01x01 - Coasts

[bunniefuu]

Almost 200 years ago,

whilst walking these very paths

in the English countryside

and observing the banks and meadows

near his home,

Charles Darwin developed

his ground-breaking ideas

about evolution,

casting a new light

on the natural world

and opening our eyes

to its true wonder.

Since then, we've explored

almost every part of the planet

and seen nature in its

astounding variety.

But there's still much to discover.

In this new series

of Planet Earth

..we travel to the most astonishing

wild places

..see mysterious creatures

..witness spectacular wonders

..and reveal breathtaking

animal dramas.

The natural world

continues to surprise us.

But since Darwin's time,

it has changed beyond recognition

..transformed by a powerful force.

Us.

We will see how animals are adapting

in extraordinary ways

to survive the new challenges

they face.

At this crucial time in our history,

we must now look at the world

through a new lens.

This is Planet Earth III.

Tasmania, Shipstern's Bluff

..where two worlds collide.

These waves have crossed more than

1,000 miles of open ocean

..building in strength.

It's here that they meet

their expl*sive end.

Coasts are dangerous

and dynamic frontiers.

To succeed here,

life must adapt to constant change.

South Africa's Robberg Peninsula.

Thousands of Cape fur seals

gather here to breed.

This pup was born

into a crowded world.

But now, at nearly a year old,

he can escape to the water.

He just has to get there.

There is no question

as to where this pup belongs.

In the water, he's fast and agile.

And he needs to be.

The rolling surf conceals

life-threatening dangers.

A great white shark.

This young pup

has had a very lucky escape.

Here on Africa's southern coast,

seals risk their lives

every time they set out to eat.

Powerful ocean currents

attract huge shoals of fish.

But in recent years,

this stretch has attracted increased

numbers of great whites too.

The great whites are shrewd hunters

and use whatever cover is available.

This shark won't need to eat

for another few days.

But he's not alone.

These usually solitary hunters

are gathering in

unprecedented numbers.

A dozen at a time.

The seals are nimble

..but great whites are patient

..and have expl*sive acceleration

..hitting top speed with just

five swipes of their tails.

Cornered

..the seals keep close

to the jagged cliffs.

They are trapped.

But as the great whites

move in for the k*ll

..the seals do something

astonishing.

Together

..they turn on their enemy.

As more join, the mob grows

..in both number and confidence.

The tables are turning.

By sheer force of numbers

..these fur seals drive the world's

most notorious predator

..back out to sea.

Here, animals are adapting

to new challenges

in a rapidly changing world.

In the Arctic

..monumental change

is a regular event.

Summer.

Visitors are arriving en masse

..attracted by the biggest

seasonal transformation

on any coast on Earth.

Over 300 billion tonnes

of ice are melting

..releasing nutrient-rich water.

Extraordinary newcomers

appear from the depths.

A sea angel.

No bigger than your little finger.

It's eaten little for months.

Its empty stomach glows orange.

And there are other hungry arrivals.

A sea butterfly.

A snail with wings.

Both angel and butterfly are blind.

But each monitors minute changes in

the water as they search for a meal.

This angel has a devilish side.

Its mouth parts invert

to form a deadly trap

of tentacles

..from which there is

little chance of escape.

With a stomach full of prey,

this angel has lost its glow

..but not its appetite.

It feasts while it can.

Both predator and prey

will soon return to the depths

..before the ice transforms

this coast once again.

Namibia

..where desert lions

roam across vast territories.

These desert cats are on

a never-ending search for food.

And that has brought

these young sisters

..here.

Africa's infamous Skeleton Coast.

Following years of persecution,

Namibia's lions are now protected

..and their range

is expanding again.

These are the first to be seen

on these shores for 40 years.

By day, there is little

for them here.

But at night,

it's a different story.

Sea birds come here to roost

in their thousands.

These hungry sisters have never

seen an opportunity like this.

But no cats,

certainly no desert cats,

enjoy getting their paws wet.

These roosting cormorants

are sitting ducks

for hunters with good night vision.

In theory.

Birds are not a big cat's

usual prey,

let alone sea birds.

And these sisters

need to get their eye in.

Catching flying prey

in the dark is not easy

..but these lions

have acquired the knack.

Coasts can not only provide food

..they can also be a sanctuary.

This female southern right whale

is nearing the end

of a 5,000 mile journey

across open ocean.

She's kept a steady course

..to a special place

she has known all her life.

Peninsula Valdes, Argentina.

In these calm, shallow waters

..her behaviour starts to change.

She rolls and shifts her great body.

Perhaps she's trying

to get comfortable.

Other females are close by.

Some have been coming here

for five decades

..seeking the shelter of this bay

at a key time in their lives.

This whale is here

..to give birth.

A new life begins.

The calf is totally dependent

on its mother.

She's producing as much

as 200 litres of milk a day.

The strength she loses,

the calf gains.

And it becomes more and more

independent and playful.

In this nursery bay,

there are plenty of playmates.

But a mother never lets her calf

stray too far

..and will always offer

a welcome embrace.

The family keeps in constant contact

with whispered calls.

New research has revealed

that in shallow coastal waters,

their calls not only fade quickly,

but are also concealed by the sound

of waves breaking on the shore

..so they won't attract

the attention of predators.

Not so long ago,

these whales faced a graver thr*at.

They were hunted to near extinction.

But 40 years ago,

commercial whaling was banned.

Today, their population

is 12,000 strong

..and this bay now attracts

one of the largest gatherings

of these whales anywhere on Earth.

There are over a million miles

of coastline around the world.

Together, they constitute the

most varied habitat on the planet.

Here on Canada's west coast,

some of the most powerful

of all ocean currents

deliver a constant

supply of nutrients

to the shores of countless islands.

And those that live here

take full advantage.

This is the aptly-named

wandering garter snake.

He may seem out of place

..but he's here to eat.

The water here is more than

ten degrees colder than the air.

But that doesn't deter this intrepid

hunter from taking the plunge.

Under the water,

there is an abundance of food

..if he can catch it.

Snakes are cold-blooded,

so he can't stay in these

chilly waters for long.

Back in the sunshine,

he warms his head,

perhaps sharpening his senses.

And then, with a gulp of air

..he continues his hunt.

It's thought that garter snakes

can use their forked tongue

underwater as they do in air,

smelling in stereo

..detecting prey wherever it hides.

He's got something.

A small fish.

Now, he has to land it.

Success.

For those animals able to cross

the divide between land and sea,

there are surprising rewards.

Raja Ampat in Indonesia.

Here, there's a greater

variety of animals

than on any other coast on Earth.

The corals are protected

by mangroves.

Salt tolerant trees that prop

themselves on curving aerial roots.

These fish have learned how to

catch prey from high in the trees.

Archerfish use jets of water

like arrows.

This pinpoint accuracy

..requires some

complex calculations.

The hunter first estimates

the range of its target

..then loads with a precise

amount of water.

Aiming, they allow

for the refraction and distortion

created by the water's

moving surface.

And then

..release

..an arrow of water.

They can hit prey

up to two metres above them.

But they're not born

with this skill.

They have to learn it.

And they do that by studying others.

This youngster is watching

a master at work.

It's time for the apprentice

to have a go.

First, he must select a target.

This seems rather ambitious.

Missed.

Others watch to learn

from his mistakes.

Or

..to steal his prize.

Enough is enough.

There is one way

to b*at the thieves.

The archer himself

..becomes the arrow.

Mangroves are unusually

stable coastal environments,

where an archerfish can focus

on b*ating the competition.

But on the exposed coast

of Mexico's Yucatan,

life is precarious.

Concentrated by

the tropical sunshine,

the brine in these shallow lagoons

cannot be tolerated by most animals.

And yet, these Caribbean flamingos

have flown hundreds of miles

to gather here.

These hypersaline waters

keep many predators at bay

..so it's here they choose to nest.

There are more than

10,000 pairs here.

It's the largest breeding colony

in North America.

Nest mounds keep chicks

clear of the brine

while they are still

at their most vulnerable.

But this generation faces a problem.

The storms that come each season

are arriving earlier every year.

And the colony lies directly

in their path.

Rising winds create a storm surge

that overwhelms

the most exposed nests.

And then

..it rains.

The adults do what they can,

bailing out their nests.

But they can only do so much.

The storm passes,

but leaves devastation in its wake.

Most nests are submerged.

The chicks are soaked and cold

..and will soon perish

..unless they can

get out of the water.

The adults are unable to help.

A chick must save itself.

Some years,

no chicks survive in this colony.

Our coasts are vulnerable places.

Increasingly so, as rising global

temperatures create bigger storms.

The biggest are hurricanes.

They form over warm tropical water,

building in strength at sea.

But their full force

is unleashed on our coasts

..where 40% of the world's human

population have made their homes.

In this changing world

..coasts are on the front line.

Raine Island.

One of the planet's most important

breeding sites

for one particularly

precious species.

The green turtle.

On a few special nights each year,

as many as 20,000 females

come ashore here.

Their instinct to nest is strong

..and many haul themselves far

inland in search of nesting space.

In a single night, they may lay

as many as two million eggs.

Dawn.

This exhausted female has nested,

but now she faces

a long return journey

through the dunes to the sea.

As the sun rises

..she's at risk of being

baked alive.

Every inch she travels is gruelling.

And the ebbing tide

has exposed a rocky reef.

It has already claimed many lives.

Other females overcome

by heat and exhaustion.

Her temperature is rising.

She has to keep going.

As many as 2,000 female turtles

may die here each year.

But the coast is always changing.

And the turning tide

may yet save her.

Half of all the green turtles

in the Pacific come here to nest,

as they have done

for at least 1,000 years.

But for how much longer?

If sea levels rise as predicted,

within the next 30 years,

Raine Island will disappear

beneath the waves.

Coasts are dynamic,

dangerous frontiers

..and they are changing faster

than ever before in human history.

Life is remarkably resilient

..and adapts to new challenges.

But there is a limit

on how fast it can do so.

As far as I know,

I was one of the first people to

film on Raine Island, back in 1957.

YOUNGER DAVID: After a fortnight

of travelling north,

we at last sighted Raine Island.

From the sea, it looked no more than

a low sandbank covered in scrub.

But as we rowed ashore,

we were deafened by the cries

of thousands of sea birds

which hung above the island

like a black cloud.

I was 31 and it was here

that I first met a green turtle.

The turtles come up to lay at night,

and after a night spent laying

maybe over 100 eggs,

she's very weary and very anxious

to get back to the sea.

Nearly 70 years later,

the Planet Earth III team

are welcomed by people

whose connection to the island goes

back very much further than mine.

Welcome to Raine!

The Wuthathi and Meriam people

have been coming here

for several thousand years.

Raine Island's a beautiful

and special place.

Like, there's nowhere

else on the planet

where you come and see

this much turtles.

It's a wonder to see.

Since I was there, it's been

discovered that Raine Island

attracts more nesting green turtles

than anywhere else on the planet.

There's so many, isn't there?

As soon as you're up, you're like,

"Oh, there are a lot."

And the crew soon meet

some other residents too.

This is behind

the behind the scenes!

See you, mate!

The team are here to record

the mother turtles'

perilous journeys back to the sea.

Oh, God.

Trapped turtles can often

free themselves

with the help of the rising tide.

Nearly. Just a bit more to

the right there. Yeah, there.

But in this case, Keron

makes the decision to intervene.

Ready? One, two, three.

Yeah, any time we're here

we'll walk the beach.

Any turtles that have no chance

of making it back to the ocean,

if we can save them, we save them,

because every turtle is precious.

At the time of my first visit,

little was known to outsiders

about Raine Island.

But for the last few decades,

scientists have been working with

the Wuthathi and Meriam people

to understand more

about this special place.

Scientists have been coming to Raine

Island since about the mid '70s

and over that time

they've been monitoring

the nesting population here.

This work involves long hours

98.7.

..and a certain degree of patience.

Oh!

SHE LAUGHS

We're going to be wearing half of

Raine Island by the end of tonight!

Helping the year's first hatchlings

is a little easier.

So we'll take these ones

down to the water's edge

and so hopefully we'll see

these turtles back here,

laying eggs in 30 years' time.

With the help of this

dedicated team,

Raine Island's turtles might

seem to have a good future.

But research is revealing

a hidden thr*at.

The direct effects

of climate change.

Do you want to hold this against

the flat part of the data-logger?

A developing turtle's sex

is determined by the temperature

of its nest.

Higher temperatures

produce female hatchlings.

The temperature of the sand on Raine

Island is now at a record high.

So 99% of the turtles

that hatch here are female.

More alarmingly, we now know

this has been case

for at least the last 20 years.

You do the maths.

All females, no males.

What's going to happen?

There's going to be

a population crash

and there'll be no more turtle.

Work is under way to find solutions.

But that's not their only problem.

Not only are temperatures rising,

sea levels are too.

Increasingly, high tides on Raine

are flooding many of the nests

from below

..drowning the developing turtles

before they hatch.

It's really upsetting.

You'll dig down to check

to see success,

and you get down to the nests

and you're just pulling up

dead eggs.

To try to stop this happening, they

have devised a heavy-duty solution.

These machines have been

shipped hundreds of miles

from the Australian mainland

to re-shape the beach.

They have already shifted sand

that would fill 16 Olympic-sized

swimming pools

and doubled the number

of safe nesting sites.

The hope is that this will ensure

that over five million more eggs

will hatch in the next decade.

But from then on, the future of

Raine Island looks very uncertain.

At this stage, we think

that we have to about 2050

until we start seeing massive

impacts of sea level rise.

It's crazy to think that,

you know, the work that we do here,

someone might not be doing this

in 30 years' time

cos there's no island to do it on.

What sort of world is it going to be

for my children and their children?

Is there going to be anything for

..for them? Or is it

..all in vain?

We'll always be here fighting

for Raine Island, for the turtles.

But we can't do it alone and

we need government and big business

to wake up and see what they're

doing to the planet and get real.

This little fellow

is newly hatched from an egg

which had been laid

a month or so earlier

and he too is very anxious

to get down to the sea.

Having at last successfully

reached the water,

he's still got a great number of

hazards to face before he grows up.

Little did I know then

what hazards that little turtle

would have to face

or the extraordinary lengths

to which people would go

to protect it and its island.

In the 66 years since my visit,

Raine Island has remained

the most important green turtle

nesting site on the planet.

The question is,

can it last another lifetime?

Next time

..an extraordinary journey

through the ocean.

The last unexplored

frontier on our planet

..where life has evolved

..in the most surprising ways.

Habitat Explorer brings animals

and their habitats to life.

Explore this free interactive

and make origami animals.

Go to bbc.co.uk/planetearth3

and follow the links

to the Open University.

Or to order a free printed version,

visit the website

or call the numbers on the screen.