One of nature's masterworks,
the ultimate long-distance athlete.
At full speed it uses less energy than any animal its size.
The Kangaroo is shaped by the land in which it lives,
one of the most challenging places on Earth.
Australia is a vast ancient weathered land,
isolated from all others for 40 million years.
It is a place of extremes,
more like another planet than another continent.
Travelling over Australia's 3 million square miles
is like crossing an ocean of dry land.
Primeval landscapes belie its rich resourceful life.
Australia is almost equal in size to the continental United States.
It is the driest vegetated continent on Earth.
Surrounded by three oceans it is the world's largest island.
It shares no border with any other country.
Here some of the Earth's oldest rocks hold fossils from the dawn of life.
In its heartland are mountain ranges that once rivalled Everest,
built up and worn down over time,
and remnants of a once vast inland sea.
Most of Australia's native animals are unique.
Their journey on this continental raft
has taken them through cool forests and fiery deserts
and changed them forever.
The survivors have been refined by poverty and uncertainty.
Some have climbed up out of adversity.
Some have outrun all their predators.
Most have adapted to hard fickle conditions.
A few are unchanged since the days of the dinosaurs.
Now sheer diversity of species
spreads the risk that life is required to bear.
The story starts millions of years ago,
when Gondwana, the great super continent, began to break apart.
Africa, South America and India were formed,
but Australia and Antarctica were still joined as one last giant land,
forested and lush.
By 50 million years ago, the breakup was complete
when Australia parted from Antarctica.
A massive ocean current began to flow around the South Pole
and Antarctica's life perished under a blanket of ice and snow.
Australia pushed northwards from the freezing latitudes
and remained isolated for the next 30 million years.
It became an ark of survival for its cargo of ancient life.
Searing winds began to dry the land
and its moist rainforest all but disappeared.
At the centre the desert was taking over.
Australia's plants and animals faced a choice -
adapt to the drying conditions or retreat.
Now the symbol of Australia's red heart is Uluru,
the Earth's largest exposed rock.
It commemorates the relationship between life and this land.
Today Australia is the Earth's flattest continent.
Its mountains were worn to their stumps millions of years ago.
The Nullarbor plain on its southern coast
has the world's longest unbroken coastal cliffs.
Once you could walk to Antarctica from here.
If the dry Outback is a land ocean, these parallel sand dunes are its waves.
Stretching beyond the horizons, they cover nearly half of the continent.
Millions of years of rain and drying winds
long ago leached the goodness from most of its soil.
In the red centre there is no regular predictable pattern of rainfall.
Poor soils and a savage climate now challenge all life in this land.
Nature responded to the changing conditions.
The kangaroo started its journey as a marsupial possum
the size of a mouse.
As forests contracted some kangaroos evolved to live in the trees,
and others learned to eat grass.
When food is plentiful, the males are active,
and courtship disputes are traditionally settled
with a round or two of kick-boxing.
Mothers and babies sensibly keep out of the way.
On most continents animals breed in response to the seasons.
In Australia, it is the availability of food,
that prompts the kangaroo to reproduce.
To capitalise on good times, the mother can support a production line -
one joey in the pouch, one at foot,
and another in the womb as an embryo.
She can even supply her babies
with two different formulas of milk at the same time,
one for each generation of young.
The koala evolved from the same marsupial possum as the kangaroo.
When the baby is big enough to leave the pouch,
it rides on its mother's back.
Like the kangaroo,
the koala evolved in the moist rainforest.
As the forest dried, it adapted to live on the leaves of the gum tree.
Now it drinks little water
and its digestive system can extract moisture
and nutrients from leaves that would be toxic to most other mammals.
Koalas use as little energy as possible resting about 19 hours a day.
Some members of the family however are active at any hour.
When moving from tree to tree they normally descend backwards.
Consequently tree top traffic jams can sometimes leave one out on a limb.
For years on end much of the Australian inland receives little or no rain.
Two thirds is classified arid and one half is desert.
The Outback as it is called covers most of the continent.
By rights nothing should live here,
this ought to be a lifeless wasteland.
But it is not.
The closer we look the more we find that some of Australia's forest inhabitants
have met the desert's challenge with subtlety and resource.
Now a diverse underworld of ants, rodents, marsupials and reptiles
are among the most successful desert dwellers on Earth.
By day most life in this land ocean is hidden beneath the surface.
Many of the desert animals come out to feed in the cool of night.
These tiny hopping mice survive because they rarely need to drink.
Most of the water they require is contained in the seeds they eat.
In the heat of the day they huddle together in deep burrows,
creating a humid atmosphere that helps to conserve moisture.
In this arid region hardy mulga trees
provide food for one of Australia's four thousand species of ants.
Six feet below the surface
honey ants hang like clusters of golden grapes in cool humid larder chambers.
These specialised ants are living honey pots.
They are force fed by worker ants on nectar
harvested from the sap of mulga trees growing above.
When food is scarce,
these honey pots feed the workers by regurgitating their nectar on demand.
Their underground storehouse will see the whole colony through the toughest of times.
Arid Australia is the land of the lizards.
There can be up to forty seven different varieties in just one area.
The Thorny Devil has a sticky tongue and it's picky about what it eats.
Out here black ants are one food that never runs out.
The devil is perfectly adapted to the desert.
Its prickly skin collects moisture from the air
and a system of fine channels along its body
carries the water to its mouth.
The biggest and most fearsome of the desert lizards is the perentie,
which is both scavenger and predator.
This lizard can exceed six feet in length and outrun a human.
It hunts anything, including the most aggressive
and deadly of Australia's many snakes, the King Brown.
Sometimes though the King Brown is more than even a perentie can manage.
The venom from this snake's bite will kill a human in minutes.
Luckily for the perentie it is immune.
While much of Australia's life was adapting to the dry inland,
some of its plants and animals retreated to the mountains of the east coast.
Here moist valleys and cool peaks
provide a haven for Australia's living links with the past.
In scattered pockets of primitive rainforest
descendants of Gondwana's original plants and animals thrive today.
These Antarctic Beech trees began growing between 3 and 5 thousand years ago,
but their roots are in the ancient super continent.
Most of Australia's native plants and animals
began to evolve in wet cool forests like these.
One of the most remarkable living links with that ancient world
is found in the creeks and freshwater rivers of the east coast.
The Platypus suckles its young like a mammal,
yet lays egg like a lizard.
It hunts under water with its eyes shut,
using electric sensors in its bill.
The first Europeans to see it were dumbfounded.
To them it was a living contradiction, if not a practical joke.
The Platypus though has survived for 120 million years.
Today it exists nowhere else on Earth.
The nearest surviving relative of the Platypus
is the Echidna.
With its tubular snout and long sticky tongue
it lives on ants and termites.
Unlike the Platypus the Echidna moved out of the cool forests
and now ranges across the whole continent.
When threatened it digs in rapidly,
presenting an array of sharp spines to its attacker.
Drought.
It can last for months or years at a time.
Long periods without rain push all life to the limit.
The young and the old are first to feel the effects.
Clear skies parched earth and searing heat become the rule of life.
Some will perish before the next rains come.
Now the kangaroos of the desert
call on another remarkable strategy for survival.
The female can halt the growth of her developing embryo,
keeping it in a state of suspension until conditions improve.
Only then will she give birth.
For the joey already born the future is now uncertain.
But the unborn embryo will be ready when good times return.
Surviving kangaroos will either move to new territory in search of food
or batten down near remaining waterholes, while at least some grass remains.
Emu families have a similar hard choice to make.
Whatever they decide it will be a gamble.
Relief from drought is unpredictable
and often arrives a long way from where it is needed.
Each year the tropical wet season brings storms
and flooding to Australia's far north.
As the monsoon unfurls curtains of rain, a transformation begins.
As the wetlands fill, crocodiles emerge from scattered waterholes
where they've been confined during the dry season.
They will build nests above the high water level
and lay up to 100 eggs.
Vast networks of wetlands that have been dry since last season are flooded again.
Sometimes this powerful event can also transform Australia's arid centre.
In years when rains are heavier and more widespread than usual,
the water flows inland to the parched interior.
Slowly heading south, water spreads across the plains.
In six months or more it may reach the centre of the continent.
Under cloudless skies the water creeps quietly inland,
filling hundreds of dry waterways.
In dry sandy creek beds millions of tiny drought resistant eggs,
like seeds, are waiting.
Subterranean life that may have been dormant for years begins to stir.
Stimulated by seeping water,
the burrowing frog awakes from its long sleep.
Carefully it parts the membrane that has kept it moist through the drought.
Like the frog many creatures are primed
for the good times that are about to unfold.
Alerted by an ancient program in their minds,
Egrets arrive and take up feeding positions.
Fish have already started reproducing in streams that until a week ago
were tracks of dry sand.
Thousands of waterbirds join in a frenzy of feeding and breeding
that may happen only once or twice in a decade.
Briefly the desert blossoms in a colourful tide of new life.
One of the few large predators in this land also participates in the bonanza.
Australia's wild dog the dingo
arrived from nearby Asia about four thousand years ago.
Its pups will feed on the plentiful supply of rodents and reptiles,
that are also multiplying in the abundant conditions.
Tens of thousands of pelicans
are drawn by the irresistible call of inland water.
Responding to reflections far away in the sky
the birds fly hundreds of miles to gather on the shores of newly filled desert lakes.
With more than half a million nesting birds
colonies of this size are a rare event.
Pelicans normally breed in small scattered communities,
producing one chick a year.
Here they'll produce five or more in quick succession
and go on doing so as long as the food supply lasts.
Millions of years ago
pelicans were breeding in the vast lake system that covered much of the interior.
Ancestral knowledge seems to draw them back to their primeval home range.
The water ends its long journey at the centre of the continent in Lake Eyre.
Nearly a million square miles
of the continent drains into the world's largest dry salt lake.
It fills completely only about twice a century.
Inevitably the flow of water stops.
The earth and blasting sun suck away at the stagnant pools, where life
newly born there is on borrowed time.
Trapped by receding waters,
some of these fish will provide a final feast for the birds.
Millions more will return to the mud of the riverbed,
enriching it for the next generation.
With their food supply running low,
the great flocks of pelicans become nomads once more,
rising to search for that far flash of water over the horizon.
Those who have left their run too late go back into the earth.
The familiar desert will now reclaim this place.
Suns will scorch it, winds will dry it out.
Most living creatures will dig in and take refuge underground.
Some will flee to the gentler edges of this great land.
And the hardy ones will await a new flood in some future year.
In Australia life has struck an unlikely deal with an uncertain climate.
The continent has been a ship of refuge
for an alternate order of ancient life.
As it crept northward through the eons,
its passengers have had to adapt again and again.
In this land beyond time
life has learned to ride out the hard times and flourish in the good times.
Far more than merely surviving, life has triumphed in Australia.