NARRATOR: 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 SURPRISINGLY DIVERSE LANDSCAPES AND THRIVE IN ITS VIBRANT SEAS...

EVEN MAKING THEIR HOMES AMONGST THE GROWING CONCRETE JUNGLE.

IN THIS EPISODE, TRAVELING 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 THE MAGICAL LAND OF OZ.

ANNOUNCER: "MAGICAL LAND OF OZ" WAS MADE POSSIBLE IN PART BY SCREEN AUSTRALIA AND BY CONTRIBUTIONS TO YOUR PBS STATION FROM VIEWERS LIKE YOU.

THANK YOU.

NARRATOR: AUSTRALIA'S OCEAN WILDERNESS IS ONE OF THE MOST EXTRAORDINARY PLACES ON EARTH.

IT IS BOTH BEAUTIFUL AND BOUNTIFUL.

IT STARTS WITH THE TINIEST FISH...

WHICH, IN TURN, SUPPORT AN ASTONISHING ARRAY OF LARGER CREATURES.

DUSKY SHARKS... FAST, STREAMLINED PREDATORS 10 FEET IN LENGTH.

THESE DENSE SCHOOLS OF SARDINES ARE KNOWN AS BAIT BALLS.

THE FISH'S QUICK SHIMMERING CHANGES IN DIRECTION MAKE IT HARD FOR PREDATORS TO PICK OUT AN INDIVIDUAL.

BIRDS ATTACK FROM ABOVE AS SHARKS, MOVING IN FROM DEEPER WATERS, HERD THE FISH TOWARDS THE SHALLOWS.

CONFIDENT THE SHARKS ARE KEEPING THEMSELVES BUSY, YOUNG BOARD RIDERS ENTER THE FRAY FOR A CLOSE ENCOUNTER.

MORE AND MORE SHARKS JOIN THE FEAST, DRAWN IN FROM FAR AND WIDE.

LIKE AN ENORMOUS LIVING STAIN SPREADING ALONG THE COAST, THE WRITHING MASS THINS AS IT'S PUSHED INTO THE SHALLOWS.

THE SHEER SIZE OF THE SCENE NOW BECOMES CLEAR.

SEVERAL LARGE SCHOOLS OF SARDINES HAVE BEEN HERDED TOGETHER INTO ONE COLOSSAL BAIT BALL.

IT'S LITTLE WONDER THAT AUSTRALIA IS ONE OF THE PLANET'S SHARK HOTSPOTS WHERE THEY ARE SUSTAINED BY IMMENSE GATHERINGS OF FISH LIKE THIS.

THE SHARK IS NOT AUSTRALIA'S ONLY MARINE PREDATOR...

BUT NOT ALL OF THEM REMAIN UNDERWATER.

IN FACT, SOME OF THE OCEANS' BEST HUNTERS HAVE FOUND THEIR WAY ONTO THE BEACHES OF REMOTE OFFSHORE ISLANDS.

40 MILES OFF SOUTH AUSTRALIA, PEARSON ISLAND AND THE COLD WATERS THAT SURROUND IT ARE THE PERFECT PLACE FOR A FEMALE 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 4 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... [GROWLING] BUT MOTHERS CAN BE PROTECTIVE... AND FATHERS DOWNRIGHT HOSTILE.

[GROWLING] 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 ARE HUNGRY.

[BIRDS SQUAWKING] 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 CHARACTERIZED 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 FOR THE SANDY BEACH.

[PUP CRYING] A FEED AT LAST.

SHE WILL SUCKLE HER PUP FOR A FULL 18 MONTHS UNTIL HE GAINS HIS INDEPENDENCE AND CAN HUNT ALONE IN THESE ABUNDANT WATERS.

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 TO OVER 3 FEET LONG, MAKING THEM THE LARGEST OF THEIR KIND.

THEY ARE ONLY FOUND IN AUSTRALIA.

MASTERS OF DISGUISE, THEY CHANGE THE COLOR 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 ONTO 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 THEIR 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 270 TONS 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.

[THUNDEROUS WAVES] 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 30-FEET 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 500 FEET BELOW.

EVERY WINTER, THESE CLIFFSIDE COVES PROVIDE REFUGE TO SOUTHERN RIGHT WHALES.

NEARLY 60 FEET LONG, THEY ARE AMONGST THE LARGEST ANIMALS EVER TO HAVE LIVED.

THIS FEMALE LEFT HER FEEDING GROUND IN THE ANTARCTIC AND TRAVELED 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 3 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.

4 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 13 FEET.

SEVERAL MALES WILL MATE WITH HER, BUT ONLY THE LAST WILL FATHER HER OFFSPRING.

[DOLPHINS CHITTERING] 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 CONSIDERED THEM "THE RIGHT WHALE" TO HUNT-- THEIR CURIOUS AND PLAYFUL NATURE MAKING THEM EASY TARGETS.

FORTUNATELY FOR THEM, SHARING THE COMPANY OF DOLPHINS POSES NO THREAT.

PORT PHILIP 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 1 1/2 FEET IN WIDTH, AUSTRALIAN GIANT SPIDER CRABS ARE AMONGST THE WORLD'S LARGEST CRUSTACEANS.

SELDOM SEEN, THEY SPEND THE YEAR SCAVENGING ON THE SEA BED.

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 2,500 FEET, THESE CRABS MIGRATE TO THE SHALLOWS EACH WINTER... NOT TO MATE BUT TO MOLT, 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 NEIGHBORS 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 A VICTIM, THE ATTACKER QUICKLY RETREATS WITH ITS PRIZE.

DESPITE THE PERILS OF MOLTING IN THE MIDST OF CANNIBALS, THESE CRABS HAVE ACTUALLY 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 6 FEET WIDE, THESE ARE THE LARGEST STINGRAYS IN THE WORLD.

DEFENSELESS CRUSTACEANS ARE SUCKED FROM THEIR SOFT SHELLS.

WITH THIS MANY MOLTING AT ONCE, EVEN THE MOST INSATIABLE RAY CAN'T EAT THEM ALL.

THE CARNAGE CONTINUES WELL INTO THE NIGHT.

IT TAKES AROUND 3 WEEKS FOR ALL THE CRABS TO MOLT, 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.

[WAVES CRASHING] 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 RAINFOREST.

THE PALMS THAT GIVE IT ITS NAME HAVE ALSO GIVEN RISE TO AN EXTRAORDINARY SEABIRD.

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 3 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 FAILSAFE 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.

4 MONTHS LATER, WITH ONLY A TINY CROWN OF FLUFFY DOWN LEFT, THE PETREL CHICK HAS BEEN ABANDONED BY ITS PARENTS.

IT'S BEEN 2 WEEKS SINCE IT 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 ITS PARENTS, IT'S UNDER THE COVER OF DARKNESS THAT THE YOUNG BIRD LEAVES THE NEST.

SEABIRDS LIKE PETRELS RELY ON THE WIND TO GIVE THEM THE LIFT NEEDED FOR TAKE-OFF.

BUT DOWN HERE BENEATH THE FOREST CANOPY, THE AIR IS LISTLESS.

AN ILL-JUDGED ATTEMPT AT FLIGHT COULD BE ITS 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 25 FEET, 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 FEATHER AS A PROP.

HAVING MADE IT TO THE TOP, MORE OBSTACLES LIE IN WAIT.

THE THICK STEMS AT THE CENTER OF THE PALM FRONDS ARE LINED WITH SHARP SPIKES.

FEATHERS ARE EASILY ENTANGLED.

PART FALL, PART FLIGHT-- EITHER WAY, IT'S AIRBORNE!

IT WON'T TOUCH LAND AGAIN FOR 5 OR 6 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.

[WHOOSH] 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.

[WHOOSH] HIS NAME MEANS "WHITE FELLA" IN ABORIGINAL LANGUAGE.

HIS PALE COLOR 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 130,000 SQUARE MILES OF QUEENSLAND'S PACIFIC COAST.

THIS ENORMOUS CORAL KINGDOM COVERS ROUGHLY THE SAME AREA AS GERMANY.

ITS WARM, SHALLOW WATERS AND DESERTED ISLANDS ARE NOT ONLY HOME TO COLORFUL 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 NOT SAND, HAULING HER 330-POUND WEIGHT UP ONTO THE SHORE IS AN ENORMOUS 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 RETURNS 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.

2 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 1 IN 1,000 HATCHLINGS SURVIVE.

100 MILES OFF THE COAST OF WESTERN AUSTRALIA LIE THE LACEPEDE ISLANDS.

[BIRDS SQUAWKING] 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?

[SQUAWKING] MAYBE NOT.

BOOBY NESTS ARE OFTEN LITTLE MORE THAN A SMALL PILE OF STICKS.

SOME ARE BARELY AN INDENTATION IN THE PEBBLES.

AS THE MIDDAY TEMPERATURES RISE TO OVER 100 DEGREES FAHRENHEIT, 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 FRIGATEBIRDS ARE PATROLLING.

THEY ARE KNOWN AS THE "PIRATES OF THE SKIES" FOR GOOD REASON.

LARGER AND FASTER THAN THE BOOBIES, THEY BULLY THE SMALLER SEABIRDS INTO GIVING UP THEIR LUNCH.

OUTMANEUVERED, 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.

THESE MINUTE PLANTS AND ANIMALS PROVIDE A BOUNTY OF FOOD FOR FISH, INCLUDING THE BIGGEST OF THEM ALL...

THE WHALE SHARK.

AROUND 40 FEET LONG AND WEIGHING AS MUCH AS 24,000 POUNDS WHEN FULLY GROWN, WHALE SHARKS ARE EXTREMELY PLACID.

DESPITE THEIR IMPOSING SIZE, THEY FEED ON MICROSCOPIC PLANKTON.

CHEMICALS RELEASED BY THE PLANKTON ARE CARRIED ON THE OCEAN CURRENT.

THE WHALE SHARKS FOLLOW THEIR SENSITIVE NOSES TO FIND THESE BLOOMS IN THE WATERS OF NINGALOO, A PROTECTED AREA OFF 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 SCIENTIST 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 FREELOADERS.

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 TRACE 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 3 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 3 OCEANS HAS PRODUCED AN EXPLOSION OF LIFE IN THE MAGICAL LAND OF OZ.

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