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David.
Attenboroughs.
Galapagos.
s01e02.
1080p.
bluray.
x264-shortbrehd
In the vastness of the Pacific,
there's a place unlike any other.
Enchanted volcanic islands,
make a home to a remarkable
collection of animals and plants.
Here evolution is proceeding
at extraordinary speed.
Galapagos.
A place of wonders.
Millions of years ago, the islands were
colonized by a strange cast of characters.
But to settle in this harsh
unforgiving landscape,
those new arrivals had to
dramatically adapt their bodies.
Today, revelatory discoveries are still
being made about them.
And from their story, we can piece together
how Galapagos came to be
one of the most diverse
environments on our planets.
It's perhaps surprising
that the Galapagos
should have become famous
for its biodiversity.
For the fact is, that living conditions here
are very tough.
On the Equator, the heat is intense.
There's very little water.
Much of the land
is covered by bare volcanic rock.
And yet every species
that lives here
is descended from an ancestor
from the continents,
that have taken on these conditions
and won.
And the way which they did so,
is extraordinary.
The total land area of 16 islands
and rocky outcrops that make up Galapagos
is less than half that of New Jersey.
And yet for its size,
There are more unique species here
than anywhere else on earth.
Why should that be?
There are clues
hidden within the landscape.
This crescent-shaped strip of cliffs
rising steeply from the Pacific Ocean,
is the island of Tortuga.
And like all the Galapagos islands,
it's a wonderful place to see wildlife.
Here and there
there's a sea lion.
And above that, nesting seabirds
*** and Galapagos Gulls.
But you only really appreciate
the true character of this island
from the air.
From here, it's clear that this is
the last fragment of an extinct volcano.
These curving cliffs are all that remains
of what was once
a completely circular crater.
And that is an indication
of something very significant,
about all these islands.
They change with enormous rapidity.
The history of these islands
is very much the same.
Each is born on the bottom of the sea,
and rises up through the waters,
to emerge as a volcano.
This is a typical Galapagos island,
in its infancy.
But then after a million years of eruptions,
volcanic activity ceases.
Two million years
after its first appearance,
the island is approaching middle age.
It has a most climate,
and is covered by forest.
It begins to sink
under its own weight of ash and lava.
It's battered by erosion,
and after 4 million years,
it's near the end of its existence.
Low-lying and arid,
with little rainfall,
it's surrounded by beaches of soft sand.
The waves and rain
continue to take their toll,
until all that is left
is a craggy outcrop of rock.
These islands, in geological terms,
are very short lived.
Today, there are islands
in the Galapagos Archipelago,
that illustrate every stage in this history.
The youngest, in the west,
are arid, black, and still breathing fire.
The oldest, in the east,
have long since ceased to erupt.
But each island provide its colonists
with a range of habitats.
And it is the youngest active islands
that pose the greatest problems
for any animals
that attempt to colonize them.
In the far west of the archipelago
lies Fernandina.
This is the youngest
of the Galapagos Islands.
It's forbiddingly desolate,
and inhospitable.
But one animal
has colonized its shoreline.
This creature is a specialist
at surviving in this harsh terrain.
And in adapting to this place,
it has become like no other animal on Earth.
Behold, the Marine Iguana.
The ancestors of these iguanas
almost certainly lived
in the jungles of Central America.
There, still today,
you can see iguanas
in the trees overhanging the rivers
nibbling leaves,
or on rafts of reeds.
Just occasionally,
some are swept out to sea.
And the vast majority of course,
die there.
But just a few, a long time ago,
were fortunate enough to be swept
by favorable currents out into the ocean,
and beached up here.
In their ancestral rainforest habitat,
iguanas are vegetarians.
Here, they browse on juicy leaves.
But the iguanas that first appeared in the
Galapagos, could find no such things.
So these iguanas, to survive,
had to eat the only kind of leaf
that was available.
Seaweed.
And to get the best of that,
they had to do something even more radical.
They had to swim.
They even learned to dive.
They acquired the ability to hold
their breath for up to an hour,
so that they could swim down
to a depth of 20 meters.
Their claws strengthened,
so they could cling to the rocks
on the seabed.
And under the water, it found
an endless supply of seaweed.
Which grow in abundance in the nutrient
rich currents that flow around the islands.
But that was not all.
Their snouts became flatter
to help them graze.
And their teeth became sharper
to grip slippery seaweed.
But cold water can be dangerous
for cold blooded reptiles.
After a few minutes feeding at sea,
The iguanas are seriously chilled
and in an urgent need of a warm up.
And their skin enabled them to get that.
It is black.
Dark objects absorb heat
and each scale in the marine iguana skin
is like an element
in a miniature solar panel.
Now all a marine iguana needs to do
to bring its body back up to temperature,
is to bask in the hot equatorial sun
for an hour or two.
But eating nothing but seaweed
creates another problem.
Too much salt.
The marine iguanas dealt with that
in a very particular way.
They evolved a special gland,
in their nose.
They simply sneeze the excess salt
from their blood.
These changes had to happen very quickly
in evolutionary terms
if the iguanas were to survive.
But here conditions sometimes change
and then even iguanas struggle to keep up.
Every three to seven years the weather
becomes very extreme and irregular.
It's a phenomenon called El Niño
And it can have a devastating effect
on wildlife.
Evolutionary biologist Maren Vitousek
has studied the effects of El-Niño
on the Galapagos Marine Iguanas.
She discovered that it decimates their food.
Marine Iguanas usually eat
red and green algae,
and that algae dies off completely
during El-Niño,
during strong El-Niños.
And is replaced by brown algae.
And Marine Iguanas aren't able to digest
the brown algae,
so they can eat it,
but it sits in their stomach,
basically in a big lump.
Um, and so you can find iguanas
dead on the beach, of starvation,
with their stomachs full of this brown algae
that they're just not able to digest.
The Marine Iguana is the worst affected
of all Galapagos animals
during an El-Niño.
As many as 90% of them can perish.
It's bad news for the iguanas,
but good news for scavengers.
But now, new research has shown
that the iguanas
have evolved an extraordinary way
to survive the famine.
Their bodies shrink.
They lose not just fat and muscle,
but bone.
The iguanas can actively reduce
their skeletons over just a few months.
So we saw that the, largest animals
were decreasing their body length
by as much as 20%.
And the magnitude of that means
that it can't be simply
that they're changing their cartilage
or connected tissue,
or reserving muscles.
Those things together account
for about 10% of length.
So instead, 20% of shrinkage
really indicates
that it's got to be the skeleton
itself that's decreasing in length.
This amazing ability to reabsorb bone
in times of hardship,
is unique to these reptiles.
It's the most recent discovery
in understanding
how the Marine Iguanas manage to survive
on the coastlines
of the youngest Galapagos islands.
But iguanas were not alone in
adapting to these desolate volcanic shores.
This is the Lava Heron.
It's well camouflaged.
It's grey feathers
make it relatively inconspicuous
against the blackened lava rocks.
So moving stealthy,
it could hunt very effectively.
Its favorite prey
is the Sally Lightfoot crab,
Whose striking red shell stands out
against the jet black lava.
But the adult crabs have tough shells
and sharp pincers
and herons know better
than to attack a full grown one.
Juvenile crabs would be
a more attractive prospect.
But they have responded
to the landscape of Fernandina,
They have black smells,
that make them far less conspicuous
to prowling herons
This time the lava heron will have
to make do, with a really tiny snack,
a Sally Lightfoot hatchling.
On the shorelines
of this infant Galapagos island,
life is tough.
Habitats are limited.
Opportunities are scarce.
But away from the coast,
survival is almost impossible.
There it's too dry and too hot
for most forms of live.
But in time, that will change.
As the island ages, this hostile landscape
will become a little more welcoming.
It will, one day,
support a rich forest,
full of new places for animals to live.
This change is driven
by the volcanic hotspot,
which brought the island into existence.
The eruptions continue.
in the next few hundred thousand years.
By the time the eruptions have ceased,
it's grown so large,
that it has acquired a new power.
It has the ability
to create its own weather.
Humid oceanic winds
blowing across the Pacific
hit this mountain of lava,
and are so force upwards.
That cools them, so that they can
no longer hold their load of moisture,
and it condenses as mist and rain.
And that allows plants
to thrive.
Santa Cruz,
in the center of the archipelago,
is typical of
these middle-aged islands.
Its slopes are covered
by a mantle of green.
This might seem to be
a forest of giant trees,
But, this being Galapagos,
this forest is different.
These plants are not true trees.
Trees tend to have big seeds.
And few of those made it across the ocean,
to the Galapagos.
And certainly, none up here
into the highlands.
But smaller plants have smaller seeds.
Some so small, they can float on the wind.
And one member of the Dandelion family,
made it up here.
And without competition from other trees,
they grew big.
This, you could say,
is a forest of giant dandelions.
This very special kind of Dandelion
is called Scalesia.
It's unique to the Galapagos,
and flourishes on the high slopes
of Santa Cruz,
and other middle-aged islands.
It's become the host for a whole community,
that could not exist without it,
because Scalesia performs a conjuring trick,
that gives life to the rest of the forest.
There's no ground water
in these thin volcanic soils,
but the Scalesia tree
is tall enough,
to collect moisture from the skies,
from clouds and from mist.
And that is sufficient
to sustain a whole community
of plants and animals.
High in the canopy, mist condenses
on the spindly criss-cross branches
of the Scalesia.
Water trickles down their *** trunks.
Ferns root themselves in the damp moss
that clings to their bark.
The moisture creates conditions
where spiders and other small creatures
can live.
And on the forest floor,
pools appear.
Here, dragonflies thrive, and, once again
they belong to a species
that occurs nowhere else but here.
But the Galapagos climate is changeable
and the mists sometimes dry up.
Leaving this delicate ecosystem,
exposed to the burning equatorial heat.
Some trees however, have evolved
a way of protecting themselves.
This tree has developed
a mutually beneficial relationship
with the lichen that grows on it.
The lichen shields the tree from the sun,
preventing it from getting scorched.
And the tree provides the lichen
with moisture and nutriment.
But, if the weather gets really sunny,
than the lichen shrivels
and stops taking nutriment
and moisture from the tree,
but at the same time,
still prevents it from getting sunburned.
An when the moisture returns,
the lichen can grow back.
So plant and lichen make the best
of the two extremes of climate.
Fresh water anywhere on land,
creates opportunities.
But on volcanic islands like Galapagos,
it gets to some very strange places.
Deep in the rocks beneath
the Scalesia forest,
there is a network of hundreds of tunnels
called lava tubes.
Here, the species transforming power
of the Galapagos
is as active as everywhere else.
For scientists like caver
Aaron Addison and biologist Steve Taylor,
these lava tubes are the Galapagos islands'
new frontier of discovery.
It is difficult to imagine,
or indeed believe that
there are still such untouched areas
within a place
that's so well known as the Galapagos
and so well studied.
But we do find those areas,
and those areas then lead us to new species
that are unknown to science because
they haven't been described
by anyone else, ever.
Black volcanic rock still lies only
a few inches down beneath the forest trees
of Santa Cruz.
It erupted millions of years ago
and flowed down
the sides of the interred volcano,
in rivers of molten red-hot lava.
As the surface of the lava cooled,
it solidified and formed
a rocky skin.
And when the eruption ceased,
the still liquid lava continued
to flow away,
leaving behind
these huge empty caverns.
And now, a constant trickle
of life-giving water
drips down into the winding tunnels.
Steve Taylor is an expert
on underground life.
The subterranean world is full of surprises.
It's just really exciting, because
these animals are pale and eyeless.
There's no selective pressure
to maintain eyes in a cave
so, they're blind.
And they often have elongated appendages
so they can either find prey,
or avoid prey.
This amblypygi,
half scorpion, half spider,
is a predator and a scavenger.
It might seem ungainly,
but it's well adapted to this black habitat.
Eyes are useless down here,
and it's become almost totally blind.
Instead, it feels its way through the cave,
with great skill and sensitivity.
Two of its eight legs are greater elongated,
and capable of extending
to twice the length of its body.
This millipede has lost all its color.
Why spend precious energy
creating a pigment,
in a place where no-one can see it?
Spiders too haunt the lava tubes.
And just like the Tortoises an Iguanas,
these creatures have evolved
into many different species.
There are 90 of them,
all unique to the Galapagos.
But spiders don't just differ
from island to island.
They do so dramatically,
even within a single lava tube.
Some that have been here for a long time,
are blind
and feel their way through the cave.
A few have lost their eyes entirely.
But living just centimetres from them
are more recent colonists.
Species that still retained their eyes.
Such variety in such a small area
seems extraordinary,
but on the Galapagos,
it's almost common.
The huge number of different habitats
has made Santa Cruz
a center of biological diversity.
And as an island ages,
so it develops more habitats.
Now, it's entering its old age.
It's no longer growing.
Its sheer mass is to heavy
for the earth's crust to support.
It begins to sink under its own weight.
And now, the rainwater that has been falling
on it throughout its middle age,
begins to carve away its substance.
So the island becomes smaller,
drier, and flatter.
That is what has happened
to Española.
It's nearing 4 million years old.
Its forests have gone.
But it now has a different range
of habitats.
Millions of years of erosion
have created beaches of soft sand.
And they suit some animals very well.
This is a natural bathing beach
for Galapagos sea lions.
They are just one of the very few mammal
species that are unique to the Galapagos.
And the beach of an aging island,
provides them with an excellent nursery.
Here, sea lion pups
can suckle in complete safety.
Though they can be a little irritating.
And in a protected cove,
close by the beach,
parent can teach their youngsters
to swim.
After a swimming lesson, the beach
is a perfect place to relax.
Sea lions seem to have an idyllic life.
But there is just one irritant.
Flies.
On the younger islands,
with rocky coastlines,
sea lions have help
to keep the flies at bay.
Lava Lizards.
But on the sandy beaches of Española,
the Lava Lizards are nowhere to be seen.
They prefer the nearby rocks,
which are warmer.
So, here, the sea lions must deal
with the fly problem by themselves.
Española's soft sand beaches
are also greatly valued
by an other species.
The waved albatross.
The island provides
an excellent nesting ground
for these huge seabirds.
With a wingspan of 2.
5 meters,
the albatross is so big and heavy
That it's to keep up
a considerable ground speed
in order to take off.
And that's what the beach provides.
As you might expect,
the species of Albatross that lives here
is slightly different than those found
in other parts of the world.
This wave-like patterns
on its neck feathers distinguish it
from all other Albatross species.
All Albatrosses spend
most of their lives on the wing,
travelling across entire oceans.
Here on Española,
the waved albatrosses can nest.
The isolation of the Galapagos,
and the protected
soft-shingled beaches of Española
make this aging island
an excellent breeding ground for them.
Waved albatrosses are monogamous.
They mate for life.
But how do you find a new mate,
or recognize your old partner
in such a crowded colony?
You dance.
The whole performance
can last for nearly an hour.
And it's repeated several times,
every day.
Sometimes, a potential rival
steps in to try his luck.
The female, in the middle, dances with
both enthusiastic males at the same time.
The reward for the victorious male is great.
A mate.
And an opportunity to pass on his genes.
The many habitats of Española,
and all aging Galapagos islands,
were created by the erosive power of sea,
and weather.
But, erosion can have only one final result,
destruction.
A Galapagos island
worn down by the waves and the weather,
eventually reaches the last stage
of its existence.
After millions of years sustaining life,
all that remains of it above water
is a rocky, curving cliff.
Like Tortuga.
There are many relic islands like Tortuga
in the Galapagos.
Devil's Crown, in the south
of the archipelago,
is even closer to disappearing altogether,
below the waves.
But even in its final days,
A Galapagos island provides
a habitat for some.
It's rock has been turned
by erosion into sediment,
and now that fertilizes the marine life
around its submerged remains.
A ring of coral, 2 meters wide,
encircles its dwindling stump.
So a whole new animal community develops.
Corals are at its center.
Bristle Worms hide inside them,
occasionally emerging
to browse on passing morsels.
Fish find safety among their brances,
and some of these species, once again,
are unique to the Galapagos.
The reef teems with life.
But the presence of warm water corals
here in the Galapagos seas,
is something of a surprize.
Because penguins, that need cold water,
live here too.
So, how can tropical corals
and penguins coexist?
The Galapagos islands
have one more trick up their sleeve.
The archipelago lies at the confluence
of several deep ocean currents.
And that creates a bizarre mixture
of marine habitats.
The subantarctic Humboldt current
flows around the islands,
and chills the water just enough
for the penguins to survive.
The corals can't grow in such cold water,
but they can go into a state
of semi hibernation for short periods.
When warm water
from Central America is dominant,
the temperature rises by about 7 degrees.
Now, the corals can grow.
And the penguins can find refuge,
in the few remaining pockets of cold water
in the coves and bays, that still remain.
So even in the last stages of its life,
a Galapagos island can support
a rich animal community.
But remarkably, even this
is not the end of the story.
Because even when an island
has totally disappeared beneath the waves,
it continues to influence life
in the surrounding seas.
The remains of ancience Galapagos islands
stretch for hundreds of miles
across the Pacific seabed.
These were once volcanoes like Fernandina,
vegetated mountains like Santa Cruz,
and low lying nurseries like Española.
Today, those environments are long gone.
But the remnants of the islands,
under the sea, are still key in the lives
of one of the oceans
most magnificent inhabitants.
Up to 12 meters long,
it's the largest fish in the world.
The Whale Shark.
Whale Sharks come to the Galapagos
in large numbers,
at the same time, every year.
But why they do so is a mystery.
Marine biologists, Alex Hearn and
Jonathan Green,
have spent the last 5 years
trying to solve the puzzle.
If you think about how Galapagos is formed
and how the currents work,
the most productive water
is actually out west.
So you would've thought that
if Whale Sharks were coming here to feed,
they'd be out
in the west of the Archipelago,
and they're not,
they're up north.
So why are they coming here?
It's clearly not to feed.
And what we found out recently is
that it's mainly large pregnant females.
Are they coming here to give birth?
This may be the pupping ground
for Whale Sharks.
I'm slightly skeptical.
I think we would've seen juveniles
and we don't.
So, that brings backs the question.
Well if they're not pupping here, and
if they're not feeding here,
why are they coming?
To understand the Whale Sharks'
migratory patterns,
Hearn and Green attach satellite tags
to the sharks they encounter.
This enables them to track their movements.
And it's revealing
some extraordinary new facts.
First, the sharks swim open-mouthed
through the rich waters
off the west coast of South America.
Then they continue their journey westwards,
to the Galapagos.
But they only spend a few days at a time
in the islands' waters,
before continuing westwards,
out into the open ocean.
Nobody has yet proved
why the Whale Sharks do this,
but Alex Hearn has begun
to formulate some ideas.
I think there are two possibilities.
Firstly, they may be using Galapagos
as a waypoint,
which directs them towards
their pupping grounds.
The other option is that Galapagos may be
providing a service for them along the way,
and that service may be cleaning,
because we do see a lot of cleaning behavior
from the reef fish.
Or it may be
a combination of the two.
The long line of submerged Galapagos islands
could play a central role in
the Whale Sharks' extraordinary journey.
It might be that they serve as signposts,
by which the sharks navigate.
If you start looking at where they're going,
especially the tracks that we have,
along those ridges, and then up to
the next ridge, and then back down again,
it certainly seems that they're associating
with those ridges,
for one reason or another.
That could be geomagnetism, or it could
also be something to do with the biology
of the water column above those ridges.
But cerrtainly, something is going on.
From their birth to their death,
the islands have acted like
evolutionary pressure cookers.
From the youngest islands like Fernandina,
the middle-aged ones like Santa Cruz,
and the old islands like Española,
they're extremely varied,
with contrasted conditions.
Deserts, rainforests, and polar waters,
crowded together in a very small area.
These huge variations
have created a wide range
of opportunities for the few animals
that have managed to reach here.
As they colonized,
so they adapted.
And consequently, flourished.
That explains many of the oddities
of the inhabitants of these islands.
Including that most
fundamental phenomenon of all,
the appearance of new species.
The giant tortoise is
the very emblem of the Galapagos,
in their heyday, there were
hundreds of thousands of them.
Not only that, there were
each in its own locality.
But why should there be so many species
within such a compounded restricted area?
In the next program, we'll look
at the deep geological forces,
that can make a single species
produce many
and turn the Galapagos
into this wonderland.
Missing parts added, corrections
and BluRay sync by: Rie van de Buggy's