David Attenborough's Tasmania (2018) - full transcript

DAVID ATTENBOROUGH: At the southern

tip of the Australian continent

lies a remote island.

An immense wilderness...

..divided by mountains.

It's a world of ancient forests...

..of pristine rivers...

..and a coastline...

..that's both wild and beautiful.

Its animal inhabitants are

as extraordinary

as they are bizarre.

This is a land of black devils...

..and white wallabies...

..where lights dance

in the southern sky

and trees tower to 100 metres.

This is Tasmania,

the weird and wonderful isle

at the bottom of the world.

Tasmania is full of surprises.

Australia, yes, but with a twist.

It was once connected to

the dry Australian mainland.

Today, along with

its plants and animals,

it's physically cut off.

Though it lies just to the south,

Tasmania is a world apart.

Its isolation and cooler climate

has created a sanctuary

unlike any other part of Australia.

And a strong seasonal cycle makes

life here very different indeed.

Winter means a struggle for survival.

In Tasmania's mountains

there are meagre pickings on offer.

This is the last landfall

heading south before Antarctica.

Cold air from further south brings

snowfall and freezing temperatures

throughout these winter months.

Many animals, like this female

wombat, are Australian species.

But their habits and lifestyles

are most definitely Tasmanian.

Mainland wombats

are largely nocturnal

but here she feeds

at any time of the day,

kept warm by her thicker coat of fur.

She must take every opportunity

to find food.

Winter is felt right across

this island wilderness.

Even lower down

in Tasmania's forests,

temperatures can fall

below freezing.

The first Europeans

to explore these forests

claimed they heard devils

screaming in the night.

(SINISTER SCREAMS)

And so Tasmania's

most famous animal got its name.

The Tasmanian Devil.

Primarily scavengers,

they can smell a carcass

from a kilometre away.

And relative to body-size,

they have the most powerful bite

in the natural world.

They can easily crunch through bone.

Devils once lived

throughout Australia,

but vanished as the continent

dried out and humans arrived.

Today, this is their last stronghold.

Like most Australian mammals,

they're marsupials.

While they may appear dog-like,

devils are more closely related

to kangaroos than canines

and, being marsupial, they rear

their young in a pouch.

A few weeks ago this female

gave birth to 40 young...

..each the size of a grain of rice.

Inside her pouch

she has just four teats,

so only four young will survive.

A devil's race for survival

begins early.

It's a tough start,

but this mum will dedicate

most of her year

to looking after

the four babies who survive.

She overcame extraordinary odds

to reach adulthood.

Now it's her turn

to raise the next generation.

Marsupials like the devils live here

because Tasmania was once connected

to mainland Australia.

The island and its inhabitants

became isolated some 12,000 years ago

when sea levels rose

following the last ice age.

But Tasmania is a window

on a far more ancient past.

Some of these forests

have barely changed

since dinosaurs walked the earth,

when the southern continents

were a single landmass

called Gondwana.

There is still a creature here

whose ancestors roamed

that ancient supercontinent.

It lives in Tasmania's rivers,

and is one of the island's

longest-lived survivors.

The Tasmanian giant lobster.

Weighing up to five kilos

and a metre long

they're the biggest

freshwater invertebrates

on our planet,

taking some 40 years

to reach full size.

Tasmania's isolation, together

with the lack of sizeable predators,

may be one reason

why they grow so massive.

But they're not entirely free

from threat.

Tasmanian platypuses are enormous.

As much as three times heavier

than their mainland counterparts.

It's an adaptation

to the cooler southern climate.

This male is after tiny invertebrates

found on the riverbed,

including young lobsters.

And to stay warm in winter,

he must find a lot.

He needs to keep moving.

With no large predators

to worry them,

platypuses here get about

in an unusual way.

Only in Tasmania

does the Platypus walk

between rivers in broad daylight.

Out of water it's easy to see why

the platypus was once dismissed

as a fraud, the work of a hoaxer.

But down here he is in his element.

His strange assemblage of body parts

soon begins to make sense.

Webbed feet help him move...

..while his otter-like fur

keeps him warm.

His beaver-like tail stores fat.

But the platypus is best known

for its duck-like bill...

..which it uses to find food.

Underwater, he's completely blind.

Not ideal for avoiding rocks.

But some 40,000 receptors in the bill

detect electrical signals

given off by the muscles

of prey animals.

With the need to eat a lot

just to keep warm,

a platypus can stay on the hunt

for some 12 hours a day.

Though also found on the mainland,

Tasmania's platypuses are by far

the biggest and boldest.

They, like others, are adapted

to the island's isolation

and cooler climate.

Lying 240km south of Australia...

..Tasmania is surrounded

by a vast expanse of open ocean.

To the west, the next landfall

is South America...

..thousands of kilometres away.

To the south lies

the great Antarctic continent.

And as winter comes to an end,

new arrivals come ashore to breed.

Penguins.

Hidden among the rocks,

this female has two

newly-hatched chicks...

..but nothing to feed them.

Her partner left some 14 hours ago

and is yet to return.

He's out fishing.

But, quite unlike any other penguin,

he must wait for nightfall

to leave the water.

Gulls and birds of prey

patrol the coast by day.

It's only safe to return

after sunset.

That is because

these are little penguins.

At only 30 centimetres tall,

they're the smallest penguins

in the world.

And with nests

several hundred metres inland...

..the only safe way to get there

is to make a dash in the darkness.

There's safety in numbers.

(PENGUINS CALL)

With hundreds of nests

in the colony,

the night soon fills

with the calls of returning adults...

..the sound of early spring

on Tasmania's coast.

(PENGUINS CALL)

This will be a welcome meal

for the newly-hatched chicks.

The little penguins' presence

is a reminder of

Antarctica's proximity.

But, while early spring

brings them ashore to breed,

it also brings

wild and unpredictable weather.

Prevailing winds carry most

of the bad weather from the West...

(THUNDER RUMBLES)

..and Tasmania's mountains

cause much of the rain

to fall on the western half

of the island.

(THUNDER CRASHES)

The result divides Tasmania in two,

with a wet western side

and a dry eastern side.

Some western areas are among

the wettest in all of Australia.

It rains here nearly every day.

And all the water supports

a surprising spectacle.

Caught in a bizarre trap,

these insects are doomed.

How they got stuck only

becomes apparent as night falls.

These strange lights belong

to the larvae of a type of gnat.

The light is formed

by a chemical reaction

in the larva's abdomen,

and can be turned on and off at will.

The sticky threads hang from

its silk and mucus-laden nest.

Insects drawn to the light

are ensnared, then devoured.

Each glow worm's thread is made up

almost entirely of water,

so the high rainfall

in Tasmania's wet west

provides ideal conditions.

And the rain that supports

these tiny glow-worms

also sustains one of the largest

organisms on the planet...

..mountain ash.

They are a type of eucalyptus...

..fast-growing trees that evolved

on the dry Australian mainland.

In Tasmania they become giants.

Strangely, for trees

living in a wet forest,

they need fire to reproduce.

The mountain ash

stores its seeds in small pods...

..which are released

as the pods burn.

Beneath the ash, the seeds live on,

quickly germinating without

competition from other plants.

This makes sense in a dry habitat

with regular fire...

..but not in Tasmania's wet forests.

Young mountain ash can grow

at a rate of several metres a year.

All that holds them back is

the next fire or a lack of water...

..and that is the secret

behind their staggering height.

In Tasmania's damp west,

fire is so infrequent

these trees keep growing

for centuries.

Those standing in this valley

all germinated

following the same devastating fire

400 years ago.

Today they reach almost

100 metres into the sky.

They may have evolved

on the dry Australian mainland,

but it's Tasmania's wet forests

that have turned mountain ash trees

into the tallest flowering plants

on Earth.

The moisture-laden air

that blows in from Tasmania's west

brings several metres

of rainfall each year.

Although it can rain most days,

winter and spring

are the wettest times

and seasonal waterfalls

burst into life.

All who live here must adapt

to the regular downpours

and cooler temperatures.

And like so many of

Tasmania's species,

their adaptations set them apart.

It may not look like it,

but this is the closest

living relative of the platypus.

The echidna, Australia's most

widespread native mammal.

But while mainland echidna

are all spines,

this Tasmanian one

is mostly covered in hair

to help keep him warm.

The milder spring months mean

an abundance of his favourite food -

ants.

But when you're this hairy,

your food gets stuck everywhere,

which is a pain

when it can bite back.

Time to move on.

As spring turns to summer,

Tasmania's inhabitants

get some relief

from the wild and cool weather.

It's now that the young devils

are ready to leave the den.

They've been out

of their mother's pouch for a while

but have remained safely hidden away.

Fully weaned, this is the start

of their independence.

This young female will have to learn

to survive and find food

all by herself.

What's more, she and her sibling

are much smaller than an adult.

They could easily be killed.

This will be her way out of danger.

Heavier adults can't climb,

so there are some benefits

to being small.

Over the next few months,

she'll also find

much of the food she needs

up here in the treetops.

But grubs and birds' eggs alone

won't be enough

to sustain her as she grows.

(GROWLS AND SHRIEKS)

If she's to make it to adulthood,

she needs to find

more substantial meals.

And that brings her

into direct competition

with dangerous

and more powerful adult devils.

The scent and sound

of crunching bones draw her in.

But she needs to be careful.

Less than half

of all newly-weaned youngsters

make it to adulthood.

(SCREECHES)

If she is to survive,

she needs to earn her place.

There's no telling

how this adult might react.

Confronting a stranger at a carcass

is a gamble...

..but one she needs to take.

(SCREECHES AND GROWLS)

Spurred on by hunger,

she seems to have the upper hand.

It looks as though

her gamble has paid off.

But her competitor

won't let the carcass go that easily.

The adult could kill her

with a single bite.

But that's not

how devil society works.

Despite living

most of their lives alone,

devils can and do share.

They defend only

the amount of meat they can eat

rather than the whole carcass.

The pecking order has less to do

with size and strength

and more to do

with whoever wants it most.

As this youngster is learning,

it's all about

who can shout the loudest.

Devils may have a fearsome reputation

but the reality is quite different.

Summer brings warmer temperatures

across Tasmania.

While in the west

it still rains frequently...

..summer is most apparent in

the dry eastern half of the island.

The driest areas of Tasmania

receive 80% less rainfall

than the wettest.

Here the landscape is

more reminiscent

of parts of the Australian mainland.

For marsupials

that graze the open grasslands,

there's a bounty of fresh shoots

in these warm summer months.

And although life here may appear

more typically Australian,

the effect of Tasmania's isolation

is felt just as strongly

in this dry half of the island.

It's given this group of wallabies

something of a Tasmanian twist.

They've turned white.

About 100 of them live

within this population.

They're so poorly camouflaged

that anywhere else

they'd be easily killed.

On Tasmania however,

there aren't any predators

big enough to kill a wallaby,

so many live full adult lives.

And without the normal controls,

their numbers are growing.

But although this may appear

a predator-free paradise,

there are killers here.

One of Tasmania's deadliest animals

lives in these dry forests.

It's a species of ant

known as the jack jumper.

Jack jumpers evolved on

the ancient Gondwanan supercontinent.

Workers hunt alone...

..a very primitive behaviour

among ants,

which are mainly social.

And instead of using scent to hunt,

they rely on acute vision.

They sting their victims to death

with a venom that can kill humans...

..making these

one of the deadliest animals

in all of Australia.

Jack jumper ants are

particularly abundant

in this dry half of Tasmania.

Their nests are small mounds

within which their larvae are raised.

Workers cover the nest

with dark materials

to help absorb warmth

in the cooler southern climate.

In midsummer however,

temperatures soar...

..and the nest risks overheating.

But jack jumpers have

a surprising way

of coping with the intense sunlight.

On hotter days,

they switch building materials.

Now the workers cover the nest

in white stones.

These reflect the sun's energy,

keeping the young cool inside.

It's an inventive solution

to Tasmania's changing seasons.

The dry eastern forests can be

a challenging place

in the heat of midsummer.

But one of Tasmania's

few marsupial predators

avoids the worst of this heat

by hunting at night.

It's the eastern quoll,

a close relative

of the Tasmanian devil.

They're very rare, but summer sees

an increase in numbers

as juveniles leave the den.

Quolls are solitary hunters...

..and in summer are drawn

to these dry pasture lands.

There's a rich bounty of moths

and grubs at this time of year.

(GROWLS)

But, with lots of youngsters around,

competition can be intense.

(GROWLS)

It's every quoll for itself.

Like Tasmanian devils,

eastern quolls were once found

on the Australian mainland.

Today, this dry

eastern half of the island

is their last refuge.

And, with an abundance

of summer insects,

they have every chance of thriving.

Summer is almost over...

..and as autumn arrives,

the stage is set

for a bizarre ritual.

Familiar screams fill the forest.

(SHRIEKS AND GROWLS)

It may not look like it

but these devils

are becoming amorous.

An eligible male clings on

as a female guides him

back to the den.

Female devils are

receptive three times

over a short period

during the breeding season.

To ensure the fittest offspring,

she'll try to mate

with as many big males as she can.

And to increase

his chances of fatherhood,

he must keep her in here

for as long as possible.

Inside the den, he moves her around

in an effort to mate.

To protect her from his biting grip,

the skin around her neck has

thickened over the last few weeks.

Though it may appear aggressive,

this is part of a bizarre

and complicated breeding system.

They'll remain in here,

mating regularly, for several days.

In spite of that fearsome scream,

there is a sensitive side

to these much-maligned creatures.

Far from devilish, they are simply

very determined survivors.

The devil mating season

marks autumn's arrival.

Each evening,

flocks of Cape Barren geese

return to their roost.

Their silhouettes in the sunset,

a sign that the year is ending.

Back on the coast,

the longer nights bring with them

a stunning spectacle...

..the southern lights,

a reminder that the next stop

from here is Antarctica.

For Tasmania's little penguins,

the breeding season has finished.

Only adults remain at the colony.

They've spent the last few weeks

fattening up at sea,

almost doubling their weight.

The efforts of raising chicks

have left them in need

of a new set of feathers.

Little penguins go through what's

known as 'catastrophic moult'...

..shedding some 10,000 feathers

all at once.

Because their feathers keep

them warm and waterproof,

they can't return to sea

until they've grown new ones.

For three long weeks

they're stuck on dry land,

unable to feed.

It's a long wait

for a little penguin.

The year is almost over.

And, high in the mountains,

there's time for one last surprise.

These are southern beech trees...

..unique to Tasmania.

Their changing colour makes

for an autumn

unlike anywhere else in Australia.

These are the only trees

on the continent

to drop their leaves

during the cooler months.

The southern beech trees'

closest living relatives

are found

thousands of kilometres away

in South America.

This rare splash of autumnal colour

lasts just a few weeks

as, across the whole of Tasmania,

temperatures begin to drop.

June marks the start

of the winter season

and, for the devils,

the beginning of new life.

With young already inside her pouch,

she will provide milk for them

through the harshest months.

Her life and theirs,

tied to Tasmania's seasonal cycle.

Just 12,000 years ago,

Tasmania separated

from its mainland parent.

The island is young, yet rich in life

and with a long and ancient past.

Now Tasmania,

and the animals it supports,

are on a different course

to the rest of Australia.

It is, as a result, home to a cast

as weird as they are wonderful.

Indeed, there's nowhere on earth

quite like Tasmania.

Captions by Red Bee Media

Copyright Australian

Broadcasting Corporation