All language subtitles for David.Attenboroughs.Conquest.Of.The.Skies.2of4.Rivals.720p.HDTV.x264.AAC.MVGroup.org.eng

We human beings are very
latecomers to the skies,

and although we might think that
we now pretty good at this,

the Natural World, with the help of
several million years of evolution,

has produce a dazzling range of
aeronauts whose talents are far beyond our.

The story of how animals manage to
colonise the air is truly astonishing.

First into the skies were Insects,

they initially had
two pairs of wings

which in due course were modified
in many different ways.

But after having had the skies for
themselves for about 100 million years,

a new group of animals
took to the air,

Vertebrates.
creatures with backbones.

They faced a different challenge, for their
bodies were much bigger and heavier.

But eventually they evolve several
ways of solving that problem.

We will travel the globe
to trace the details

of the extraordinary skills
of the backbone flyers.

English: Bobiko

~ Conquest Of The Skies ~

- RIVALS -

This is Borneo.

And here there are still great
tracks of pristine rainforest.

Forest that is wonderfully rich
in animals of all kinds.

I'm being winch up into
one of the tallest trees here,

in search of a creature
that can give us a hint

of how backbone animals
first took to the air.

Hidden among these leafs of this fern,
high up here in the canopy,

is a very remarkable little frog.

It's a Harlequin Tree Frog,
and it a very-very good climber.

It spend most of its life up here,
clumping around in the branches.

Here it's away from the
numerous predators there are,

that might attack it
down on the forest floor.

But if in fact, a predator were
able to get up here, to hunt it,

a snake perhaps, well, the Tree Frog
has a remarkable trick for defense.

It glides.

It has membranes between
greater elongated toes,

so that each foot becomes a parachute
which slow the frog descent,

and so enable it to make
a relatively safe landing.

The Vertebrates made their first forage
into the air around 260 million years ago,

and it very likely that some of these
pioneers use skinny membranes

to control their falls in much the
same way as this little frog does.

It has to be said that is not a
very good aerial navigator,

it seems that it just jumps
and hopes for the best.

But there are animals up here,
that glide around from tree to tree,

which are very good
navigators indeed,

so good in fact, that they can
go from one tree to another

and never go down to the
ground in their entire life.

One of them is a
little lizard called Draco.

Each male has his own little
territory in the branches,

and tries to attract females and
warn off rivals by flashing his dewlap.

He also spread colored
flaps of skin from his flanks,

that when fully extended do
more or less the same thing.

But there are predators
among the branches.

Snakes also live up here,
and they hunt Lizards.

But Draco side flaps now
serve another purpose.

He uses them to glide by hinging
forward a specially elongated ribs.

And he so skilled in the air
that he can steer land

on the trunk of his choice.

So, if you live up in the
branches it's less laborious,

and indeed, safer to travel by air,
than to come down to the ground.

But if you want to be a true flyer,
you have to be able to fly

not only downwards but upwards,
you have to have powered flight.

This is another reptile,

and one with even greater flying
abilities than that little gliding lizard.

Today, sadly, it's extinct.

This is Dimorphodon,
we can deduce from its fossils

that he had the muscles
needed to beat its wings.

And computer imagery can show us
what he must was look like.

Dimorphodon was one of the first
large animals ever to travel by air,

200 million years ago.

It belong to a group called the Pterosaurs,
The Winged Reptiles.

It was probably a forest dweller and
it descendant of a tree living glider.

This gliding ancestor might
have had wings like those of Draco,

that was made of skin, and perhaps
extended from its fingers down to its ankles.

But Pterosaurs have evolved larger wings
with a hugely elongated fourth finger.

The wing membrane was strengthen
internally by thin rods of a stiffer tissue.

They were muscles fibers too, that enable
it to modified its contours as it flew.

Looking at the wings insection
revealed a secret of their efficiency.

They have a rounded front edge
and a sharp back edge,

a shape known as an aerofoil.

It's works by forcing the air flowing
above the wing, to speed up.

This faster air has a lower pressure,
and the wing is suck upwards.

The larger the surface area of the wing,
the greater lift it can produce.

So, it seem certain that Pterosaurs
were very competent flyers.

And judging from their teeth,
it's seem likely

that many fed on the
great variety of Insects

that had preceded
them into the air.

Insects have had the skies to themselves
for around 100 million years.

Now, bigger creatures had arrived.

Reptiles.

The Pterosaurs design for flight
proved hugely successful,

and before long they had spread out
of the forest into new environments.

And some became monstrous.

The first large animals to fly
were winged reptiles. Pterosaurs.

They appeared in forests
around 220 million years ago.

As they became more successful,
they ventured into more open countries

and spread around the world.

A great number of them
lived and fed near water.

We know this because
fossils of many species

occur in rocks that was once mud
at the bottom of lakes and shallow seas.

This one shows the skeleton of little
animal that 150 million years ago

fell to the bottom
of a shallow lagoon.

This is its head, here is
its backbone, tail, hind legs,

and here stretching from these long
extended finger bones are its wings.

And this fossil is
particularly remarkable,

because it show an impression of the
membrane in extraordinary detail.

You can see every
little tiny fold.

You can judge how an
animal lived by its skull.

And this one,
have these long jaws,

with forward pointing teeth,
and we think that this indicates

that it lived by skimming
across the surface of the lagoon,

and snatching up fish
with impaled on those teeth.

The Pterosaurs diversified into
a huge variety of forms.

Many seem to been particularly
skilled at soaring and gliding

over the oceans,
looking for fish.

Some developed huge head crests
that were probably colored

and use for display
during courtship.

And a few became very big indeed.

This species had a wingspan
of over 20 feet, 7 meters.

But not all Pterosaurs lived
in the forests or near water.

An open arid landscape like
this one, was the likely home

of one of the most extraordinary.

Around 70 million years ago
a pterosaur appeared

that was of truly
colossal proportions.

That was one of the largest
creatures that had ever flown,

it was in the size of a small aeroplane,
and it was called Quetzalcoatlus.

Its immense wingspan allowed it
to ride on the currents of warm air

that rise up from
sun heated land.

It could then glide great
distances, searching for food.

Small creatures like lizards, or the
dead bodies of much larger ones,

Dinosaurs.

But the Pterosaurs, with their
wings of toughen skin

weren't the only group of reptiles
to make it into those ancient skies.

About 150 million years ago,
another reptilian group appeared

on the Planet that also flew.

Like most reptiles,
including Pterosaurs,

these creatures began
their lives inside an egg.

But they had evolved a
revolutionary new design for flight.

One that would usher in a remarkable
fresh chapter in our story.

And unlike the Pterosaurs,
they still with us today.

There are of course the Birds.

Some today can provide clues
about how their ancestors

manage to get into the air.

This is the chick of a bird found
in farmyards everywhere.

A Bantam Hen.

And at this very early stage in its life,
it can show us something very interesting

about the origin of that crucial
piece of flying equipment.

A feather.

Its feathers are downy, that to say
they made up of simple filaments,

and their function is not for flight,
but insulation,

to keep this little
creature warm.

And back in the Jurassic period,
long before the arrival of True Birds,

very similar looking feathers appeared
on very different animals.

Reptiles.
Dinosaurs if to be precise.

To find evidence for that
astonishing statement,

which not so long ago
was highly controversial,

we heading for China.

And here, I was able to see
the evidence for myself.

Some truly sensational fossils.

Northeast of China Great Wall,
near the borders of Mongolia,

lies the chilly province of Liaoning.

Here, there are great areas of
rocks that was lay down as mud

in the bottom of immense
fresh water lakes.

The bodies of animals that was
swept down into these lakes

was slowly entombed
by the fine grains sediment

that preserved them entire
and in exquisite detail.

And from these rocks
have come specimens

that solve one of the most hotly
debated of evolutionary arguments.

The origin of the Birds.

The key specimens are
now in Beijing,

where they been delicately
prepared under the microscope.

They have been studied here by one
of the world greatest Dinosaurs experts,

professor Xing Xu.

First, he showed me one
of his oldest specimens,

part of a Dinosaur arm.

But thanks to the finest of the
mud of those ancient lakes,

there is more here
than just bones.

You see here, this species
it called a Beipiaosaurus,

So, because this is a very
not like us, two or three meters long,

so quite a big animal.
And here is an arm,

hand, you see here...

dark filamentous structures...
-yes.

along that arms and hand,
they are actually primitive feathers.

And those feathers very simple,
very simple,

so we believed they represent the very
primitive stage for feather evolution.

These simple strands were
made of the same material

as the feathers of today Birds.

They were relatively thick
and must have been quite stiff,

so they would of stuck out
beyond the dinosaur arm.

Behind them, were shorter strands
that covered its all body.

Like the down on the chick,
these might have kept the dinosaur warm.

But those long strands most
likely had a different function.

Clues to what that might
have been can be found

on an even more
extraordinary fossil.

These claws and finger bones belong
to a creature called Caudipteryx.

The long dark shapes around them
are the remains of feathers.

The single strands are here
rather more complex.

They had barbs, thin filaments
attached to either side of a central rod.

This look more like a bird feather.

Caudipteryx had around 26
of them along each arm.

This may look like a wing,
but the feathers were not very long.

And when you compare them
to the size of this creature body,

and its long legs,
it's clear

that they weren't big enough
to enable Caudipteryx to fly.

So, what were these feathers for?

Microscopic examination has revealed
that they were colored and patent.

So, maybe they were
used for display,

perhaps to wave around during
courtship to attract a mate.

But then is seems that they also
helped the dinosaur in a different way.

We can find a hint of how
they might have done this,

by watching the way some young
birds use their first feathers today.

These are tender old
Pheasant chicks.

Their feathers are not
yet fully developed.

At this stage they similar in structure to
the feathers on that dinosaur, Caudipteryx,

and going aline along each
arm in much the same way.

But these early feathers are also too
short to enable these creatures to fly.

Nevertheless they very helpful.

Pheasant chicks has to
nest on the ground,

but they soon need to roost high up,
where they are be safe from predators.

Flapping these simple wings
gives the chicks a little extra lift

to help them climb into a tree.

And when the time comes
to return to the ground,

those first feathers
again are a help.

They don't provide a large
air-catching surface,

but they enough
to slow a chick fall,

and make that landing
just a little softer.

Maybe the feathers that had
initially kept the Dinosaurs warm,

now also help them
to get into the air.

And then,
only a few years ago,

the mudstone of Liaoning produce
yet another extraordinary fossil.

It been named Microraptor,
and it clearly a small dinosaur.

But this specimen it particularly
exciting, because of its feathers.

Feathers on the forearm there.

Feathers on its hind limbs.

And even feathers right at
the end of its very long tail.

But there is something that
makes these feathers

different from any other feathers
you seen on Dinosaurs before.

They are narrower on one side
of the quill than on the other.

Just like bird feathers.

Microscopic structures within them suggest
that they had flashes of iridescence.

So, these feathers were
probably use for display.

But their asymmetric shape is
characteristic of flight feathers.

The air flowing over the narrow
front of the feather can produce lift.

So, could this strange looking dinosaur
with feathers all over it actually fly?

Some people think that those
feathers on its hind legs

would have made it rather difficult
for it to walk around on the ground,

and that it would had been
more at home climbing.

And those claws on the
fingers and toes

are obviously very helpful
in climbing up tree trunks.

But those aerodynamically shape
feathers certainly suggest

that its arms were
been used as wings.

This four wing dinosaur must had
been a really extraordinary animal.

Its front wings were broad
enough to enable it to glide,

and its muscles on the chest
were sufficiently strong

to enable it to flap
every now and then,

and help it on its way.

But the wings on the hind legs
were probably not held spread out,

but kept beneath the body
to help the animal to steer.

Now, clearly, these Dinosaurs
were on their way

to joined the Pterosaurs
in the sky.

And then, around 130 million years
ago the True Birds appeared.

And here, on the Lochs in Scotland
are some of the most majestic

of those little around today.

Whooper Swans.

These particular birds were
in contact with human beings

from the very first moment
of their hatched,

so they allow me to get
really close to them.

The small feathers on their bodies are still
essential for keeping their owners warm.

But this one is a wing feather.

It extremely strong,
but very light,

and the filaments on either
side of the quill and the barbs,

zip together to form a continues surface
which will strong enough to hold the air.

But if the air is to support
a wing bird as it flies,

it has to move over
the wing very fast.

And in order for that to happen,
these Swans will move at speed

across the surface of the water like
an aircraft taxiing before take-off.

When you close up to
a flying bird like this,

you can see how a wonderful piece of
complex engineering their wings are,

able to change their shape
and their beat

to respond to every little change in
the currents of the air around them,

and so propelled them forward
and lift them upwards.

So, how the bird wings
actually work?

If we slow them down we can watch
in detail the mini subtle changes

they make as they
move up and down.

The feathers overlap to form
a smooth contoured surface

that extends far beyond
the bones within.

With a curved leading edge of the front,
and a sharp trailing edge of the back

they have a classic aerodynamic
shape that produced lift.

They are aerofoils.

With this downward beat the air
pressure above is reduced,

so that the bird is sucked upwards.

Wings like these consisting of jointed bones
covered with closely fitting feathers

can make very subtle delicate movements.

The feathers slide over one another,
so that when the wing changed its shape

there is no loss of smoothness
on the contour.

When the Swan slightly retract
its wings in between beats,

the sliding feathers ensure that
the aerofoils still produces lift.

And the bird bodies have become
modified in another way.

They become light weight.

The Dinosaurs heavy
bony jaws lined with teeth

have been reduced to a
light weight beak of horn.

The bony tail has shrunk to a stump,
nearly an attachment point for the tail feathers.

And many of the bones within
the body had become hollow,

so reducing weight even further.

The result is an extremely
efficient light weight flyer.

We are traveling around 30
miles an hour now,

and yet these birds could easily accelerate
and leave us behind if they wanted to.

So feathers, since they're first
appeared on the bodies of Dinosaurs,

have acquired several different functions.

Initially they served to keep
their owners warm.

Then, some grew large and acquired color
and were probably use in courtship displays.

And only then,
after millions of years,

where they used to help their
owners get into the air.

But the Birds were not the last
animals to acquire the ability to fly.

When the Pterosaurs vanished
together with the Dinosaurs,

there was room in the skies
for yet another aeronaut,

And one appeared with yet
another kind of wing.

Animals on our Planet have
flown for over 320 million years.

First came insects, then a group
of winged reptiles, Pterosaurs,

and next, Birds.

Then, around 66 million years ago,
came the global catastrophe

that triggered the disappearance of a vast
proportions of the animal life of this Planet.

An asteroid hitting the Earth was the
most likely cause of this mass extinction.

In the devastation that followed,
the dominants creatures of that age,

the Dinosaurs, disappeared.

The Pterosaurs were completely wipeout.

And only a few of the Birds survived.

The skies for a short period
must have been relatively empty.

But then, a new kind
of flying animal appeared.

Now had a chance for a group of
furry warm blooded little creatures,

that has been scampering around the feet of
the Dinosaurs for several millions years.

They were the mammals.

The first of them to take to the air
were doubtous gliders.

And one mysterious creature
still alive today,

can give us an idea
of what there were like.

It lives in the rainforests of Borneo,
and it called the Cobego.

It has an enormous blanket
of furry skin that stretched

from the sides of its head right
down to the very tip of its tail.

But to see how he travel through
the air, we must wait until nightfall.

As soon as it lands, it regain the
height it inevitably lost

by clambering up the trunk.

It by far the most skillful
of the forest gliders,

and can travel over a
100 meters in one leap.

It undoubtedly a very ancient animal,
and some believe that it may well

have survived virtually unchanged
from that time long ago

when mammals first took
to the skies as gliders.

But soon, the mammals
deed better than that.

This is a fossil that dates from
about 52.5 million years ago.

Here its head, a very well
develop teeth, backbone and ribs,

a long tail, hind legs,
and most importantly of all,

from our point of view, hands with
enormously elongated fingers.

And there was skin
between those fingers.

These were wings
and they could flap.

This is the earliest fossil
yet discovered of a bat.

We have new evidence to show
exactly how a bat fingers

first began to lengthen
to support their wings.

But we can understand how
those early bats flew,

by looking on their
modern descendants.

These are some of the largest.

They so big, that they often
called Flying Foxes.

And they have a wingspan
of over a meter.

When you slow a bat
flight down like this,

you can see that its four fingers
are spread wide under down stroke,

keeping the membrane wide and taut,
and then clump together on the up stroke,

with just a thumb
off the top three.

This folding of the wings reduces the
bat air resistance between each beat.

To maximise the size of its wing,
the back edge of the wing membrane

is attached to the ankles.

Bats roost by hanging upside down.

And this is how they tend
to spend their days.

Is thought that the first
mammals were nocturnal,

that doubtless was the best thing
to be out of the way of the Dinosaurs

that were rampaging around
during the day.

So, the bats continue the nocturnal
habit of their ancestors,

and they are also inherited the acute
sensors needed to move around at night.

Eyes specially adapted to
operating well in low light.

And an acute sense of smell that
enable them to find food in the dark.

In any case, Birds already
dominate in the daytime skies.

With their wings of skin
and nocturnal senses

the Bats became a
hugh global success.

Today there are over
1,100 species of them,

that's over a fifth of all mammals.

So, by 50 million years ago,
three groups of large backbone animals

had joined the Insects in the air.

The pioneers were reptiles,
Pterosaurs,

with membrane of skin stretch
from elongated fingers.

Then, came a group of Dinosaurs
that acquired feathers and became Birds.

But when the Pterosaurs and Dinosaurs
were swept away in a global extinction event,

the stage was set for the Birds
and the newly emerge Bats

between them to
take command on the skies.

Each of these two groups had evolved
its on techniques for getting into the air,

and each was destined to bring
theirs skills to astonishing extremes.

Next time, we see how Birds
adapted and diversified

to become the remarkable creatures
we see in our skies today.

Lethal hunters...

formation flyers...

an aerial acrobats.

We explore how the Bats
develop a new super sense

that enable them to hunt in the
pitch-blackness of the night.

And we visit one spectacular place
were the battle for the skies,

between Insects, Bats
and Birds still continues.

English: Bobiko

Written and Presented by
David Attenborough