BARRY HUMPHRIES: 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, WE TRAVEL TO AUSTRALIA'S FAR-FLUNG CORNERS.

TO DISCOVER HOW THESE CONTRASTING LANDSCAPES EACH CREATE THEIR OWN SET OF CHALLENGES AND FIND OUT WHAT IT TAKES TO SURVIVE IN 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.

HUMPHRIES: AUSTRALIA IS A LAND DEFINED BY ITS VAST, HOT, OUTBACK, BUT IN THE SOUTHERNMOST REGIONS, DESERT GIVES WAY TO SNOW.

ON THE COUNTRY'S HIGHEST PEAKS, THE SNOWY MOUNTAINS, WINTER TEMPERATURES PLUMMET TO WELL BELOW ZERO.

[WIND WHIPPING] REACHING OVER 6,560 FEET, THIS RANGE SPENDS HALF THE YEAR BENEATH A BLANKET OF SNOW.

ONLY THE TOUGHEST STAY TO SEE OUT A WINTER UP HERE.

THIS ECHIDNA HAS HIBERNATED ON AND OFF THROUGH THE COLDEST MONTHS, EMERGING AT THE TAIL END OF WINTER, VERY HUNGRY...

BUT THERE'S NO FOOD HERE FOR AN INSECT-EATER.

TO GET AROUND THIS PROBLEM, THIS SOLITARY MAMMAL, TWICE THE SIZE OF A HEDGEHOG, HAS THE REMARKABLE ABILITY TO LOWER HIS BODY TEMPERATURE TO BELOW 41 DEGREES FAHRENHEIT.

THUS HE CONSERVES ENERGY AND REQUIRES LESS FOOD TO GET BY.

IT'S A LONELY MARCH ON AN EMPTY STOMACH UNTIL THE THAW WHEN HE CAN FEED AGAIN.

AS THE WARMER DAYS OF SPRING ARRIVE, RIVERS BEGIN TO FLOW DOWN THE MOUNTAIN.

FOR THE ECHIDNA, SPRINGTIME BRINGS THE PROMISE OF FOOD AFTER THE WINTER'S FAMINE, BUT ONE OBSTACLE STILL STANDS IN THE WAY OF A FULL BELLY, A FAST FLOWING ONE.

USING HIS LONG BEAK AS A SNORKEL AND LARGE FEET AS PADDLES, HE'S PERFECTLY CAPABLE OF A RIVER CROSSING.

THIS ADAPTABLE LITTLE CREATURE EVOLVED TENS OF MILLIONS OF YEARS AGO AND IS THE MOST WIDESPREAD OF ALL AUSTRALIA'S NATIVE ANIMALS.

HE WILL NOW SPEND 18 HOURS A DAY FORAGING, USING HIS HIGHLY SENSITIVE NOSE TO HOOVER UP ANTS AND TERMITES WHEREVER HE CAN FIND THEM.

THE ECHIDNA IS A MONOTREME, BELIEVED TO HAVE EVOLVED FROM A PLATYPUS-LIKE ANCESTOR.

DESPITE THE PLATYPUS BEING FURRED, DUCK-BILLED, AND TRULY AQUATIC, THE PAIR STILL SHARE SOME UNIQUE CHARACTERISTICS.

THEY ARE THE WORLD'S ONLY EGG-LAYING AND MILK-BEARING MAMMALS, BUT ONLY THE PLATYPUS FORAGES UNDERWATER, USING ELECTRICAL RECEPTORS IN HIS BILL TO FIND PREY.

THE PLATYPUS IS ONE OF AUSTRALIA'S EVOLUTIONARY MASTERPIECES, A FINELY TUNED HUNTER AND A LIVING FOSSIL WHOSE FAMILY EXISTED AT THE TIME OF THE DINOSAURS...

BUT IT'S THE MAMMALS THAT CAME LATER IN THE EVOLUTIONARY CALENDAR THAT NOW DOMINATE THE GRASSLANDS AND FORESTS THAT RADIATE OUT FROM THE BASE OF THE SNOWY MOUNTAINS-- THE MARSUPIALS.

MOST FAMILIAR OF THEM ALL IS THE EASTERN GREY KANGAROO.

THE WEIGHT OF A MAN BUT HEAD AND SHOULDERS TALLER, THIS TOP-RANKING MALE IS DISPLAYING HIS MIGHT.

THE CHALLENGE HERE ISN'T FINDING FOOD OR FACING THE ELEMENTS.

IT'S SOCIAL HARMONY.

HE SCENT-MARKS HIS TERRITORY WITH STICKY SECRETIONS FROM HIS CHEST, LEAVING NO ONE IN ANY DOUBT THAT HE IS IN CHARGE OF THIS PATCH.

HE PRESIDES OVER A HAREM OF 9 BREEDING FEMALES, ALL WITH AT LEAST ONE JOEY...

BUT DESPITE THEIR POSTURING, MALES ARE NOT THE DRIVING FORCE BEHIND THIS EXTRAORDINARILY SUCCESSFUL SPECIES.

THAT ACCOLADE BELONGS TO THE FEMALE AND HER UNIQUELY MARSUPIAL POUCH.

WHILE ONE JOEY IS STARTING TO EXPLORE THE WORLD, A TINY BABY IS ALREADY DEVELOPING IN HIS MOTHER'S POUCH.

EACH JOEY FEEDS ON A DIFFERENT TEAT, DEPENDING ON THEIR STAGE OF DEVELOPMENT-- HIGH IN CARBOHYDRATES FOR THE NEWBORN OR HIGH FAT FOR THE OLDER JOEY, WHO IS BEING FORCED TO SPEND MORE TIME OUTSIDE THE POUCH, GIVING HIS MUM AND NEW SIBLING A BREAK.

WITH THE YOUNG JOEY NOW ALMOST PERMANENTLY OUT OF THE POUCH, SHE IS READY TO FALL PREGNANT AGAIN, A FACT NOT LOST ON THE AMOROUS DOMINANT MALE.

HE WILL PURSUE HER RELENTLESSLY FOR DAYS MUCH TO HER IRRITATION...

BUT RIVAL MALES ARE A CONSTANT THREAT.

THIS TIME, IT'S NO PLAY FIGHT.

MAINTAINING HIS STATUS AS THE DOMINANT MALE IS SO TAXING, HE MAY ONLY HOLD ONTO HIS POSITION FOR A YEAR.

IN A LARGE SOCIETY, ACHIEVING SOCIAL HARMONY IS ALWAYS A CHALLENGE, BUT THE FACT THAT IT IS A LARGE SOCIETY DEMONSTRATES THAT KANGAROOS ARE DOING WELL.

THERE ARE NOW MILLIONS OF THEM.

THEY ARE AMONG THE FEW NATIVE ANIMALS TO BENEFIT FROM THE INCREASE IN AGRICULTURAL GRAZING LAND AND THE DECLINE OF AUSTRALIA'S NATURAL APEX PREDATORS.

AUSTRALIA'S TOP CARNIVORE, THE TASMANIAN TIGER, WAS HUNTED TO EXTINCTION IN THE EARLY 1900S... AND THE GRAND HUNTER FROM THE SKIES, AUSTRALIA'S OWN EAGLE, HAS COME PERILOUSLY CLOSE TO THE SAME FATE.

AUSTRALIA'S WEDGE-TAIL EAGLE IS ONE OF THE WORLD'S LARGEST.

FOR YEARS, IT WAS MERCILESSLY PERSECUTED, INACCURATELY PORTRAYED AS A PROLIFIC KILLER OF LAMBS.

WITH A BOUNTY ON ITS HEAD, UP TO 30,000 EAGLES WERE KILLED EACH YEAR.

EAGLES ARE NOW PROTECTED, AND MOST FARMERS ACCEPT THAT THEY ARE NO THREAT TO THEIR LIVESTOCK.

THEY ARE NOW AFFECTIONATELY KNOWN AS WEDGIES, AND THEIR CALLS ECHO ONCE MORE ACROSS FARMLAND.

AUSTRALIA'S BIGGEST BIRD OF PREY HAS A CHANCE OF A COMEBACK THANKS IN PART TO A DEVASTATING LEGACY OF EUROPEAN SETTLERS, FLUFFY EAGLE FODDER BROUGHT HERE 150 YEARS AGO AND NOW IN PLAGUE PROPORTIONS.

THE WEDGE-TAIL EAGLE IS A STUNNING AVIAN PREDATOR.

WITH A 6-FOOT WINGSPAN, THE WEDGE-TAIL CAN SOAR TO HEIGHTS OF 6,500 FEET AND CARRY HALF HER 12-POUND BODY WEIGHT IN HER HUGE TALONS.

HER EAGLE EYES PICK UP SOMETHING CURIOUS... AN EASTERN LONG-NECKED TORTOISE.

DESPITE HIS ALMOST IMPENETRABLE SHELL, HE'S NOT TAKING ANY CHANCES.

SHE'S SURE THAT ROCK WAS MOVING.

BAFFLING!

THE EAGLE RESUMES HER SEARCH FOR AN EASIER TARGET...

THIS TIME, A MORE FAMILIAR ONE.

IN SOME PARTS OF AUSTRALIA, RABBITS MAKE UP 90% OF THE EAGLE'S DIET.

THE TORTOISE--ZERO... AND EAGLES ARE NOW THE FARMER'S FRIEND, HELPING TO KEEP THE RABBIT POPULATIONS DOWN.

BY HELPING TO SOLVE ONE OF MAN'S SELF-INFLICTED PROBLEMS, WEDGE-TAIL EAGLES HAVE EARNED THEIR SURVIVAL, BUT THERE'S ONE SPECIES THAT OFFERS US NOTHING MORE THAN ITS CHARMING EXISTENCE, AND ITS PLIGHT IS FAR LESS VISIBLE.

100 MILES SOUTHEAST OF PERTH LIE THE DRYANDRA WOODLANDS.

COVERING JUST OVER 100 SQUARE MILES THEY'RE TINY BY AUSTRALIAN STANDARDS, BUT THEY'RE CRITICALLY IMPORTANT.

THIS STAND OF WANDOO EUCALYPTUS IS ONE OF THE LAST STRONGHOLDS OF AN ENCHANTING CREATURE THAT ONCE ROAMED THE ENTIRE CONTINENT.

AS THE MORNING SUN HITS THE CARPET OF WILDFLOWERS AND INSECTS BEGIN MASSING ON THE FOREST FLOOR, A SMALL MARSUPIAL IS MAKING ITS FIRST MOVE.

THE SHY AND SECRETIVE NUMBAT, THE CLOSEST LIVING RELATIVE TO THE EXTINCT TASMANIAN TIGER, IS ON A TERMITE HUNT.

SHE NEEDS 20,000 TERMITES TO FILL HER BELLY.

BACK IN HER DEN ARE 4 RAPIDLY GROWING PUPS THAT SHE HAS FED THROUGH THE NIGHT.

THE YOUNG ARE 8 MONTHS OLD AND STARTING TO BECOME CURIOUS ABOUT LIFE BEYOND THE BURROW.

ONE IS BOLDER THAN THE REST.

SHE'S BEGUN TO EXPLORE THE TREE STUMP FORTRESS PROTECTING THE BURROW EXIT.

HER SIBLINGS FOLLOW, TREMBLING AS THE COOL MORNING AIR HITS THEIR FUR.

EACH DAY, THE LEADER INCHES CLOSER TO THE FORTRESS WALLS.

NOW SHE HAS HER FIRST GLIMPSE OF THE WORLD BEYOND.

[BIRD SQUAWKING] EVERY NEW SOUND IS STARTLING, HERALDING A POTENTIAL THREAT.

[SQUAWKING] THEY ARE WISE TO BE CAUTIOUS.

NUMBATS ONCE RANGED WIDELY ACROSS AUSTRALIA.

TODAY, THERE ARE FEWER THAN THE FAMOUS ENDANGERED SNOW LEOPARD OR GIANT PANDA.

THEY NEED SOMETHING THAT IS NOW IN SHORT SUPPLY, UNDISTURBED WOODLAND WITH PLENTY OF LOGS FILLED WITH TERMITES.

THE ADULT FEMALE USES HER WORM-LIKE TONGUE TO EXTRACT TASTY MORSELS FROM HARD TO REACH CREVICES.

EACH DAY SHE'LL SWALLOW 10% OF HER OWN BODYWEIGHT.

HER YOUNG ARE GETTING BRAVER AND REVELING IN THE SUN.

THEIR ROUNDED SNOUTS, SUITED TO MILK FEEDING, ARE BECOMING MORE ELONGATED BY THE DAY.

WITHIN A MONTH, THEY TOO WILL BE RELIANT ON TERMITES... [BIRD SQUAWKING] SO THE JOB OF WORKING OUT WHAT IS FOOD AND WHAT IS NOT IS THE LESSON OF THE DAY EXCEPT FOR ONE OF THEM.

THE INTREPID EXPLORER WANTS TO DISCOVER WHAT LIES BEYOND THE WALL, WHILE HER SIBLINGS STAY CAUTIOUSLY CLOSE TO THE BURROW.

SHE'LL KEEP WANDERING FURTHER FROM THE BURROW UNTIL ONE DAY SHE LEAVES HER MOTHER'S TERRITORY FOR GOOD, PERHAPS CROSSING PATHS WITH OTHER YOUNG NUMBATS ALSO EMERGING FROM HOLLOWS IN THIS FOREST.

TOGETHER, THEY CARRY THE SURVIVAL OF THEIR ENTIRE SPECIES ON THEIR SHOULDERS.

OVER THE PAST 200 YEARS, HABITAT LOSS AND PREDATION BY INVASIVE SPECIES HAS LED TO NUMBATS DISAPPEARING FROM 99% OF THEIR PREVIOUS RANGE.

THERE ARE NOW FEWER THAN 1,000 LEFT IN THE WILD.

WHERE AUSTRALIA'S ANCIENT ECOSYSTEMS ARE LEFT INTACT, ANIMALS THRIVE.

IN FAR NORTHERN QUEENSLAND, A REMNANT OF THE WORLD'S OLDEST RAIN FOREST RUNS LIKE A GREEN RIBBON ALONG THE COAST.

OLDER EVEN THAN THE AMAZON, AUSTRALIA'S FERTILE TROPICS DATE BACK 180 MILLION YEARS.

THEIR YEAR-ROUND HEAT AND HUMIDITY PROVIDE THE PERFECT CONDITION FOR ALL MANNER OF SPECIES TO THRIVE.

IT'S IN THESE RAIN FORESTS THAT AUSTRALIA'S MAMMALS FIRST EMERGED AND THEN SPREAD FAR AND WIDE ACROSS THE CONTINENT'S GRASSLANDS...

BUT THERE IS ONE KANGAROO THAT HAS NEVER LEFT ITS RAIN FOREST HOME... A SHY CREATURE RARELY SEEN ON THE FOREST FLOOR... BECAUSE ITS HOME IS HIGH IN THE CANOPY... A TREE KANGAROO.

THIS YOUNG MALE HAS EVOLVED FOR A LIFE IN THE TREES WITH LARGE STRONG ARMS, BIG CURVED CLAWS, AND A TAIL AS LONG AS HIS BODY...

BUT EVEN 65 FEET UP, HE'S STILL CLEARLY A KANGAROO...

IF A LITTLE LESS AGILE THAN MOST.

AT ALMOST TWO YEARS OLD, HE HAS ONLY RECENTLY LEFT HIS MOTHER TO FIND HIS OWN TERRITORY.

UNLIKE HIS GROUND-DWELLING COUSINS, HE WILL LIVE A SOLITARY LIFE, ONLY SEEKING A FEMALE WHEN IT'S TIME TO MATE, BUT HE'S FINDING IT HARD TO MAKE THE BREAK.

HE CAN HEAR HIS MOTHER IN A NEARBY TREE AND CROSSES THE CANOPY TO REACH HER, BUT IT'S NOT A WARM WELCOME.

SHE DOESN'T WANT HIM NEAR AND MOVES AWAY.

HER TOUGH LOVE MAKES SENSE.

AT 8 MONTHS, HER YOUNGEST JOEY HAS STARTED TO LEAVE THE POUCH AND IS EXPLORING HER HIGH-WIRE WORLD.

SHE'S WOBBLY ENOUGH.

A TEENAGE SIBLING MIGHT TOPPLE HER ALTOGETHER.

WITH HIS MOTHER FULLY OCCUPIED, HE'LL HAVE TO ACCEPT HE'S NOW AN ADULT, AND IT'S TIME TO GO IT ALONE.

AND SPACE IS SOMETHING THAT IS IN SHORT SUPPLY IN THE RAIN FOREST, WHERE ALMOST HALF OF AUSTRALIA'S COLORFUL BIRD SPECIES ARE COMPETING TO RAISE THE NEXT GENERATION, BUT MOST COCKATOOS AND PARROTS PREFER THEIR HOMES READY-MADE, AND THERE AREN'T ALWAYS ENOUGH TO GO ROUND.

THIS FEMALE ECLECTUS PARROT HAS LAID HER EGGS IN A MUCH SOUGHT-AFTER TREE HOLLOW.

HER GREEN MATE WILL DELIVER FOOD TO HER SO SHE CAN STAY ON GUARD DUTY.

HIGH AND DRY, THE HOLLOW IS SAFE FROM FLOODING AND PREDATORS.

IT'S THE PERFECT SPOT FOR HER PRECIOUS CLUTCH.

IT SHOULD BE A TEXTBOOK INCUBATION... [BIRDS SQUAWKING] BUT THE NEIGHBORS NOBODY WANTS ARE LOOKING TO MOVE INTO THIS LEAFY SUBURB.

THE SULPHUR-CRESTED COCKATOO.

LOUD, ASSERTIVE, AND READY TO LAY, THIS PAIR WANT THE HOLLOW FOR THEMSELVES, BUT THE ECLECTUS, THAT IS LUCKY TO RAISE EVEN ONE CLUTCH A YEAR, ISN'T EASILY INTIMIDATED.

AS THE DAY HEATS UP, TEMPERATURES INSIDE THE NEST REACH MORE THAN 90 DEGREES FAHRENHEIT... AND WITH HER OWN BODY HEAT RAISING THE TEMPERATURE FURTHER...

IT SOON BECOMES TOO HOT FOR HER EGGS.

SHE HAS NO OPTION BUT TO LEAVE TO LET THINGS COOL.

IT'S A BIG GAMBLE.

IF THE COCKATOOS GET INSIDE, THEY WILL SMASH THE EGGS TO MAKE ROOM FOR THEIR OWN.

IT LOOKS AS THOUGH ALL IS LOST.

THE ECLECTUS WILL LOSE HER CHANCE TO RAISE CHICKS THIS YEAR.

[SQUAWKING] BUT NOT HERE AND NOT TODAY.

VICTORY BELONGS TO THE ECLECTUS.

SUCH ARE THE CHALLENGES OF RAISING THE NEXT GENERATION IN THE COMPETITIVE ENVIRONMENT OF THE RAIN FOREST...

BUT IT'S NOT JUST ABOUT HAVING A PLACE TO RAISE A FAMILY.

IT'S ALSO ABOUT BEING HEARD ABOVE THE DIN.

SONGBIRDS ORIGINATED IN AUSTRALIAN RAIN FORESTS 24 MILLION YEARS AGO, AND SOME OF NATURE'S GREAT VOCALISTS ARE STILL TO BE FOUND HERE... [BIRDS SINGING] BUT THERE'S ONE SPECIES THAT HAS DEVELOPED A WAY OF COMMUNICATING THAT IS FAR IN ADVANCE OF ANYTHING WITNESSED ELSEWHERE IN THE AVIAN WORLD.

THE PALM COCKATOO, OR "PALMIE," IS KNOWN FOR ITS SUPERIOR INTELLIGENCE AND LONGEVITY.

IT HAS A BRAIN-TO-BODY-WEIGHT RATIO COMPARABLE TO A DOLPHIN OR A GREAT APE, AND IT CAN LIVE FOR OVER 50 YEARS.

LIKE ITS PARROT RELATIVES, IT, TOO, NESTS IN TREE HOLLOWS.

THIS PROUD PAIR WORK IN SHIFTS WITH ONE PARENT ALWAYS ON GUARD.

THEY MATE FOR LIFE, AND LIKE ALL SUCCESSFUL MARRIAGES, THAT MEANS GOOD COMMUNICATION IS THE KEY.

THE PAIR GREET EACH OTHER WITH A KISS AS THEY SWAP GUARDING AND FORAGING DUTIES.

THE HARD FRUITS OF THE NONDA PLUM TREE ARE TOO TOUGH FOR MOST BIRDS, BUT THE PALMIE HAS ONE OF THE LARGEST AND STRONGEST BEAKS IN THE BIRD WORLD, SO LARGE IT NEVER QUITE CLOSES.

AS THE FEMALE RETURNS TO THE NEST, HER BELLY FULL, SHE OFFERS A DISTINCT KNOCK, TO SAY, "IT'S ME"... [KNOCKING] BUT HER MATE WORKS HARDER STILL TO MESSAGE HIS PARTNER...

COMMUNICATING IN A WAY NO OTHER BIRD, INDEED NO OTHER WILD ANIMAL, IS ABLE.

THE MALE PALMIE HAS AN ABILITY LONG THOUGHT EXCLUSIVELY HUMAN.

HE FASHIONS A DRUMSTICK AND DELIBERATELY BEATS OUT A RHYTHM.

EACH MALE HAS HIS OWN INDIVIDUAL DRUMMING STYLE.

WHY HE DOES IT IS UNCLEAR.

PERHAPS IT'S A SHOW OF STRENGTH TO WARD OFF COMPETITORS OR A MESSAGE TO HIS PARTNER THAT SHE NEED LOOK NO FURTHER.

HE AND HIS NEST ARE BEST.

RAIN FORESTS THRIVE BECAUSE OF THEIR STABLE CLIMATE.

THE OPPOSITE IS TRUE OF THE NORTHERN MONSOON REGION THAT COVERS ALMOST A QUARTER OF THE CONTINENT.

HERE, THE LAND SEE-SAWS BETWEEN TWO EXTREMES...

THE FLOODS OF THE SUMMER'S WET SEASON... AND THE RAGING FIRES THAT CAN BURN FOR MONTHS THROUGH PARCHED WINTERS.

IT IS THESE EXTREMES THAT HAVE HELPED SCULPT SOME DRAMATIC LANDSCAPES.

SAVANNAS SWEEP ACROSS MORE THAN HALF MILLION SQUARE MILES INTERSECTED BY PERMANENT TIDAL RIVERS...

THE HUNTING GROUND OF THE SALTWATER CROCODILE.

THIS MALE, KNOWN LOCALLY AS CASANOVA, HAS BEEN TOP CROC ON THIS RIVER FOR DECADES.

HE HAS 60 FEARSOME TEETH, MEASURES OVER 13 FEET LONG, AND WEIGHS 1,500 POUNDS.

NOW IN HIS LATE 50s, HE MIGHT BE CONSIDERED AN OLD CROC, BUT THAT HASN'T STOPPED HIM LEARNING A NEW TRICK.

CASANOVA HAS ADAPTED TO THE PRESENCE OF HUMANS IN AN UNEXPECTED WAY.

HE HAS LEARNED TO ASSOCIATE THE RUMBLE OF A BOAT ENGINE, FILLED WITH DELICIOUS TOURISTS, WITH DINNER!

MAN: LIFE JACKETS.

YEAH.

THEY'RE SITUATED JUST UP THERE.

I'M NOT EVEN GOING TO SHOW YOU HOW TO PUT ONE ON.

DOES ANYONE KNOW WHY?

CROCODILES ARE ATTRACTED TO BRIGHT COLORS, OK, AND SPLASHING, SO--AND THERE'S ABOUT 5,000 CROCODILES IN THIS RIVER.

IF YOU END UP IN THE WATER, YOU WON'T HAVE TIME TO DROWN ANYWAY, YEAH, SO, NUMBER ONE, AVOID GOING IN THE WATER, BUT IF WE DO, LIFE JACKETS ARE USELESS.

HUMPHRIES: IT'S FAIR TO SAY CASANOVA MAKES QUITE A SPLASH FOR THE TOURISTS WHO COME TO SEE HIM PUT HIS NATURAL HUNTING ABILITIES TO USE.

A WAVE-LIKE THRUST, CREATED BY HUNDREDS OF MUSCLES WORKING IN TANDEM PUSH AGAINST THE WATER.

HE FINISHES THE LEAP WITH A SNAP OF HIS JAWS, EXERTING THE STRONGEST DOWN FORCE OF ANY ANIMAL.

ON THIS RIVER, CROCS HAVE A SEEMINGLY EASY LIFE, BUT IT'S NOT ENTIRELY WITHOUT ITS CHALLENGES.

DESPITE BEING AUSTRALIA'S APEX PREDATOR, CROCODILES ARE RELENTLESSLY HUNTED BY THE MARCH FLY.

AT ALMOST 1-INCH LONG, IT'S THOUSANDS OF TIMES SMALLER THAN ITS PREY.

IT SEEKS OUT WEAK SPOTS IN THE CROCS' ARMOR AND BORES ITS SCISSOR-LIKE PROBOSCIS INTO THE SOFT SKIN BELOW.

AN ANTICOAGULANT IN THE FLY'S SALIVA PREVENTS THE BLOOD FROM CLOTTING, AND THE FLY THEN SUCKS UP THE BLOOD WITH ITS FLESHY MOUTH PARTS...

FILLING TO BURSTING POINT ON ITS VICTIM'S RICH, COLD BLOOD.

THE DELICATE 3-LAYERED EYELID IS PARTICULARLY VULNERABLE TO ATTACK.

NOSTRILS ARE TARGETED, TOO.

EACH BITE IS A PAINFUL IRRITANT, AND THERE ARE PLENTY OF THEM.

FROM THIS PERSPECTIVE, THE MENACING CROC IS REDUCED TO AN INVOLUNTARY BLOOD DONOR, ALTHOUGH IT DOES HAVE ONE PEST CONTROL STRATEGY... MUD.

NOT ONLY A BARRIER TO FLIES BUT ALSO A SALVE TO SOOTHE IRRITATING BITES... AT LEAST FOR A MOMENT.

IN THE END, THE FLIES ALWAYS FIND A WEAK POINT.

THE CROCODILE HAS HAD TO CHANGE VERY LITTLE SINCE THE TIME OF THE DINOSAURS, BUT IT ISN'T PERFECT.

WITH LEGS THIS SHORT, THERE'S ALWAYS GOING TO BE AN ITCH THAT JUST CAN'T BE SCRATCHED.

WHILE THE CROC FIGHTS DAILY BATTLES WITH ITS FLIES, OTHER CREATURES OF AUSTRALIA'S MONSOON REGION FACE THE CHALLENGES PRESENTED BY CHANGES OF SEASON.

BIRDS MIGRATE, MOVING WITH THE DRAMATIC PULSES OF THE WET AND DRY.

OTHER CREATURES, UNABLE TO FLEE INHOSPITABLE SEASONS, MUST REMAIN AND FACE THE ELEMENTS.

ON THE FLOODPLAINS OF MANINGRIDA, THE MONSOON WILL SOON ARRIVE.

THIS REGION IS HOME TO ONE OF THE MOST REMOTE COMMUNITIES IN AUSTRALIA.

THE CHILDREN HERE ENJOY A PLAYGROUND OF EPIC PROPORTIONS, AND THEY HAVE DISCOVERED AN EXTRAORDINARY WEB OF LIFE BENEATH THEIR FEET.

IN JUST ONE SMALL AREA, THEY HAVE HELPED SCIENTISTS IDENTIFY AN ASTONISHING 46 NEW SPIDERS, INCLUDING ONE TARANTULA.

LIKE MOST SPIDERS, THEY HAVE 8 EYES AND 8 LEGS, BUT WHAT SETS THESE TARANTULAS APART IS THEIR DASHING RED COAT.

ALMOST EVERY METER OF THIS FLOODPLAIN HAS A SPIDER BURROW, FORMING A MEGA-CLUSTER OF AMBUSH HUNTERS.

THIS FEMALE HAS SETTLED DOWN TO WAIT FOR THE PERFECT DINNER GUEST.

SHE'S SPUN A SERIES OF SILK TRIP WIRES AROUND HER BURROW ENTRANCE... AND SHE'LL STRIKE ONLY WHEN SUCCESS IS GUARANTEED.

THIS LONG-HEADED HOPPER IS LUCKY.

ONCE IN THE TARANTULA'S 8-LEGGED GRASP, THERE'S NO CHANCE OF ESCAPE.

SHE INJECTS TOXIC VENOM INTO THE GRASSHOPPER WITH HER ONE-INCH FANGS, DEALING THE UNFORTUNATE VICTIM A FINAL PARALYZING BLOW.

[THUNDER] RUMBLES OUTSIDE SUGGEST HER WORLD IS ABOUT TO BE DRENCHED.

THE MONSOON HAS ARRIVED.

AS PRESSURE BUILDS, ELECTRIC CHARGES BEGIN TO SPARK AND FIRE.

EACH THUNDERSTORM RELEASES AN ATOMIC BOMB'S WORTH OF ENERGY.

A FLOOD MAKES ITS WAY TOWARDS THE PLAIN.

FOR A CREATURE THAT LIVES UNDERGROUND, THIS COULD SPELL DISASTER...

BUT SHE'S NO ORDINARY TARANTULA.

SHE WON'T FLEE HER BURROW.

THIS SPIDER IS EVOLVED TO COPE WITH FLOOD.

SHE HAS HER OWN SILVERY LIFE SUPPORT SYSTEM.

HER HAIRY COAT TRAPS AIR BUBBLES, PROVIDING THE PERFECT BACKUP AIR SUPPLY AS SHE BREATHES THROUGH HOLES IN HER ABDOMEN.

LIKE A COSMONAUT IN SPACE, SHE HAS CREATED HER OWN ATMOSPHERE.

HER DISCOVERY IS SO RECENT, SHE HAS NO OFFICIAL NAME.

SHE IS SIMPLY REFERRED TO AS THE DIVING TARANTULA, A TRULY UNIQUE AUSTRALIAN PHENOMENON.

NOBODY KNOWS WHAT HER UNDERWATER ENDURANCE LIMIT MIGHT BE, BUT THE MONSOON FLOODS MAY LAST FOR 4 MONTHS.

SCIENTISTS ESTIMATE THERE ARE 25,000 DIVING TARANTULAS ON THIS ONE FLOODPLAIN.

WHEN THE WET SEASON ENDS, THE FLOOD WATER RECEDES, LEAVING A VIVID AND REPLENISHED SAVANNA.

IT WILL SOON BE THE DRY SEASON'S TURN TO REPAINT THE LANDSCAPE.

MONTHS WILL PASS WITHOUT RAIN.

THE LAND WILL BE PARCHED, BUT FOR SOME, THIS CHALLENGE ALSO PRESENTS AN OPPORTUNITY.

TRADITIONAL BURNING OF THE GRASSLANDS BY INDIGENOUS PEOPLE HAS OCCURRED FOR THOUSANDS OF YEARS.

IT TRIGGERS GERMINATION AND PREVENTS UNCONTROLLABLE WILDFIRES LATER IN THE SEASON.

THE DRY GRASS IGNITES QUICKLY, AND THE FLAMES MOVE ON, LEAVING THE TREES INTACT.

THE RISING SMOKE HAS NOT GONE UNNOTICED.

A BLACK KITE HAS BEEN DRAWN IN.

THE RANGERS HAVE PREPARED AN EASY MEAL, AN EXODUS OF CREATURES FLEEING THE FLAMES.

OUT IN THE OPEN, THEY ARE A PRIME TARGET FOR AERIAL ATTACK...

BUT THE PLEASURE OF SOLITARY DINING WILL BE SHORT-LIVED.

THE SMOKE SIGNAL HAS SPREAD FAR AND WIDE, AND THE BLACK KITE IS SOON JOINED BY OTHERS.

HUNDREDS OF THEM.

SQUABBLES BREAK OUT, AND TALONS CLASH OVER THE SPOILS BELOW.

SOON, THE INSECT SUPPLY WILL BE EXHAUSTED, BUT THESE KITES HAVE A CLEVER WAY OF OBTAINING MORE.

THEY'VE DEVELOPED A TECHNIQUE THAT HAS BECOME IMMORTALIZED IN LOCAL FOLKLORE THAT HAS LED THEM TO BEING CALLED THE FIREBIRD OR KARRKKANJ.

[MAN SPEAKING ABORIGINAL LANGUAGE] THESE INGENIOUS PYROMANIACS HAVE BEEN SEEN CREATING NEW FRONTS DURING BUSH FIRES, EXPANDING THEIR HUNTING AREA, AND FLUSHING OUT FRESH PREY.

APART FROM HUMANS, THEY ARE THE ONLY ANIMAL KNOWN TO HARNESS FIRE FOR PERSONAL GAIN.

DESPITE BEING ONE OF THE WORLD'S MOST COMMON RAPTORS, IT'S ONLY HERE IN AUSTRALIA THAT BLACK KITES PLAY WITH FIRE.

LIKE ITS LANDSCAPE, AUSTRALIA'S WILDLIFE IS DRAMATIC AND MAGICAL.

WE'VE SEEN HOW ANIMALS SURVIVE HERE-- THROUGH INTELLIGENCE...

UNIQUE EVOLUTION, AND ADAPTABILITY.

SOME ARE THRIVING...

WHILE OTHERS ARE ON THE BRINK OF EXTINCTION.

EACH INDIVIDUAL FACES ITS OWN SET OF CHALLENGES...

BUT IT IS THE CHALLENGE OF THE MODERN WORLD THAT IS PROVING THEIR BIGGEST TEST YET.

(dramatic music) - Next time on Magical Land of Oz.

Australia's oceans are some of the most extraordinary places on Earth.

Follow the continent's currents to find the rarest species, armies of molting crabs, giant cuttlefish looking for a mate, and sea creatures from around the world, each drawn to the Magical Land of Oz.

ANNOUNCER: TO ORDER "MAGICAL LAND OF OZ" ON DVD, VISIT SHOPPBS OR CALL 1-800-PLAY-PBS.

THIS PROGRAM IS ALSO AVAILABLE ON AMAZON PRIME VIDEO.