speaking ] ♪ Narrator: To do this... ...Cristian must take drastic measures.

♪ ♪ [ Radio beeps ] This year's fawns need to be darted and sedated.

♪ It may look dramatic, but it's harmless for the deer.

They get a health check and a collar that will help keep them safe.

[ Saucedo speaking ] Narrator: For this new generation of huemuls, life will now be a little safer with Cristian and Daniel watching over them.

♪ But for another of Patagonia's forests, the future is less certain.

In the far south, an unwelcome developer is causing big trouble with deadly consequences.

♪ ♪ Narrator: In Patagonia's far south sits Tierra del Fuego, a rugged collection of islands covering almost 30,000 square miles.

In Karukinka Park, winter's icy grip is tightening.

♪ ♪ Beavers are getting busy.

And their numbers are booming... ...which is a problem, because they're not supposed to be here.

♪ Their relentless chewing is decimating the forests.

♪ ♪ In 1946, just 10 pairs of beavers were imported here from Canada.

The idea was to launch a new fur trade.

No one realized how much damage beavers can do if left unchecked by predators.

Today, more than 100,000 beavers are ravaging Patagonia.

There's no easy solution, as Cristobal Arredondo from the Wildlife Conservation Society is well aware.

[ Arredondo speaking Spanish ] Narrator: Unlike their North American cousins, these trees can't grow new shoots from chewed stumps.

And in waterlogged conditions, they simply drown.

Thousands of acres of trees are dying every year, driving Cristobal and his team to do the unthinkable... ♪ ...exterminate the invaders.

They set up humane but lethal traps.

♪ ♪ Only then can they destroy the beaver dams.

♪ ♪ Finally, the forest waters can flow freely again.

♪ Eradicating the beavers will be tough, but it's important work, not just for this wilderness, but for the planet.

Patagonia's vast forests, like the jungles of the Amazon, trap huge amounts of carbon, helping to fight climate change.

[ Arredondo speaking Spanish ] ♪ Narrator: Only now are we waking up to the importance of protecting Patagonia's forests.

But some have known how vital they are all along.

In the monkey puzzle forests, conservation has been going on unnoticed for generations.

Petrona Pellao and her Mapuche community have been taking care of their trees for hundreds, if not thousands, of years.

[ Pellao speaking native language ] Narrator: The respect the Mapuche show for their trees demonstrates how forests can survive... ...and thrive long into the future.

♪ ♪ Next on "Patagonia: Life on the Edge of the World," we go behind the scenes... Oh!

...and reveal how our crews battle the elements... Oh!

...to film the animals and the people who live in one of the wildest places on Earth.

♪ [ Whispering ] Stay still.

Do not run.