All language subtitles for Earthsounds.S01E02.ATVP.WEB-DL.DDP5.1.H.264-NTb.en[cc]

[Hiddleston] The Himalayas.

The highest mountain range on Earth.

With peaks rising over five miles
into the clouds.

Here, deep canyons create
the world's largest echo chamber...

[bird squawking]

...where the slightest noise
ricochets through the valleys.

[squawking echoes]

For the few extraordinary animals
that live here,

sound is key to their survival.

[footsteps approaching]

A snow leopard.

[leopard sniffing]

The ghost of the mountains,

and the Himalayas'
ultimate stealth hunter.

[huffing]

This male is searching for a meal.

To get close to his prey,

it's vital that he avoids being seen.

But in the silence of the mountains,

it's just as important
that he's not heard either.

- [birds chirping]
- [river burbles]

With prey scattered far and wide,

snow leopards take advantage
of the unique high-altitude soundscape.

[footsteps]

Their hearing is three times
more sensitive than ours.

Allowing them to pick out faint noises
from miles away.

[rustling]

[screeches]

[screech echoes]

And they listen out
for one particular animal.

[rocks tumbling]

[crashing]

Himalayan ibex.

[crashing echoes]

As the hunter closes in,
he switches to stealth mode.

[faint footsteps]

An ambush predator,
he needs to get within just a few feet.

[wind whooshing]

The long fur between the pads of his toes

helps soften his footsteps,
allowing him to sneak closer.

All it takes is one loose rock...

and the ibex will be spooked.

[rocks tumble]

[bird chirping]

Cover blown.

He's forced to attack from a hundred feet.

In the thin mountain air,
every stride uses precious energy.

On the sheer cliffs,
all it takes is one slip...

and the chase is over.

This time, he goes hungry.

But in just a few weeks,
he'll use the mountains echo chamber

for a very different type of pursuit.

Beyond the peaks
lies a whole new soundscape,

where the acoustic rules
are turned upside down.

The Tibetan plateau.

On these flat, featureless planes,

sound doesn't echo around
but dissipates into the cold, dry air.

[growling, huffing]

So up here, you've got to shout
to make yourself heard.

The chiru, perhaps the world's
strangest antelope.

[growls]

Each winter, herds of these curious
creatures gather to breed.

[grunting]

This male guards a harem of ten females.

And to keep them close...

he struts his stuff.

He needs to watch out

as he's not the only male
with mating on his mind.

Rivals are gathering
and fighting amongst themselves.

[huffing, grunting]

The winner will get to challenge
our male for his harem.

So he sends them a blunt reminder
of who's boss.

[growling]

Deep sounds travel further.

So chiru use low, loud growls to broadcast
their warnings for nearly a mile.

[growling continues]

But not every male is intimidated.

[growling]

A rival roars in reply.

It's a direct challenge our male
will have to silence.

And so begins the battle of the bellows.

Possibly the world's worst
singing contest.

[growling]

On most occasions, these growl-offs
are enough to settle any dispute.

But today our male has met
his vocal match.

Now, with his harem at stake,
he must see the intruder off.

Even with little oxygen in the air,
chiru can run at 50 miles an hour.

[grunts]

This time, his rival is all talk.

In the Himalayas,
conditions can change in an instant...

shifting the soundscape.

A fresh fall of snow muffles sound,

making the mountains quieter.

Now, to hear any signs of life,
you must listen even more carefully.

[faint chirping]

Beneath the surface, microphones
pick up the secretive chatter

of one of the Himalayas'
cutest-looking creatures.

[ruffling]

The plateau pika.

These social little mammals
live in family groups around 20 strong.

[squeaking]

They use a repertoire of seven different
calls to keep in touch...

[chattering]

...and to settle disputes with neighbors.

[chattering, squeaking]

But all this chatter
attracts unwanted attention.

[chattering continues]

A Tibetan fox.

Foxes have excellent hearing,
six times more sensitive than our own.

- [rummaging]
- [squeaking]

They're tuned in to high-frequency sounds
like the squeaking of pika.

Honing in, the fox starts to stalk.

Keeping a low profile and moving slowly

to minimize making any noise.

[squeaking continues]

Their ears can rotate independently,

helping them pinpoint the slightest sound...

and creep in close.

[chattering, squeaking]

[rummaging]

This unsuspecting pika
is just inches from the fox's jaws.

[squeaking]

But luckily, pika have a
neighborhood watch scheme like no other.

Their squeaky alarm calls
are highly directional,

helping them pinpoint
where the warning is coming from...

so they can make their escape.

But the wily fox doesn't give up easily.

[pika chattering]

Once back in their burrows,
the pika start chatting again.

[chattering continues]

And the hunter listens in from above.

He starts to dig.

He can burrow three feet into the ground.

Now, it seems the pika
are in serious trouble.

But these smart little mammals
are one step ahead.

Because their tunnels have emergency exits

so they can escape
even the most determined fox.

The pika live to squeak another day.

[squeaking]

In the Himalayas,
the loudest sounds of all...

[rumbling]

...come from the peaks themselves.

Weather fronts collide with mountains,
weakening rock faces.

[tumbling, thudding]

Glaciers groan as they carve deep valleys.

[rumbling]

[ice crackling]

[thundering]

And avalanches thunder down slopes.

[crashing]

Every year,
these peaks get half an inch taller.

The sounds of the world's highest
mountains growing even higher.

[rumbling, crackling]

[birds chirping]

But in the foothills,
one noise can be heard above all others.

[water burbling, splashing]

Fueled by meltwater and monsoon rains,

fast-flowing mountain rivers
charge with white water...

creating a background din
as loud as a jet engine.

[rumbling, crashing]

This drowns out any other sounds
and makes communication a challenge.

But one little bird has found a way
to cut through the chaos.

A Himalayan dipper.

This female is hunting
for aquatic insects...

[chirping]

...to feed her hungry chick.

Even though he's just a few days old,

he's already a whopper
with an appetite to match.

[chirping]

When close by,
they easily call to each other.

But to hunt for food,
Mum must travel far along the river.

And that makes keeping in touch
much harder.

Especially if your chick
is a little clumsy.

[chirping]

He's swallowed up by the torrent
and washed downstream.

When Mum returns,
her chick is nowhere to be seen.

So she produces a high-pitched call.

[chirping]

By blocking out the background noise...
we can tune into it.

The dipper's vocalizations
are way above the range of the water.

A bandwidth that scientists term
"the silent window."

It's their own communication channel
that cuts above the background din

so her chick can still hear her.

[chirping continues]

Even at such a young age, he's already
found his voice and calls back.

High-pitched sounds are easier to locate.

So, from his call alone,
Mum can track him down.

And the pair are reunited.

But for Mum, there's no time to rest.

Of all the sounds in the Himalayas,

there's one special call that's rarer
than any other.

The love song
of the ghost of the mountains.

For two years,
a remote surveillance network

eavesdropped on the highest peaks.

And recorded rare footage
of elusive snow leopards.

Each spring, for a few weeks,
females begin an annual search for a mate.

A seemingly impossible challenge
given the vastness of the mountains.

The first step is to leave a scent trail.

Wandering huge distances,
they mark across their territories

of over a hundred square miles.

And this is what they're hoping for.

A young male.

[sniffing]

As he rolls in the scent,

we can hear his intimate call,
known as a chuffle.

[chuffing]

Having drawn a male close...

the female now switches
from scent to sound.

[bellowing]

Her song can travel for miles.

[bellowing continues]

For a male, it's an irresistible draw.

And just inches from our camera,

his reply is the closest ever recording
of a snow leopard's call.

[bellowing]

[distant bellowing]

Their haunting duet lasts
for just a few minutes.

But it's enough to bring
two solitary cats together.

Having spent most of their lives alone...

this new couple appears a little nervous.

Their tender courtship
is a rarely seen moment.

[chuffing]

Thanks to the mountain's
unique soundscape,

snow leopards are able to find love...

in the vastness of the Himalayas.

[leopards bellowing]

To capture the mountain's rarest call,

the Earthsounds team traveled
to Ladakh in northern India.

At over 15,000 feet.

Where's the chairlift?
They said there'd be a chairlift.

[breathing heavily]

[Hiddleston] They hope to record the sound

of one of the world's
most elusive animals,

the snow leopard.

These secretive big cats only call during
the few weeks of their breeding season.

So being in the right place at
the right time would be a huge challenge.

They'd need the help of expert guide,
Khenrab Phuntsog.

[Phuntsog] The landscape is so vast.

You'll have to be exactly in a place
where they make the call.

Which is very difficult to predict.

[Hiddleston]
Their first task was to find the cats.

Not an easy job
in the world's largest mountain range.

Yeah.

[Hiddleston] But for Khenrab,
these peaks are full of hidden signs

that snow leopards leave behind.

So it went down this way.

- It's very clear, isn't it, in snow?
- Yeah.

[Phuntsog] Good sign that cats are around.

[Hiddleston] But finding the snow leopards
is just the start.

To capture their vocalizations, the team
has to rely on remote camera traps.

Here we're burying it in the ground
with the hope that we'll get the...

one of the snow leopards
walking over the top of it.

[breathes heavily]
And I guess I would just stop about here.

[Guy] Yeah.

[Anderson] And then I'd walk over the top.

- And then there's that tail's trail...
- [Guy] Yeah.

[Anderson] That'd be cool.

[Hiddleston] And to guarantee
they get the sound they've come for,

- Nick has a plan.
- [howling]

Just looking for somewhere to place
this little, uh, remote sound recorder.

This is like a camera trap,
but it's just for the sound.

Dot these around and bug the mountain.

[Hiddleston]
Once everything is set and tested...

It's good. It's okay.

...all the team can do
is head back down the mountain and wait.

- [crew chattering]
- [groans]

[crew members chattering, chuckle]

[Hiddleston] After three weeks, it's time
to check whether they've struck lucky.

- [Guy] Oh, something is coming.
- [footsteps approaching]

[Hiddleston] And the team
get their first glimpse of a snow leopard.

But despite getting closer to these
mysterious cats than they ever imagined...

Nick's sound recordings were silent.

I've been doing this too long
to get too disappointed.

You take the rough with the smooth
when you're camera trapping.

But it is disappointing.

[Hiddleston] Capturing the rarest call in
the Himalayas was never going to be easy.

Maintaining all the traps
would require the equivalent effort

of the crew climbing Everest four times.

Finally, two years later,
Khenrab hits the jackpot.

A male snow leopard triggers the camera.

And as he leaves the shot,
he begins to call.

[leopard bellowing]

The clearest and closest ever recording
of a wild snow leopard call.

[distant bellowing]

The extraordinary love song
of the ghost of the mountains.

- [wind blowing]
- [bird chirps]

- [rocks tumbling]
- [river burbling]

[bird screeches]

[rocks tumbling]

[leopard bellowing]