Original subtitles

DAVID ATTENBOROUGH: When you look down on the Earth's surface,

it's impossible not to be impressed

by the sheer grandeur, splendour and power

of the natural world.

It's been ten years since we explored these wonders

in the first series of Manet Earth.

And since then, much has changed.

We can now show life on our planet

in entirely new ways,

bring you closer to animals than ever before,

and reveal new wildlife dramas for the very first time.

(GROWLING)

But that is not all.

The planet has changed, too.

Never have our wildernesses been as fragile

and as precious as they are today.

At this crucial time for the natural world,

we will journey to every corner of the globe

to explore the greatest treasures of our living planet,

and reveal the extreme lengths animals go to to survive.

Finally, we will explore our cities

to see how life is adapting to the newest habitat on Earth.

This is Planet Earth II.

(THEME MUSIC PLAYING)

There are hundreds of thousands of islands,

each one a world in miniature.

A microcosm of our living planet.

The struggles to survive on these remote lands

reflect the challenges faced by all life on Earth.

The tiny island of Escudo off the coast of Panama,

home to the pygmy three-teed sloth.

This is a male, and life here suits him well.

Mangroves provide all the leaves he can eat

and there are no predators to worry him.

Island life may seem idyllic,

but it comes at a price.

There are only a few hundred pygmy sloths in existence,

and he needs a mate.

RILL CALL)

That's an enticing call...

(CALL CONTINUES)

...from a female

somewhere out there.

And this, for a sloth, is a quick reaction.

(CALL CONTINUES)

The problem is there's deep water between them.

So what should any red-blooded sloth do?

Swim, of course.

Could this be her?

He does his best to put on a turn of speed.

But she's not the one.

She already has a baby

and she won't mate again until it leaves her

in about six months' time.

Even life on a paradise island can have its limitations.

(CALL CONTINUES)

But at least she can't be far away.

The world's entire population of pygmy sloths

is isolated on a speck of land no bigger than New York's Central Park.

The size of an island has a huge influence

on the fate of those cast away there.

The island of Komodo in Indonesia.

Home to dragons.

Three metres long and weighing a massive 70 kilos,

these are the largest living lizards on the planet.

It's unusual to find large predators on islands.

Yet, for four million years, the Komodo dragon has dominated here.

It might seem there wouldn't be enough food

to support such giants on this relatively small island,

but reptiles, being cold-blooded,

need only about a tenth of the food a carnivorous mammal would.

A single meal will last a dragon a month.

They're so successful, that their only serious competition

comes from others of their own kind,

and there are some 2,000 of them here.

This giant, however, isn't looking for food.

He's looking for a mate.

Female dragons come into season only once a year.

She is receptive.

So far, so good.

But he strayed into someone else's patch.

Another huge male thinks he is the king here.

Space being limited on islands, dragon territories overlap,

and that creates continual conflict.

In dragon society, size is everything.

But if rivals are closely matched, the outcome can be uncertain.

Muscular tails strike with the power of sledgehammers.

And their serrated teeth are as sharp as steak knives.

Each tries to topple his opponent.

Defeated.

Only the most powerful dragons win the right to mate.

(FLY BUZZING)

(SNORTING)

The limited food and space on the small islands

can often lead to intense competition.

But some islands are immense.

More like miniature continents.

And these provide opportunities for life to experiment and evolve.

Madagascar is one of the biggest islands

and also one of the oldest,

having split away from Africa over 120 million years ago.

With time and isolation, its animals have adapted

to take advantage of every available niche.

The island now has some 250,000 different species,

most found nowhere else on Earth.

These are not monkeys, but lemurs.

From a single ancestor, about a hundred different types have evolved.

The largest, the Indri, seldom comes down from the branches.

The much smaller ring-tails wander in troops across the forest floor

searching for fruit.

And tiny bamboo lemurs eat nothing except bamboo.

With few competitors,

lemurs have been free to colonise almost every environment on the island,

even the most extreme.

This baby sifaka has a hard life ahead of it.

He's been born in the most arid and hostile corner

of Madagascar's vast landscape.

If he is to survive here, he has much to learn.

The spiny forest is like a desert.

It rarely rains, so water and food is very hard to find.

Moving from tree to tree is a perilous business.

Here, nearly all the plants are covered with ferocious spines.

His mother searches the treetops for the youngest leaves.

They provide the only food and water to sustain the family.

At three months old, the youngster is starting to explore.

All too soon, he will have to fend for himself up here.

But it's altogether easier to stay on Mother's back.

If he can master the strange ways of this forest,

he will have a little corner of Madagascar to himself.

Island life encourages animals to do things differently,

and on some islands, that is essential.

(VIOLENT RUMBLING)

There are islands still forming today

built by volcanoes.

Some erupt explosively,

others pour out rivers of molten rock,

lava.

In the last 50 years,

ten new volcanic islands have been formed.

Newly created and often remote, they're hard for colonists to reach.

Even those that do, find these are tough places to survive.

This is Fernandina,

one of the Galapagos Islands in the Pacific.

Young and still volcanically active, it's a desolate place.

The surrounding sea, however, is particularly rich with life,

and the frontier between these two very different worlds

is the home of one of the strangest of reptiles,

sea-going iguanas.

They are vegetarians,

but since there's little food for them on the land,

marine iguanas graze on the sea floor.

A big male like this one can dive to 30 metres

and hold his breath for half an hour.

There are more than 7,000 individuals on Fernandina alone.

And by bringing nutrients from the sea to the land,

the iguanas help other animals to survive here, too.

Crabs feed on dead skin on the iguanas' back

and, in turn, provide a welcome exfoliation service.

(FLIES BUZZING)

While smaller lizards prey on the flies that pester the colony.

But not all the relationships on this island are so harmonious.

Marine iguanas lay their eggs in sand.

In June, when the hatchlings emerge, they're vulnerable.

They must join the adults at the edge of the sea.

But the journey will be a dangerous one.

Racer snakes.

The snakes missed their chance.

But more babies are hatching.

And now the snakes are on the alert.

This is the best feeding opportunity they will get all year.

On flat ground a baby iguana can outrun a racer snake.

But others are waiting in ambush.

Another hatchling has its first glimpse of a dangerous world.

A snake's eyes aren't very good, but they can detect movement.

So if the hatchling keeps its nerve, it may just avoid detection.

A near miraculous escape.

The lucky survivors

can begin learning the unique way of life

demanded by this hostile island.

Although marine iguanas are expert swimmers,

they can't cross open oceans.

But even the stormiest waters

are no barrier for birds.

Gale force winds and cold temperatures

make the subantarctic islands off New Zealand

particularly unwelcoming in winter.

But when the brief summer comes, temperatures rise and winds slacken.

It's now that visitors arrive.

All here to breed before winter returns.

There's the Snares penguins.

Shearwaters come, too.

This is an excellent place for them to dig their nesting burrows,

for no predators have managed to get here.

Soon the island is crowded with birds.

Every one of them eager to make the most of the short breeding season.

But not everyone has a partner.

A male Buller's albatross waits for his mate.

Each year they spend six months apart, travelling the ocean.

They reunite here to breed.

But this year, she's late.

No, that's not her.

The other birds come and go.

The clock is ticking.

If she doesn't appear soon, it will be too late for them to breed successfully.

Every morning the shearwaters fly off to collect food for their young.

(HOOTING)

(CHIRPING)

Everybody else seems to be getting on with it.

The shearwaters' return marks another lost day.

There are three million birds on the island,

but only one matters to him.

Could this be her?

At last.

(SQUAWKING)

At first, he's a little coy.

(SQUAWKING)

But not for long.

They greet each other with the special dance

they've perfected over many years.

There is much to do, if they're to raise a chick before winter returns.

But when you've been apart for six months,

some things can't be rushed.

Islands in warm tropical waters don't experience seasonal extremes.

The Seychelles, lying off the coast of East Africa,

provide a sanctuary for seabirds all the year round.

(BIRDS CHIRPING AND SCREECHING)

Fairy terns are permanent residents.

They take a fairly relaxed view about what constitutes a nest.

A bare branch is quite enough.

Climbing onto it to incubate has to be done with care.

Once a year, the noddies arrive.

They do make nests, and Pisonia trees

provide their young with a rather less precarious start in life.

Nesting on this island looks idyllic,

but behind the beauty there's a sinister side.

The Seychelles fody makes quick work of an unattended egg.

She knows something's not quite right,

but her drive to incubate is strong.

The noddies, too, have a problem.

As their chicks grow,

so the Pisonia tree develops seeds that are sticky

and equipped with hooks.

By the time the young noddies leave

they carry these hitchhiking seeds away to other islands.

But sometimes the Pisonia trees are too successful.

If a fledgling testing out its wings drops to the ground,

it can get covered with the seeds.

Entangled and weighed down,

if it can't free itself, the youngster will starve.

The Pisonia may have failed to disperse these seeds,

but it will soon have fertiliser for its roots.

This is why some people call the Pisonia the "bird catcher tree".

(SQUAWKING)

The Fairy tern laid another egg,

and now she has a tiny chick to feed.

This chick is lucky.

By the time it fledges, the Pisonia seeds will have dispersed

and the danger they brought will be gone.

Even the most idyllic looking of islands

presents challenges for the animals living there.

But the greatest threat they face is change.

Christmas Island in the Indian Ocean.

For millions of years this remote speck of land has been ruled by crabs.

Their ancestors came from the sea,

but most have now adopted a land-based existence.

Given there are so many of them, they get along relatively harmoniously.

They're the gardeners and caretakers of a tiny crab utopia.

Once a year, they must all return to the sea to breed,

and the march of the red crabs

is one of the greatest natural spectacles on Earth.

There are 50 million of them.

It's an event that has brought the island worldwide fame.

But in recent years,

millions of red crabs haven't managed to reach the sea.

An invader has occupied this island.

Yellow crazy ants.

They escape from visiting ships, and with no predators

to control them, they have now created vast

super colonies in the forest.

When migrating red crabs march into their territory,

the ants attack,

squirting acid into the crabs' eyes and mouths.

The crabs have no defence.

Blinded and confused, they're doomed.

Humans brought these ant invaders here

and now humans are having to control them.

Isolated communities may evolve for millions of years in relative peace,

but when new challenges arrive, they can struggle to cope.

Of all the species that have become extinct in recent years,

around 80% have been islanders.

Our impact on the Earth is greater today than ever before.

Yet some islands are so remote,

that few humans have even set foot on them.

Zavodovski Island is one.

It lies in the great Southern Ocean.

It's not only surrounded by the stormiest of seas,

it is itself an active volcano.

It's the last place on Earth you'd choose to live.

Unless you're a chinstrap penguin.

There's plenty of food in these waters, but to exploit it,

the penguins have to risk their lives.

Life here is dangerous in the extreme.

(PENGUINS CHATTERING)

But there are some benefits from living on a volcano.

Its warmth melts the snow early in the year

and by January, the Antarctic's mid-summer,

the island is covered in chicks.

(CHIRPING)

Parents take turns at guarding them

until they're large enough to be left alone.

This mother's chicks are hungry, but she has no food left to give them.

Their survival depends on their father returning with their next meal.

But some don't make it.

Skuas harass the colony hoping to snatch a chick.

(SKUA HONKING)

She can't risk leaving them.

Everything will be fine as long as their father comes back soon.

He's been fishing 80 kilometres offshore,

but now, he's not far away.

For him, however, and for all the other parents here,

the worst of the journey is still to come.

Tiny claws help him to get whatever grip he can on the rough lava.

For these commuters, it's rush hour.

Some have had a really bad day.

The father now has a three-kilometre walk to the nest,

and a stomach loaded with food doesn't help.

This is the largest penguin colony in the world.

(PENGUINS CHATTERING)

But as he makes the same journey every other day,

he should be able to do it with his eyes closed.

It's true that there can be safety in numbers,

but numbers can also be something of a problem

when you're trying to find your own nest.

The mother is still waiting.

Her chicks are now desperate.

(CHICKS CHIRPING)

In the midst of all this deafening chorus,

he can recognise her particular cry.

(CRYING OUT)

At last.

Both chicks will get a meal.

With a head bob of acknowledgement, their mother now leaves.

It's her turn to do the feeding run.

This formidable commute is the price these penguins pay for sanctuary.

A strange vision of paradise to us, perhaps,

but for one and a half million penguins,

this island has it all.

Islands may seem remote and insignificant,

but they are home to some of the most precious wildlife on Earth.

Next time,

we ascend into the planet's high mountains

to discover a spectacular but hostile world

where life must be at its most resourceful,

and only the toughest animals can endure.

(THEME MUSIC PLAYING)