Original subtitles

(energetic drum music)

Southeast Australia

is the stronghold of an endangered marsupial.

Koalas thrive in a eucalyptus forest

surrounded by their favorite food.

Much of their day is spent eating and sleeping.

But their gentle appearance belies a fierce nature.

(rhythmic drum music)

Males constantly clash over females.

And battles between the sexes

(Koalas screeches) can be ferocious.

Each year the trees welcome new arrivals

as the next generation

joins the koalas of Otway Forest.

(growls)

(rhythmic drum music)

Otway Forest in Victoria, Southeast Australia

is crowded with rare and unique wildlife.

(lighthearted guitar music)

Although much of Australia is dry,

due to heavy frequent rain in the east

thick forest blankets a large area near the coast.

Otway Forest

is relatively undisturbed by people.

And full of eucalyptus.

Evergreen trees native to Australia.

It's home to some of Australia's famous faces.

Like the eastern grey kangaroo.

An alpha male keeps a watchful eye

over a ten-strong group.

(playful guitar music)

A new arrival peers at the outside world.

Kangaroos are marsupials.

Their young,

not born fully developed,

are carried and suckled in a special pouch

on the mother's belly.

And high up among the trees,

are some of the most famous marsupials of all,

koalas.

They're doing what Koalas are famous for,

sleeping.

(lighthearted piano music)

(scratching)

This is a female.

She's carrying her baby,

known as a joey, inside her pouch.

Special muscles open and close the pouch

and help keep her joey safe.

A large male, meanwhile, is on the move.

Koalas are surprisingly nimble.

They can easily leap almost seven feet.

Especially when they're looking for food.

(birds chirping)

(koala chewing)

Eucalyptus leaves

are the koala's staple diet.

They can be difficult to reach.

They're often bunched high up among the trees.

Koalas have to crawl along spindly branches to get them.

That takes a lot of concentration.

Koalas might seem the wrong shape

for what looks like tightrope walking.

But they are built to forage high up in the trees.

(lighthearted music)

Two of the toes on the front paws

are opposed like human thumbs.

And a big gap between their second

and third toe, helps them grip.

They can wrap their paws around branches.

Special hind paws help too.

Their big toes have no nails,

which helps them to hold on tightly when they're climbing.

There are more than 700 types

of eucalyptus trees.

But koalas only eat the leaves

from about 60 of them.

(koala chewing)

And one is a particular favorite.

Eucalyptus viminalis.

Better known as manna gum.

(playful xylophone music)

Manna gum trees are common in Otway Forest.

So are koalas.

A close look reveals the forest

is dotted with them.

Here there's at least one koala

on every other tree.

Some trees are even more crowded with koalas.

Most of them are asleep.

(playful xylophone music)

But despite their docile appearance,

they can be fiesty.

Especially large males.

Males are bigger than females

and usually weigh about 26 pounds.

He has a patch of bare skin on his chest.

It's a scent gland

and secretes a substance he uses to mark his territory.

This male is especially big.

He has several battle scars on his nose

and has been named Bull.

Bull is one of the strongest koalas

in this part of the forest.

And the stronger the males are,

the more females they attract.

(dramatic flute music)

Bull seems in a hurry to get down on the ground,

but he has to be extra vigilant on the forest floor.

The hairs on his ears stick out,

a sign he's listening for danger.

Predators, like dingos.

Male koalas in Otway Forest

only travel around 65 feet

every few days,

because there are so many eucalyptus.

(rhythmic music)

Crossing the ground can be

a quick way of moving around the forest.

But he's much more at home among the trees.

Bull rubs his chest against the trunk as he climbs.

He's scent-marking his territory

using the gland on his chest to warn other males.

And he reinforces his presence with growls.

(koala growling)

They are surprisingly deep and intimidating

at a pitch more typical of a much larger animal.

Like an elephant.

(deep growling)

They can be heard several miles away.

(deep growling)

But Bull doesn't have everything his own way.

This part of Otway Forest is home

to another bruiser.

(dramatic piano music)

Kong.

Kong is just as big as Bull

and he doesn't seem intimidated by Bull's growling.

Kong slowly climbs a tree close

to where Bull sits.

It's unlikely he's actually seen him though.

Koala's have poor eyesight.

(koala growling)

But once he's up among the trees,

Kong lets it rip.

(koala growling)

He tells everyone listening that he's arrived.

(deep growling)

His growls seemed to have stunned his rival into silence.

But a few branches above him,

Bull gets his nerve back.

(koala growling)

(koala growling)

The war of words escalates.

Neither koala backs down.

(deep growling)

So Bull changes tactics.

Climbing down to the ground,

it looks like Bull plans to take the fight to his rival.

(dramatic music)

But Kong is up to the challenge.

He meets Bull head-on.

Bull seems surprised,

but quickly recovers.

(dramatic music)

Kong considers his next move.

Fighting could be fatal.

He needs to be careful.

But Bull won't give up.

He tackles Kong again.

But Kong is more than his match.

And Bull finally has had enough.

Kong's won this battle,

but there will be many more.

Koalas in Otway Forest

don't have set breeding seasons.

There are always some females ready to breed.

So males fight every day

to prove their superiority.

(birds chirping)

It's now the end of June

and mid-winter in Australia.

(soft piano music)

Early morning

and plants glisten with frost

as temperatures dip.

High among the branches

several koalas are sleeping soundly.

(soft piano music)

They sleep rolled up in a ball,

legs and arms tucked into their fur

to help stop heat escaping

and save energy.

As the sun warms the forest,

a koala stirs.

It's a gentle start to the morning.

First, some light stretching.

(soft violin music)

Two of its toes are fused together

but the claws are separate.

This makes a good comb

and it works especially well on unkempt fur.

The sun rises slowly.

So does a sleepy koala.

(soft piano music)

It takes a near disaster

to wake it up properly.

And it sounds like someone nearby

finds it funny.

(bird laughing)

Laughing kookaburras

are a large species of kingfisher

and among Australia's most famous birds.

(bird flutters)

The crimson rosella is less well known

and quieter.

It comes to the forest to feed on eucalyptus seeds.

The koala is still getting ready for the day.

Hanging from a branch is an opportunity to stretch

and have a good scratch.

(birds chirping)

(playful xylophone music)

Finally, it's ready for breakfast.

Eucalyptus leaves are low in nutrients,

high in fiber,

and very hard to digest.

(koala chewing)

Koalas have a special part

in their intestine called a caecum,

which is very long and contains millions

of microorganisms that break down the leaves

so they're easier to absorb.

Before it eats a leaf,

the koala sniffs it.

This helps it select leaves

that should be easier to digest.

Very few animals can eat such tough leaves.

Koalas have the eucalpytus

practically to themselves.

But having such a high fiber diet

comes at a cost.

They have to keep the eucalyptus leaves

in their digestive system for a long time

to maximum the energy they can extract.

And that means

they need a lot of sleep.

Another settles down for a nap.

Its body wedged between the branches.

After the brief burst of activity,

all falls quiet.

Koalas can sleep for up to 20 hours a day.

Longer periods of sleep

are broken up by many shorter periods of feeding.

(soft xylophone music)

One hour's eating

several hours sleeping.

The pattern continues day and night.

Koalas need to consume almost one and a half pounds

of eucalyptus a day to get the nourishment they need.

And that means an incredible number of leaves.

(koala chewing)

At least 1400.

(koala chewing)

It's impossible to digest that many leaves at once.

That's why koalas eat a small number

at regular intervals throughout the day.

(thunder rumbles)

But that's not always easy.

(thunder cracks)

A storm rolls in.

Hail peppers the forest.

(raining)

(thunder cracks)

And fierce winds

whip through the trees.

(strong wind blowing)

(thunder clapping)

A koala seems determined to keep feeding.

(strong winds blowing)

Eventually though, it's too dangerous.

It's forced to sit out the storm.

(thunder clapping)

(strong wind blowing)

(thunder clapping)

Another koala makes an escape.

(rain falling)

(thunder clapping)

The rain builds

and the waiting game begins.

(soft piano music)

Fortunately,

the next day it's a different picture.

(birds chirping)

Soggy fur slowly dries under the warmth of the sun.

(soft piano music)

The koalas energy levels are low

because of the interruption

to their feeding pattern.

It's important they eat right away.

(koala chewing)

(koala growling)

One koala

has something else on his mind.

Bull is on the move.

(koala growling)

Loud growls fill the air

but Bull isn't put off.

(koala growling)

He can see the koala making the noise above him.

It's a female

and she's trying to get away.

(dramatic music)

But Bull hopes to mate and keeps up his approach.

(koala growling)

The female's growls grow more hoarse.

(koala growling)

They're a warning to Bull

not to come any closer.

(koala growling)

But Bull won't be deterred.

He doesn't know if she's in season or not

and continues to advance.

(dramatic drum music)

It's a tense standoff.

The female stands her ground.

But Bull edges even closer

and makes a sudden move.

(koala growling)

The female ignores him.

Bull won't give up.

(koala growling)

But the female wants nothing to do with him.

(koala growling)

Bull backs off.

The female has a baby

and she won't accept any male's advances.

(koala growling)

Because male koalas can't tell

when females are in season,

they try to mate whenever they can.

But Bull seems to have got the message.

Meanwhile, another female's being pursued.

Her growls deepen.

(koala growling)

(dramatic drum music)

The male is slowly getting closer.

He ignores her growls and continues his approach.

(koala growling)

But this is a different situation to Bull's mating attempt.

The female hasn't got a baby

and is in season.

(koala growling)

He makes his move

and the female fights back ferociously.

(koala growling)

The male backs down.

Female koalas choose the strongest males to mate with.

Scientists believe that females use fighting

to test the male's strength and suitability.

The male comes back again

to try to prove himself.

(koala growling)

It's a vicious fight

and it looks like they're evenly matched.

(koala shrieking)

(koala growling)

But eventually,

the female proves stronger.

The male gives up.

(deep growling)

After his unsuccessful mating attempt,

he sends out one last thunderous growl.

(loud growling)

Maybe it's a last attempt to show his strength.

Or maybe, it's just frustration.

(light xylophone music)

August arrives

and Otway Forest welcomes a new face.

The joey is six months old

and about to leave its mother's pouch

for the first time.

Before it can digest eucalyptus,

its mother first needs to provide it with special bacteria.

She excretes a substance called pap

which the joey eats.

It's full of the microorganisms it needs

and is even thought to taste like eucalyptus.

After it's fed the joey disappears

back into the safety of its mother's pouch.

And the mother gets back to business.

(koala chewing)

(upbeat piano music)

Another mother is trying to sleep

but her joey is getting restless.

As the joey stirs,

its mother wakes.

It's time for food.

The joey clings on tightly to its mother's fur.

(lively piano music)

As the mother feeds,

the joey takes the opportunity to leave the pouch.

(dramatic music)

Suddenly the mood changes.

The mother shields her joey

and growls defensively.

(koala growling)

A male koala has seen them.

(dramatic piano music)

(koala growling)

The mother growls a warning,

but the male is blinded by a desire to mate.

He doesn't seem to notice the joey.

As the male edges closer,

the mother is very vulnerable.

(koala growling)

She has to try and dodge the attack

and protect her joey.

(dramatic drum music)

They're 30 feet above the ground

and the joey might not survive a fall.

The mother puts up a fierce fight

until the male finally retreats.

Mother and joey are safe.

Once the male has definitely gone,

the joey climbs back into its mother's pouch,

shaken but unharmed.

For some young koalas,

the maternal bond seems hard to break.

Nearby is a female and her two-year-old joey.

He had left his mother

but he's returned to see her.

Unfortunately,

it's not a happy homecoming.

(lively xylophone music)

(koala growling)

She's angry he's not become completely independent.

The son stays close,

but his mother makes it clear she doesn't want him

anywhere near.

(koala growling)

His days with his mother are over.

(birds chirping)

(slow violin music)

Otway Forest is crowded with joeys of all ages.

And for one, this is a special day.

It's around eight months old

and spending more time outside the pouch.

It's got the bacteria it needs

to digest eucalyptus leaves.

But now it has to learn how to eat them.

It watches its mother and gives it a try.

(koala chewing)

But eating the leaves isn't as easy at it looks

and it hasn't got all its adult teeth yet,

but it doesn't give up.

Closely watching which leaves its mother eats

and remembering their smell is a vital lesson.

It keeps practicing one bite at a time.

The joey will suckle for another six months,

and during this time,

it will master how to eat eucalyptus.

By the time it's a year old,

it will be able to digest a whole leaf.

Then, it'll finally be time to leave its mother

and venture out alone.

(dramatic drum music)

Otway Forest is one of the last strongholds of the koala.

With their favorite food throughout the forest,

they flourish.

Koalas are well known for the hours they spend sleeping.

(koala shrieking)

But they can be surprisingly fiesty.

(deep growling)

It's all part of the extraordinary life

of Australia's much-loved and matchless marsupial,

the koala.

(deep growling)

(fast paced upbeat music)