Cast adrift in the far reaches of the Southern Hemisphere
lies a continent separated from all other lands...
..for 45 million years.
Evolving in isolation,
nature has created a unique world of wonders.
Spiders that dance...
..birds that spread fire...
..where bouncing beats walking
and youngsters are carried in pouches.
It's a world where animals have had to adapt
to surprising diverse landscapes...
..and thrive in its vibrant seas...
..even making their homes amongst the growing concrete jungle.
In this episode,
travelling the currents that circle the continent,
we discover what makes Australia's coastline so special...
..and why sea creatures from the world over
are drawn to Earth's Magical Kingdom.
Australia's ocean wilderness is one of the most extraordinary places
on Earth.
It spans three oceans and more than 4 million square miles.
But that wasn't always the case.
At one time, Australia was almost double its current size,
until the seas rose to divide the land.
The mountains that remain became Australia's 8,000 offshore islands.
Often remote and uninhabited,
today they provide space for rare animals to congregate and breed.
40 miles off the coast of South Australia lies Pearson Island.
It's the perfect place for an Australian sea lion
to raise a pup.
Not so long ago, the Australian sea lion
was one of the rarest of its kind in the world.
But they are thriving here.
Protected from hunting, this colony has become
one of the healthiest in Australia.
Currents from the Southern Ocean bring cold,
nutrient-rich upwellings, helping to create
one of the world's least polluted and best stocked waterways.
Ideal fishing grounds for a sea lion mum.
The island's small, sandy bay is the perfect nursery for her pup.
At four months, he's not confident enough to follow his mother
into the waves just yet.
So, he waits alone and watches more experienced youngsters
play in the shallows.
Perhaps someone closer to his own age will provide some company.
But mothers can be protective...
..and fathers downright hostile.
Mothers come ashore and reunite with their pups for a feed.
But his wait continues.
Finally, in what might be described as the toddler pool,
he finds a playmate, from a different species,
a long-nosed seal pup.
Sheltered rock pools provide the perfect playground
for youngsters of both species.
Play is only a short-term distraction when you're hungry.
But his wait will soon be over.
Sea lions are some of nature's greatest ocean acrobats.
So, simply coming ashore should be easy.
Pearson Island is characterised by large, flat slabs of rock
lying just below the water's surface.
A successful landing calls for good timing.
When the surf is this strong,
it's more prudent to opt to the sandy beach.
A feed at last.
She will suckle her pup for 18 months
until he gains his independence and can hunt alone
in these abundant waters.
But, for some island residents,
there's no leaving this rocky outpost.
When rising seas created this archipelago 10,000 years ago,
some of its inhabitants were marooned,
stranded since the last Ice Age
on what was once an ancient mountain top.
Including a particular type of wallaby.
Now a unique subspecies,
the Pearson Island black-footed rock wallaby ekes out an existence
among the cracks and crevices of this harsh, rocky environment.
With a population of 300 and no water source on this island,
every drop is worth squabbling over.
Their fluffy coats can become matted into dreadlocks
like true castaways.
Unlike the sea lions, these wallabies are stuck here for good.
In the ocean, animals have the freedom
to move and disperse over vast distances.
Sometimes they travel alone.
At other times they form great gatherings.
In the wide shallows of Spencer Gulf on Australia's south coast,
June is the time for an unusual midwinter gathering.
This garden of seaweeds and sponges
hosts a spectacle unique to these waters.
Giant cuttlefish, a relative of the octopus,
grow up to a metre long, making them the largest of their kind.
They are only found in Australia.
Masters of disguise,
they change the colour and texture of their skin
to blend with their surroundings.
At this time of year, though,
it's all about standing out from the crowd.
This small patch of reef, less than half a square mile in size,
has been inundated with thousands of courting cuttles.
But, with a ratio of 11 males to every female,
not every male is going to get lucky.
This female has accepted the protection of a large alpha male.
But now he must hold on to his mating rights
in the face of constant challenges from persistent rivals.
By splaying out his tentacles, turning white,
angling his body at 45 degrees,
he attempts to appear larger than his challenger.
The female is hidden below,
while waves of black add to his display of strength.
As rivals converge on either side, the alpha male is distracted...
..and his mate drifts from cover.
A smaller male sees an opportunity and moves in.
The interloper drags her as far as he can
before forcing her into his twisted embrace.
But the larger alpha male is quick to reclaim his prize.
He will flush out the sperm of his competitors
to ensure only he fertilizes her eggs.
Given a moment's respite,
the pair can get down to the business of finding a place to nest.
Any prospective home for the eggs requires close inspection.
Satisfied, she deposits their first clutch.
Now, with a prime nest site and a mate to guard,
the male must continue to fend off rivals.
Nest sites like these are coveted across the reef,
and males are tireless in their efforts to claim them.
This one is already taken.
It's being guarded by a monster.
One of the largest males on the reef.
His dazzling white skin and flattened tentacles
proclaim his strength and size.
Other males, hoping to mate with his female under the rocks,
move in.
They cautiously test his resolve.
The urge to mate emboldens them.
The monster allows them even closer.
Cuttlefish expel ink to confuse predators.
But this is a desperate attempt to escape the clutches
of one of their own.
For now, the monster has secured his legacy.
This marine spectacle was nearly lost forever.
In a single season, fishermen caught 250 tonnes of cuttlefish
at this breeding site before it was protected in 1998.
Today, this annual gathering continues in peace
in these inshore shallows.
Stretching between Antarctica and Australia's outer fringes
is the Southern Ocean, wild and remote.
Far out at sea, polar winds from Antarctica whip up huge swells.
This is the ocean's engine room,
generating waves that roll across the planet.
Australia's southern coastline is shaped by this powerful force.
As the ocean swells near Australia's outer edge,
waves build to a monumental size.
Monsters ten meters high are not uncommon.
In winter, when the sea is at its most savage,
many ocean wanderers leave this violent seascape.
They head north and seek refuge in the calmer waters
of the Great Australian Bight.
The Nullarbor Plain comes to a dramatic end
with vertical cliffs plummeting to the ocean 120 metres below.
Every winter, these cliffside coves provide refuge
to southern right whales.
Nearly 18 meters long,
they are amongst the largest animals ever to have lived.
This female left her feeding ground in the Antarctic
and travelled over 2,000 miles to give birth.
The warmer water is gentle on her newborn,
which has yet to develop its insulating blubber.
She will nurse her calf here for the next three months
until it's strong enough to face the long migration south
at the start of spring.
But these coves don't just provide nursery waters.
They are the arena for spectacular mating events.
This female is without a calf.
Four males close in on her.
A group of bottlenose dolphins become curious onlookers.
To ensure only the most well-endowed succeed,
the female goes belly up.
The penis of a southern right whale extends to almost four metres.
Several males will mate with her
but only the last will father her offspring.
Unlike the whales, this pod of dolphins
will remain by the coast throughout the year.
Despite the size difference, the dolphins are happy
to share their home with the visiting giants.
The whale even appears to mimic its more agile playmates.
Renowned for being easy to approach, right whales were named by whalers
who consider them the right whale to hunt...
..their curious and playful nature making them easy targets.
But play is not limited to whales and dolphins.
Every winter, surfers take to the water.
It's a time when waves are often at their best
thanks to the Southern Ocean swell.
The dolphins seem to take pleasure in joining them.
Research has shown that these synchronised displays
help male dolphins form alliances.
Wild dolphins enjoy the lighter side of life on the southern coast.
1000 miles east, there are far darker goings-on.
Port Phillip Bay is on the doorstep of Melbourne,
Australia's second largest city.
But few residents have witnessed the marine spectacle
that unfolds in these shallows every winter.
At nearly half a metre in width, Australian giant spider crabs
are amongst the world's largest crustaceans.
Seldom seen,
they spend the years scavenging on the seabed.
But this crab has got a feeling that it's time for a change.
It is soon joined by others.
Normally dwelling in depths of up to 800 meters,
these crabs migrate to the shallows each winter.
Not to mate, but to moult - to shed their old shells.
It's believed that an influx of cold water from the Southern Ocean
triggers this mass migration.
Before long, the ocean floor is a writhing carpet
of claws and spindly legs, sometimes several creatures thick.
In the world above, normality rules.
Life continues as usual.
Scratching at its face is a sign that this crab's change has begun.
Like all crustaceans, its body is protected by a hard exoskeleton.
But, in order to grow, the crab must remove its old shell
and reveal a new one beneath.
Its new orange shell, though larger, is flexible and able to bend
as the crab works its way out.
But this temporary softness will prove to be its downfall.
It's one of the first to expose its new, soft shell,
and its hard-bodied neighbours waste no time
in seizing an opportunity for a meal.
When growing a new shell, crabs need as much protein as they can get,
no matter how macabre the source.
Once a limb is plucked from the victim,
the attacker quickly retreats with its prize.
Despite the perils of moulting in the midst of cannibals,
these crabs in a tree gathered together for safety in numbers.
There is a greater threat to their kind.
Smooth stingrays, armed with venom-tipped tails,
have stalked the crabs to the shallows.
At over two metres wide,
these are the largest stingrays in the world.
Defenceless crustaceans are sucked from their soft shells.
With this many moulting at once,
even the most insatiable ray can't eat them all.
The carnage continues well into the night.
It takes around three weeks for all the crabs to moult
and then, just as suddenly as they came, they're gone,
disappearing back into the deep
where their lives largely remain a mystery.
A few leftovers from the feast of rays are all that remain.
One reason for Australia's many marine marvels
is that while the Southern Ocean chills the south,
two more oceans bring warm, tropical water from the north.
In the west, it's the Indian Ocean. In the east, the mighty Pacific.
On this side of the country, the land dives beneath the waves
and stretches far out to sea.
This shallow continental shelf shapes life here.
It forms gentle, sloping beaches.
And islands mark where it breaks the surface.
100 miles up the coast from Sydney sits a rather special one.
Cabbage Tree Island is the only island in the entire region
that remains covered in rain forest.
The palms that give it its name have also given rise
to an extraordinary sea bird.
Beneath the forest canopy,
the rocky slopes are littered with nooks and crannies
and, at the right time of year,
a little ball of fluff can invariably be found inside each one.
It is one of only two breeding colonies
of Gould's petrel in the world.
This chick is around three weeks old.
It's been left alone to fend for itself
while its parents are fishing at sea.
The spider poses no real threat but best not to take your chances
when its legspan is wider than you are.
By nightfall, there is still no sign of mum or dad.
But then...
A somewhat undignified entrance but then landing takes practice
and it's a skill seldom used by petrels.
This species spends years out at sea without touching dry land.
So, walking over a rocky forest floor is an alien sensation.
To make matters trickier, almost every hole under a rock...
..has a chick in it.
It is believed that adults use a keen sense of smell
to find their way back to their nest hole.
But it doesn't appear to be a fail-safe method.
Wrong hole.
Finally, after some searching, mum and chick are reunited,
and chick gets a meal of regurgitated squid.
Over the next 12 weeks, night after night,
crash landing after crash landing,
chicks all over this tiny island will wait for parents to return.
Until the one night when they won't come back.
Four months later, with only a tiny crown of fluffy down left,
the petrel chick has been abandoned by its parents.
It's been two weeks since it's had anything at all to eat.
The bird knows something must be done.
But hunger, desperation and instinct need to sufficiently combine
before it has the will to make its move.
For those who don't, the island holds no future.
Like his parents, it's under the cover of darkness
that the young bird leaves the nest.
Sea birds like petrels rely on the wind
to give them the lift needed for takeoff.
But, down here, beneath the forest canopy, the air is listless.
An ill-judged attempt at flight could be his last.
Sharp palms and jagged rocks don't make for good crash mats.
To stand any chance of getting off the island,
it must get out from under the canopy.
But trees cover the whole island.
There's only one thing for it.
Webbed feet and wings are not ideal equipment
for a sheer vertical climb of eight meters.
But the petrels have evolved sharp claws and a hooked beak
to aid their ascent.
As the saying goes, if at first you don't succeed.
Attempting to climb again pushes the starving fledgling
closer to exhaustion.
But frantic wing flapping helps to propel the bird up the tree.
The fledgling wraps its wings around the trunk
for a moment's respite, using its tail feathers as a prop.
Having made it to the top, more obstacles lie in wait.
The thick stems at the centre of the palm fronds
are lined with the sharp spikes.
Feathers are easily entangled.
Part fall, part flight, either way, it's airborne!
It won't touch land again for five or six years.
As the Gould's petrels head off for a life far out at sea,
other ocean wanderers are being drawn
to Australia's Pacific coastline.
Once a year, humpback whales pass Cabbage Tree Island
on their journey north.
They have come to give birth to their young in the warm shallows.
One occasional visitor is the subject of myth and legend.
Migaloo. The albino humpback whale.
His name means white fella in Aboriginal language.
His pale colour is most likely due to a rare genetic mutation.
Believed to be 32 years old, Migaloo is in his prime,
and he knows how to demonstrate his power.
Scientists believe tail slapping and rolling
is a form of communication between whales.
First sighted in 1991,
Migaloo was thought to be the only white whale in existence.
Since then, white calves have been spotted in the Pacific
around New Zealand and Australia.
It's thought Migaloo may be the father of these pale youngsters.
Migaloo travels up Australia's east coast, or Humpback Highway,
as he heads each year
for one of the country's most precious natural wonders.
The Great Barrier Reef spans 130 square miles
of Queensland's Pacific coast.
This enormous coral kingdom covers roughly the same area as Germany.
It's warm shallow waters and deserted islands
are not only home to colourful characters,
they also provide a pit stop for ocean voyagers
and ancient mariners such as the green sea turtle.
After years of life in the open ocean,
this expectant mother has come back to lay her eggs
in the very same place where her life began...
..Raine Island.
With flippers designed for sea and not sand,
hauling her enormous body up onto the shore
takes an extraordinary effort.
She carefully carves out a nest in the sand,
her one and only act of parental care.
And deposits a clutch of around 100 eggs.
As she returned to the waves, more mothers clamber up the beach.
In fact, many, many more.
14,000 turtles can come ashore here in a single night.
After laying, the females return to the waters around Raine Island
for a couple of weeks before returning to lay another clutch.
Two months later, the sand begins to stir.
Hatchlings begin their race to the water.
But by night, ghost crabs haunt this beach.
Another crab lies in ambush.
But ghost crabs...
..are not the greatest threat that they will face.
In the open ocean, more predators await.
It's estimated that just one in a thousand hatchlings survive.
The young turtles will travel on Australia's ocean currents.
Some will be carried east, into the South Pacific.
Others will be swept north, towards Asia.
The separation of the land between Asia and Australia
creates a passageway for tropical water.
Australia is the only continent with warm currents flowing south
on two sides.
Without this, the Indian Ocean off Western Australia
would be far colder...
..instead of the tropical environment that it is.
On this remote coastline, humans are few and far between.
It's an example of what marine ecosystems should look like.
Healthy, interconnected and teeming with life.
100 miles off the coast lie the Lacepede Islands.
18,000 pairs of brown boobies nest here.
It's breeding season and, on an exposed edge of the beach,
a new couple are hoping to start a family.
With a weedy offering, he attempts to woo her.
Perhaps another try.
No.
Surely his efforts have been sufficient?
Maybe not.
Booby nests are often little more than a small pile of sticks.
Some are barely an indentation in the pebbles.
Parenting is approached in a variety of styles.
Some respond to nagging.
While others stand their ground.
A beak skills lesson is taking place.
Imitating parents helps chicks practice their catching skills.
Becoming adept at flipping sticks and stones will prepare them
to manipulate slippery fish mid-flight.
As midday temperatures rise to around 40 degrees Celsius,
parents hover like beach umbrellas over their chicks.
Domestic duties are shared between parents.
And this chick needs feeding.
Out at sea, the boobies move en masse.
They have spotted splashing in the distance.
A school of tuna have driven a shoal of sardines to the surface.
Fish are pushed up, straight into the boobies' waiting beaks.
Frigate birds join the plunder.
Having taken their fill, parents head home to their hungry chicks.
Back at the island, other frigate birds are patrolling.
They are known as the pirates of the skies,
for good reason.
Larger and faster than the boobies,
they bully the smaller sea birds into giving up their lunch.
Outmanoeuvred, it's forced to disgorge its food mid-air.
Onshore, the tiny chick's wait for a meal should finally be over.
The mates greet each other but lunch was stolen.
Now the onus of providing a meal falls to the other parent.
Fortunately, at this time of year, food is abundant.
In winter, cycling ocean currents fuel huge blooms of plankton,
providing a sudden bounty of food for small fish.
Enormous schools of sardines form.
And these, in turn, attract bigger fish.
Dusky sharks.
Fast, streamlined predators around three metres in length.
Bigger sharks come to feast, too, including the biggest of them all.
The whale shark.
12 meters long and weighing as much as 11 tonnes.
Despite their imposing size,
they feed on the same microscopic plankton as the sardines.
Chemicals released by the plankton are carried on the ocean currents.
The whale sharks follow their sensitive noses
to find these blooms in the waters of Ningaloo,
a protected area of Australia's west coast.
Scientists want to understand
how the individuals here are related.
They believe that they may be part of a whale shark family
that spans both the Pacific and the Indian Oceans.
To be sure, the scientist needs a sample of each whale's DNA.
Remarkably, the giant animal will hang calmly
while its nose is scratched.
Completely relaxed,
the shark seems to enter a trance-like state...
..allowing the scientists to scrape tiny parasites off its body.
These parasites, known as copepods,
chew the shark's skin and drink its blood.
So, in return for the DNA sample,
the whale shark gets rid of a few free loaders.
Research has now shown that Australian whale sharks
are the offspring of ocean-wandering parents from as far away
as Indonesia and New Guinea.
Here in Ningaloo, the giants have a precious sanctuary
from hunters in a place where they are a protected species.
Most sharks are cold blooded and are therefore restricted
to warm waters, like those along Australia's remote western coast.
Shark Bay, 500 miles north of Perth, can justly claim its ominous name.
The water is bath-like for most of the year.
Sharks have an acute sense of smell,
capable of detecting the faintest traces of blood in the water.
But an entire whale carcass is like a siren going off...
..alerting sharks for miles around.
Tiger sharks.
Threatened globally, here they can still be found in numbers.
New arrivals skirt the dead whale before entering the fray.
These predators have hunted the world's oceans
for more than 50 million years and they're not above scavenging.
The feeding frenzy has attracted sightseers.
Despite a notorious reputation for attacks on people,
tourists are keen to catch a glimpse of these striking animals.
Attacks on people are very rare
but sharks have been persecuted for centuries,
and the government of Western Australia still employs hunters
to kill these endangered animals.
But, when a chance encounter like this enables people
to get close to animals that they may fear,
their enjoyment could trigger a change in attitude.
Nowhere is that more important than here in Australia,
where coasts are nourished by three oceans,
creating a nexus for marine life.
From the warm Indian Ocean,
with its schools of awe-inspiring predators,
to the calm shallows of the Pacific,
with its reefs and islands,
and the rich and varied southern seas
with gatherings of species found nowhere else on Earth,
the meeting of these three oceans has produced an explosion of life
in Earth's Magical Kingdom.