Original subtitles

Modern Australia... lt seems a familiar sort of place...

...but step outside these cities and you could almost be on another planet.

Because Australia is the strangest continent on earth.

lts wildlife is so weird

that at first some people thought the animals were a hoax...

...or the work of the devil.

lt's a paradox, a place of extremes -

its centre a burning desert,

but also with rugged mountains, covered in deep winter snow.

lt has endless horizons of magical, time worn landscapes...

...and in them an amazing variety of wildlife...

...more species of animals than Europe and North America combined...

...almost all of them unique - they live nowhere else on earth.

lt's a place that likes to do things differently.

And somehow, this remarkable mix of wildlife

manages to survive on the harshest, driest inhabited continent on earth.

So how did Australia come to be so special?

To answer that, you need to travel back in time to

when this was a very different kind of place, covered in trees.

1 00 million years ago,

massive forces shattered the super-continent of Gondwana

and eventually a giant fragment floated off northwards,

with a unique cargo of wildlife.

Australia was born.

This was an extraordinary world,

lush, green and dripping with life.

Today, there are still a few places in Australia

where you can get a feel for that past.

These are the rainforests of Tasmania.

They're ancient, mysterious places

and some of Australia's oddest animals live here, like the Tasmanian devil.

They're scavengers,

sort of antipodean hyaenas,

and they use their powerful jaws to crush up every bit of a carcass.

You may get a dozen or so around a dead Wallaby...

...and they find it hard to share, let alone be sociable.

With such lethal teeth, manners like these can be very dangerous.

Screaming at each other is safer,

but better still is bum barging your neighbour

with a few powerful blows from behind.

This competitive spirit starts early in life.

Devils are marsupials -

their babies develop inside a pouch -

and while this mother is jostling for a meal

the young are tucked away inside doing much the same thing.

Mothers produce about 20 embryos

and they have to fight for just six teats,

Competition is fierce and even the ones

that survive still have to fight for a drink.

Only three or four usually make it out of the pouch.

By then the competitive spirit is well established -

and will stay with them for the rest of their lives.

Dense forests are not just confined to Tasmania -

they spread right up the eastern coast of the continent because,

soon after Australia became an island,

its eastern side was buckled into mountains.

These trap rain, blowing in from the ocean.

So their lower slopes are covered in thick forest.

Higher up, there are rugged peaks.

And in the south, in winter, the rain falls as snow.

These are the Australian Alps, covered in snow for months of the year.

ln places it drifts up to 30 metres deep.

lt's not something you'd expect to see in a land,

which is mostly dusty and hot,

but this weather can be ferocious and unpredictable...

Sometimes there are blizzards.

But even here, there are marsupials determined to make a living.

This is a wombat, doubling up as a snowplough in an attempt to find food.

Wombats are world-class diggers,

and they use their strong front legs and snout to bulldoze through the snow,

in search of grass beneath.

They're normally nocturnal,

but now it's far too cold to come out at night,

so they forage during the day, even in the worst of the weather.

lt's a tough place

but there are other marsupials up here as well - dainty little wallabies.

Surprisingly, both the wallaby

and the wombat have young families in these conditions,

in the depths of winter.

But there's a good reason for this -

these joeys will emerge in spring,

just in time to feed on the new green shoots.

Meantime, a centrally heated pouch is the warmest place to be.

Even the world's weirdest mammal, the platypus,

makes a living in the icy waters of these mountains.

Uniquely Australian, it has a duck's bill,

an otter's tail and webbed feet with claws.

Males have poisonous spurs and females lay eggs, like birds -

so it's hardly surprising that early reports of them were treated as hoaxes.

lt's actually a monotreme, a typically Australian group of mammals.

That weird looking bill is highly specialised,

with tiny sensors

to detect the minute electrical signals from the muscles of its prey.

So sophisticated, the platypus can swim with its eyes and ears closed.

By swinging its head from side to side,

it builds up a radar-like map of the stream,

pinpointing the shrimp and worms it likes to eat.

lt's a very adaptable animal, making its home in forest streams like these...

all the way up the east coast of Australia...

...from the snowy mountains of the south,

right up to these tropical rainforests in the north.

Like the Tasmanian forests,

these are also ancient and have been here since before Australia was born.

The land they cover today is relatively small,

just one thousandth of the continent,

but they have just about the richest mixture of wildlife

of any of Australia's environments.

lt's here, of all places,

you can see what a truly strange place Australia is -

here more than anywhere, you see how its original cargo of wildlife

has evolved into such a variety of unique species.

lmprobable giants, like this flightless Cassowary.

And marsupials, in every shape and form, including the possums.

One of the most striking is the striped possum,

which scampers over tree trunks looking for grubs and nectar.

There is no better source of nectar than the bumpy satin ash -

covered in thousands of tiny blossoms growing straight from the trunk.

The possum gets a sticky meal

and it also picks up pollen on its fur, transferring it from tree to tree.

There are 26 species of possum in Australia

and almost half of them live in these rainforests.

Some have found ingenious ways to move around.

This is a sugar glider...

Flying through the air - or perhaps just falling with style -

they use their own built in sky diving suits,

to glide from tree to tree for up to fifty metres.

They can steer, even change direction by ninety degrees,

by adjusting their flaps of skin, and using their tails as a rudder.

When it's time to land,

they just lower their flaps and put out their landing gear.

Although touchdown could be better!

But why did some possums evolve to glide?

Soon after Australia became an island, its climate started to dry out.

The thick, tangled forest that had covered most of Australia

for so long began to thin out into open woodland.

lt was a change that stamped the character of the Australian bush we know today.

The lush rainforest was replaced by Eucalpts, or gum trees.

With trees now further apart,

some possums evolved to glide across the gaps.

And there was now space for other types of travel too.

Kangaroos evolved in woodlands just like these.

You need room to bounce around like this,

a uniquely Australian solution to budget travel.

At certain speeds,

a hopping kangaroo is more efficient than any horse or antelope.

They live in family groups called mobs,

and females can be impressive breeding machines -

there are over fifty million kangaroos in Australia,

more than twice the human population.

Having such a successful design is all very well,

but you need to know how to use it.

Just three days out of the pouch,

this Joey has more than just a spring in his step.

Learning to get about on two supercharged pogo sticks is no mean feat.

That was exhausting - time for a nap.

But as you grow older, fitting those legs inside isn't easy

and within two months he'll be out of the pouch for good.

Up in the gum trees,

there's another marsupial with a less energetic approach to life...

lt has the laid back Aussie love for leisure.

This koala is putting his back into taking it easy.

Koalas eat gum leaves, which are full of toxins and hard to digest.

To survive on a diet like this they've turned napping into a national sport.

Of course, it looks like dozing,

but these guys are working really hard to digest their meal.

But at one time of the year this all changes...

lt's spring and the males want to mate.

To kick-start the season, they begin by calling.

But if your date is almost comatose, that may not be enough.

For some of the older males, this is already too much like hard work.

They can't keep the mood going for long.

For those who can gather enough energy, the chase is on.

But this female, with a baby on her back, is not ready to mate...

For a koala, this is really getting a move on.

But males can be very determined.

Gentlemanly courtship is not his style.

Nor is the female willing to give in.

ln fact his only skill seems to be the ability to turn a drama into a crisis...

The baby is now in serious danger

and in the scramble gets separated from its mother.

But it gets even worse.

ln the confusion the youngster ends up dangling from the bottom of the male.

This farce could easily turn into tragedy.

The male has bungled the whole episode.

lt's time to exit,

but as he slams into reverse, he takes the baby with him.

Escape at last, but the baby isn't out of danger yet.

Young koalas depend on their mothers until a year old...

and this one is too small to survive on his own.

Encouraged by her calls, though, he manages to sprint the last few metres -

back into her arms.

Now he's safe.

Raising babies, with or without rampaging males in the neighbourhood,

is not easy in these Eucalypt woodlands.

They're tough places, dusty and dry, without a lot of food.

...especially with mouths like these to feed.

This is a kookaburra

and these chicks are demanding customers.

They want round the clock room service.

lt's a problem for parents to provide this on their own

so they enlist the help of last year's brood.

lt's a sort of Kookaburra Catering Corps,

with a bit of work experience thrown in.

They'll be learning all about bringing up chicks.

Kookaburras are the largest kingfishers in the world -

but being Australian, they don't always catch fish

and they don't always live near rivers.

To keep the brood well fed, they catch everything they can find...

spiders, snakes, sometimes even small mammals -

anything to keep the noise down.

With the entire family working together on constant dinner duty,

they can deliver a conveyor belt of food round the clock.

But it seems the faster they shovel it in,

the louder the babies cry.

Now and then, though, a big mouthful of lizard seems to do the trick.

These parched woodlands aren't just tough places to live in

and bring up a family -

they're dangerous as well.

They're tinder dry and easily ignite.

When a spark hits the volatile oils in their leaves and bark,

gum trees burst into flame.

Within minutes the woodland is a fireball.

Animals that can move fast get out quick.

lf the wind gets up it can fan the blaze,

causing crown-fires that race through the treetops.

And afterwards, Armageddon.

The morning after there may be a few dead insects around, the odd shoot,

but any animals that survived will have to move on.

And they may have a long way to go.

Hundreds of kilometres of woodland can disappear in days.

Three million hectares a year are incinerated by fires like this.

But then, something extraordinary happens.

Many gum trees have evolved to survive bushfires,

and some have energy stores beneath their bark,

which allow them to burst back into life.

Within a week or two

their trunks are covered in dazzling green foliage.

The drying out of Australia's climate over millions of years

not only had a major effect on its forests,

but also had a dramatic effect on its rivers.

Long ago, Australia had a network of mighty rivers

stretching right into the heart of the continent.

But when the climate dried, they dried up too.

Today, the largest river system left is the Murray Darling.

And here it is

barely wider than the average road.

lt's extraordinary

that a 2,500 kilometre long river should be so narrow...

And this is in full flood.

Even in a year, less water flows down

the Murray Darling than down the Amazon in a single day.

Most of Australia's rivers are even smaller.

Many are steams that dry up for part of the year,

others are creeks that haven't seen water for years.

But in many riverbeds water remains in pools called billabongs.

ln Australia's parched landscape

these stand out as irresistible lures,

drawing in wildlife from every direction.

Billabongs are vital for life in the outback

and many animals live or die by their skills at finding them.

None arrive in greater numbers than corella parrots.

These turn up in their thousands,

in flocks so huge that early explorers in search of water

learnt to look for them on the horizon.

ln this early evening rush hour, they're joined by budgies -

tough little nomads, who will travel a long way for water.

By the end of the day thousands of birds are gathered here,

and every available tree seems packed with budgies and corellas.

Most animals that live in the parched outback

get at least some water from their food.

But corellas and budgies eat seeds, which are very dry,

so they need to drink every day.

Kangaroos can survive for longer without water, but rarely stray far from it.

On the other hand, emus may have followed a trail for over a hundred kilometres.

They use cues like distant clouds or the sound of far off thunder

to help them find water.

And it's not just vital for daily life - animals need it for breeding as well.

Because rain is so unpredictable kangaroos have to breed when they can and,

when there's water about, females move into mass production.

She may be suckling an older Joey,

with another one in the pouch and probably an embryo inside her as well.

Budgies too make the most of it.

Where they find water they can set up home and raise a family in an instant.

But they have to put up with some rather annoying neighbours.

All the activity at this budgie household seems too much for the corellas.

They are intelligent birds, but they're also busybodies

and enjoy sticking their beaks into other people's business.

For the budgies, they're the neighbours from hell.

The corellas are just being nosey,

but it is probably best for the budgie chicks to stay in their hole.

These are playful birds

and after a few drinks at the billabong, they like a bit of fun.

Fooling around like this helps to strengthen their relationships...

...but some of it's just showing off.

While the water lasts they make the most of this time off,

in the cooler evening light.

Although much of Australia has very little water,

there's one area that's awash with it.

Since becoming an island,

Australia has been drifting north at about five centimetres a year,

so its top end is now in the tropics,

right in the path of the tropical monsoon.

This is one of the most powerful weather systems on the planet.

lt lasts for only a few months each year,

but while it does northern Australia becomes a very different place.

lt has a dramatic wet season.

For a short time,

rain falls so hard that rivers turn into raging torrents.

Where they burst out of their gorges they flood out onto open plains,

creating some of the world's largest tropical wetlands.

The most famous of these is called Kakadu.

Every year, huge numbers of birds arrive to feed and breed.

Two million magpie geese alone jostle for space with ducks, herons,

ibis and other water birds, some feeding on the flooded grass,

others on shrimps and small fish.

But birds aren't the only animals here...

ln the quiet streams on the edge of the swamp are residents

who live here all year round.

This strangely prehistoric looking reptile is an amphibious lizard

called Merton's water monitor.

They're graceful swimmers, spending some of their time completely submerged,

propelled by a long, powerful tail, which doubles up as a rudder.

They're scavengers and, even underwater,

they can 'taste' the scent of rotting food.

Finally, it finds the meal it's been looking for -

a dead fish.

There are other reptiles here, too -

freshwater crocodiles, also uniquely Australian.

These are daintier cousins of the giant saltwater crocs

and they feed on smaller prey, like fish and crustaceans.

This is boom time...

but it won't be long before the monsoon ends and the blazing sun takes over again.

As the water evaporates, the swamp congeals into an ocean of sticky mud.

On the margins of Kakadu the streams dwindle into pools of sludge.

The monitors can move back on land, but these freshies rely on water to keep cool.

Their situation is beginning to look increasingly sticky.

Before they get stuck fast, these crocs must do something, and quickly.

As the evening heat dies down they slide to the edge of the pool.

Their only chance of surviving is to travel over land in search of more water.

They'll need to find it before sunrise.

lnstead of the normal crocodile 'belly crawl'

they march overland with this unusual ''high walk''.

lt's the fastest way to travel if they're going to find water by dawn.

When the sun comes up, they're in real danger of overheating -

but these freshies have one last trick.

With a unique gallop they make an Olympic dash,

and become the fastest crocodiles in the world.

With any luck,

a deep pool like this will survive until the monsoon returns.

But most of the streams and pools

will have all their water sucked out of them by the burning tropical sun.

Throughout its long history, Australia has dried out so much

that about half the continent is now desert -

in places so arid and alien, it looks more like the surface of Mars.

ln the harshest areas, there are vast lakes of dry salt.

With almost no vegetation, the bones of the continent are laid bare.

Like a gigantic ribcage,

these parallel sand dunes stretch for hundreds of kilometres.

And at the heart of the desert, Uluru - one of the world's largest rocks,

and this is just the tip.

The rest extends six kilometres below ground.

ln such a dry landscape, it seems bizarre

that Uluru was actually weathered into shape by millions of years of rain.

At first glance there doesn't seem much sign of life in the desert.

But during the day,

most sensible Australians stay out of the sun...

and the planigale is no exception.

lt's one of Australia's smallest marsupials - and one of the toughest.

lt needs to be - most of its meals are larger than it.

Dwarfed even by this moth, the planigale doesn't give in.

With true outback grit,

it tries to wrestle this oversize meal to the ground...

...and fails again.

ln these underground cracks

it's almost fifteen degrees cooler than out in the sun,

so the planigale can hunt for a smaller meal in comfort.

Or so he thinks...

This is no time to relax,

when above you is the world's deadliest snake... the inland taipan.

This snake scares even Australians.

lt's loaded with venom -

enough to kill thousands of planigales and you or me, in minutes.

Now being small has its advantages.

With a specially flattened head it can squeeze into tiny crevices.

Even the world's most venomous snake can't always get a meal.

The Australian desert is full of deadly snakes.

ln fact, all sorts of reptiles flourish here,

especially lizards.

Australia has more than any other continent

and in the desert a single sand dune can support forty species -

this really is the land of the lizard.

The largest are more than a metre long.

This is a sand goanna, also known as a racehorse goanna for obvious reason.

Lizards are much more successful here than mammals because they need less food.

Meals can be scarce and goannas will eat virtually anything they can catch...

Even scorpions.

Goannas do get stung, but they seem to be immune to the poison.

lt may not be much, but this could be its last meal for weeks.

Animals don't come much tougher than the adult goanna,

but their eggs are more vulnerable.

They need protection from the harsh desert climate

and termite mounds make perfect incubators.

These eggs were laid about nine months ago

and they're now ready to hatch.

Fully formed miniature adults emerge.

The termite mounds gave perfect protection

but now they're a barrier to the outside world,

and these babies need to get out.

The walls can be rock hard.

But the youngsters are already as determined as adults.

One by one, they clamber out

to enter one of the toughest habitats on earth.

Over its long history, Australia has dried out so much,

that in places its desert heart has now expanded right up to the coast.

Millions of years of drying

has had an enormous impact on the character of Australia

but one further event put the finishing touches to its shape.

Just ten thousand years ago, at the end of the ice age,

sea levels around the world rose.

Australia's coastline was flooded, creating thousands of beautiful islands.

This flooding also helped shape the world's largest living structure,

the Great Barrier Reef.

This reef was once dry land -

aborigines might even have hunted kangaroos here.

Now, at over two thousand kilometres long,

it's the greatest coral complex to have ever existed.

lt's hard to imagine a more colourful and vibrant contrast to the dry,

crusty old continent.

Over four hundred different corals in every shape and size,

support more than two thousand species of fish.

And for just a few days in spring,

the reef bursts into a special frenzy of activity.

With precision timing, using cues from the moon and the tides,

many fish begin to breed.

Thousands of them condense their courtship

and spawning into just a few minutes of frantic fertilisation.

But, on just a few nights each year,

an even more remarkable event takes place...

On certain tides, just after the full moon, the reef itself begins to erupt.

Two thousand kilometres of coral

takes part in a synchronised release of eggs and sperm, in vast quantities.

No one knows quite how so many billions of eggs

are timed to release on the same night, so precisely.

lt's the biggest synchronized breeding event on the planet.

lt seems extraordinary that Australia,

the harshest, driest inhabited continent on earth,

has also produced such a colossal, vibrant, growing, structure.

But from the moment Australia became an island,

its isolation and unique history have shaped it into this continent of extremes.

Australia's story has created a land of fantastic diversity -

the weirdest mix of animals and plants,

living in some of the toughest but most beautiful landscapes imaginable.

This really is the strangest continent on earth.