Original subtitles

The Echo Toll THE EQUATER!

It runs across the scorched plains of East Africa.

This is as far from the poles as you can get.

But ice and snow are here too, up in the mountains.

Every continent on Earth has such high snowfields.

And each has its own community of animals that have adapted

in their own way to the crushing conditions that come with

the cold.

Dawn in East Africa, on the high slopes of Mount Kenya, 4 ,000 metres up.

The temperature is just beginning to creep above freezing.

It's hardly the place where you would expect to find a cold -blooded reptile.

But there is one that lives up here, the high cask

chameleon. This female has survived the night's freezing

temperatures by allowing both her metabolism

and her heart rate to drop significantly.

Now, in the morning, she needs to eat.

But it's so cold, she can't move her legs.

Her spring-loaded tongue, however, still works.

As the sun rises higher in the sky, frozen land begins to

thaw and the giant lobelias spread their leaves to soak up

the sunshine.

With her body temperature still only 5 degrees Celsius, the

chameleon becomes more mobile and climbs up to bask in the

sun.

Her skin darkens, enabling her to absorb the sun's heat more

quickly. She is pregnant, and soon her temperature reaches

20 degrees Celsius, which gives her the energy she needs to give birth.

Most chameleon species lay eggs, but here it's too cold for

an egg to develop in the open. So she produces live young.

It takes just an hour for her to give birth to six baby chameleons.

One of the advantages of life on the frozen peaks is that

there are fewer predators here, and less competition for

food. But there's a reason why comparatively few reptiles

live in the high mountains. As the sun sets, the temperature

falls to below zero in a matter of minutes.

The babies must act fast.

To escape the nightly freeze, they need the cover of thick vegetation.

A young chameleon caught out in the cold will

quickly lose its ability to move and may well die.

Most, however, react instinctively and find shelter as quickly as they can.

Peaks on the equator, such as Mount Kenya, are

frostbound for only a few hours each night.

But north of the equator, in the 750-mile long

European Alps, the cold endures for months.

The high mountains are continuously frozen for half the year.

A testing time for the Alps' greatest aerial predator.

The golden eagle.

In winter, there is just enough prey up here, dead or alive, to sustain them.

But when spring arrives, the mountains are transformed.

For a male and his lifelong partner, the need to find food is urgent.

They have a three-week-old chick.

It needs to be fed several times a day.

To do that, both parents have to hunt.

Yet, even in spring, few animals live up here in

the high mountains. And finding prey is not easy.

But chamois, a kind of mountain goat, are here and they are giving birth.

One of their kids can weigh as much as an eagle. When

eagle's hunters appear, they coordinate their approach.

One scoops,

reaching a speed of over 150 miles an hour.

Its attack scatters the herd.

And that makes it easier for the other to select a target.

A successful catch.

It could still be alive.

So the eagle carries it away, high over the gorge.

And then deliberately drops it.

The impact will kill it instantly.

A chick can eat up to a third of its own body weight in a day.

Parents can't afford to rest for long. Taking advantage

of the long summer days, eagles hunt ceaselessly.

Day in, day out.

After eight weeks, a chick is almost fully grown.

And then, as summer comes to an end, the pressure

on parents to feed their chicks disappears.

Their young have flown the nest.

And just in time. The worsening weather signals

that the leaner times of winter are on their way.

Finding prey has now got much harder.

The young chamois have also grown up.

A juvenile now weighs almost five times as much as an eagle.

Animals of this size are no longer easy prey for the birds.

They barely flinch under attack.

But it's dangerous for a chamois to stray close to a cliff edge.

The eagles seize their chance.

Got it! The eagle drags the chamois towards the edge.

It's an extremely risky move. If the eagle breaks a wing, it will be fatal.

A kill this size will feed a pair for days.

This is when they must build up the fat reserves that they

will need to sustain themselves through the lean months that

lie ahead.

Winters in the Alps are daunting. But in other

mountain ranges, the challenges are even harder.

In the Far East, warm, wet winds blow in across the Sea of Japan.

As they meet the 3,000-meter-high Japanese Alps, they're forced upwards.

As the moist air rises, it freezes.

And the water droplets they carry turn into snow.

No two snow crystals are exactly the same.

In the mountains of Japan, 13 meters of snow can fall

in just a few months. It's the snowiest place on Earth.

To survive here, an animal needs all the help it can get.

In winter, Japanese macaques can live at altitudes of up

to 1,500 meters, higher than almost any other primate. But

here, warm volcanic pools are always ready and waiting.

A nice hot bath lowers stress hormones for them, just as it does for us.

Admission to this spa, however, is tightly controlled.

The high-ranking females dictate who is allowed in, and

who will be left out in the cold.

This three-year-old male has recently been expelled from his troop.

He's hungry. Macaques are largely vegetarian. In the winter,

when food of any kind is scarce, they will tackle anything

remotely edible. However, a lone young male is unlikely

to survive much longer unless he can find a way of keeping

warm.

And to do so, he may have to travel through up to 50 miles of empty forest.

Bare hands and feet can become painfully cold.

Rubbing them helps restore the circulation.

Frostbite could be

fatal.

Young male Macaques are most likely to die

in their first winter than at any other time.

But just like him, here is another young male outcast.

Offering to groom is a standard way of establishing a relationship.

And the stranger's warm embrace is very welcome.

By huddling together, they shield each other from the

snow, and both their temperatures rise. Just a little.

This could be enough to save the lives of both of them.

Snow on lower mountain slopes can be a major

challenge for any of the animals that live there.

On the high peaks, however, really heavy snowfalls can be lethal.

The Rockies in North America.

They rise to heights of over 4,400 meters.

In the winter, the winds blowing across the high summits can

create snowy overhangs, cornices, up to 10 meters thick and

weighing many tons. In the spring, as the

temperatures rise, the cornices may become unstable.

And that can be catastrophic.

As it crumbles

downwards, it accelerates to speeds of 100 miles an hour or more.

Only a racer drone camera can follow its course.

In just two minutes, up to a million tons of snow. Turtle down the mountainside.

Avalanches can be hugely destructive, and climate

change is making them more and more unpredictable.

In the South Pacific, on the islands of New Zealand,

one highly intelligent creature has learned how to take

advantage of the volatile nature of mountains.

The Kea.

A species of parrot.

It's the only one of its family that can live above the

snow line, and the only one that actively looks for meat.

The carcass of a mountain goat.

This adult male Kea has a razor sharp beak, which is well suited for butchery.

Flesh rich in calories will help him through the winter.

But he doesn't have it for himself for long.

A gang of juvenile Keas.

These younger Keas shadow the older, more experienced

adults. To learn the tricks of mountain survival.

And where to find food. But while waiting their turn, there's time to play.

There's a benefit to this apparently carefree behavior.

It helps establish long lasting relationships between the

youngsters.

And even diffuses tension.

So that when one Kea finds a rare but

substantial meal, it often willingly shares it.

And that is very important behavior,

particularly in winter when food is so scarce.

In larger mountain chains, the quest for food can become

even more demanding. The Andes in South America. The longest

range on earth. It stretches for over 4500 miles down towards the Antarctic.

At its southernmost end, the sun remains so low in the sky

that it brings little warmth and temperatures regularly drop

below freezing.

In winter, the land is shrouded in darkness for almost 15 hours a day.

Here, a predator has to hunt when it's so dark that only a

thermal camera can make its activities visible to our eyes.

The puma.

This one year old female faces a daunting prospect.

She has just left her mother and become

independent at the most demanding time of the year.

When prey is at its most scarce.

The only substantial targets are a kind of llama.

An adult stands one and a half meters tall and is twice the puma's weight.

This female, however, has one advantage. Excellent night vision.

If the youngster can get within five meters of a huanaco, she has a chance of success.

But the huanaco do have a very acute sense of smell.

And excellent hearing.

After six hours of patient stalking from downwind.

The puma is finally within striking distance.

The puma. The puma.

A wasted opportunity.

Three failed attempts in one night. Have drained her reserves.

Her inexperience is leaving her close to starvation.

Another faint scent.

But it's leading this youngster into the territory of another puma.

Her neighbor, a female, is older and more experienced

than she is. And has already made a successful kill.

The younger female must approach with

caution. Adult pumas are solitary by nature.

And don't normally welcome rivals.

She falls back in the gesture of submission.

But if she doesn't eat within the next few days, she's unlikely to survive.

The larger female is now no longer actively feeding. So she makes another approach.

The puma.

At last, the owner ignores her. Pumas are

the only solitary big cat known to share a meal with a neighbor.

Maybe the young puma, with the help of its neighbor, will

after all survive her first winter. And maybe the older cat

one day will be in need of a favor returned.

The lower slopes of the Andes are harsh.

But climb higher and the mountains become otherworldly.

Their altitude prevents rain clouds from blowing in from the east.

Whilst another lower range, nearer the west coast, prevents

rain coming in from the Pacific Ocean. This creates between

them one of the driest high altitude deserts on Earth. The Atacama.

There is nonetheless a lake here. A volcanic one that

is filled with extremely salty water from underground.

And this attracts flamingos.

They come here each summer.

And here they nest and raise their young,

taking advantage of the lake's plentiful algae.

But with the arrival of winter, temperatures

at night drop to below freezing.

Conditions that even these hardy birds cannot endure for long.

The adults start to leave and head for

warmer temperatures lower down the mountain.

But they leave behind their four-month-old chicks, which are

old enough to feed themselves, but not yet strong enough to

fly.

With each passing night, temperatures continue to fall.

And then, one morning, after a particularly cold

night, the chicks find themselves surrounded by ice.

Huddling together allows some to preserve precious body heat.

But those on the outside are left even more exposed.

And some have already succumbed to the freezing conditions.

The salty ice is now so cold that it congeals on the chicks' feathers. Way down,

their chances of flying are even more remote.

Now, 40-mile-an-hour winds whip across the

lake, driving down temperatures even further.

Yet this very wind that could kill them might just be their savior.

The youngsters turn to face it.

If they can catch it just right, it could give them

the lift they need to take their very first flight.

For those encumbered with heavy loads, the chicks are ready

to fly. With loads of ice, the struggle is almost too much.

Freedom at last.

Many animals that live amongst the frozen peaks have over

thousands of years become adapted to meet the challenges of

a high-altitude existence.

But now, their world is changing because of global warming.

Ice that has remained frozen deep within mountain glaciers is starting to

melt,

accelerating their movement.

Over the three years that it took to film this film, it's

been a long journey. In the ice series, the Kelkaya ice cap,

five and a half thousand meters up in the Peruvian

Andes, has receded by a staggering 60 meters.

In Europe, some Alpine glaciers are now shrinking by a hundred meters a year.

One of them, the St. Annaphyon glacier in

Switzerland, has almost completely disappeared.

Most of the others are expected to have followed it by the turn of the century.

The warming of the frozen slopes could threaten the life

of perhaps the most famous mountain resident of all.

Hidden within the bamboo forests of western

China is a hot and bothered male giant panda.

He has spent the winter sheltering lower down the valley.

Now, it's early summer, and his thick coat that protected

him throughout the winter has become very uncomfortable.

He needs to reach the cold of the higher slopes.

But before he can start the ascent, he needs a good

meal to give him the necessary energy. Giant pandas

eat almost nothing except bamboo.

But bamboo is so low in calories that he needs to spend ten hours a day eating.

With breakfast over, he begins his climb to higher ground.

But in no time at all, he's hungry again.

This is going to be a long journey.

And it may be an even longer one in the near future.

As climate change raises the temperature in these mountains,

giant pandas may well need to climb higher and higher to

find cooler conditions.

But the cold-loving bamboo they most favor cannot move

so easily and may disappear from the warmer, lower slopes

altogether.

So far, these snow-covered peaks continue to provide this

male with enough space to feed and find a mate. So he scent

marks his territory, panda style, with a hand sand.

It may well be that in the next few decades,

the mountains of the world will warm.

Should that happen, many species will inevitably disappear.

But we should never forget the versatility and endurance

of the animals that have succeeded in colonizing these icy

islands in the sky.

In the frozen peaks, the team's greatest challenge was to

film a successful puma hunt at night for the first time.

The crew traveled to Patagonia in the depths of winter

to Torres del Paine, home to over 200 pumas, the highest

density on Earth.

Still to find them in this remote wilderness, greater than

the size of London, they joined the local puma expert Diego

Araya, who has over 20 years' experience of tracking these

big cats. This is something completely new for us because

we've never been actually in pitch black following cats. And

being able to keep up with it on foot, I think is going to

be an incredible task. This vast south at the tip of South

America, winter only gives them nine hours of daylight to

find the pumas before night descends. But it's

not long until they're treated to a surprise encounter.

Definitely we are not part of the menu. Getting this close

to a wild puma is a rare privilege for camerawoman Helen

Hobin. It's very surreal actually, being in real life.

By day, these well-studded pumas are approachable.

But as dusk descends, they pick up the pace as they switch to hunting mode.

We're just going into the pitch black pretty soon and have

to rely on thermal the rest of the night. Armed with a state

-of-the-art thermal imaging camera and spotting scopes,

they attempt to follow the puma in the pitch black. Cats are

moving so fast at the moment and they can cover miles. It's

quite hard to keep up with all of our equipment. Not really

being able to see where you're going.

A few hours later and the pumas have given them the runaround. Do you see her?

Yeah, I think I've got eyes on her. Where is she?

I feel like we had a puma that we all lost somehow. But I'm

pretty sure we've been standing here staring at a bush with

a hair in it.

As weeks pass, the crew experience the full force of the

Patagonian winter. A hundred miles an hour gusts of wind and

blizzard conditions. Just one thing after another at the moment.

Finally, with a break in the weather, their persistence pays

off. The situation is that we found a puma and there's a

group of Wanakos. This could be the break the team need and

offer them the opportunity to film a night hunt. To optimize

their chances, Helen launches her secret weapon.

A thermal camera drone that will act as their eyes in

the sky. Guiding the ground crew to within 20 meters of a

hunting big cat. It's pitch black. There's a puma. It's a little bit on the left.

She's off.

She was so close to that one to start. She just didn't quite

reach it. It's like that close. Super frustrating because

now we get to walk many more miles. Over the coming nights,

the team continues to follow the young puma as she attempts

hunt after hunt. It's just a roller coaster all the time.

Something looks like it's going to happen. Your adrenaline

gets pumping trying to get the shot and then just.

Last count. How many failed attempts? Too many.

With only a week left to film a successful night hunt, the

pressure is mounting on the crew. We're still struggling to

get the key behavior we're looking for.

But then the young female does something truly remarkable.

She didn't manage to make a kill, but she came across

another cat that has. She's been slowly over the course of

the last, I don't know how long, I think it's been hours

creeping towards her really submissively trying to ask for a

bit of food.

It's quite the experience when you're standing in their

proximity and you can't see them, but you can just hear the

crunching of the bones.

This is so amazing to see. You can hear it going all around as well with the growl.

Until recently, pumas were considered solitary animals.

But the crew's success with the thermal camera reveals two

unrelated cats sharing the same kill at night.

You realize how far they are from solitary individuals.

This is like a fellowship of creatures living in the same

territory.

New technology has shed light on the surprising

survival strategy of the Andean puma.

Just one of the many mysterious animals that

inhabit our planet's remote, frozen peaks.

Thanks for watching!