All language subtitles for History.Of.Life.Series.2013.S01E04.1080p.AMZN-WEB.DL.DDP20.H.264-iND_track3_[eng]

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There is a wild
island in Indonesia.

Early in the morning, when the
rays of the sun spread to the

foot of the mountain, a
monster stirs from its sleep.

This is an island
full of danger.

Predators are
lurking in every shadow.

Finally, the
monster begins to move.

This vicious and ill-tempered
predator is the Komodo dragon.

The creature spies its target.

It rushes towards its
prey at full speed.

The monster rarely fails
in its hunting attempts.

It swallows both flesh and
bone with its gaping jaws.

Wherever this
monster goes, death

follows close on its heels.

Designated by UNESCO
as a Natural Heritage,

Komodo National Park is a
natural Komodo dragon reserve.

This giant lizard can grow
up to 3 meters in length and

reach 70 kilograms in weight.

It is a fearsome predator and
natural-born killing machine.

It can easily detect
the movement of

prey with its sharp eyes.

Also, it uses its highly
sensitive tongue in order to

track down and
hunt its victims.

It can even sense prey as
far as 4 kilometers away.

It is also armed with a tail
powerful enough to fell a wild

boar with a single stroke.

And its saliva is a cocktail
of toxic bacteria so that even

a single bite will
cause its victim to die.

This animal was
born to kill, and will

whenever it gets the chance.

Komodo dragons rush towards
a freshly killed animal,

fighting for an
extra morsel of flesh.

Such feasts also afford the
dragons with an opportunity.

The Komodo dragons
are solitary animals,

so they don't gather
together very often.

So when you have
a dead animal,

a carrion, and then you
have different animals,

different komodo dragons that
feed on those dead animals,

then you will have a
mixture of males and females.

So that will be an opportunity
for Komodo dragons actually to

meet at the same place.

The Komodo dragon
is a solitary animal,

but from May to August
which is mating season,

it begins to search
for its other half.

But this mating
instinct is often the

cause of fierce battles.

Only the strongest
of this species can

earn the right to mate.

The males engage in fierce
battles which often prove

to be fatal for the loser.

This is a sight that can only
be seen during mating season.

When a male Komodo
concedes defeat,

it may never get the
chance to mate again.

And to the victor
goes the spoils,

which in this
case is a female.

Rubbing a female on the
cheek is an act of courtship.

And if the female acquiesces,
mating can commence in earnest.

Love seems to be a basic
instinct to even to these

vicious and cruel creatures.

And it is this basic
instinct that makes them

more aggressive
than any prey could.

What is it about mating that
makes the Komodo dragon risk

its life for the privilege?

We have millions of species.

We've had millions of
species that have gone extinct

in the past and I
think that without sex,

we will live in a much simpler,
less interesting world.

Under the sea, a pair of
Mandarinfish engage in an

elegant courtship dance.

The tiny ladybug holds
marathon mating sessions that

last a mindboggling 9 hours.

Early in the autumn, a
pair of Truljalia hibinonis

crickets enjoy making love.

This is a once-in-a-year
occurrence for them.

Earthworms, which possess both
male and female reproductive

organs, release sperm into
each other's spermatheca.

In this way, mating is a
wonderful and oftentimes

dangerous
endeavor to undertake.

Countless creatures big and
small mate all over the world

in order to produce offspring.

So, when did genders and
sex first come into existence?

The answer to this riddle
can be found in Chlamydomonas,

a kind of green algae.

This tiny, single-celled life
form is invisible to the naked

eye, and it has no gender.

It copies its DNA in
order to propagate.

3.5 billion years ago, Earth was
home to such microorganisms.

For single-celled organisms,
self-replication is the

fastest and most
efficient way to propagate.

But as nutrients in the oceans
began to dwindle due to a

change in the
Earth's environment,

these organisms were pushed
to the brink of extinction.

And they were
forced to look for another

strategy for reproduction.

We moved Chlamydomonas
to an environment

devoid of nutrients.

This caused pairs of
Chlamydomonas to quiver

and collide with each other.

Soon thereafter, the two
organisms fuse into one.

In order to survive in a
nutrient-poor environment,

the two organisms decided
to pool their resources.

A significant change occurs
when the two single-celled

organisms come together.

The new organism
retains the DNA of both

single-celled organisms.

When this organism
undergoes mitosis,

a completely new
species with a completely new

genetic sequence results.

And when this process
is repeated, it results

in the creation of male
and female, that is gender.

You can think of it as
shuffling the deck in a game

of cards, that is, if you
don't mix things up when you

prepare to play cards so that
all the cards are re-assorted,

you'll end up getting
the same cards over and

over again in the process.

And the reason why you want
to mix things up is to

take advantage of
increasing the diversity of

what you might get dealt.

This is a tropical rainforest
in Peru, South America.

Somewhere in this
forest lives an insect prized

for its rarity and beauty.

Each year, countless insect
collectors venture into this

forest in order to find
this precious species.

We find this rare insect
amidst a patch of leaves

glistening in the sunlight.

It is an agrias butterfly,
the jewel of the forest.

The butterfly
spreads its wings,

revealing its
beautiful vivid colors.

Each butterfly of the
species is marked with a

different pattern on its wings.

The butterfly is testament
to the diversity that arises

from sexual reproduction.

Such diversity is not
merely an external phenomenon.

It also affects such important
matters as the ability to

survive and adjust to
various environments.

Sex is very good, enabling you
and your offspring to quickly

find new combinations to
changing circumstances,

whether it's the introduction
of an antibiotic or a

different temperature, or some
change in the environment.

Through sexual reproduction
which brings together male and

female and allows for
a combination of their

genes to be passed
down to later generations,

creatures big and small were
able to evolve a diverse array

of characteristics to
help them adapt to Earth's

endlessly
changing environment.

Also, males and females each
took on specialized roles.

Males provided the sperm which
fertilized the eggs of females.

But somehow, it seems that
females became trapped in an

unfair arrangement where
they must carry their offspring

and give birth all alone.

Nevertheless, this
arrangement does have its

advantages for females.

This arrangement has
given specialized roles

to the males and females.

Males must court females
for a chance to reproduce,

while females are able to
pick and choose their mates.

This is a tideland, home to
countless species of fauna.

From May to August, during
the low tide when the water

recedes, a unique courtship
ritual takes place here.

It is the courtship
ritual of the fiddler crab.

A male crab waves its
large claws in the air in

a threatening manner.

This is actually a
serenade of sorts.

It is courting females
through this behavior.

The tidelands serve as a
ballroom where fiddler crabs

perform their mating dance.

The males court the females
ardently and persistently.

They even engage in
fierce battles for the

affections of the females.

Such violent altercations are
a chance for males to prove

their physical
strength and prowess.

While the loser often
meets with a tragic end,

the victor is able to
court the female unimpeded.

It enters its home, waiting
for the female to follow suit.

But the female does not
seem at all interested.

The male has no choice but
to resume his courtship.

Courting a female can be a
trying and frustrating task,

but the male must not give up.

The male is the sex that must
seduce while the female is the

sex that can pick and choose
whichever partner she pleases.

This is a rule decreed
by Mother Nature herself.

When mating season arrives,
male fiddler crabs in the

tidelands began
courting females.

Female fiddlers tend to
be finicky and capricious.

They will break off a
relationship even as they are

mating if
something displeases them.

Finally, the male
finds a willing partner

and begins to mate.

What is the true
significance of the courtship

ritual of the fiddler crab?

Why must males
struggle so hard to find a

female to mate with?

The female is the one who
automatically makes a big

investment by having an
egg and being pregnant.

The female has more to lose
than the male who makes many

cheap sperm in a mating event.

So automatically those basic
differences between the male

and the female where they
exist ought to make the female

the more selective sex.

They have the most to lose so
they are under more selective

pressure to make
a good choice.

Fifteen days later, the female
undergoes a physical change.

It is carrying eggs.

When a male fails
to seduce a female,

this means that the male will
fail to produce offspring.

While it is the common
arrangement for males to court

and females to choose, there
is a species that has adopted

an entirely different
reproductive strategy.

The Okinawa-benihaze
is a transparent

fish with an orange hue.

These tiny,
2-centimeter-long fish live in

homes as narrow as pipes.

The male stays in its home.

Then, when a female
appears, it approaches it

and begins its courtship.

It circles the female
in the hopes that it

will accept its overture.

The female seems
hesitant at first.

Then, it follows the
male inside its home.

This is a sign that it has
accepted the male's courtship.

Now, after the
female lays its eggs,

the male sprays its
sperm to fertilize them.

This mating
behavior seems typical

of other animal species.

But when the benihaze is faced
with a dearth of partners,

it adopts an entirely
different strategy for

producing offspring.

There are two female living
with a male in this tank.

But when the scientist removes
the male that inhabits the

pipe, only the
two females remain.

We observed this situation
to see what would happen.

16 minutes later, a female
enters the pipe previously

occupied by the male.

After about 30 minutes, the
female inside the pipe swims

outside in search
of the other female.

It is behaving like a male.

4 days later, the female
has transformed into a male.

The female benihaze
had undergone a sexual

transformation
and become a male.

This is the reproductive
strategy of the species.

Sometimes, the
opposite occurs.

We tried adding a new
male to a tank occupied by

the lone benihaze male.

A moment later, a tussle
occurs between the two males.

They are fighting to determine
the stronger of the two fish.

The victor occupies
the much coveted pipe.

The male benihaze which lost
in the fight changes its sex

and becomes a female.

It employs this strategy
in order to hand down its

genes to the next generation.

Male becomes female
and female becomes male.

This shifting of genders is a
strategy adopted to preserve

of the species in situations
where sexual reproduction

seems all but impossible.

In 2006, an amazing phenomenon
occurred in London Zoo which

overturned commonly
held beliefs about mating.

At the center of this
phenomenon was none

other than the Komodo dragon.

A female Komodo which had been
isolated from males for years,

suddenly gave birth
to a nest of eggs.

A DNA analysis of the Komodo's
offspring revealed that the

mother Komodo had no
contact with any male.

Basically this is a
parthenogenetic event,

which is common in
some species of reptiles.

It's particular because that
was the first time that was

described on a large
charismatic reptile like

the Komodo dragon.

It is commonly thought that
sexual reproduction is much

more advantageous than
asexual modes of reproduction.

Under normal circumstances,
the Komodo dragon mates

through the union
of male and female.

In other words, it was thought
that a female that had no

contact with males
could not lay eggs.

But in this instance, the
female chose parthenogenesis

in order to reproduce.

In this way, animals often
adopt outdated methods of

reproduction in order to
preserve their species.

3.5 billions years ago, the
first life appeared on Earth.

This simple single-celled life
form gave rise to male and

female through its
struggle to survive.

Afterwards, life on earth
became increasingly diverse.

And each species
adopted its own unique

strategy for propagation.

But it was an entirely
different challenge to

successfully birth and
raise the offspring which had

been created through mating.

This also required new
and innovative strategies.

The traces of one such
strategy can be found in the

fossil of a primitive fish
which is housed in the Museum

of Natural History in London.

It is the fossil of a
placoderm which lived

380 million years ago.

There is an important
clue in the fossil.

It is the petrified images
of fry which were found

inside the mother's body.

The Incisoscutum specimen in
the British museum was very

exciting, very important
because it showed that the

largest group of
placoderm fishes,

the Arthrodira such
as these ones here,

were actually giving
birth to live young.

And therefore, they
were reproducing

by having copulation.

380 million years ago, some
of the seas of the world were

home to fish that gave
birth to live young.

And the fossil of
Incisoscutum is proof of this.

Why did this species
choose to reproduce through

internal fertilization
instead of external

fertilization like modern fish?

To switch from laying
lots of eggs in the water,

where they can be
easily eaten by prey,

to giving birth to just a
few live young inside gave a

definite advantage to this
group because they could

nurture their young to a point
where they are able to be born

and then fend for themselves
and be more able to survive.

This is Selingan
Island in Malaysia.

But the beautiful oceans
surrounding the island are as

perilous as they were
380 million years ago.

This is because they are full
of vicious predators that prey

on the creatures of the sea.

Nevertheless, there is an
animal which braves this

dangerous sea every August.

It is the sea turtle which
swims thousands of kilometers

in order to reach this island.

The turtle returns to
this island every year

in order to lay its eggs.

When night falls, the sea
turtle climbs up to the beach.

It looks for an appropriate
spot to lay its eggs and

begins to dig a hole.

While the eggs of the
sea turtle are soft,

they are covered by an outer
shell which keeps the eggs

from drying even when they
are buried deep in the sand.

It is thanks to the
shell that the eggs are

able to hatch successfully.

Once you got a shelled
egg, you can lay it on land;

conditions in which
amphibian eggs wouldn't

survive where it's much drier.

So you can begin to inhabit a
greater area of land surface

than if you're tied to
water the whole time.

Shells were adopted by
creatures eons ago after they

left the sea for the land.

The shells protect eggs and
keep them from drying up even

on land where they are
not surrounded by water.

Thus, the eggs can be hatched
successfully as long as they

are kept hidden from the
prying eyes of predators.

Two months have
passed since the mother

turtle returned to the sea.

The hatchlings, which have
just come out of their shell,

crawl towards the water.

They must crawl as
quickly as they can in order

to avoid hungry seagulls.

Even if they reach
the water successfully,

most of the hatchlings will be
devoured by fish and seagulls,

and only 5 percent will
survive to see adulthood.

It will take years until these
fragile turtle grow big enough

to fend off the
attacks of predators.

It's the end of August, and
the forests are becoming dense

with the foliage of summer.

It is egg-laying
season here in Indonesia's

Komodo National Park.

This bird which is
digging up dirt using its

red legs is the megapode .

Using the earth it digs
up, it builds a nest that is

reminiscent of a grave.

But there is a creature
lurking in the shadows and

watching the bird
as it digs its nest.

It is a Komodo dragon.

These birds lay the
eggs in the nest,

but also the Komodo
dragons use these

nests to lay their own eggs.

During egg-laying season, you
can see Komodo dragons digging

holes in the ground everywhere
in Komodo National Park.

These Komodos are
all carrying eggs.

This is a decoy nest.

Komodos hide their eggs inside
the nest of the megapode

and dig multiple holes
which serve as decoys

to trick hungry predators.

This increases the
chance of the eggs' survival.

When they use these
nests, they kind of excavate

different holes and they
will choose only one

hole to lay their eggs.

The other holes are just fake.

It's the end of March, and the
rainy season which has lasted

for half a year is
coming to an end.

Thanks to the
constant deluges,

the environment is pristine
and the food abundant.

Around this time, one will
find that there are baby

Komodos living
high up in the trees.

Females, they lay their
eggs from the end of August

to the beginning of October.

Then you have a period of
incubation of the eggs that

will hatch at the end
of the rain season,

where the
environment is greener,

where there are more preys
in terms of little lizards,

geckos, or little
species that the hatchlings,

they are very small, about
40cm in length, can feed on.

The Komodo dragon is one of
the largest predators on Earth.

Nevertheless, hatchlings
are exposed to many dangers

because of their
diminutive size.

They are easy prey for hungry
predators and must take refuge

high up in the trees.

They live in the trees
subsisting on insects until

they are large enough to
survive on the ground.

When they have just
been hatched, even these

fearsome predators are too
weak to protect themselves.

Meanwhile, mammals adopted the
strategy of giving birth to

live young and raising them.

The Australian kangaroo
gives birth to live young and

raises them inside its pouch.

In the pouch, the baby
kangaroo feels its mother's

warmth and listens
to her heartbeat,

and this accelerates
the growth of the baby.

The baby kangaroo stays
inside its mother's pouch for

a year and feeds on her milk.

The baby kangaroo suckles
its mother and receives her

protection inside her
pouch until it grows big

enough to fend for itself.

Although the pouch provides
the baby with protection,

it is an
uncomfortable and dangerous

burden for the mother.

So, why did
kangaroos adopt this strategy

for rearing their young?

Though I think the move
towards live birth and a lot

of development really reflects
ecological and evolutionary

conditions that
select for fewer,

more competitive,
fully equipped offspring.

Tsubaki the chimpanzee
is about to give birth.

She thrashes around, unable
to bear the pangs of labor.

Chimpanzees can go
through up to 7 hours of labor.

In an act of
desperation, the chimp

grabs onto her trainer's legs.

In chimps as in humans, labor
seems to be a painful ordeal.

Natsumi the newborn chimp is
so physically developed that

it is able to embrace its
mother as soon as it's born.

6 years have passed since
Natsumi the chimp was born

here in the Great Ape
Research Institute.

This playful chimp running
across the field with its

mouth full of food is Natsumi.

Her mother, Tsubaki, also
seems to be in good health.

During the past 6 years,
Tsubaki has additionally

given birth to Hatsuka.

Three-year-old Hatsuka is
still young and needs her

mother to look after her.

Natsumi also grew up under
the protection of her mother.

Like humans, chimps also
live in clans and societies.

Usually, they spend their
day picking each other's fur.

Chimps have a strictly
hierarchical society.

This is Roy, the head of
the chimp society here.

In the society of chimps,
the alpha male always has the

first choice, whether
it be in food or mates.

The alpha male's anger is
stoked when a lower-ranked

male steals its food or mate.

Roy has been
angered by Namba, the 2nd

ranked male in this society.

As a result, Namba has been
brutally assaulted and injured

by the stronger alpha male.

Male chimpanzees
often get into violent

confrontations over females.

In chimp society, males are able
to mate with multiple females.

Also, the female may
choose any male to mate with.

Because of this, female
chimpanzees often goad the

males to fight over them.

Thanks to their mother's
efforts to birth the strongest

possible young and protect
them through childhood,

Natsumi and Hatsuka
are healthy and strong.

And someday, they will find
appropriate males to mate with

in order to give birth to a
new generation of chimpanzees.

This is because it is the
basic instinct of all living

things to birth offspring
and preserve their species.

A planet where sex hadn't
evolve would be very boring,

have very few life forms
and within those life forms,

there would not be the
elaborate beauty that we think

exists in the world.

In fact, you might not even be
able to detect beauty if you

didn't have sex
because beauty itself,

the ability of humans and
other things to see things as

beautiful or not beautiful,
is the result of sex.