All language subtitles for History.Of.Life.Series.2013.S01E03.1080p.AMZN-WEB.DL.DDP20.H.264-iND_track3_[eng]

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This is the upper
region of the Amazon River.

A descendant of dinosaurs
inhabits this dense jungle.

It is a bird called the Hoatzin
and has deep maroon eyes.

Living in swamp
areas, the Hoatzin only

eats leaves and fruits.

It has a few
peculiar characteristics.

The reason why Hoatzin
is called a descendant of

dinosaurs is because
juvenile Hoatzins have

two claws on each wing.

These claws will disappear
once they become adults.

So no claws can be seen
on these adult Hoatzins.

But the bird has
inherited something more

marvelous from dinosaurs.

Feathers.

A marvelous
invention of nature.

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This exhibit at the Natural
History Museum in Berlin,

Germany, shows
beautiful bird feathers.

There is one
eye-catching display of a

feather imprinted on stone.

It is a delicate
imprint that perhaps,

a master painter
could have drawn.

But in reality, it is a
150-million-year-old fossil.

And the feather is
from Archaeopteryx,

the oldest known bird.

Yet, Archaeopteryx is
more like a dinosaur

than a bird in some ways.

It has a bony tail
like a dinosaur and

sharp claws on its wings.

It also has teeth.

However, its feathers are
unmistakably bird feathers.

Is Archaeopteryx the
earliest ancestor of modern

birds or is it a dinosaur?

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150 million years ago, a
single feather from an

Archaeopteryx fell and
became fossilized, holding

the key to the the evolution
of birds and dinosaurs.

Some facts in
history are sometimes

upended by new discoveries.

In 1996, a Chinese farmer in
a small village in Liaoning

discovered a rock that
challenged the existing body

of knowledge on dinosaurs.

The rock contained a
fossil of a creature

that looked like a lizard.

But what made this
find astonishing was that

it had primitive feathers.

The fossil was that of
a carnivorous dinosaur.

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Sinosauropteryx means "Chinese
reptilian wing" and several

other fossils of this
dinosaur have been found,

ranging in different sizes.

It was an important
discovery because it showed a

dinosaur with a furry coat.

Fossils are not
just ancient rocks.

They can reveal
secrets from the past.

Xu Xing, a famed
paleontologist identified

feathers on a
120-million-year-old fossil.

The dinosaur was
covered with feathers.

Unlike existing
bird feathers, these

were thick, proto-feathers.

This dinosaur was
Beipiaosaurus, a carnivore.

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More fossils of feathered
dinosaurs were unearthed.

China became the
focus of interests among

paleontologists from around
the world when the first

feathered dinosaur was
found in the country.

Long ago in prehistoric times,
feathered dinosaurs might have

been the dominant species
on the Asian continent.

The Linheraptor
lived in a region that

is now Inner Mongolia.

As an agile predator, it
could quickly chase prey and

pounce on it using its claws.

It was a bird-like dinosaur
that had proto-feathers.

The velociraptor was portrayed
inaccurately in a movie,

where it was shown
without feathers and

larger than its actual size.

The feather-covered
velociraptor looks quite

different from typical
illustrations of dinosaurs.

There is a mystery
as to why carnivorous

dinosaurs needed feathers.

Let us take a look at
another feathered dinosaur.

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Despite being small in
size, Dilong is a member of

Tyrannosauroidea of which the
Tyrannosaurus rex belongs to.

However, Dilong's proto-feathers
had different characteristics.

Dr. Xu Xing thought
dinosaur feathers were

used as thermal insulation.

A fossil discovered in 2004
supported his hypothesis.

Meilong means
sleeping dragon in Chinese.

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Standing erect, it
reveals its small body.

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Meilong was a small
carnivorous dinosaur and

probably took naps after
chasing small prey all day.

But it moved like a bird.

Meanwhile, Professor Richard
Prum of Yale University found

that dinosaur's proto-feathers
were similar to that of

the earliest bird feathers.

This is a simple hollow tube.

This is the kind of
feather that's very like the

hypothesized structure of
the very earliest feather.

A simple tube.

The black tube that Professor
Prum showed us is from the

feather of cassowary, a bird
that inhabits tropical forests

in Australia and New Guinea.

The Cassowary is a
flightless bird that uses

its feathers to stay warm.

Likewise, primitive feathers
probably kept dinosaurs warm.

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The first feather was probably
hollow like a cassowary's

feather and began as
a strand of fiber.

This simple tube-shaped
fiber evolved into a complex

structure with
interlocking barbules.

A vaned feather has branches,
which are called barbs.

Barbs, in turn, have smaller
branches called barbules

that have minute hooks.

The hooks interlock to The
evolution of feathers began

from such a simple structure.

And over millions of years, it
evolved and diversified into

various colors and sizes.

Magnificent feathers
cannot be replicated by man.

Other mysteries about
feathers can be unlocked

through scientific analysis.

Prof. Prum has studied
many different kind of birds

and found evidence that
dinosaur feathers had other

uses than thermal insulation.

One of the more exciting
discoveries that have recently

been made about fossil feathers
have been the discovery that

one of the most abundant or
common pigments of feathers

actually fossilized very
well under good conditions.

This fossil is dated
160 million years and has

well-preserved pigments.

It is the fossil of Anchiornis,
a feathered dinosaur.

This bird feather is magnified
under an electron microscope.

The tiny flecks are
melanosomes which contain

melanin, a common
natural pigment in nature.

It determines the
color of the feathers.

Professor Prum and a team of
researchers discovered melanin

pigments in an
Anchiornis fossil as well.

Melanin pigments
that make the black,

brown and deep reddish
colors of hair or feather are

packaged into tiny organelles
that look like grains of rice.

The pattern of melanin
pigments found in the

Anchiornis fossil is similar
to that of Hamburg chickens.

Anchiornis probably
sported colors similar to

modern chickens
160 million years ago.

Featuring a red comb, the
Anchiornis had white and

black-striped wings which it
likely showed off to rivals.

Modern birds like
Hoatzin use its feathers

for extravagant display.

The male's beautiful plumage
helps it court females.

Not only does the Hoatzin
ward off competitors with its

plumage but it also uses
it to court the female.

Meanwhile, Dr. Xu Xing
learned that Anchiornis also

used its plumage for courtship.

Long feathers grew on
Anchiornis' hind legs.

And they served a
special purpose.

The feathers
allowed Anchiornis to

glide like a flying squirrel.

Australia boasts unique
animal life that is not found

elsewhere on the planet.

The ostrich-like emu
grows as tall as 2 meters,

making it the world's
second largest bird.

But it is flightless.

The reason why emus cannot fly
is because of their feathers.

It's impossible to fly with
such easily bendable wings.

What does a feather of a
flying bird look like?

The rachis or
shaft is not placed in

the middle of the feather.

In this vaned feather, you can
see that rachis is closer to

one side, demonstrating
its asymmetrical design.

Flightless birds like an
ostrich have feathers where

its shaft is
placed in the middle,

giving it a
symmetrical design.

A bird with such
feathers cannot fly.

Only birds that have
asymmetrical feathers can fly.

In order to create the
physical forces that are

required for bird flight,
the feathers on the bird

have to be asymmetrical.

A flying robot was tested at
KAIST to see how asymmetrical

and symmetrical
feathers affect flight.

A basic model of symmetrical
feathers found in flightless

birds was tested
in a wind tunnel.

The "feathers" in the
model could not withstand the

crosswinds and began
shaking vigorously.

Under stronger winds, the
"feathers" were blown away.

This feather model would
never make flight possible.

Now the asymmetrical
feather model was tested

under the same conditions.

The model stayed stable
under the crosswinds.

And maintained its
balance under stronger winds.

People cannot tell if a bird has
asymmetrical feathers on sight.

But all birds of
flight have these feathers.

Even this 150-million-year-old
feather of Anchaeopteryx

has an asymmetrical design.

This means that Anchaeopteryx
was probably able to fly.

Paleontologists who studied
feathered dinosaurs realized

this as an
important discovery.

The theory that
Anchaeopteryx could fly despite

its dinosaur-like body...

They needed to focus on
feathered dinosaurs that had

asymmetrical feathers
like the Anchaeopteryx.

Dr. Xu Xing and his team of
researchers found a dinosaur

that had
asymmetrical feathers.

The feathered dinosaur,
Microraptor lived

120 million years ago.

The curved feet in this
microraptor fossil is an

indication that it dwelled in
trees like the anchaeopteryx.

Its body was also
covered with feathers.

Peculiarly, it also had long
feathers on its hind legs.

Faint patterns showed it
had feathered tail too.

Possessing feathers
designed for flight,

the microraptor's legs
also had long feathers.

Paleontologists from
around the world were drawn

to this four-winged dinosaur.

Among them was
Professor Larry Martin of

the University of Kansas.

Microraptor is the animal
that turned the corner on the

theories about the
origin of flight.

Microraptor had a
tail that was several

times the length of its body.

From studying its
bone structure,

paleontologist can tell
how it flew in the air,

its habitat and if it was
a meat-eating carnivore.

We were able to see that the
bones would articulate in such

a way that it
could for instance,

climb a tree very easily.

But it could also take the
arms and spread them out to

form a wing and to
take the legs and spread

them out to form a wing too.

This is a model of a
Microraptor with its muscle

structure and
feathers recreated.

With its wings spread,
it looks like a bird.

The long feathers on it
legs prove that Microraptor

inhabited trees
like modern birds.

It means that it couldn't walk
comfortably on the ground,

let alone run.

And that means that this
was an animal that probably

lived entirely in the trees.

And was using these wings
to glide from tree to tree.

120 million years ago in
a prehistoric forest...

This four-winged microraptor
climbs a tree using its claws.

Like a modern
bird, the microraptor

was at home in trees.

was at home in trees.

When it moved to
another tree, it spread all

four of its wings to glide.

This is probably how
the earliest flight in the

animal kingdom occurred.

The discovery of the
microraptor and four wings

and recently anchiornis,
which also has four wings,

in fact, is older than
Archaeopteryx, indicates very

strongly that the proto-bird
was an arboreal quadrupedal.

Like the microraptor, which
lived 120 million years ago,

the hoatzin dwells in trees.

But it has far
superior flying capabilities

compared to the microraptor.

The secret to how feathers
and flight evolved is revealed

by studying Hoatzin feathers.

Using a microscope to
magnify the feather,

you can see small barbs
with hooked barbules

interlocking with each other.

This is a characteristic of
feathers from birds of flight.

After the evolution of a
coherent vane or a tight vane

with hooked barbules
that create a surface,

it was only then we could
have the evolution of feathers

that were useful in flight.

As feathers evolved into
more complex structures,

they improved the flying
capabilities of birds.

This proves that feathered
dinosaurs that mastered flight

were actually a new
evolution in dinosaurs.

The theory that feathered
dinosaurs could fly have

altered our
knowledge of dinosaurs.

Like the velociraptor, there
were other dinosaurs on

land that had
primitive feathers instead

of scaly lizard-like skin.

The mounting evidence of
feathered dinosaurs has also

affected studies
linking birds to dinosaurs.

We conceptualized
dinosaurs as being big,

sluggish lizards with their
tails dragging on the ground.

They're actually very
active animals like birds.

And then when we found the
feather impressions on that

that only
cemented the argument.

Dr. Luis Chiappe of the
Natural History Museum of Los

Angeles County proposes a
theory that velociraptors

might have been the
ancestors of birds.

As evidence, he points
to their bone structure.

This is the wishbone
of the velociraptor.

There's a bone here in the
wrists that allowed the wrist

to fold and essentially to
swivel just the same way that

it swivels in modern birds.

Here's a reconstruction
of archaeopteryx.

You can see
again the wishbone.

You can see the details in the
wrist that are very similar to

those of the velociraptor.

The feathered dinosaur
velociraptor lived 80

million years ago and
might have been evolving

into a bird at the time.

On its chest, it
had a V-shaped bone.

And its wrist could
swivel side to side.

The direction of its hip
bone was facing forward.

This bone structure is
similar to an owl's bones.

A V-shaped chest
bone is a pronounced

trait among flying birds.

Dr. Chiappe posits that the
bone structure of dinosaurs

give away telling
signs of how they evolved.

This is the University of
Montana Flight Laboratory.

Professor Ken Dial
uses a different approach

from paleontologists
and ornithologists

to study bird flight.

He unlocked the secrets to
flight by studying how chicks

flap their wings to climb.

A one-day hatchling
cannot fly at all.

But it uses its wings to
prevent itself from slipping

as it climbs a ramp.

Birds use their wings to
move aerodynamically

through the air.

To help their feet when
they're going up an incline or

they use their wings when
they're coming to descend down.

Over time as the young bird's
wings become more developed,

its ability to
fly also improves.

An adult bird with fully-grown
wings can easily climb a

ramp at a 90-degree angle.

Every day if you
watch baby birds develop,

they're teaching you
how a partial wing,

how a half a wing, how a
three-quarters shaped

wing can be functional.

Every day they grow up.

The way young birds learn
how to use their wings step by

step could have been
similar to the evolutionary

stages of feathered dinosaurs.

During the period when
feathered dinosaurs began to

fly, there was also a
flying reptile species.

This is the fossilized
footprint of a Pterosaur which

was called the
ruler of the skies.

Some pterosaur specimens
were rather small while others

became the largest flying
animals of all time with

wingspans exceeding 10 meters.

The size of this
pterosaur can be deduced by

the size of its footprint.

Pterosaur first appeared
250 million years ago, which is

much earlier than the evolution
of feathered dinosaurs.

These reptiles ruled
the skies unchallenged

for 200 million years.

But the wings of a pterosaur
were different from that of

feathered
dinosaurs or modern birds.

Professor David Martill of the
University of Portsmouth is

knowledgeable about
pterosaurs and explains the

structure of its unique wings.

This is the palm of the hand.

Whereas our palm of the
hand is very, very short.

In pterodactyls,
it's very, very long.

And then most
pterodactyls have three very,

very short fingers just here.

They seem to have
lost the thumb.

But they have one
very, very long finger,

which is equivalent to our
number four finger and this

finger extends all
the way along here.

So this is an enormous finger.

One of the longest
fingers you'll find

in the animal kingdom.

And all of this makes
the spar of the wing.

This is the
support of the wing

How did the pterosaur
fly with such long wings?

First, it had to crouch
into a launching posture,

after which it would
have lifted its rear legs and

then lean on its forelimbs.

It could flap its wing
at this point to fly.

With its
membrane covered wing,

the pterosaur flew
gracefully in the air.

It had the ability to cover
hundreds of kilometers in a

single flight And experts
considered the pterosaur to be

a very well-adapted animal as it
survived for 200 million years.

Its bone structure
gave it an advantage.

Pterosaur had
hollow bones that were

less than a millimeter thick.

These hollow bones are
even lighter than bird bones.

Air occupied the inside of
the bones to assist flight.

But the thin
membrane on its wings was

fragile and easily infected.

If a pterosaur had
an injured wing,

it could not fly
until it healed.

Thus, these fragile wings,
which were susceptible to

the environment,
put the pterosaur at a

great disadvantage later on.

65 million years ago,
practically all life on earth

was wiped out by a
cataclysmic event.

Pterosaur and all dinosaur
species became extinct.

If there was a period
of even just perhaps,

six months where they were
unable to fly because of high

winds and other aspects of
the climate that made it

problematic for them to
feed, it would be very,

very easy to wipe out the
last few pterodactyl species.

Yet, how did birds survive
this unfortunate event which

exterminated pterosaurs?

The answer is found
in prehistoric birds.

The prehistoric bird
Confuciusornis existed

125 million years ago.

Upon inspecting the bone
structure of Confuciusornis,

signs of the evolution of
bird flight are revealed.

Its tail bone was short and
stunted and it had a toothless

beak like a modern bird.

Based on these
characteristics,

Confuciusornis look
similar to birds of today.

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Prehistoric birds were able to
avoid extinction because their

bone structure allowed them
to fly under any conditions.

Not only did they have
feathers but they also had a

body structure that
was highly adaptable.

Yanornis lived in the same
period as Confuciusornis

and is even more
similar to modern birds

than its prehistoric relative.

Small feathers were
discovered on its wings.

And its shoulder
blades were well developed,

allowing it to flap
its wings vigorously.

Yanornis lived near the coast
where food was plentiful.

It flew freely in the
skies 125 million years ago.

It was able to adapt to a
variety of environments,

allowing the species to
flourish for millions of years.

Yanornis is an
ancestor to modern birds.

Birds that descended from
prehistoric birds continued

to hone their flying ability.

The condor that inhabits the
Andean mountains can fly 6000

meters above sea level easily.

Inhabiting the coastal regions
of the Atlantic Ocean and

Pacific Ocean, frigatebirds
can reach a maximum speed

of 400 kilometers per hour.

Hummingbirds, which are
the world's smallest birds,

can beat their wings
80 times per second.

They can also hover
mid-air and fly backwards.

They can also hover
mid-air and fly backwards.

One flock of snipes migrated
from Australia to Siberia,

flying nonstop for five
days and covering an

astonishing 10,000 kilometers.

When a bird can fly for five
days nonstop using a million

wing strokes and not develop
lactic acid buildup - and

therefore, just fall out of
the sky - you come to learn

that there's something about
the physiology of birds that

have become very
specialized in certain groups

for long distance movement.

Birds have populated diverse
habitats through their amazing

feats of flight that
defy human comprehension.

Every October, Baikal teal
arrive in South Korea and then

fly a thousand kilometers
to their nesting grounds in

Siberia when spring comes.

Birds were able to survive and
prosper on earth because they

possessed the ability to fly.

Dinosaurs that once ruled
the planet developed feathers.

These feathers gave dinosaurs
the ability to take flight and

opened up new,
unlimited possibilities.

Flight feathers are one of the
most interesting and important

innovations in the
history of vertebrate life.

We have witnessed this
marvelous innovation around us.

So dinosaurs still rule.

We call this the age of mammals
because we write the textbook.

But if you're just
counting number of species,

the dinosaurs have been running
the show for 240 million years.

A single feather
dated 150 million years

contained many secrets.

Archaeopteryx is believed
to be the ancestor of birds.

But perhaps, the
feather of Archaeopteryx

is a dinosaur feather.