Original subtitles

Flowing lava.

Sun scarred landscapes.

And few signs of life

that early explorers to name the Galapagos Islands

hell on earth.

But beyond these parched beginnings,

this volcanic archipelago is now our planet's greatest Eden.

A wilderness so pristine and rich in life

it allowed one man's studies to alter our entire view of the natural world.

Older islands fade away

while new ones emerge from beneath the sea.

The Galapagos continue to evolve

and continues to be

nature's greatest evolutionary arboratory.

The Galapagos Islands rank among

the most spectacular scientific discoveries in history.

Situated 1,000 km west of Ecuador in South America,

the archipelago contains 13 main islands

and a hundred or so smaller rocks and reefs.

Some are so desolate and barren,

they reveal few signs of life.

Others are rich haven providing a home

to bizarre and unique creatures.

Human influence has been so limited across the islands,

it allowed one man to study and rethink

the laws of nature.

In 1835, 26 year old Charles Darwin

sailed to the Galapagos Islands in HMS Beagle.

The ship's mission was to survey the coast of South America.

Darwin was the ship's botanist.

Thirty years later, Darwin published his theory of evolution,

one of the most revolutionary ideas science has ever known.

It was the islands' small land birds like finches and mockingbirds

that proved key to Charles Darwin's theory.

Each of the 13 species of finch has a different beak

for a different purpose.

Some are thick and heavy for crushing seeds.

Others long and pointed for accessing pollen in flowers.

They all descended from a common ancestor

that arrived on the islands millions of years ago.

The finches established themselves and began to determine territories.

With no competition from other birds,

they diversified.

They developed unique adaptations for each type of habitat.

New species were born.

Darwin explained that natural selection

was the driving force behind this rapid evolution.

Following the publication of his theory,

these ordinary looking small birds have been given a new collective name,

Darwin's finches.

The Galapagos Islands were named after their giant tortoises.

The old Spanish word, galapago, meant saddle.

A term early explorers used for the tortoises

due to the shape of their shells.

The Galapagos tortoise is the largest in the world.

Some reach a meter and a half in length

and can weigh 250 kg.

These slow moving reptiles lead an uncomplicated life.

Most days are spent grazing on grass and leaves

in between basking in the sun.

Like all reptiles,

giant tortoises rely on the sun to warm their bodies

and become active.

However, the midday sun can be too much to bear

even for cold blooded creatures.

Fortunately, the islands' lakes don't just provide a valuable source of drinking water.

Bathing in the muddy shallows is the perfect way to cool down.

A slow metabolism and large internal stores of water

allow the tortoises to survive for up to a year

without eating or drinking.

Inactivity also helps.

They sleep for around 16 hours a day.

These giants can live for over 150 years.

Darwin noted a variation in the shape of the shell

of tortoises from different islands.

This became additional evidence

for developing his theory of evolution.

Galapagos creatures evolve and adapt to their habitat.

And their island homes are ever changing too.

The youngest islands furthest west are still forming.

A static volcanic hot spot 1,000 km beneath the sea

continually forces lava to the surface.

These newly formed masses eventually cool

and then drag southeast at a rate of 5 cm a year

from shifting oceanic plates.

On their 200 km journey east,

they witness many changes.

Ultimately all Galapagos islands face the same fate.

Disappearing beneath the ocean without a trace.

Darwin described how eager he was to witness an active volcano.

Although there were no eruptions during his visit,

his geological observations altered many volcanic theories.

The newest and most westernly Galapagos island is Fernandina.

Still situated directly over the oceanic hot spot,

this volcanic mass has erupted 24 times

in the past 200 years.

It's one of the youngest and most active volcanoes on earth.

Fernandina's peak stretches 1,500 meters high

and its crater spans 6-1/2 km.

The island's lava clad rocky shores and black sand beaches

seem the most forbidding of all the Galapagos Islands.

Yet life has started to take hold.

Pioneer plants such as these lava cactus

are often first to take root.

Their seeds carry from older islands by bird droppings

or directly by the wind.

But there is one creature that has colonized the entire archipelago

and its mode of travel relies on the sea.

Marine iguanas are excellent swimmers.

They can reach over a meter in length

and weigh as much as 9 kg.

Over 250,000 of these swimming dragons

inhabit the Galapagos.

They are the world's only species that marine lizard.

It's thought that millions of years ago, land dwelling iguanas from South America

drifted out to sea on floating debris.

They eventually landed on the islands.

Isolated from the main land, a new iguana evolved

and adapted to life at sea.

Like all iguanas, this species is vegetarian.

Yet Fernandina offers very little in the way of visible food.

But this species rarely goes hungry.

Being cold blooded, iguanas need to raise their body temperatures

to approximately 36° C in order to function.

After an hour or so basking in the equatorial sun,

this iguana launches its feeding mission.

A flattened tail allows it to dive down to depths of 12 meters

to access tufts of red and green algae

on the submerged rocks.

A shortened blunt snout allows it to crop the plant close to its face.

This algae is the marine iguana's exclusive diet.

Fernandina's currents are surprisingly cold.

The iguana's body temperature can plummet 10° on an extended dive.

After just 10 minutes, its muscles begin seizing up.

Getting back to dry land in time is critical to survival.

Long, sharp, recurved claws enable the lizard

to hold fast to the lava in heavy seas

or when submerged.

Along with the algae, marine iguanas ingest a great deal of salt.

Specially adapted glands above each eye

are connected by ducts to each nostril.

The excess salt is sneezed out.

Only the larger marine iguanas

risk running the gauntlet of the islands' chilling seas.

Smaller individuals choose a safer option

and graze only at low tide on dry land.

Fernandina is less than half a million years old

and offers little sanctuary to land living creatures.

But drifting 75 km further east

are islands more than twice its age

and different worlds entirely.

Isabella is the largest of all the Galapagos Islands.

Consisting of six overlapping volcanoes,

its over 100 km long.

It makes up half of the total land area of the Galapagos.

The volcanic hot spot still simmers beneath Isabella's seas.

While above the surface, a creature key to Darwin's evolutionary theory

prepares to dive the deep.

This cormorant is unique to the Galapagos.

Its wings are disproportionately small to the size of its body.

They're about one third the size required for it to take to the air.

This species has evolved to be flightless.

Its legs are much stronger than those of other cormorants.

Enlarged feet propel its stream lined meter long body

in search of octopus and small fish.

Darwin noted that the flightless cormorant

could not have swum from the mainland to the islands.

It never ventures further than 100 meters from the shore.

It diverged from its flighted cousins

and eventually became marooned on the islands.

An abundance of food and an absence of predators

has allowed this mutant bird to flourish.

Its the largest of all cormorant species.

Seaweed makes the perfect nest material

on top of jagged lava rock.

Both parents play a part in raising their young.

Although it can no longer fly,

the bird still holds its wings up to dry.

It's a memory left over from ancestral habits.

Further inland, saltwater lagoons provide the perfect refuge

to one of the world's most iconic birds.

Greater flamingos usually live in large colonies

of up to 10,000.

The Galapagos plays home to the world's smallest population

numbering less than 600.

Most of their day is spent feeding.

The shallow water enables them to turn their heads upside down

and sweep from side to side.

They filter up to 20 mouthfuls a second,

separating brine shrimp and small crustaceans

from the mud and silt.

The consumption of shrimp provides the pink pigment of their feathers.

The small population size of the Galapagos

has resulted in changes to their breeding behavior.

Flamingo populations elsewhere rely on very large groups of birds

for breeding to occur.

Galapagos flamingos can breed with just a few pairs present.

It's the start of the nesting season,

and their unique courtship ritual begins.

Males and females mate for life.

These coordinated displays are key to reaffirming their bonds.

Wing salutes, turning their heads in unison,

and twist preening are important courtship signals.

The Galapagos flamingos originally flew in from the Caribbean.

Whereas one mammal swam over 5,000 km

to set up home here.

Galapagos sea lions arrived from California.

They're slightly smaller than their North American relatives.

But at over 2 meters in length and weighing as much as 250 kg,

they are by far the largest mammals of the entire Galapagos Islands.

They're most likely one of the first animals Darwin encountered

when he came ashore around 180 years ago.

Sea lions are well adapted to a semi-aquatic lifestyle.

Along with a streamlined body,

they can control their hind flippers independently.

This makes them far more agile than true seals.

Females give birth to just one pup

and remain with them on shore for the first week.

After this, they go off on foraging trips

that can last up to three days.

Pups left behind gather in nurseries

where they socialize and play.

One female remains behind to keep watch.

When returning from a trip, females alert their pups

with distinctive calls.

These reunions initially rely on the mothers.

But once they're older, the youngsters call out too.

Pups are suckled for up to 12 months,

three times longer than many other seal species.

Adult male sea lions play no role in raising their young.

A dominant bull also known as a beach master

spends the majority of his day patrolling the territory occupied by his harem.

This particular male has some unwanted company.

The intruder is defeated

for now at least.

Keeping other males at bay is exhausting work.

Some beach masters succeed for just a few days.

Even the toughest only manage to protect their patch for a maximum of three months.

With the storm over, everyone can relax.

However, another predator prepares to move in.

It's been patiently waiting for the sea lions to drop their guard.

Lava lizards are carnivores.

This one has singled out its prey.

Flies are a constant irritation to the sea lions

so they welcome this free grooming service.

These Galapagos reptiles play an important role in controlling insect populations.

Male lava lizards can live up to 10 years

and may have three or more mates in their harem.

This male approaches one of his conquests.

He bobs his head up and down to signal his intentions.

This female isn't ready or willing to mate.

Turning her back and raising her tail lets the male know

he's been rejected.

The Galapagos Islands sit on the equator

except the climate here isn't typically tropical.

The reason lies within the surrounding seas.

Three major ocean currents collide at the very point

where the Galapagos Islands lie.

The warm Panama Current from the north

supports the island's more tropical marine life.

The icy Humboldt Current from the south

brings nutrient rich waters from Antarctica.

And from the west, the deep water Cromwell Current

rises to the surface upon hitting the Galapagos shelf.

Elsewhere, the temperature at sea level

is usually warmer than at higher altitudes.

But here, the opposite is true.

The cold waters from the south and west cool the air above them.

Colder waters are rich in green algae,

which supports a diverse and vibrant food chain.

Over 500 species of fish rely on these plankton rich seas.

Large schools of hammerhead sharks patrol the islands' waters all year round.

This unusual looking predator can reach over 4 meters in length.

Its eyes are a meter apart.

Darwin found the Galapagos to be home to many unusual creatures.

But none more unexpected than this.

Galapagos penguins descended from ancestors in the Antarctic,

10,000 km further south.

They are the only kind living in the northern hemisphere.

It's thought they arrived during the last Ice Age

after being swept north by the Humboldt Current.

They later became stranded here after the earth warmed.

The islands furthest west still suffer the effects

of the Pacific Ocean hot spot.

But drifting further east is a volcanic island

that last erupted over a million years ago.

Santa Cruz is situated in the middle of the Galapagos chain.

It's thought to be around 2 million years old.

Here the terrain is mixed.

Ranging from arid low land

to humid high altitudes.

Ancient volcanoes have been swallowed by forest,

and the islands' peaks are high enough to form rain clouds.

Cactus forests line the lower plains.

These succulent green plants store water

in their stems and leaves.

They thrive in hostile climates during times of drought.

Most cactus species have spines to guard against grazing animals.

But this isn't enough to deter one Galapagos resident.

Cactus finches not only feed on the plant's flowers.

They also nest among its leaf-like pads.

This particular bird may look ordinary,

but it became one of the most important species in the entire archipelago

after Darwin put all Galapagos finches on the map forever.

The Galapagos Islands are home to another bird,

who's awkwardness on land but precision out at sea

also helped influence Darwin's theory of evolution.

Blue footed boobies use a unique method

to capture their prey.

They plunge dive in unison from heights of around 30 meters.

They hit the water at just under 100 km/h,

reaching depths of 25 meters.

Meals are usually consumed while still under water.

On North Seymour Island just off Santa Cruz,

it's breeding season.

Over 20,000 pairs of blue footed boobies live on the Galapagos Islands

around three-quarters of the world's population.

This male attempts to woo a mate.

Blue footed boobies take great pride in their feet.

This male shows them off with a high stepping strut.

Females prefer partners with bluer feet.

And this girl seems impressed.

He hunches and crosses his wings before sky pointing his bill.

The female mimics the male's behavior

indicating her acceptance.

Another ritual can now begin.

The male picks up a twig and gently places it

at the female's feet.

This symbolic act of nest building seals their relationship.

However, this couple has some unwanted company.

Another male approaches.

Fencing with their long beaks is how booby conflicts are resolved.

Eventually the intruder gives up.

The bachelor leaves to try his luck elsewhere.

Brightly colored body parts play a vital role in the courtship of another island resident.

Frigate birds are the real masters of the skies.

Strong breast muscles work together with their wings,

enabling them to fly fast and soar high.

Forked tails help them steer.

They have the largest wing span to body weight ratio of any bird.

Males tip the scales at just over a kilo,

but their wings can stretch to nearly 2-1/2 meters.

Frigate birds can stay aloft for more than a week,

landing only to roost or breed.

This female is preparing to land,

but she's facing a tough choice.

The males below have chosen potential nest sites.

They advertise their positions

in a most colorful, eye catching way.

With wings outstretched, they inflate their enormous throat pouches

and call to the passing females.

The biggest and brightest air sacs have the most appeal.

The female makes her choice.

And the male shields her from the nearby competition.

After pairing, the male saws material to construct their nest.

Frigate birds have such short legs,

they're unable to walk on land or swim in water.

They can not take off from flat surfaces so collecting twigs requires enormous skill.

Most of their food is obtained on the wing.

Robbing other sea birds in flight can account for nearly half their diet.

Internal pilfering also plays a part during nest building.

Parental care in frigate birds lasts longer

than that of any other bird species.

Both parents take turns to feed their young

for the first three months.

After this, the mother takes sole responsibility

for up to a year and a half.

Many creatures have evolved in order to survive on the Galapagos.

However on South Plaza Island,

a plant has also been forced to change.

Unlike many cactus species, these plants have grown extra long trunks.

Their fleshy pads and flowers are the favorite meal

of a creature that roams this tiny island in large numbers.

The beast, that Darwin referred to, is hideous.

Land iguanas are large stocky lizards.

They can be over a meter long and weigh up to 13 kilos.

They feed mainly on low growing plants and shrubs,

which also provides them with moisture

during the islands' long dry periods.

Younger prickly pear cacti have sharp spines

that grow on their fleshy trunks, pads,

and flavorful fruits.

The spines do little to deter the iguanas.

Rolling the fruit in soil removes most of the spines.

Now it's ready to eat.

In time, the cacti grow taller,

and the spines on the trunk are replaced by a thick, scaly bark.

These older plants become too tall for the iguanas to reach.

However, the lizards still value these tall structures.

Each iguana claims a tree.

They sit patiently in the plant's shade for up to a month,

waiting for the right fruit to drop.

Feeding territories overlap due to the large number of iguanas living here.

Claiming fallen fruit isn't that straight forward.

This iguana bobs its head towards the intruder.

It's a sign of aggression

meaning stay away.

Undeterred, the trespasser steals his neighbor's bounty.

The central Galapagos Islands are incredibly fertile,

playing home to a rich array of wildlife.

But far to the east lies an island that's a shadow of its fruitful past.

Espanola is the oldest of all the Galapagos Islands.

It's traveled approximately nine meters east since Darwin's visit,

and over 160 km since its creation

around 4 million years ago.

This arid and relatively flat island is dying.

The further it drifts from the region's volcanic hot spot,

the more it cools, contracts and sinks.

Espanola's remote location may be hostile to many creatures,

but the island's steep cliffs serve as perfect runways

for one of the largest flying birds in the world.

The waved albatross stands over a meter tall

and has a wing span approaching 2-1/2 meters.

Espanola is this bird's only nesting place.

The entire world population relies on this island.

Each April, 12,000 breeding pairs return to Espanola's shores.

Males are the first to arrive

followed shortly by their partners.

Waved albatross mate for life,

and the male begins his annual courtship dance.

This performance of strutting, honking,

and beak clicking can last up to five days.

Once reacquainted, the female lays a single egg.

Both birds share the responsibility of incubation.

Feeding newly hatched chicks also requires joint effort.

Both parents can make round trips of over 3,000 km while out fishing.

The colony remains on Espanola until December

when the chick is fully grown.

In January, most of the colony leaves the island

to fish on the nutrient rich Humboldt Current.

Young albatross won't return for five or six years.

Only then will they be ready to seek a mate.

Espanola is eroding away.

Waves crash into lava fissures creating blow holes

that spray water nearly 30 meters into the air.

The powerful Humboldt Current will eventually swallow Espanola

and every other Galapagos island heading this way.

The Galapagos Islands are a wilderness of wonder.

Uninfluenced by people for so long,

they provided one man with a unique snapshot of evolution.

Creatures here have adapted to their ever changing environment

as the land beneath their feet comes and goes.

Darwin's Eden-like wilderness continues to be

a vital part of our natural world's history.