Planet Earth III

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 explosive 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 explosive 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 kill...

..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 threat.

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