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Cast adrift in the far reaches
of the Southern Hemisphere

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lies a continent separated
from all other lands...

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..for 45 million years.

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Evolving in isolation,

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nature has created
a unique world of wonders.

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Spiders that dance...

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..birds that spread fire...

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..where bouncing beats walking

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and youngsters are carried
in pouches.

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It's a world where
animals have had to adapt

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to surprising diverse landscapes...

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..and thrive in its vibrant seas...

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..even making their homes
amongst the growing concrete jungle.

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In this episode,

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travelling the currents
that circle the continent,

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we discover what makes
Australia's coastline so special...

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..and why sea creatures
from the world over

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are drawn to
Earth's Magical Kingdom.

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Australia's ocean wilderness is
one of the most extraordinary places

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on Earth.

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It spans three oceans and more
than 4 million square miles.

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But that wasn't always the case.

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At one time, Australia was almost
double its current size,

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until the seas rose
to divide the land.

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The mountains that remain became
Australia's 8,000 offshore islands.

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Often remote and uninhabited,

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today they provide space for rare
animals to congregate and breed.

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40 miles off the coast of
South Australia lies Pearson Island.

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It's the perfect place
for an Australian sea lion

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to raise a pup.

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Not so long ago,
the Australian sea lion

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was one of the rarest of its kind
in the world.

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But they are thriving here.

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Protected from hunting,
this colony has become

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one of the healthiest in Australia.

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Currents from the Southern Ocean
bring cold,

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nutrient-rich upwellings,
helping to create

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one of the world's least polluted
and best stocked waterways.

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Ideal fishing grounds
for a sea lion mum.

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The island's small, sandy bay
is the perfect nursery for her pup.

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At four months, he's not confident
enough to follow his mother

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into the waves just yet.

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So, he waits alone and watches
more experienced youngsters

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play in the shallows.

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Perhaps someone closer to his own
age will provide some company.

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But mothers can be protective...

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..and fathers downright hostile.

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Mothers come ashore and reunite
with their pups for a feed.

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But his wait continues.

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Finally, in what might be described
as the toddler pool,

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he finds a playmate,
from a different species,

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a long-nosed seal pup.

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Sheltered rock pools provide
the perfect playground

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for youngsters of both species.

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Play is only a short-term
distraction when you're hungry.

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But his wait will soon be over.

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Sea lions are some of nature's
greatest ocean acrobats.

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So, simply coming ashore
should be easy.

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Pearson Island is characterised
by large, flat slabs of rock

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lying just below
the water's surface.

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A successful landing
calls for good timing.

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When the surf is this strong,

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it's more prudent
to opt to the sandy beach.

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A feed at last.

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She will suckle her pup
for 18 months

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until he gains his independence
and can hunt alone

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in these abundant waters.

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But, for some island residents,

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there's no leaving
this rocky outpost.

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When rising seas created
this archipelago 10,000 years ago,

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some of its inhabitants
were marooned,

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stranded since the last Ice Age

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on what was once
an ancient mountain top.

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Including a particular type
of wallaby.

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Now a unique subspecies,

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the Pearson Island black-footed
rock wallaby ekes out an existence

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among the cracks and crevices
of this harsh, rocky environment.

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With a population of 300
and no water source on this island,

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every drop is worth squabbling over.

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Their fluffy coats can become
matted into dreadlocks

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like true castaways.

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Unlike the sea lions, these
wallabies are stuck here for good.

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In the ocean,
animals have the freedom

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to move and disperse
over vast distances.

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Sometimes they travel alone.

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At other times
they form great gatherings.

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In the wide shallows of Spencer Gulf
on Australia's south coast,

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June is the time for
an unusual midwinter gathering.

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This garden of seaweeds and sponges

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hosts a spectacle
unique to these waters.

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Giant cuttlefish,
a relative of the octopus,

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grow up to a metre long, making them
the largest of their kind.

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They are only found in Australia.

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Masters of disguise,

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they change the colour and texture
of their skin

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to blend with their surroundings.

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At this time of year, though,

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it's all about standing out
from the crowd.

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This small patch of reef, less than
half a square mile in size,

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has been inundated
with thousands of courting cuttles.

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But, with a ratio of 11 males
to every female,

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not every male
is going to get lucky.

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This female has accepted the
protection of a large alpha male.

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But now he must hold on
to his mating rights

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in the face of constant challenges
from persistent rivals.

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By splaying out his tentacles,
turning white,

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angling his body at 45 degrees,

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he attempts to appear larger
than his challenger.

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The female is hidden below,

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while waves of black
add to his display of strength.

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As rivals converge on either side,
the alpha male is distracted...

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..and his mate drifts from cover.

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A smaller male sees an opportunity
and moves in.

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The interloper drags her
as far as he can

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before forcing her
into his twisted embrace.

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But the larger alpha male
is quick to reclaim his prize.

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He will flush out the sperm
of his competitors

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to ensure only he fertilizes
her eggs.

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Given a moment's respite,

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the pair can get down to the
business of finding a place to nest.

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Any prospective home for the eggs
requires close inspection.

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Satisfied, she deposits
their first clutch.

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Now, with a prime nest site
and a mate to guard,

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the male must continue
to fend off rivals.

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Nest sites like these
are coveted across the reef,

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and males are tireless
in their efforts to claim them.

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This one is already taken.

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It's being guarded by a monster.

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One of the largest males
on the reef.

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His dazzling white skin
and flattened tentacles

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proclaim his strength and size.

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Other males, hoping to mate
with his female under the rocks,

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move in.

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They cautiously test his resolve.

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The urge to mate emboldens them.

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The monster allows them even closer.

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Cuttlefish expel ink
to confuse predators.

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But this is a desperate attempt
to escape the clutches

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of one of their own.

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For now, the monster
has secured his legacy.

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This marine spectacle
was nearly lost forever.

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In a single season, fishermen caught
250 tonnes of cuttlefish

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at this breeding site
before it was protected in 1998.

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Today, this annual gathering
continues in peace

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in these inshore shallows.

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Stretching between Antarctica
and Australia's outer fringes

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is the Southern Ocean,
wild and remote.

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Far out at sea, polar winds
from Antarctica whip up huge swells.

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This is the ocean's engine room,

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generating waves
that roll across the planet.

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Australia's southern coastline
is shaped by this powerful force.

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As the ocean swells
near Australia's outer edge,

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waves build to a monumental size.

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Monsters ten meters high
are not uncommon.

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In winter, when the sea
is at its most savage,

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many ocean wanderers
leave this violent seascape.

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They head north and seek
refuge in the calmer waters

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of the Great Australian Bight.

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The Nullarbor Plain
comes to a dramatic end

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with vertical cliffs plummeting
to the ocean 120 metres below.

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Every winter, these cliffside coves
provide refuge

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to southern right whales.

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Nearly 18 meters long,

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they are amongst the largest animals
ever to have lived.

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This female left her feeding ground
in the Antarctic

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and travelled over 2,000 miles
to give birth.

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The warmer water is gentle
on her newborn,

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which has yet to develop
its insulating blubber.

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She will nurse her calf here
for the next three months

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until it's strong enough to face
the long migration south

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at the start of spring.

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But these coves don't just provide
nursery waters.

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They are the arena for
spectacular mating events.

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This female is without a calf.

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Four males close in on her.

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A group of bottlenose dolphins
become curious onlookers.

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To ensure only the most
well-endowed succeed,

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the female goes belly up.

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The penis of a southern right whale
extends to almost four metres.

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Several males will mate
with her

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but only the last
will father her offspring.

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Unlike the whales,
this pod of dolphins

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will remain by the coast
throughout the year.

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Despite the size difference,
the dolphins are happy

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to share their home
with the visiting giants.

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The whale even appears to mimic
its more agile playmates.

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Renowned for being easy to approach,
right whales were named by whalers

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who consider them
the right whale to hunt...

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..their curious and playful nature
making them easy targets.

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But play is not limited
to whales and dolphins.

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Every winter,
surfers take to the water.

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It's a time when waves
are often at their best

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thanks to the Southern Ocean swell.

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The dolphins seem to take pleasure
in joining them.

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Research has shown that
these synchronised displays

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help male dolphins form alliances.

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Wild dolphins enjoy the lighter side
of life on the southern coast.

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1000 miles east,
there are far darker goings-on.

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Port Phillip Bay is on the doorstep
of Melbourne,

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Australia's second largest city.

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00:21:47,600 --> 00:21:51,840
But few residents have witnessed
the marine spectacle

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00:21:51,840 --> 00:21:55,280
that unfolds in these shallows
every winter.

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00:21:58,360 --> 00:22:04,120
At nearly half a metre in width,
Australian giant spider crabs

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are amongst the world's largest
crustaceans.

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Seldom seen,

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00:22:11,360 --> 00:22:14,600
they spend the years
scavenging on the seabed.

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00:22:17,680 --> 00:22:22,080
But this crab has got a feeling
that it's time for a change.

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00:22:28,200 --> 00:22:30,240
It is soon joined by others.

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00:22:32,480 --> 00:22:36,120
Normally dwelling in depths
of up to 800 meters,

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00:22:36,120 --> 00:22:39,720
these crabs migrate to the shallows
each winter.

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00:22:42,800 --> 00:22:47,480
Not to mate, but to moult -
to shed their old shells.

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00:22:51,320 --> 00:22:55,000
It's believed that an influx of
cold water from the Southern Ocean

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triggers this mass migration.

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00:23:12,720 --> 00:23:16,840
Before long, the ocean floor
is a writhing carpet

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00:23:16,840 --> 00:23:21,280
of claws and spindly legs,
sometimes several creatures thick.

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00:23:25,680 --> 00:23:28,320
In the world above, normality rules.

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00:23:29,920 --> 00:23:31,560
Life continues as usual.

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00:23:54,080 --> 00:23:58,800
Scratching at its face is a sign
that this crab's change has begun.

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00:24:02,480 --> 00:24:07,200
Like all crustaceans, its body
is protected by a hard exoskeleton.

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00:24:09,600 --> 00:24:14,360
But, in order to grow,
the crab must remove its old shell

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00:24:14,360 --> 00:24:16,280
and reveal a new one beneath.

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00:24:22,200 --> 00:24:27,640
Its new orange shell, though larger,
is flexible and able to bend

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00:24:27,640 --> 00:24:29,840
as the crab works its way out.

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00:24:33,120 --> 00:24:37,160
But this temporary softness
will prove to be its downfall.

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00:24:39,840 --> 00:24:44,520
It's one of the first
to expose its new, soft shell,

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00:24:44,520 --> 00:24:48,600
and its hard-bodied neighbours
waste no time

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00:24:48,600 --> 00:24:50,960
in seizing an opportunity
for a meal.

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When growing a new shell, crabs need
as much protein as they can get,

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no matter how macabre the source.

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Once a limb is plucked
from the victim,

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00:25:22,920 --> 00:25:25,960
the attacker quickly retreats
with its prize.

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00:25:45,880 --> 00:25:49,680
Despite the perils of moulting
in the midst of cannibals,

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these crabs in a tree gathered
together for safety in numbers.

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There is a greater threat
to their kind.

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Smooth stingrays,
armed with venom-tipped tails,

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have stalked the crabs
to the shallows.

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00:26:18,120 --> 00:26:19,880
At over two metres wide,

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00:26:19,880 --> 00:26:23,040
these are the largest stingrays
in the world.

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00:26:30,920 --> 00:26:34,960
Defenceless crustaceans
are sucked from their soft shells.

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00:26:39,160 --> 00:26:41,680
With this many moulting at once,

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00:26:41,680 --> 00:26:45,040
even the most insatiable ray
can't eat them all.

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00:26:55,840 --> 00:26:58,840
The carnage continues
well into the night.

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00:27:20,120 --> 00:27:23,960
It takes around three weeks
for all the crabs to moult

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and then, just as suddenly
as they came, they're gone,

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00:27:29,000 --> 00:27:31,520
disappearing back into the deep

246
00:27:31,520 --> 00:27:34,720
where their lives
largely remain a mystery.

247
00:27:39,600 --> 00:27:43,880
A few leftovers from the feast
of rays are all that remain.

248
00:27:56,280 --> 00:27:59,760
One reason for Australia's
many marine marvels

249
00:27:59,760 --> 00:28:04,360
is that while the Southern Ocean
chills the south,

250
00:28:04,360 --> 00:28:07,200
two more oceans bring warm,
tropical water from the north.

251
00:28:09,920 --> 00:28:13,760
In the west, it's the Indian Ocean.
In the east, the mighty Pacific.

252
00:28:17,400 --> 00:28:21,800
On this side of the country,
the land dives beneath the waves

253
00:28:21,800 --> 00:28:24,080
and stretches far out to sea.

254
00:28:25,160 --> 00:28:28,560
This shallow continental shelf
shapes life here.

255
00:28:31,400 --> 00:28:34,120
It forms gentle, sloping beaches.

256
00:28:36,360 --> 00:28:39,000
And islands mark
where it breaks the surface.

257
00:28:43,800 --> 00:28:48,680
100 miles up the coast from Sydney
sits a rather special one.

258
00:28:54,600 --> 00:28:59,640
Cabbage Tree Island is the only
island in the entire region

259
00:28:59,640 --> 00:29:02,240
that remains covered in rain forest.

260
00:29:09,840 --> 00:29:13,200
The palms that give it its name
have also given rise

261
00:29:13,200 --> 00:29:15,240
to an extraordinary sea bird.

262
00:29:19,240 --> 00:29:21,600
Beneath the forest canopy,

263
00:29:21,600 --> 00:29:25,600
the rocky slopes are littered
with nooks and crannies

264
00:29:25,600 --> 00:29:28,040
and, at the right time of year,

265
00:29:28,040 --> 00:29:33,160
a little ball of fluff can
invariably be found inside each one.

266
00:29:34,480 --> 00:29:37,600
It is one of only two
breeding colonies

267
00:29:37,600 --> 00:29:41,480
of Gould's petrel in the world.

268
00:29:43,160 --> 00:29:46,960
This chick is around
three weeks old.

269
00:29:46,960 --> 00:29:50,360
It's been left alone
to fend for itself

270
00:29:50,360 --> 00:29:52,440
while its parents are fishing
at sea.

271
00:30:07,960 --> 00:30:13,400
The spider poses no real threat
but best not to take your chances

272
00:30:13,400 --> 00:30:16,200
when its legspan
is wider than you are.

273
00:30:22,120 --> 00:30:25,600
By nightfall, there is still no sign
of mum or dad.

274
00:30:30,760 --> 00:30:31,880
But then...

275
00:30:35,800 --> 00:30:41,240
A somewhat undignified entrance
but then landing takes practice

276
00:30:41,240 --> 00:30:44,680
and it's a skill seldom used
by petrels.

277
00:30:48,280 --> 00:30:53,000
This species spends years out at sea
without touching dry land.

278
00:30:53,000 --> 00:30:57,200
So, walking over a rocky forest
floor is an alien sensation.

279
00:31:07,320 --> 00:31:11,240
To make matters trickier,
almost every hole under a rock...

280
00:31:13,280 --> 00:31:14,920
..has a chick in it.

281
00:31:18,000 --> 00:31:22,040
It is believed that adults
use a keen sense of smell

282
00:31:22,040 --> 00:31:25,400
to find their way back
to their nest hole.

283
00:31:25,400 --> 00:31:29,520
But it doesn't appear to be
a fail-safe method.

284
00:31:29,520 --> 00:31:30,960
Wrong hole.

285
00:31:39,120 --> 00:31:44,240
Finally, after some searching,
mum and chick are reunited,

286
00:31:44,240 --> 00:31:47,600
and chick gets a meal of
regurgitated squid.

287
00:31:50,920 --> 00:31:53,920
Over the next 12 weeks,
night after night,

288
00:31:53,920 --> 00:31:56,840
crash landing after crash landing,

289
00:31:56,840 --> 00:32:01,200
chicks all over this tiny island
will wait for parents to return.

290
00:32:02,880 --> 00:32:06,600
Until the one night
when they won't come back.

291
00:32:22,160 --> 00:32:28,480
Four months later, with only
a tiny crown of fluffy down left,

292
00:32:28,480 --> 00:32:31,880
the petrel chick has been abandoned
by its parents.

293
00:32:35,800 --> 00:32:39,640
It's been two weeks since
it's had anything at all to eat.

294
00:32:41,040 --> 00:32:43,960
The bird knows
something must be done.

295
00:32:43,960 --> 00:32:49,000
But hunger, desperation and instinct
need to sufficiently combine

296
00:32:49,000 --> 00:32:51,960
before it has the will
to make its move.

297
00:32:54,080 --> 00:32:58,120
For those who don't,
the island holds no future.

298
00:33:08,200 --> 00:33:11,640
Like his parents,
it's under the cover of darkness

299
00:33:11,640 --> 00:33:14,120
that the young bird leaves the nest.

300
00:33:21,240 --> 00:33:25,000
Sea birds like petrels
rely on the wind

301
00:33:25,000 --> 00:33:27,880
to give them the lift needed
for takeoff.

302
00:33:29,200 --> 00:33:33,440
But, down here, beneath the forest
canopy, the air is listless.

303
00:33:37,080 --> 00:33:40,680
An ill-judged attempt at flight
could be his last.

304
00:33:43,640 --> 00:33:48,440
Sharp palms and jagged rocks
don't make for good crash mats.

305
00:33:50,720 --> 00:33:53,840
To stand any chance
of getting off the island,

306
00:33:53,840 --> 00:33:57,360
it must get out
from under the canopy.

307
00:33:57,360 --> 00:33:59,720
But trees cover the whole island.

308
00:34:11,840 --> 00:34:13,960
There's only one thing for it.

309
00:34:25,480 --> 00:34:29,200
Webbed feet and wings
are not ideal equipment

310
00:34:29,200 --> 00:34:32,560
for a sheer vertical climb
of eight meters.

311
00:34:34,000 --> 00:34:38,400
But the petrels have evolved
sharp claws and a hooked beak

312
00:34:38,400 --> 00:34:40,080
to aid their ascent.

313
00:34:47,000 --> 00:34:51,040
As the saying goes,
if at first you don't succeed.

314
00:34:58,960 --> 00:35:03,000
Attempting to climb again
pushes the starving fledgling

315
00:35:03,000 --> 00:35:04,880
closer to exhaustion.

316
00:35:05,880 --> 00:35:10,400
But frantic wing flapping helps
to propel the bird up the tree.

317
00:35:12,560 --> 00:35:15,760
The fledgling wraps its wings
around the trunk

318
00:35:15,760 --> 00:35:19,440
for a moment's respite,
using its tail feathers as a prop.

319
00:35:37,160 --> 00:35:40,960
Having made it to the top,
more obstacles lie in wait.

320
00:35:53,000 --> 00:35:55,920
The thick stems at
the centre of the palm fronds

321
00:35:55,920 --> 00:35:57,600
are lined with the sharp spikes.

322
00:35:59,880 --> 00:36:02,000
Feathers are easily entangled.

323
00:36:11,080 --> 00:36:15,720
Part fall, part flight,
either way, it's airborne!

324
00:36:18,720 --> 00:36:23,240
It won't touch land again
for five or six years.

325
00:36:25,640 --> 00:36:30,400
As the Gould's petrels head off
for a life far out at sea,

326
00:36:30,400 --> 00:36:33,240
other ocean wanderers
are being drawn

327
00:36:33,240 --> 00:36:35,640
to Australia's Pacific coastline.

328
00:36:42,960 --> 00:36:47,840
Once a year, humpback whales
pass Cabbage Tree Island

329
00:36:47,840 --> 00:36:49,600
on their journey north.

330
00:36:54,000 --> 00:36:58,160
They have come to give birth
to their young in the warm shallows.

331
00:37:19,160 --> 00:37:23,640
One occasional visitor is
the subject of myth and legend.

332
00:37:28,040 --> 00:37:31,560
Migaloo.
The albino humpback whale.

333
00:37:41,920 --> 00:37:45,520
His name means white fella
in Aboriginal language.

334
00:37:58,360 --> 00:38:02,960
His pale colour is most likely due
to a rare genetic mutation.

335
00:38:08,720 --> 00:38:14,800
Believed to be 32 years old,
Migaloo is in his prime,

336
00:38:14,800 --> 00:38:17,440
and he knows how to demonstrate
his power.

337
00:38:27,120 --> 00:38:31,920
Scientists believe
tail slapping and rolling

338
00:38:31,920 --> 00:38:34,200
is a form of communication
between whales.

339
00:38:44,960 --> 00:38:48,120
First sighted in 1991,

340
00:38:48,120 --> 00:38:52,040
Migaloo was thought to be
the only white whale in existence.

341
00:38:55,040 --> 00:38:58,640
Since then, white calves
have been spotted in the Pacific

342
00:38:58,640 --> 00:39:00,920
around New Zealand and Australia.

343
00:39:00,920 --> 00:39:05,960
It's thought Migaloo may be
the father of these pale youngsters.

344
00:39:08,640 --> 00:39:14,520
Migaloo travels up Australia's
east coast, or Humpback Highway,

345
00:39:14,520 --> 00:39:15,960
as he heads each year

346
00:39:15,960 --> 00:39:19,880
for one of the country's
most precious natural wonders.

347
00:39:23,520 --> 00:39:28,080
The Great Barrier Reef
spans 130 square miles

348
00:39:28,080 --> 00:39:30,760
of Queensland's Pacific coast.

349
00:39:36,440 --> 00:39:41,960
This enormous coral kingdom covers
roughly the same area as Germany.

350
00:39:44,400 --> 00:39:47,840
It's warm shallow waters
and deserted islands

351
00:39:47,840 --> 00:39:50,680
are not only home
to colourful characters,

352
00:39:50,680 --> 00:39:54,520
they also provide a pit stop
for ocean voyagers

353
00:39:54,520 --> 00:39:59,160
and ancient mariners
such as the green sea turtle.

354
00:40:09,120 --> 00:40:11,800
After years of life
in the open ocean,

355
00:40:11,800 --> 00:40:15,440
this expectant mother has come back
to lay her eggs

356
00:40:15,440 --> 00:40:18,680
in the very same place
where her life began...

357
00:40:21,120 --> 00:40:22,600
..Raine Island.

358
00:40:31,520 --> 00:40:35,560
With flippers designed for sea
and not sand,

359
00:40:35,560 --> 00:40:39,600
hauling her enormous body
up onto the shore

360
00:40:39,600 --> 00:40:41,800
takes an extraordinary effort.

361
00:40:52,840 --> 00:40:56,720
She carefully carves out a nest
in the sand,

362
00:40:56,720 --> 00:40:59,480
her one and only act
of parental care.

363
00:41:07,200 --> 00:41:11,120
And deposits a clutch of
around 100 eggs.

364
00:41:14,160 --> 00:41:18,400
As she returned to the waves,
more mothers clamber up the beach.

365
00:41:18,400 --> 00:41:20,800
In fact, many, many more.

366
00:41:23,000 --> 00:41:27,040
14,000 turtles can come ashore here
in a single night.

367
00:41:51,000 --> 00:41:56,000
After laying, the females return
to the waters around Raine Island

368
00:41:56,000 --> 00:42:00,320
for a couple of weeks before
returning to lay another clutch.

369
00:42:11,040 --> 00:42:14,600
Two months later,
the sand begins to stir.

370
00:42:30,040 --> 00:42:32,920
Hatchlings begin
their race to the water.

371
00:42:38,480 --> 00:42:42,840
But by night,
ghost crabs haunt this beach.

372
00:43:03,400 --> 00:43:05,440
Another crab lies in ambush.

373
00:43:12,160 --> 00:43:13,360
But ghost crabs...

374
00:43:15,640 --> 00:43:18,680
..are not the greatest threat
that they will face.

375
00:43:22,960 --> 00:43:26,400
In the open ocean,
more predators await.

376
00:43:26,400 --> 00:43:31,360
It's estimated that just one
in a thousand hatchlings survive.

377
00:43:35,120 --> 00:43:39,360
The young turtles will travel
on Australia's ocean currents.

378
00:43:42,600 --> 00:43:46,080
Some will be carried east,
into the South Pacific.

379
00:43:47,720 --> 00:43:50,560
Others will be swept north,
towards Asia.

380
00:43:54,480 --> 00:43:59,120
The separation of the land
between Asia and Australia

381
00:43:59,120 --> 00:44:01,440
creates a passageway
for tropical water.

382
00:44:02,800 --> 00:44:07,040
Australia is the only continent
with warm currents flowing south

383
00:44:07,040 --> 00:44:08,480
on two sides.

384
00:44:12,640 --> 00:44:15,720
Without this, the Indian Ocean
off Western Australia

385
00:44:15,720 --> 00:44:17,160
would be far colder...

386
00:44:21,440 --> 00:44:24,680
..instead of the tropical
environment that it is.

387
00:44:28,200 --> 00:44:32,600
On this remote coastline,
humans are few and far between.

388
00:44:34,480 --> 00:44:39,320
It's an example of what marine
ecosystems should look like.

389
00:44:39,320 --> 00:44:42,960
Healthy, interconnected
and teeming with life.

390
00:44:45,200 --> 00:44:49,240
100 miles off the coast
lie the Lacepede Islands.

391
00:44:54,560 --> 00:44:59,240
18,000 pairs of brown boobies
nest here.

392
00:45:03,520 --> 00:45:07,560
It's breeding season and,
on an exposed edge of the beach,

393
00:45:07,560 --> 00:45:10,600
a new couple are hoping
to start a family.

394
00:45:14,480 --> 00:45:17,680
With a weedy offering,
he attempts to woo her.

395
00:45:19,680 --> 00:45:20,840
Perhaps another try.

396
00:45:22,160 --> 00:45:23,520
No.

397
00:45:23,520 --> 00:45:25,920
Surely his efforts
have been sufficient?

398
00:45:31,600 --> 00:45:32,800
Maybe not.

399
00:45:38,240 --> 00:45:42,440
Booby nests are often little
more than a small pile of sticks.

400
00:45:43,720 --> 00:45:46,920
Some are barely an indentation
in the pebbles.

401
00:45:49,440 --> 00:45:52,800
Parenting is approached
in a variety of styles.

402
00:45:56,040 --> 00:45:57,720
Some respond to nagging.

403
00:46:04,200 --> 00:46:06,440
While others stand their ground.

404
00:46:15,200 --> 00:46:17,800
A beak skills lesson
is taking place.

405
00:46:21,120 --> 00:46:25,520
Imitating parents helps chicks
practice their catching skills.

406
00:46:30,640 --> 00:46:35,280
Becoming adept at flipping
sticks and stones will prepare them

407
00:46:35,280 --> 00:46:37,920
to manipulate slippery fish
mid-flight.

408
00:46:44,040 --> 00:46:48,720
As midday temperatures rise
to around 40 degrees Celsius,

409
00:46:48,720 --> 00:46:52,560
parents hover like beach umbrellas
over their chicks.

410
00:46:55,400 --> 00:46:58,440
Domestic duties are shared
between parents.

411
00:47:00,080 --> 00:47:02,280
And this chick needs feeding.

412
00:47:07,760 --> 00:47:10,440
Out at sea,
the boobies move en masse.

413
00:47:11,520 --> 00:47:15,640
They have spotted splashing
in the distance.

414
00:47:15,640 --> 00:47:20,120
A school of tuna have driven
a shoal of sardines to the surface.

415
00:47:27,480 --> 00:47:31,200
Fish are pushed up, straight into
the boobies' waiting beaks.

416
00:47:35,200 --> 00:47:37,040
Frigate birds join the plunder.

417
00:47:46,840 --> 00:47:51,480
Having taken their fill, parents
head home to their hungry chicks.

418
00:47:57,840 --> 00:48:01,600
Back at the island,
other frigate birds are patrolling.

419
00:48:03,240 --> 00:48:06,800
They are known as
the pirates of the skies,

420
00:48:06,800 --> 00:48:07,920
for good reason.

421
00:48:09,960 --> 00:48:13,000
Larger and faster than the boobies,

422
00:48:13,000 --> 00:48:17,000
they bully the smaller sea birds
into giving up their lunch.

423
00:48:23,160 --> 00:48:28,040
Outmanoeuvred, it's forced
to disgorge its food mid-air.

424
00:48:41,640 --> 00:48:46,200
Onshore, the tiny chick's wait
for a meal should finally be over.

425
00:48:48,000 --> 00:48:51,360
The mates greet each other
but lunch was stolen.

426
00:48:56,080 --> 00:49:00,200
Now the onus of providing a meal
falls to the other parent.

427
00:49:07,360 --> 00:49:11,280
Fortunately, at this time of year,
food is abundant.

428
00:49:15,480 --> 00:49:22,160
In winter, cycling ocean currents
fuel huge blooms of plankton,

429
00:49:22,160 --> 00:49:25,960
providing a sudden bounty of food
for small fish.

430
00:49:28,760 --> 00:49:30,800
Enormous schools of sardines form.

431
00:49:33,880 --> 00:49:36,560
And these, in turn,
attract bigger fish.

432
00:49:38,080 --> 00:49:39,320
Dusky sharks.

433
00:49:41,320 --> 00:49:45,360
Fast, streamlined predators
around three metres in length.

434
00:50:03,520 --> 00:50:08,040
Bigger sharks come to feast, too,
including the biggest of them all.

435
00:50:08,040 --> 00:50:09,560
The whale shark.

436
00:50:11,840 --> 00:50:15,640
12 meters long and
weighing as much as 11 tonnes.

437
00:50:21,200 --> 00:50:23,440
Despite their imposing size,

438
00:50:23,440 --> 00:50:27,200
they feed on the same microscopic
plankton as the sardines.

439
00:50:33,160 --> 00:50:38,600
Chemicals released by the plankton
are carried on the ocean currents.

440
00:50:38,600 --> 00:50:42,320
The whale sharks follow
their sensitive noses

441
00:50:42,320 --> 00:50:45,960
to find these blooms in the waters
of Ningaloo,

442
00:50:45,960 --> 00:50:49,240
a protected area
of Australia's west coast.

443
00:50:54,840 --> 00:50:57,320
Scientists want to understand

444
00:50:57,320 --> 00:51:00,400
how the individuals here
are related.

445
00:51:00,400 --> 00:51:04,640
They believe that they may be part
of a whale shark family

446
00:51:04,640 --> 00:51:08,600
that spans both the Pacific
and the Indian Oceans.

447
00:51:11,920 --> 00:51:16,160
To be sure, the scientist needs
a sample of each whale's DNA.

448
00:51:22,000 --> 00:51:25,840
Remarkably, the giant animal
will hang calmly

449
00:51:25,840 --> 00:51:27,800
while its nose is scratched.

450
00:51:30,240 --> 00:51:32,480
Completely relaxed,

451
00:51:32,480 --> 00:51:35,480
the shark seems to enter
a trance-like state...

452
00:51:43,040 --> 00:51:47,720
..allowing the scientists to scrape
tiny parasites off its body.

453
00:51:50,640 --> 00:51:54,000
These parasites, known as copepods,

454
00:51:54,000 --> 00:51:57,800
chew the shark's skin
and drink its blood.

455
00:51:57,800 --> 00:52:01,120
So, in return for the DNA sample,

456
00:52:01,120 --> 00:52:04,360
the whale shark gets rid
of a few free loaders.

457
00:52:19,840 --> 00:52:23,560
Research has now shown
that Australian whale sharks

458
00:52:23,560 --> 00:52:27,520
are the offspring of ocean-wandering
parents from as far away

459
00:52:27,520 --> 00:52:29,640
as Indonesia and New Guinea.

460
00:52:32,800 --> 00:52:36,400
Here in Ningaloo, the giants
have a precious sanctuary

461
00:52:36,400 --> 00:52:40,840
from hunters in a place
where they are a protected species.

462
00:52:55,080 --> 00:52:59,160
Most sharks are cold blooded
and are therefore restricted

463
00:52:59,160 --> 00:53:03,840
to warm waters, like those along
Australia's remote western coast.

464
00:53:09,000 --> 00:53:14,640
Shark Bay, 500 miles north of Perth,
can justly claim its ominous name.

465
00:53:15,680 --> 00:53:19,160
The water is bath-like
for most of the year.

466
00:53:29,280 --> 00:53:32,160
Sharks have an acute sense of smell,

467
00:53:32,160 --> 00:53:38,040
capable of detecting the faintest
traces of blood in the water.

468
00:53:38,040 --> 00:53:42,280
But an entire whale carcass
is like a siren going off...

469
00:53:44,760 --> 00:53:47,120
..alerting sharks for miles around.

470
00:53:48,720 --> 00:53:49,960
Tiger sharks.

471
00:53:51,920 --> 00:53:56,880
Threatened globally, here they can
still be found in numbers.

472
00:54:06,600 --> 00:54:10,880
New arrivals skirt the dead whale
before entering the fray.

473
00:54:17,440 --> 00:54:21,080
These predators have hunted
the world's oceans

474
00:54:21,080 --> 00:54:25,760
for more than 50 million years
and they're not above scavenging.

475
00:54:39,560 --> 00:54:42,800
The feeding frenzy
has attracted sightseers.

476
00:54:45,880 --> 00:54:49,720
Despite a notorious reputation
for attacks on people,

477
00:54:49,720 --> 00:54:54,000
tourists are keen to catch a glimpse
of these striking animals.

478
00:55:13,040 --> 00:55:14,920
Attacks on people are very rare

479
00:55:14,920 --> 00:55:18,120
but sharks have been persecuted
for centuries,

480
00:55:18,120 --> 00:55:23,080
and the government of Western
Australia still employs hunters

481
00:55:23,080 --> 00:55:26,080
to kill these endangered animals.

482
00:55:28,320 --> 00:55:31,960
But, when a chance encounter
like this enables people

483
00:55:31,960 --> 00:55:35,040
to get close to animals
that they may fear,

484
00:55:35,040 --> 00:55:38,680
their enjoyment could trigger
a change in attitude.

485
00:55:43,760 --> 00:55:47,880
Nowhere is that more important
than here in Australia,

486
00:55:47,880 --> 00:55:51,840
where coasts are nourished
by three oceans,

487
00:55:51,840 --> 00:55:54,920
creating a nexus for marine life.

488
00:56:00,360 --> 00:56:02,240
From the warm Indian Ocean,

489
00:56:02,240 --> 00:56:06,320
with its schools
of awe-inspiring predators,

490
00:56:06,320 --> 00:56:08,760
to the calm shallows
of the Pacific,

491
00:56:08,760 --> 00:56:12,000
with its reefs and islands,

492
00:56:12,000 --> 00:56:15,440
and the rich and varied
southern seas

493
00:56:15,440 --> 00:56:20,720
with gatherings of species
found nowhere else on Earth,

494
00:56:20,720 --> 00:56:26,760
the meeting of these three oceans
has produced an explosion of life

495
00:56:26,760 --> 00:56:29,640
in Earth's Magical Kingdom.