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
lts 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
lts 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
lts 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