Original subtitles

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(TRUMPETING)

(GROWLING)

'Across the planet...'

(ROARING)

'There are giants.

'Creatures that have pushed their bodies to the limits.'

In this series, I'm on a mission to find

some of the biggest animals on the planet

and discover why, in the natural world, size really matters.

'Travelling to Asia...'

Look at the size of that thing.

'The Americas...

'And Africa.'

Whoa! Look at the power! Look, it's got it!

'I'll show the surprising ways animals use bulk to survive...

'And stepping back in time,

'I'll also meet the prehistoric monsters

'that once roamed the Earth.

'Today, many of our big animals are in trouble.

'From plastics in our oceans to climate change...

'It's often the biggest creatures that are hardest hit.

'In this episode, I'm in the Americas,

'from the forests of Alaska to the coasts of Patagonia.

'I'm gonna get up close to the continent's goliaths

'and discover the crucial roles they play

'in maintaining the health of our planet.'

Prepare to meet the big beasts, the last of the giants.

'The backcountry of Montana, USA.

'Home to one of North America's biggest land predators.'

(GROWLING)

'The grizzly.

'Adult males stand up to three metres tall.

'And can use their muscle power to take down prey as big as bison.

'But that's not the only reason these brown bears need to be so big.

'To find out why they've become super-sized,

'I'm going to get as close as I dare.'

Now that is a big, big bear.

Oh, my goodness.

That guy's coming up to me.

Wow.

He's just extraordinary.

Look at those huge canines.

(ROARING)

'The only reason I can get so close

'is because this bear was rescued as a cub and raised by humans.

'But now, he's a fully-grown 16-year-old male in his prime.'

(GROWLING)

I mean, it's only when you get this close

that you understand the magnitude and size of these grizzly bears.

He weighs over half a tonne, and that's pure muscle.

Look at those claws, they're huge.

They can have claws up to eight centimetres long.

And those shoulder muscles mean that grizzly bears

have some of the most powerful front limbs

of any animal on the planet.

They use that strength to excavate their winter dens.

This is great.

So, I can actually see him putting those muscles

and those front legs to good use.

Grizzly bears will move about a tonne of earth make their dens.

'Brown bears spend up to seven

'of the coldest months in hibernation.

'Relying on their fat reserves,

'they can lose a third of their body weight.

'Only by bulking up can they survive the bitterly cold winter.

'That's why grizzlies get so huge.

'But what makes these giants truly astounding

'is the impact their size is having on the world around them.

'And the best place to see this Alaska.

'Home to the largest population of wild grizzles on Earth.

'These coastal bears are at their thinnest

'after a winter in their dens.

'With food scarce, tempers flare.'

(ROARING)

(GROWLING)

'But every year, nature lays on an incredible feast for all.

'Each summer, hundreds of millions of ocean-living salmon

'surge up these glacial rivers to spawn in the gravel beds

'where they themselves were born.

'It's an extraordinary mass migration.

'And for the bears, a calorie-rich super-highway.

'Despite their bulk, grizzlies have a surprising turn of speed.

'Muscular limbs make them quick off the mark.

'They can reach 65 kilometres an hour.

'Driven by an insatiable biological desire to eat known as hyperphagia.

'They can catch as many as 30 salmon a day.

'In six months, they can gain up to 180 kilos

'as they prepare for another winter in hibernation.

'The leftovers from this feast make for rich pickings.

'But surprisingly, it's not just animals that benefit.'

(GROWLING)

'Salmon contain ocean-borne nutrients,

'like nitrogen and phosphorous,

'that are crucial to the life cycle of trees and plants.

'When they fish these rivers on such a scale,

'and when they do what bears do in the woods,

'these grizzles fertilise the forests around them.

By bringing the salmon that they eat up from the seat to the land,

bears are responsible for nearly a quarter

of all the nitrogen in the surrounding forests.

'Because of their big appetites,

'grizzlies are monster muck-spreaders

'that fertilise the soil and enrich their ecosystem.

'But worryingly, outside of Alaska, only 1500 grizzlies remain.

'Throughout history, big animals like bears

'have often struggled to adapt to changing conditions.

'Two million years ago, a much larger ancestor

'of the grizzly reigned throughout the Americas.

'The giant short-faced bear.

'Weighing in at 1,600 kilos...

'It was a powerful meat-eater.

'But when leaner, meaner predators evolved,

'its size was no longer was an advantage,

'and this gigantic bear disappeared from our world.

'The remaining Alaskan grizzlies are having such a profound impact

'that they continue to feed

'part of the largest temperate rainforest in the world.

'But giants are making even greater waves in our oceans.'

'My journey through the Americas to find its biggest creatures

'now takes me south, to the deep waters of the Caribbean.

'There's a giant here whose huge size

'is helping to maintain the health of our oceans.'

The creature I'm on the lookout for is a true sea monster,

a real life Moby Dick that can grow to the size of a double decker bus.

'The sperm whale.

'They're the largest of all the toothed predators

'with the biggest brains in the animal kingdom.

'These deep sea specialists spend most of their lives

'hunting squid in the abyss.

'Tracking sperm whales is a challenge.

'But fortunately, they hold another record.

'They're also the loudest animals on the planet.

'They make booming clicks,

'powerful shockwaves that can be heard up to 10 kilometres away.

'Self-style whale whisperer, Andrew Armour,

'is helping me pinpoint them using an underwater microphone.'

So, we stick this in the water and we spin it around

and wherever we get sounds the loudest

is where the whales are coming from.

Your job now is to listen to the clicks.

Right, let's give it a go. Let's hear from some whales.

'Like an underwater Morse code,

'whales communicate using patterns of clicks known as codas.'

Talk to me.

(CLICKING)

Is it click click, click click click?

Listen to it. (CLICKING)

Yeah, there we go. Click click, click click click.

You've got it. (CLICKING)

That's the Caribbean codas.

We know these are Caribbean whales from that sound.

(CLICKING)

So this coda, this pattern of sounds and clicks that they make,

that's specific? That's unique to Caribbean sperm whales.

Yes. So we know they're homeboys.

(CLICKING)

That's where the whales are,

so we're gonna crank up and get outta here.

Let's go find the whales, Patrick.

'Sperm whales are found in all the oceans of the world

'and new research suggests that each population has its own dialect.

'When it comes to understanding these intelligent creatures,

'we're only just scratching the surface.'

Whale at the surface!

There she goes! There! Oh, yeah, yeah.OK, got her?Yeah.

Five minutes!

'Between dives, sperm whales rest for up to ten minutes.

'They take around 50 breaths to fully re-oxygenate their blood.

'This is my chance to get up close.'

I still don't forget my first time with the sperm whales.

You seem them coming at you and you see that big head

and you feel the clicks.

You could feel it right in your chest, you know?

It's scary.

'Bubbles from scuba gear could spook the whales

'so I've been learning to free dive.

'But nothing can prepare you for this.

'A female, approaching on her side.

'She's over 12 metres long.

'A prehistoric beast that has barely evolved in ten million years.

'Her head alone takes up one third of her body.

'Her nose a powerful natural sonar system

'that allows her to home in on her prey.

'Long, powerful jaws house 50 sharp teeth,

'each weighing over a kilogram.

'I don't wanna get too close.

'But up here on the surface, I'm not her target.

'Sperm whales spend 85 per cent of their lives

'hunting deep in the ocean.

'Their muscles have adapted

'to contain an oxygen-storing protein called myoglobin.

'So the bigger they grow, the more oxygen they can carry,

'which gives them more time to hunt for good.

'That is why size is key to the sperm whale's success.

Oh, wow.

That is one of the most incredible things I've ever seen in my life.

'I was trying my best to keep up with her,

'but she was motoring along.

'And with just one flick of her tail,

'she dove deep into the abyss.

'Sperm whales can reach depths of over two kilometres

'and can stay beneath the surface for up to 80 minutes.

'They are the ultimate free diving champions of the natural world.'

Amazing.

Oh!

'Long dives mean they can satisfy huge appetites.

'Each day, adults eat up to a tonne of fish and squid.

'Globally, it's been shown that sperm whales

'are taking the same amount of fish from our oceans

'as all the world's fisheries.

'But what makes them so important for us all

'is what they do when they surface from this feast.'

I noticed that there was a brown mist that came out at the end.

I think I have an idea of what it was.

Well, that's the poo! (BOTH LAUGHING)

You see a cloud and that's the poo.

That's what the sperm whale's all about.

'Sperm whale faeces is full of iron and nitrogen.

'Once deposited at the surface,

'it feeds great blooms of plant plankton.

'When these microscopic plants photosynthesise,

'they remove harmful carbon dioxide from our atmosphere

'and sink it to the safety of the ocean floor.

'Latest science shows that sperm whales

'are responsible for a 200,000 tonne carbon dump

'in the Southern Ocean alone,

'with extraordinary benefits to our planet.'

Now we must continue to protect these big beasts

and allow them to do what they do best,

diving into the deep and returning to the surface

with nutrients that re-feed the ocean

and play a vital role in the battle against climate change.

'For 300 years, we hunted sperm whales,

'slashing their numbers by two thirds.

'Only now are we beginning to understand

'the amazing ways that some of our biggest beasts

'are helping to protect us all.'

'My journey to meet the biggest beasts of the Americas

'now takes me south to a remote corner of Brazil.

'This 150,000 square kilometre wetland and surrounding plateau

'harbours some seriously super-sized animals.

'The biggest cat in the Americas,

'the floodplain jaguar grows twice as big as others on the continent.

'On the riverbanks, capybara, the world's largest rodents,

'prolific grazers that are top of the menu

'for the gargantuan beast I want to track down.

'This reptile can grow to become as long as a bus

'and as wide as 30 centimetre ruler.

'I'm on the search for

'the biggest snake in the world, the green anaconda.

'The Bodoquena Plateau is one of the last remaining strongholds

'for this giant ambush predator.

'Adult females are the largest, weighing up to a quarter of a tonne.

'Known to live for up to 30 years, they never stop growing,

'regularly shedding their skin

'to accommodate their ever-burgeoning body.

'I'm joining a team of experts

'to find out why the green anaconda is so vital

'to the future of this unique wilderness.

'As we venture up-river, we encounter other giants.

Can you hear that? (GRUNTING)

That is the sound of giant river otters.

They are really elusive.

(GASPS) River otters! (LAUGHS)

'There are only 5,000 giant otters left in the wild.

'Most of them are here.

This is a real treat.

'Nearly two metres from head to tail,

'they are voracious hunters.

'The waterways teem with over 300 different species of fish.

'Giant otters keep their numbers in check

'and allow the nutrient-rich rivers

to sustain a huge diversity of life.'

This is really exciting because if we've got giant river otters here

that means that this entire ecosystem is really, really fertile.

'In this largely untouched wilderness,

'where all species can thrive, and all of life is connected,

'big predators are vital for keeping things in balance.

'Up-river on the plateau,

'we're closing in on the green anaconda.

'The team have fitted a few of these giant snakes with radio tags.

'We're tracking them down to monitor their breeding success.

'This female is about five metres long.

'And she's not alone.

This is just incredible behaviour.

I don't wanna disturb this female

because right now she is in a breeding ball.

There are about three or four males coiled round her body.

'Each dry season, up to 13 males will compete to mate

'with one much larger female.'

(HISSING)

'With tiny spur-like limbs, a relic from their ancient lizard ancestors,

'males vie for her attention and coax her into a position to mate.'

She's just tasting the air.

That forked tongue is picking up all the scent molecules

and so she must be aware of our presence

and she's just writhing back and forward.

'To give her the best chance of mating successfully, we move on.

'Further up-stream, the team get a signal from another female

'they witnessed in a breeding ball several weeks ago.

I think she's in that direction.

(BEEPING)

Yeah, we're getting closer to her.

I can't see her anywhere up on the bank

which is where I'd expect her to be.

So whereabouts is she, Juliana?

We can't see her on the riverbank, so she's probably under the water.

She's in the water?

'To see if she's pregnant, there's no choice but to get in.

'This huge female is at least seven metres long.'

That snake is massive.

And you know what? I think she looks even bigger than normal.

What I thought was a tree trunk was a body of this snake.

I can clearly see a huge bulge, which means that she's pregnant.

'The largest can give birth to up to 50 live young.

'A new generation of big predators bodes well

'for the future of this delicately balanced ecosystem.'

Pfft. That is an incredible beast.

'Today, the green anaconda is the heaviest snake in the world.

'But 16 million years ago,

'far bigger serpents ruled the Americas.

'Fossils were found in a Colombian mine

'of a snake that stretched

'almost one and a half times the length of a London bus.

'The titanoboa weighed over a tonne

'and grew up to a metre wide.

'But it's thought these cold-blooded giants

'failed to adapt to an abrupt change in temperature

'and died out forever.

'The lush waterways of Brazil remain a haven

'for over 4,000 plant and animal species.

'The delicate balance of life is maintained by top predators

'keeping prey populations in check.'

(GROWLING)

'For now, at least, the big beasts of Brazil

'can still act as guardians of their rich and fragile realm.'

'Through the Americas, I've seen how giants are vital for our planet.

'But we're living through a period of unrivalled change

'and history tells us that during these times,

'the biggest animals are often the first to disappear.

'Until recently, South America was home

'to a whole host of colossal creatures.

'Flightless terror birds towered three metres tall.

'Their long beaks could shatter bone.

'The glyptodon was a giant armadillo that grew to the size of a car.

'And huge ground sloths loomed as tall as giraffes.

'But around 11,000 years ago, these lumbering giants

'were unable to adapt to a shift in climate

'and were all driven to extinction.

'Today, the biggest, heaviest creatures left on the continent

'are found on the beaches of Argentina.

'But what makes them extraordinary is how they're working alongside us

'in a race to understand our changing planet.

'Each spring draws huge gatherings of the most bizarre of beasts.

'The southern elephant seal.'

(SQUEAKING)

'It's pupping season.

'Females return to land to give birth and nurse their young.

'In just three weeks, they'll have them weaned

'and be ready to breed again with the dominant male.'

(GROWLING)

'Known as the beachmaster,

'this male has established a harem of over 90 females.

'A four-tonne torpedo of blubber,

'he can be up to ten times the size of the females.

'To ensure his lineage, he must guard them from rival bulls.'

(GROWLING)

'The beachmaster uses his bulk to scare off smaller intruders

'and warning calls that reach 120 decibels.'

(ROARING)

'But sometimes, he faces a far bigger challenge.

'An equally huge bull willing to take him on.

'Only one in ten males on this beach will ever secure the chance to mate.

'The stakes couldn't be higher.

'The beachmaster is defeated.

'He retreats, leaving the stronger bull

'to take over the harem and give rise to a new generation of giants.

'In a few weeks, the breeding season will be over

'and the whole colony will head back out to sea.

'It's in the largely unexplored Southern Ocean

'that these big beasts are using their size

'to join us in a very different fight.

'Elephant seals can travel up to 20,000 kilometres a year

'and dive deep beneath the Antarctic sea ice in search of squid.

'Scientists have fitted them with satellite tags and sensors

'and the data they're helping to gather suggests an ominous trend.

'In recent years, the sea ice has melted faster than ever recorded.

'We're harnessing the power of these huge, ocean-going pioneers

'and working with them to monitor the health of our planet.

'There's something undeniably awe-inspiring about big animals.'

But what connects them all is the crucial role

they play within their ecosystem.

'Across the Americas...'

(GROWLING)

'Big beasts are acting as guardians of their realm.

'In a world where all of life is connected,

'we must live and work alongside them

'and allow their size to help sustain our fragile Earth.'

If we lose our giants, we risk

upsetting the delicate balance that they maintain.

And so it's now more than ever,

with our increasing ability to shape the planet,

that we learn from these big beasts

and protect them for generations to come.

subtitles by Deluxe E-mail sky.subtitles@sky.uk

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