All language subtitles for David Attenboroughs Natural Curiosities - 04x06 - Ferocious Fighters Eng

The natural world is full of
extraordinary animals

with amazing life histories.

Yet certain stories are
more intriguing than others.

The mysteries of a butterfly's
life cycle,

or the strange biology
of the emperor penguin.

Some of these creatures were
surrounded by fantastic myths

and misunderstandings.

Others have only recently
revealed their secrets.

These are the creatures
that stand out from the crowd,

the curiosities that I find
particularly fascinating.

Some animals take fighting
and sparring to an extreme.

Kangaroos have kicks that can
disembowel an opponent...

..while Siamese fighting fish
will battle to the bitter end.

What makes these animals
such ferocious fighters?

These are grey kangaroos.

It's hard to imagine
that anyone could think

that such gentle,
enchanting creatures

could once have been considered
as superb fighters.

And yet, 120 years ago,

one of them was put
into a boxing ring

and matched against
a human opponent.

In 1891, the Melbourne Punch
published a cartoon

about Jack the fighting kangaroo,

who was pitted against a man
named Professor Lendermann.

The show attracted huge crowds,

and soon Jack was
not the only kangaroo

to be seen in a boxing ring.

All across the world,

gloves were being strapped
on kangaroos' front legs,

and the questionable sport
became a full-blown trend,

which lasted well into
the 20th century.

Kangaroo boxing was big money,

and some animals became celebrities
in their own right.

When Jack died, not surprisingly,

he was quietly replaced
with another Jack.

Today, kangaroos are among
the most familiar animals...

..and yet, when they were
first discovered,

they confused
the scientific community.

Early explorers described them as
creatures with heads like deer,

that stood upright like men,
but hopped like frogs.

The first image of a kangaroo
seen by 18th-century Britons

was this beautiful painting
by George Stubbs.

It was commissioned after
Captain Cook's ship, the Endeavour,

arrived back from his first voyage
in 1771,

bringing with it
numerous specimens of animals

totally unknown to Europeans.

And one of the strangest
was the kangaroo.

Cook's crew encountered a kangaroo

when they became the first Europeans

to sail up the east coast
of Australia,

and their ship was beached
for repairs.

The men explored their surroundings

and saw what
the ship's naturalist described

as "an animal
as large as a greyhound,

"of a mouse colour and very swift.

"To compare it to any other animal,"
he went on, "would be impossible,

"as it has not the least resemblance
to any one that we've seen.

"Its forelegs are extremely short,
and of no use to it in walking.

"Its hind legs again
as disproportionately long."

Before they left, they learned
that the local aboriginal people

called the mysterious animal
a kangaroo.

George Stubbs struggled to work out

what the living creature
must have looked like.

He only had one or two simple
pencil sketches like this one,

which was drawn
by one of the ship's artists.

But he also had
a dried kangaroo skin,

and it's likely that he softened it

and then inflated it with air

to work out
the extraordinary proportions

of this really amazing creature.

Eventually, he produced a likeness

that captured
the public's imagination.

Although Stubbs' painting enchanted
the Western world,

there is still some debate today
as to what kind of kangaroo

Captain Cook's crew
actually encountered.

Early naturalists, thinking
that it must be a gigantic rat,

first gave it the name Jerboa
giganteus, or "giant leaping rat".

Today, we know that there are
in fact over 50 different species

of hopping creatures in Australia,

and, strictly speaking,

only the largest
are called kangaroos.

Those that are medium-sized
are known as wallabies...

..while the smaller species
go by fascinating names

like quokka, bettong and potoroo,

to name just a few.

All these animals are known
as macropods,

and nearly all of them hop.

It's this particular way of moving
that may also be the reason

for the kangaroo's unique style
of kick boxing.

This is the skeleton
of a red kangaroo,

and it's typical of all macropods.

Kangaroos have the same basic
leg bones as we do,

but they are modified for hopping.

The thigh bone, here, is relatively
short...

..while the two bones of the
lower leg are relatively long.

The tendons, which connect with
the muscles along the lower leg,

act as springs, and the longer they
are, the more energy they can store,

and this allows the kangaroo
to jump higher and faster.

The ankle, on the other hand,
can only move in one plane -

backwards and forwards.

And this gives it more stability

when it impacts with the ground.

And then there are
these overly long feet -

which are the reasons for
the group's name, macropod,

which means, literally, "big foot".

The kangaroo skeleton is adapted
for a life of hopping.

But powering each hop

are exceptionally strong
elastic tendons and muscles.

They compress with each bound...

..and then, when the energy
is released,

it propels the kangaroo
into the air.

And the large tail acts
as a counterbalance

to stabilise the motion.

The impact from each landing
can be so hard

that most other animals would suffer
damaged knees and broken feet.

But kangaroos have evolved
thick pads of cartilage

which act as shock absorbers

and help to minimise wear and tear.

Kangaroos are not
the only animals to hop,

but they are by far the largest.

So, it's not hard to imagine
the astonishment and disbelief

of the early European explorers

at the sight of
the giant hopping creature.

It was not until the first live
animals began to arrive in Europe

at the end of the 18th century

that we began to understand
their curious body shape.

Kangaroos adapted well to captivity,

and soon became popular
in early British zoos.

People flocked to see
the unusual creature.

Soon, kangaroos were breeding
so freely across the country

that in 1806
an eminent naturalist said,

"The kangaroo may now be considered
as a great degree naturalised

"in England, promising to render
this most elegant animal

"a permanent acquisition
to our country."

It was not long after
that this book was published,

which has an intriguing picture
that sheds light

on how the sport of kangaroo boxing
may have come about.

The author, Thomas Smith,

visited a menagerie
in the Exeter Exchange in London,

and he describes how the animal

wrestled with and kicked
at its keeper for 10-15 minutes

until it was reunited
with its female.

And his description was accompanied
by this drawing.

It's the first image
of a boxing kangaroo,

and shed some light on how
the sport of kangaroo boxing

may well have originated.

Today, we know that, in the wild,
this boxing happens

when two males compete for dominance
and mating rights.

Most contests are brief
and settled by posturing.

Males will rise up
on their back legs

and display their size
and large muscular forelimbs

to impress their opponents...

..but when two rivals
are evenly matched,

things can get really violent.

With their huge feet,

they deliver kicks that can break
bones and rip open a stomach.

It's these ferocious battles

that gave kangaroos the reputation
for being champion boxers.

The kangaroo's strange technique
of fighting

is a consequence of
its odd body shape.

Those powerful hind legs
with which it strikes

evolved in order to enable it
to hop,

and that muscular tail
on which it props itself upright

serves, normally,
as a counterbalance

when it's hopping.

But why did this odd shape
occur in the kangaroo family

and in no other large animals
in the world?

The reason, it seems,
is because of a shift

from a life in the trees
to life on the ground.

The kangaroo's early ancestors were
tree-living, possum-like creatures

that came down to the forest floor.

As the continent of Australia
drifted north,

some five or ten million years ago,

a period of global cooling
and drying

saw rainforests give way
to vast grassy plains.

This provided an abundant supply of
food for ground-dwelling grazers.

And what better way to cruise
the plains than by leaps and bounds?

Hopping, in fact, is a very energy
efficient way of getting around.

Kangaroos can reach speeds of 40mph,

yet they use half as much energy

as a similar sized animal
running on four legs.

When kangaroos speed up,

they don't increase the frequency
of their hops,

but, instead, lengthen their stride.

The longer the stride,

the more energy they pack into
their muscles and tendons.

In a vast, dry country
like Australia,

being able to travel long distances
while using minimal energy

may be crucial to survival.

There is another,
more recent, theory

as to why it is that kangaroos hop.

Like most mammals in Australia,

kangaroos carry their babies
in a pouch.

But when the baby is first born,

it's no bigger than a jelly bean,

and it has to haul its way
across its mother's abdomen

to get into her pouch.

To do that, it could be more
important to have short, muscular,

powerful arms to help pull
themselves through the bristly fur

than to have long front legs

suitable for standing up
and for running.

The tiny baby is born
blind and naked.

It now has to haul itself through
the thick fur on its mother's belly

and up into her pouch.

If it can't make the journey,
it won't survive.

The hind limbs, however, develop
like those of other mammals,

and they're much longer,

so it could be
that the kangaroo's hop evolved

because of the difference in the
growth of their fore and hind limbs.

For the first 12 months of its life,

the young joey spends most of its
time in its mother's pouch.

But when outside,
it practises hopping and jumping,

as well as the art of boxing.

And its patient mother puts up with
being used as a punching bag.

It'll be another few years
before this young joey

is ready to fight for real stakes.

With the kangaroo,

we discovered a creature
so fascinating

that we took it into the boxing ring
and made a show of it.

Thankfully, this cruel sport is
no longer deemed acceptable today.

Now, kangaroos have lost
much of their mystique.

But their familiar exterior conceals
an extremely efficient body design

that continues to impress us.

Our next animal also has
a reputation for fighting -

so much so that it's called
the fighting fish.

What makes this small creature
so aggressive?

These are Siamese fighting fish -

or, to give them their scientific
name, Betta splendens -

and they come in a great variety
of ravishing colours.

So it's not difficult to understand

why they are very popular
aquarium fish.

I used to keep them myself.

They swim with all the grace
of a virtuoso ballet dancer -

but don't be deceived.

Watch what happens
when I lift this...

..and they see one another.

Because the males are so aggressive,

it's illegal to put them together
in the same tank.

Even so, each is determined
to defend its territory.

They distend their fins
and push out their gill covers

so that they appear larger
and more imposing.

If these two males were kept
together in the same tank,

they would soon turn on each other

and one of them would almost
certainly be killed.

In the wild, fights between males
only last a few minutes

before one fish backs off -

but in a confined space,
they can carry on for hours

and cause severe damage
to each other.

It's this fierceness
that first attracted the attention

of local people in Southeast Asia,

where Siamese fighting fish
occur in the wild,

and this led to them being bred
as fighting fish,

on which people would bet.

Villagers collected the fish
from shallow pools and rice paddies

and pitted them against each other
to determine a village champion.

It was a favourite pastime
for centuries.

And it wasn't long before
people started breeding the fish

for their fighting abilities.

Seeing the popularity of the fights
in the 19th century,

the King of Thailand,
or Siam, as it was once known,

started collecting the fish himself.

In 1840, the king gave some of
his prized fish to a friend,

who passed them to a physician
working in Calcutta at the time,

Dr Theodore Cantor.

Cantor was the first to draw
and describe the wild fish,

and, by the turn of the century,

the first ones were being imported
into Europe and North America.

One of the species
that we know today

as the Siamese fighting fish
arrived in Britain in 1897.

And this is the actual specimen.

It looks very different

from the flamboyant aquarium fish
we know today.

The name betta was given to the fish

after a tribe in northern Siam
who were ferocious warriors.

For centuries,

Siamese fighting fish were bred
to increase their aggressiveness.

But soon, different colours
and fin shapes

started to be valued, as well.

It's likely that there were
variations between populations

and that breeders selected
the more vibrant colours.

Selective breeding also created
a variety of tail fins,

some draping down like a veil...

..others spiky, or half-moon shaped.

Although today Siamese fighting fish
are more widely sought after

for their showy appearance,

they're still one of the most
aggressive of all fish.

Given a chance,

they will lock mouths
and tear at each other's fins

with their sharp teeth.

It's a way of fighting that
at first sight seems much the same

as that used by many other fish.

Cichlids in Lake Tanganyika
fight in a very similar way.

The males face their rivals head on
and lock mouths.

Each tries to push the other
to the bottom.

Cichlids may fight in much the same
way as the Siamese fighters,

but they seldom wound
and never kill one another.

Most animals fight for territories
or for mates,

and some will risk serious injury
in doing so -

but few will fight to the death,
as these Siamese fish do.

Why should this little fish
be so aggressive?

Well, it seems that it may have
something to do

with the extreme conditions
in which they live.

In the wild,
they live in rice paddies

in shallow pools and ditches.

But suitable breeding territories
in such places are in short supply.

Keeping rivals at bay
is particularly difficult,

and only the most ferocious

will be able to hold a territory
and attract a mate.

And the fish have another problem.

The warm, stagnant water
is low in oxygen,

and their small gills can't keep up
with the vigour of a fight.

But they've evolved a way
of dealing with that.

Most fish breathe

by extracting oxygen from the water
with their gills.

But one group has
an additional structure

which sits directly above the gills.

It's called the labyrinth organ,

and it enables the fish to extract
oxygen directly from the air,

much as our lungs do.

It's a remarkable adaptation
that allows Siamese fighting fish

to live in waters that contain
so little oxygen

that no other fish
could survive there.

When males fight,

they come to the surface regularly
for gulps of air...

..but the rivals face
a tactical problem.

If one comes to the surface alone,

it makes him vulnerable to attack
from its opponent below...

..and from predators above.

So, Siamese fighting fish

have come to a seemingly gentlemanly
arrangement.

They both surface at the same time.

This way, neither risks
being attacked by the other

when its back is turned.

At the end of the day, all the
fighting is about one thing only,

how to attract a female
and produce young.

The female is much more drab,
doesn't have the same huge fins,

and she will do very little
apart from producing the eggs.

It's the male who builds a nest

and cares for the young
until they hatch.

So, these males have good reason
to be fierce -

they invest a lot in breeding,

and fighting off rivals
is just the first step.

They build a nest from bubbles.

The male takes a gulp of air...

..and blows a bubble
enclosed in mucus.

He does this again and again,

until he's created a whole raft
of bubbles

floating just underneath
the surface.

Within a few hours,
the nest is complete.

In the wild, the bubble nest
is crucial

for the survival of the eggs.

It ensures that they remain floating
near the surface

of this stagnant water,
and so get sufficient oxygen.

Siamese fighting fish are unlikely
to survive for more than a year,

and they will produce maybe
three or four broods in that time,

but even so,
each brood is very precious.

Mating takes place directly beneath
the nest,

and the male has to lead the female
to the right position.

He now tempers his aggression

and courts her
in a surprisingly tender way.

Finally, she releases the eggs.

He catches each one in his mouth

and deposits it within the nest.

During nesting, males are
at their most aggressive.

They can't leave the eggs unguarded

because the bubble nest is fragile
and constantly needs repair.

And other fish,
including their own females,

will also eat the eggs,
given the chance.

So, as soon as the female
has released her eggs,

he will turn on her
and chase her off.

But the usually aggressive male
takes great care of his brood.

He continually adds bubbles
to the nest,

replacing those that have burst.

If the temperature
of the water rises,

he fans the eggs with his fins
to keep them aerated.

After 36 hours, the small fry
are ready to hatch.

Within a few months,

the young fish will be fighting fit
and ready to mate.

And there may be another reason

why Siamese fighting fish
are so aggressive.

Recent research on coral reef fish

have shown that some species,
as the temperature rises,

undergo a personality change.

Researchers working on
Australia's Great Barrier Reef

have found that some reef fish

are either consistently timid
or consistently bold.

But global warming seems to have had
an effect on their temperament.

A rise in water temperature
of just 1 or 2 degrees

has made them 30 times
more active and aggressive.

So, could the Siamese fighters
also be affected

by the temperature of the water?

We know that Siamese fighting fish
display more the warmer the water,

and that they can survive
in temperatures

of up to 30 degrees centigrade.

So, perhaps it's the warmth
of the stagnant water

that makes them so aggressive.

So, it seems
that Siamese fighting fish

will fight to the death
to produce offspring...

..while the kangaroo's
lethal kick and punch

is the result of a body
made for hopping.

Both have certainly earned their
reputations as ferocious fighters.