Original subtitles

Just off the east coast of Australia lies a miracle of an island, one built entirely on sand.

But somehow it has become a magnet for life.

Ocean giants, peaceful and playful, grace its waterways,

pursued by not-so-gentle giants.

Great rainforests, acid swamps,

and improbably lakes conceal devious killers

that fight to outwit and devour the weak...

and each other.

It's a tough place to be top dog.

A restless battleground

where life holds on against all odds

on this great island of shifting sands.

Fraser Island.

[♪]

It's spring, and the humpback whales

of the southern hemisphere

are on the southbound leg of an annual 3,000-mile journey

from their breeding grounds inside the Great Barrier Reef

to the rich feeding grounds of cold Antarctic waters.

En route, many mothers and their newborn babies

take a little side trip to a favourite site:

the sheltered waters of Fraser Island.

Platypus Bay between the island and the mainland

is a perfect spot for the little ones to nurse

and grow strong for the epic journey ahead...

and to have a little fun.

[♪]

[♪]

The bay is too shallow for the males that sometimes escort them

to attempt their courting and mating rituals,

so mother and calf can bond in peace.

Suckling on her mother's fat-rich milk,

this young calf will nearly double her birth weight

in a matter of weeks.

Her mother, however, won't eat,

and will lose a third of her weight

on the southward migration.

Whales send messages to each other

by slapping the water with their fins and tails.

Tail-slapping may be a form of short-range communication.

They employ vocalizations for long-distance calls.

Out in deeper water,

the males sing their haunting songs as they continue south,

whereas the females remain silent.

The complex songs are particular

to this East Australian population.

They can last hours and be heard hundreds of miles away.

After a five-day sojourn in the bay, it's time to go.

The calf will travel in her mother's slipstream

to ease her journey.

The mother and her calf head north and east out of the bay,

slipping around the tip of Fraser Island

and heading south against the prevailing currents.

Fraser Island, just one mile from the mainland,

lies at the southern tip of the Great Barrier Reef.

Its creation began hundreds of thousands of years ago,

as mainland rivers carried sediment

from Australia's east coast into the ocean.

Currents swept billions of tonnes of sand

up along the coast,

where rocky outcrops forced the ocean to drop its payload.

Eventually, an enormous island of sand rose out of this earth.

Today, Fraser is 75 miles long and 14 miles wide,

and some of its dunes tower 780 feet high.

The Aboriginal people call it K'gari, or "paradise".

More than 15,000 years ago, when sea levels were lower,

Platypus Bay would have been an exposed sand flat

connecting the island to the mainland.

Across that sand flat

came Australia's largest surviving predator mammal:

the dingo.

When sea levels rose again, cutting off the island,

its dingo population scratched out a living in isolation.

Without possible interbreeding

with the mainland's domestic dogs,

Fraser Island's dingoes remain the purest dingo population

in Australia.

While they're the top predators on the island,

dingoes can't afford to turn their noses up

at any source of food.

On the east coast, a whale whose journey south ended

almost as soon as it began becomes a welcome opportunity.

The dingo is not alone.

The island's largest lizard, the lace monitor,

has also caught the scent of the rotting carcass.

It, too, is both hunter and scavenger.

But dingoes also hunt lace monitors.

So the lizard wisely decides to look for dinner elsewhere.

The dingo's mate joins him at the carcass.

They're the alpha pair of the local pack.

This female is suckling a litter of pups,

and needs to supplement her diet

with whatever comes her way.

While it's a mega-meal, it's also a tough one to unwrap.

Until the whale hide weakens over time,

the dingoes focus on the softest parts.

While the dominant pair are at the carcass,

other pack members keep their distance.

There are dozens of dingo packs on the island.

Each pack has about a dozen members

and is controlled by the alpha male and female.

The female's pups are entirely reliant on her milk

for their survival.

She makes her way inland, deep in the forest,

where she's hidden her day-old pups in a log den.

[Dingoes whining]

Unlike domestic dogs, dingoes breed only once a year.

The pups won't be independent for another seven months,

when they'll take their place in the pack hierarchy.

[♪]

Back at the coast, this sea eagle uses its keen eyesight

to spot prey from up to 65 feet away.

While he usually prefers fishing,

the lure of the whale carcass is hard to resist.

The carcass will remain a hub of activity

until it's picked clean or washed back into the ocean.

Even a whistling kite will scavenge the carcass,

grabbing a bite on the wing.

Not interested in sharing,

he takes his meal into a nearby tree,

away from other scavengers.

Down below, the red-capped plover has to keep on his toes.

The whistling kites prefer hunting

and shorebirds are a favourite prey.

Microscopic invertebrates and algae living in the wet sand

supply him with all the food he needs.

Beachcombing is busy work,

and he spends most of his time foraging this way.

Further down the beach,

huge flocks of crested terns congregate.

Drawn to Fraser Island to feast in the rich waters.

[♪]

The seas are relatively calm for now,

but this eastern edge of the island

takes the brunt of prevailing winds.

[Wind howling]

Here, on the most hostile side of the island,

the pitched battle between shifting sands and rooted plants

continues to play out

as it has since the days when the island took shape.

Without plants to anchor the dunes,

the sand would simply keep marching inland,

and this would be a completely barren place.

Hardy pioneer plants like spinifex

are the first to put down roots.

They've evolved extraordinary ways to cope

with the coast's abrasive conditions.

Spinifex grasses have a covering of fine, waxy hairs

that repel the salt and retain water.

When mature, their seed heads dislodge

and are blown about the dunes,

where they germinate and begin their work

turning the sand dunes into a thriving ecosystem.

The spinifex root systems and creeping stems act like mesh,

securing the sand in place below.

Once stable, sand dunes make perfect nesting burrows

for the rainbow bee-eater.

Masterful hunters, rainbow bee-eaters

acrobatically catch insects on the wing.

This pair has mated for life,

and return to the island every spring for the breeding season.

This means picking a very stable dune

and excavating a three-foot-long tunnel into it.

The female does most of the digging.

These two are such old hands at this

that their burrow from last year is still intact,

which will save them a lot of trouble.

All it needs is a little renovation

and their nursery will be snug and ready

to welcome their eggs.

The lace monitor, rebuffed from the whale carcass,

has travelled down the beach in search of a meal

that he can really get his mouth around:

bird eggs.

He haunts the dunes looking for failed architecture.

High tides and winds can dislodge eggs

from poorly placed nests.

The monitor reaps the benefits...

and one pair of bee-eaters helplessly watches

its next generation disappear.

The experienced bee-eaters,

with their deep and stable nesting site, have less to fear.

Their eggs will hatch deep out of reach

of even the most determined lace monitors.

[Wind howling]

But not all the dunes on the east coast can be tamed.

The assault of wind and sand that build the island

still creates dunes that relentlessly march inland,

blown by powerful prevailing easterlies,

the dunes align with the onshore winds

that drive them and form ridges.

Over time, they assume massive U-shapes

known as parabolic dunes.

Lakes often form in the sheltered swoops

between these windblown dunes.

One of the liveliest is Lake Wabby.

At 39 feet, it's the deepest lake on the island

and unlike some of the island's other lakes,

its emerald waters are fresh,

harbouring catfish and rainbowfish,

irresistible to the local waterfowl.

Cormorants frequent Lake Wabby,

dipping and diving for their supper.

Unlike many diving birds, their wings do not produce oils

to make them waterproof.

Instead, their feathers have microscopic structures

that repel water,

and these require careful maintenance and drying.

But sometimes the elements just won't cooperate,

and they simply have to put up with a good soaking.

The rains that fall on Fraser Island

seep into an enormous dome-shaped water table

below the dunes

that in some places may reach 100 feet below sea level.

[Thunder rumbling]

Lake Wabby dips into this aquifer,

and is known as a window lake.

But this is a lake under siege...

by the same dune process that formed it.

Lake Wabby is being engulfed by sand

at the rate of six feet a year.

In 100 years, the sand will completely reclaim the lake.

[Insects buzzing]

Moving inland beyond the advancing sand

and where the water table is high,

swamps and heathlands can flourish.

With their feet in the sand,

the plants can find nutrients hard to come by.

But these hardy survivors manage to create sweet salvation

for the locals.

The energy these plants might otherwise invest

into tall trunks and branches

goes into producing abundant nectar,

attracting honey-eaters that in turn

spread pollen from plant to plant.

The nectar is in great demand,

and birds squabble among themselves

to defend their patch.

[Birds chirping]

Insects too are drawn to the bounty.

But not all nectar is what it seems.

On the heathland floor grows a clever carnivore.

The drosera, or sundew plants, put out modified leaves

that glisten with what looks like irresistible nectar.

But these gooey droplets are actually laced

with flesh-digesting enzymes.

Any unfortunate insect tempted by the apparent feast

quickly finds itself in a sticky situation...

and well on the way to a syrupy end.

It's a brilliant solution

for a plant stuck in an infertile, sandy environment.

With no nitrogen to suck up from the soil.

It sucks it out of its unlucky victims instead.

Fraser Island's ongoing battle between sand and life

has turned the plants into carnivores.

The jabiru, Australia's only stork,

wades along the edges of these swampy regions,

searching for frogs, fish, and other tasty morsels

hiding in the reefs.

Its long legs are ideal for swamp-walking, and its bill,

designed for stabbing and grabbing.

Swamp hens take a different approach,

feeling their way among the reeds

with their elongated toes ready to snatch anything edible.

Those long toes also provide great stabilization

for the gentle, if brief art, of mating.

Ironically for an island surrounded by salt water,

Fraser Island has a higher concentration

of permanent freshwater lakes

than any other part of the mainland,

with more than 100 of them.

But not all of the freshwater lakes are welcoming to life.

Some are highly acidic, thanks to the tannins

leached out of the decaying vegetation in the water.

Remarkably, they're home to some of Australia's

most delicate creatures.

Even though they absorb water and breathe through their skin,

four species of frogs on Fraser Island

have adapted to the harshly low pH of the acid lakes.

They thrive in the absence of competitors and predators,

who can't tolerate the acidity.

Known as acid frogs,

they huddle silently in the reeds during the day.

But at night, they begin to make their way upwards...

to sing.

[Frogs squeaking]

As the sun sets, the lakes come alive with noise...

[Frogs squeaking]

...catching the attention of nocturnal predators.

This male acid frog has found a stage from which to serenade

the resident females.

[Frogs squeaking]

Magnified by an enlarge vocal sack,

his calls echo around the swamp.

But it's not only the females that take notice.

A brown tree snake, also known as the night tiger,

is drawn to the vibrations of his calls.

[Frogs squeaking]

Its long, lean body effortlessly spans large distances

between branches.

It hunts by sight and by tasting the night air

for the scent of prey.

The acid frog senses his approach and freezes, silent.

[♪]

Despite the night tiger's keen eyesight,

this meal has eluded him.

He'll have to search elsewhere.

Night-time is also the right time for this little marsupial.

The squirrel glider.

His giant eyes give him acute night vision.

He is searching for fruits

and insects washed down with sap and nectar.

His slightly smaller neighbour, the sugar glider,

is also out and about.

Both species are perfectly adapted

to life in the forest canopy,

out of reach of the predators that might be lurking below.

Stretchy membranes on the sides of their bodies

give the gliders their name.

At the first sign of trouble,

this pint-sized parachutists can launch themselves into the air,

trimming their furry membranes

to control their trajectory and landings

with astounding accuracy.

[♪]

Beyond the swamps and open forest where the dingoes hunt

lie the high central dunes, 650 feet up.

Here, a true miracle of the island rises into the sky:

a massive rainforest,

the only one in the world to grow in such high sand dunes.

Usually complex forests of this size grow only on soil.

Some plants here are rare relics from the age of the dinosaurs.

These are king ferns,

whose lineage stretches back 300 million years.

The fronds of this fern are the largest in the world,

stretching some 26 feet from their base.

Their kind existed on the planet

before Australia separated

from the ancient supercontinent of Gondwana.

Only a few pockets of them still exist in Australia.

This stand from Fraser Island's interior is one of the finest.

The sands of Fraser Island even support true giants

such as these Satinay trees.

Towering up to 100 feet,

these trees occur only in this sandy corner of Australia.

They were once highly sought after as timber

because of their ability to resist termites and borers,

and were used to build the Suez Canal.

Now they are mostly protected

by the island's World Heritage status.

The enormous trees are no obstacle to the lace monitor

in its never-ending search for bird eggs.

They also provide an escape from the attention of the dingoes

that are constantly on the prowl below.

[♪]

The fallen timbers provide ideal pupping and nursing dens

for another of the island's packs,

and hollow boughs serve as daytime sleeping places

for the gliders.

The rotting giants eventually decompose,

giving back their nutrients to the soil

and helping sustain the improbable forest.

The thick carpet of leaves on the forest floor

conceals a killer that is both dangerous and endangered.

The death adder has an ingenious hunting strategy

designed to bring prey to it,

not the other way around.

Its stout body tapers into a tail with an agile, wormlike end

that it can wiggle even as the rest of its body

remains motionless.

The well-camouflaged body blends into the background,

but the tail flaunts itself as a lively, tasty worm.

Known as caudal luring, this lethal mimicry

is the death adder's weapon of choice.

A skink that falls for the trick is doomed.

The death adder strikes with an astounding accuracy,

delivering highly potent venom,

with the fastest strike of any snake in the world.

But this clever killer is in dire straits.

Its numbers are rapidly declining on the mainland,

a victim of the infamous cane toad.

Introduced to Australia in the 1930s

as an insect control measure,

the plan has gone horribly wrong.

Cane toads are an environmental nightmare.

They reproduce prolifically and have few natural predators.

They eat anything they can put their giant mouths around,

and anything that eats them gets a giant dose of poison,

including the death adder.

Despite the presence of the toads,

death adders are holding on better here on Fraser Island

than elsewhere because of the island's chemistry.

Many of its lakes and swamps

are simply too acidic for the toad to survive in,

and there's another snake here

that manages to keep the cane toad in check.

[♪]

The keelback has developed a taste for the toad

and a tolerance for the powerful toxins

that seep from the toad's skin.

Unlike most snakes, the keelback attacks from behind...

...avoiding the full impact

of the toad's poison-laden cheek glands.

The snake lives another day

and there is one less toad in the swamp.

[♪]

The highest lakes on Fraser Island

are almost 800 feet above sea level,

too high to connect to the water table below.

These perched lakes are lined with decaying vegetation,

creating an impermeable, compacted base layer

that collects and holds water like a great saucer.

The waters of these lakes are often so pure

they're crystal clear.

These are the sparkling waters

and snow-white beaches of Lake McKenzie.

This is one of the last lakes to be found on the ascent

from the east coast

before the island slopes down once more

towards the sheltered western shore.

Rain falling on this leeward side of the island

is filtered and fed into Wanggoolba Creek.

It flows westward and into the narrow shallows

that separate the island from the mainland.

Here, the island reveals its alter ego:

a serene, sheltered environment

subject not to the turmoil and uncertainty

of the winds and waves,

but the gentler push and pull of the tides.

The west shoreline

receives a rich payload of silt and nutrients

fed by the mainland's rivers.

This is where the sands run out and the mudflats begin.

The ebb and flow of the tide reveals and conceals

riches below the surface.

When the tide runs out,

vast armies of light blue soldier crabs quickly emerge.

They defy crab-walking convention

by marching forwards rather than sideways.

As they march, they sift through the wet sand,

searching for tiny morsels of food.

They feverishly sort the edible bits from the sand,

then race to bury themselves before the tide comes in.

Corkscrewing into the sand with their specialized claws,

they dig burrows complete with air pockets

so they can breathe while submerged.

But these hatchers leave a tell-tale sign

for predatory birds.

Whimbrels stalk the crabs.

At the slightest sign of danger,

the crabs bury themselves as quickly as possible.

The whimbrels use their sharp eyesight to spot and seize

the helpless crabs.

Their downward-curved bills can stab deep into the sand,

foiling the soldier crabs' best defenses.

They aren't the only birds hunting crabs.

The beach stone-curlews join the feast,

eating as many crabs as they can

before the tide returns.

The danger is never far away.

This brahminy kite keeps a close watch,

hoping to catch one of the birds off guard.

But the driftwood that lines the shore provides excellent cover

for the curlews.

They camouflage themselves amongst the debris.

The west coast is the perfect environment

for some of the hardiest and most salt-tolerant

of all plants:

mangroves.

Their sturdy prop roots provide a firm footing

in the silt-laden underworld.

These are drowned and revealed each day

with the ebb and flow of the tides.

And they're a rich hunting ground for some local residents.

The rakali is a native rodent with partially webbed feet,

thick water-repellent fur, and long whiskers.

Australia's equivalent to the otter.

It is one of Australia's shiest and least-known native mammals.

To even catch a glimpse is a rarity.

But their insatiable taste for freshwater mussels

means you can always tell where they've been.

They're masters at making themselves scarce

when they sense danger,

and this saltwater crocodile definitely counts as danger.

The salty is the world's largest crocodile.

They can grow to over 20 feet and weight a tonne.

They haunt rivers and estuaries

and make great oceanic journeys in search of prey.

But a visit from the mainland

to the rich hunting grounds of the Fraser Island mangroves

is barely a day-trip for this great predator.

This classic ambush predator lurks just beneath the surface,

with only its prominent eyes and nostrils visible as it hunts.

It will eat anything it can get its impressive jaws on.

One of the sea's gentler giants is also drawn to Fraser Island.

Dugongs can only survive where seagrass grows,

and the great sandy straits support seagrass meadows

the size of Rhode Island.

This dugong cow is part of a healthy local herd.

Her heavy bones give her negative buoyancy,

anchoring her to the sea floor

as she grazes on the seagrass beds.

A relative of the American manatee,

she can munch her way through 60 pounds of seagrass

in a single day.

She can stay under for up to six minutes

before surfacing to breathe.

Sea grass meadows stabilize the shifting sediment

and trap nutrients.

The world's seagrass meadows

also act like great carbon sinks,

sequestering twice the amount of carbon

a tropical forest of the same size can store.

Just 2.5 acres of seagrass can capture

more than 30 million tonnes of carbon each year

and produce over 26,000 gallons of oxygen per day,

enough for nearly 200 people to breathe.

Green sea turtles also come here to feed,

grazing on the seagrass before heading north to breed

on the Great Barrier Reef islands.

Towards the end of spring,

they leave the shallows and head to the waters

off the northern tip of Fraser Island.

These are amongst the most important

courting and mating grounds

for the Pacific Ocean's green sea turtles...

and predators know it.

The large blunt-nose tiger shark

is known to eat almost anything that crosses its path,

but it's specially equipped to deal with large turtles.

Having killed this turtle,

the tigers proceed to eat the easy bits first:

the flippers.

They then use their serrated-edge teeth

to saw through the turtle's hard shell.

[♪]

But green sea turtles have adapted

and spend little time at the surface,

where they can be ambushed.

Instead, they grab a quick breath

and head right back to the relative safety of the bottom.

The fertile sands of Fraser Island

serve as a valuable fuelling station

for many migratory seabirds.

This bar-tailed godwit

is preparing for one of the most incredible journeys

in the animal kingdom.

It will gorge itself on molluscs, worms, and insects,

in preparation for the long-haul flight ahead.

By the time it embarks on the journey,

more than half of its body will be fat reserves.

These reserves will provide much-needed energy

as the godwit's flight is the longest nonstop journey

made by any animal.

It leaves Fraser Island and does not touch ground again

until arriving at their breeding grounds in Alaska,

over 7,000 miles away.

From the windswept shores of the east coast,

across the marching dunes and placid lakes...

through towering forests

with their feet in shifting sands,

down to the seagrass meadows on the west.

Fraser Island truly lives up to its more ancient name:

K'gari.

Paradise.

A paradise that these great whales return to every year,

that protects the purest strain of dingoes in the world,

where plants and animals

have found their own unique way of surviving...

on the world's largest island of sand.