Original subtitles

IN THE NARROW STRIP LOCKED BETWEEN LAND AND SEA,

IS AN ALIEN WORLD

OF POUNDING WAVES

AND RELENTLESS SUN.

AN INTERTIDAL ZONE

IN CONSTANT FLUX.

DEMANDING TOUGHNESS,

ADAPTABILITY,

AND INGENUITY

FROM THE SPECIES FORGING A LIFE HERE.

RISKING THEIR LIVES DAILY

IS A NECESSARY SACRIFICE TO REAP THE REWARDS

FROM THIS HOSTILE ENVIRONMENT.

IT'S A DAILY RACE AGAINST TIME AND TIDE.

THIS IS THE SWEEPING SHORE.

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A ROCKY COAST IN SOUTHERN AFRICA.

A PLACE OF EXTREMES AND INCREDIBLE ADAPTATION.

IT'S AN ARDUOUS PLACE TO SURVIVE.

EVERY SIX HOURS, AS THE TIDE RISES AND FALLS,

THIS WORLD UNDERGOES A MASSIVE CHANGE.

AN ENTIRE ECOSYSTEM FLOODED WITH ICY WATER.

AND THEN BAKED BY 104-DEGREE HEAT.

IT'S A WORLD OF HARSH CONTRASTS,

BUT REMARKABLE SPECIES HAVE ADAPTED

TO COPE WITH THE ENDLESS CYCLE OF CHANGE.

THIS NARROW STRIP OF COAST

CAN GO FROM WELCOMING TO LETHAL IN JUST A FEW SECONDS.

POUNDING WAVES.

A RELENTLESS CYCLE OF DELUGE AND DROUGHT.

A HABITAT AS UNFORGIVING AS ANY IN THE WORLD.

WHY WOULD ANY SPECIES LIVE HERE, LET ALONE THRIVE?

THE SIMPLE ANSWER: ENORMOUS AMOUNTS OF FOOD.

THE BOUNTY ON THE ROCKS BELOW

HAS CONVINCED TWO PAIRS OF OYSTERCATCHERS

TO START FAMILIES HERE,

ON EITHER SIDE OF THIS BAY.

FOR THIS PAIR, NESTING HIGH ABOVE THE ROCKS,

BREEDING SEASON IS GOING WELL:

THEY HAVE TWO PRECIOUS EGGS

AND WILL BE INCUBATING THEM FOR THE NEXT MONTH.

THESE OYSTERCATCHERS MATE FOR LIFE,

AND THAT'S QUITE A COMMITMENT: THEY CAN LIVE UP TO 20 YEARS.

PARENTING, THOUGH, IS NOT QUITE A FULL TIME JOB - YET.

ALTHOUGH THE PARENTS TAKE TURNS SITTING ON THE NEST,

THEY CAN LEAVE IT TO GO AND FORAGE.

THEY'LL NEED TO MAKE IT A SHORT TRIP;

THE EGGS ARE VULNERABLE TO NEARBY PREDATORS

WHEN LEFT UNGUARDED.

THE NESTING STYLE OF THE OYSTERCATCHER

BROUGHT THEM PERILOUSLY CLOSE TO EXTINCTION.

AS HUMANS ENCROACHED ONTO PRISTINE COASTAL AREAS,

NESTS BECAME INCREASINGLY VULNERABLE

TO DOMESTIC PETS AND OFF-ROAD VEHICLES.

BY THE 1980S,

JUST 4600 AFRICAN BLACK OYSTERCATCHERS

REMAINED IN THE WILD.

BUT NEW CONSERVATION LAWS

HAVE SEEN THE BIRDS STAGE A CAUTIOUS COMEBACK,

AND TODAY THEY NUMBER BETWEEN FIVE AND SIX THOUSAND.

ON THE OTHER SIDE OF THE BAY,

NESTING HAS GIVEN WAY TO PARENTING.

WHAT LOOKS LIKE THREE ADULTS IS IN FACT A SMALL FAMILY:

TWO HARD-WORKING PARENTS AND A STRAPPING YOUNGSTER,

DISTINGUISHED BY HER GREY LEGS

THAT WILL SOON BECOME REDDISH LIKE THOSE OF HER PARENTS.

SHE'S ALMOST READY TO STRIKE OUT ON HER OWN,

BUT SHE HAS YET TO LEARN ALL THE SECRETS OF FORAGING.

FOR NOW, SHE STILL NEEDS HER PARENTS TO FEED HER.

BUT SHE'LL HAVE TO WAIT.

THE OYSTERCATCHERS' FEEDING TIMES

ARE DICTATED BY THE TIDE,

AND RIGHT NOW THE TIDE IS AT ITS HIGHEST.

DESPITE THEIR NAME,

AFRICAN BLACK OYSTERCATCHERS RARELY EAT OYSTERS.

THEIR MAIN SOURCES OF FOOD

ARE THE MUSSELS AND LIMPETS THAT CROWD THE ROCKS BELOW.

BUT UNTIL THE OCEAN RETREATS ENOUGH TO REVEAL THEM,

THE BIRDS WILL HAVE TO WAIT.

THE NESTING PARENTS, TOO, ARE BIDING THEIR TIME.

WHEN THE TIDE GOES OUT,

THEY WILL HAVE ONLY A FEW HOURS IN WHICH TO FEED

BEFORE THE WAVES COME THUNDERING AGAIN.

THE PLETHORA OF FOOD AVAILABLE ON THE ROCKS

OWES ITS EXISTENCE

TO A PHENOMENON THAT OCCURS BELOW THE WAVES.

THE WATER THAT SURGES ONTO THESE ROCKY SHORES

HAS BEEN BROUGHT HERE BY THE COLD BENGUELA CURRENT

THAT FLOWS NORTHWARD

UP THE WESTERN SHORES OF THE AFRICAN CONTINENT.

AS THE CURRENT MEETS POWERFUL PREVAILING WINDS,

A PHENOMENON TAKES PLACE

THAT HAS MASSIVE IMPLICATIONS FOR LIFE ON THE ROCKY SHORE.

WATER FROM MORE THAN 650 FEET DOWN IN THE ABYSS

IS DRAWN UP TO THE SURFACE.

AS IT RISES,

IT BRINGS WITH IT MILLIONS OF YEARS OF DISSOLVED NUTRIENTS -

A GIGANTIC INJECTION OF FOOD FOR THE ENTIRE COAST.

ONE OF THE MAIN BENEFICIARIES OF THIS BONANZA OF FOOD IS KELP,

A TYPE OF GIANT ALGAE.

THIS GOLDEN FOREST OF KELP

THRIVES AROUND AFRICA'S SOUTH-WESTERN COAST.

ITS INFLUENCE ON THE ROCKY SHORE IS VAST.

THE STRONG, FLEXIBLE STEMS AND LARGE FRONDS OF THE KELP FOREST

ACT AS A BUFFER BETWEEN THE OPEN OCEAN

AND THE SMALL SPECIES THAT CLING TO THE ROCKS.

AS THE KELP IS PUMMELED AND CHURNED UP BY THE OCEAN,

IT BECOMES FOOD FOR MARINE LIFE ON THE SHORE.

THIS COLD WATER IS A SOUP OF NUTRIENTS AND SHREDDED KELP.

FOAM WHIPPED UP BY THE CHURNING WAVES

IS FULL OF MICROORGANISMS,

OFFERING A RICH SOURCE OF FOOD FOR LIFE ON THE ROCKS.

FOR THE AFRICAN BLACK OYSTERCATCHER,

CROWDED ROCKS MEAN FULL STOMACHS,

AND HEALTHY CHICKS.

ALMOST EVERY SPECIES THAT LIVES ON THIS SHORE

HAS HAD TO ADAPT TO TWO INESCAPABLE CONSTANTS:

THE TIDE, AND THE TWICE-DAILY EXPOSURE TO THE SUN AND AIR.

THE RESULT?

AN ARMY OF BIZARRE AND ALIEN-LIKE INHABITANTS.

HOW THEY MOVE, HOW THEY LOOK AND EVEN HOW THEY EAT

IS ALL DETERMINED BY HAVING TO LIVE BOTH ABOVE

AND BELOW THE WATERLINE.

MOST VISIBLE AMONG THESE HARDY SPECIES:

THE CRUSTACEANS AND MOLLUSKS.

DEVELOPING SHELLS FOR PROTECTION AGAINST EXPOSURE

AND FINDING WAYS TO BENEFIT FROM THE BUFFETING WAVES,

THESE CREATURES MAKE THE MOST OF THEIR UNWELCOMING SURROUNDINGS.

AND THERE IS NO TIME MORE CHALLENGING

THAN WHEN THE TIDE BEGINS TO FALL.

WHILE EXPOSED TO THE BAKING SUN AND DRYING AIR,

THEY CAN LOSE UP TO 70% OF THEIR BODY FLUIDS.

AND ON THE ROCKS UP ABOVE, THE OYSTERCATCHERS ARE WAITING.

THE CHANGE OF THE TIDES IS A STRESSFUL TIME

FOR BOTH HUNTERS AND THEIR PREY.

FOR ONE FORMIDABLE CREATURE,

THE TIDES ARE NO OBSTACLE TO HIS HUNTING SCHEDULE.

THE COMMON OCTOPUS.

HE'S ON THE HUNT FOR UNSUSPECTING PREY.

IN THIS ENVIRONMENT, THE OCTOPUS IS A LETHAL PREDATOR.

REGARDED AS ONE OF THE MOST INTELLIGENT

OF ALL INVERTEBRATES,

HE'S MASTERED THE ART OF LIFE ON THE ROCKY SHORE.

EXAMINING EVERY NOOK AND CRANNY,

HE CAN MOVE FREELY BETWEEN THE ZONES

THAT MAKE UP THIS TURBULENT, CHANGEABLE WORLD.

ARMED WITH EIGHT DEXTEROUS TENTACLES

LINED WITH POWERFUL SUCKERS,

HE POSES A HUGE THREAT TO HIS SMALLER INVERTEBRATE NEIGHBORS.

WHILE MOST OF HIS MOLLUSK RELATIVES

HAVE DEVELOPED HARDY SHELLS

TO PROTECT THEM IN THIS ENVIRONMENT,

THE OCTOPUS HAS TRADED THIS SECURITY

FOR THE ULTIMATE MOBILITY AND AGILITY.

WITHOUT A SKELETON,

THIS OCTOPUS'S ARMS CAN GO MORE OR LESS ANYWHERE.

HE AVOIDS GETTING TANGLED

THANKS TO A SPECIAL CHEMICAL PRODUCED BY HIS SKIN,

WHICH SENDS A MESSAGE TO HIS SUCKERS,

PREVENTING THEM FROM CLINGING ONTO ANY PART OF HIS BODY.

JUST AS WELL IF HE'S GOING TO SNARE HIS FAVORITE MEAL -

A MEATY CRAB.

THE OCTOPUS'S AGILITY PROTECTS IT AGAINST THE SUN AND AIR.

IT CAN KEEP ITSELF MOIST

SIMPLY BY SIDLING INTO THE NEAREST POOL.

AS LONG AS HIS GILLS ARE MOIST

HE CAN SPEND EXTENDED PERIODS OUT OF THE WATER.

FOR SOME OTHER MOLLUSKS, THOUGH, THERE'S NO EASY ESCAPE.

THESE PEAR LIMPETS

HAVE HAD TO EVOLVE A BRILLIANT STRATEGY

TO AVOID DRYING OUT.

THEY GROW TO FIT THE SHAPE OF THE ROCK EXACTLY,

LEAVING NO GAPS THAT WILL ALLOW MOISTURE TO ESCAPE

WHEN IT'S TIME TO SETTLE DOWN FOR LOW TIDE

AND THE HEAT OF THE DAY.

LIMPETS DON'T USE SUCTION

TO STAY ATTACHED TO THESE HARD SURFACES.

THEY USE ADHESION -

THE SAME PRINCIPLE

THAT KEEPS TWO FLAT PANES OF GLASS STUCK TOGETHER

WHEN THERE IS MOISTURE BETWEEN THEM.

A FINE LAYER OF MUCUS BETWEEN THEIR FOOT AND THEIR ROCK

IS ALL THEY NEED TO STAY PUT.

IT'S AN INCREDIBLY POWERFUL BOND:

REMOVING A FIRMLY STUCK LIMPET

REQUIRES MORE THAN 14 POUNDS PER SQUARE INCHES OF FORCE.

BUT A WIDE, FLAT SHELL OVER A LARGE FOOT

SPEEDS UP DANGEROUS DEHYDRATION.

NOT ONLY IS THERE A BIGGER AREA

BEING BLASTED BY THE SUN FROM ABOVE,

BUT A WIDER FOOT ABSORBS MORE HEAT FROM THE ROCK BELOW.

TO IMPROVE THEIR ODDS,

SOME SPECIES OF LIMPET

BECOME MORE STEEPLY DOMED AS THEY GROW OLDER,

GROWING UPWARDS INSTEAD OF OUTWARDS

AND SO INCREASING THEIR VOLUME

WITHOUT SPREADING THEIR AREA TOO WIDE.

CORRUGATIONS IN THEIR SHELL

ALSO HELP BOUNCE BACK MORE OF THE SUN'S HEAT,

SLIGHTLY REDUCING RADIATION.

SURVIVING THE SUN AND AIR, HOWEVER,

IS ONLY HALF THE CHALLENGE.

NOW THERE ARE HUNGRY OYSTERCATCHERS TO CONTEND WITH.

THIS IS WHAT THE BIRDS HAVE BEEN WAITING FOR ALL DAY.

THEIR WINDOW OF OPPORTUNITY IS OPENING,

AND NOW IT'S A RACE AGAINST TIME.

AFRICAN BLACK OYSTERCATCHERS

CAN EAT AN AVERAGE OF A HUNDRED LIMPETS A DAY -

AND THAT'S JUST FOR THEIR OWN CONSUMPTION.

THEY'LL EAT PLENTY MORE IF THEY HAVE CHICKS.

THEY LOVE MUSSELS,

BUT FOR NOW LIMPETS AND WORMS ARE THE EASIER CATCH.

THE ADULTS PICK THROUGH THE FEAST,

FOLLOWED CLOSELY BY THEIR HUNGRY YOUNGSTER.

THEY ONLY HAVE A FEW HOURS TO FEED BEFORE THE TIDE RETURNS.

THE LIMPETS CAN'T HOLD ON

AGAINST THE BIRDS' STRATEGIC LEVERING TECHNIQUES.

OYSTERCATCHERS ONLY EAT LIMPETS OF A CERTAIN SIZE.

TOO SMALL, AND THE LIMPET IS NOT WORTH THE EFFORT.

TOO BIG, AND IT MIGHT BE MORE EFFORT THAN IT'S WORTH.

THIS WORKS OUT WELL FOR THE LIMPETS,

AS IT'S THE BIGGER SNAILS THAT ARE ABLE TO REPRODUCE

AND KEEP LIMPET NUMBERS STABLE.

THE YOUNGSTER WATCHES CLOSELY

AS THE ADULTS MOVE TO THE MUSSEL BED.

GETTING A MUSSEL REQUIRES SKILL,

AND YOUNG AFRICAN BLACK OYSTERCATCHERS NEED TO BE TAUGHT

TO TEAR THE MUSSEL FROM THE THICK WEB OF FIBERS

THAT ANCHORS IT TO THE ROCK AND ITS COLONY.

SHE MUST MASTER THE ART OF PRYING THE TWO SHELLS APART,

AND STABBING AT THE SOFT, EXPOSED FLESH.

THE APPRENTICESHIP CAN TAKE UP TO 9 MONTHS.

FOR NOW, SHE STILL GETS FED BY HER PARENTS.

HER BEAK NEEDS STRENGTHENING

BEFORE SHE CAN USE IT AGAINST THESE HARDY MOLLUSKS.

WHILE THE TIDE IS STILL WITHDRAWING,

THE PICKINGS ARE SLIM.

THE MUSSELS ARE STARTING TO SEAL TIGHT AGAINST THE SUN.

BUT SOMETIMES PERSEVERANCE PAYS OFF.

AS THE OCEAN RETREATS,

THE TWO GREATEST THREATS OF THE SWEEPING SHORE

ARE ABOUT TO MAKE THEMSELVES FELT.

HEAT - AND WIND.

THE ANEMONE, FACING DEHYDRATION,

MUST RETREAT INTO ITSELF TO TRY AND RETAIN MOISTURE.

IT WILL HAVE TO HOLD ON UNTIL THE TIDE RETURNS

FOR SOME RELIEF.

WHAT WAS A HOLLOW IN A SUBMERGED PLATFORM

IS NOW A POOL, EXPOSED TO THE SUN AND THE AIR.

AS TEMPERATURES SOAR, IT'S BECOMING A CAULDRON.

ANY ANIMAL MAROONED INSIDE IT

WILL HAVE TO HOLD ON UNTIL THE TIDE RETURNS.

BUT IT'S NOT JUST THE ELEMENTS

THAT ARE DANGEROUS IN THESE POOLS:

THE ANEMONES THEMSELVES

POSE A DANGER TO OTHER CREATURES.

SEA ANEMONES PREY ON ANYTHING THAT SWIMS OR DRIFTS

INTO THE REACH OF THEIR POISON-LACED TENTACLES.

MANY MARINE SPECIES

HAVE EVOLVED TO AVOID THESE COLORFUL CARNIVORES.

THEIR POTENT STINGERS MAY HAVE IMPORTANT USES TO HUMANS.

COMPOUNDS DEVELOPED FROM ANEMONE TOXINS

ARE SHOWING PROMISE IN THE TREATMENT OF INSULIN RESISTANCE

AND FOR USE IN NEW INSECTICIDES.

ANEMONES ARE EQUIPPED WITH CHEMICAL WEAPONS,

BUT URCHINS RELY ON MUCH MORE OLD-FASHIONED DETERRENTS:

POINTY STICKS.

EACH OF THESE SPIKES IS INDIVIDUALLY MOUNTED

AND CAN PIVOT IN ANY DIRECTION.

IT'S IN NO DANGER NOW, THOUGH:

A WANDERING FEATHER STAR POSES NO THREAT.

THE URCHIN'S ARMOR IS FORMIDABLE,

BUT IT CAN'T KEEP THE SUN AT BAY.

TO PROTECT THEIR SENSITIVE SKIN,

THEY'LL USE SHELL FRAGMENTS AS PARASOLS.

SOMETIMES, THOUGH, SPINES AREN'T ENOUGH.

A CRAB MAKES SHORT WORK OF THE URCHIN.

BUT THE CRAB NEEDS TO BE ON ITS GUARD AS WELL.

THE OCTOPUS IS STILL ON THE HUNT.

HE IS A MASTER OF CAMOUFLAGE, THANKS TO HIS SKIN.

THIS SKIN IS MADE UP OF MANY FINE LAYERS,

EACH PACKED WITH SPECIALIZED CELLS

THAT CAN CHANGE COLOR OR TEXTURE.

EVEN MORE REMARKABLE,

THE SKIN ITSELF CAN SENSE CHANGES IN LIGHT AND SHADE

THANKS TO LIGHT-SENSITIVE CELLS.

COUPLED WITH THE OCTOPUS'S LARGE AND HIGHLY SOPHISTICATED EYES,

THIS HELPS THE ANIMAL

CREATE EXACTLY THE RIGHT PALATE

OF COLORS AND TEXTURES TO DISAPPEAR.

SOON, THAT COMPLEX CLOAK OF INVISIBILITY WILL PAY OFF

LOW TIDE.

THE SUN IS BAKING DOWN.

TEMPERATURES ARE AT THEIR PEAK.

FOR THE MOLLUSKS AND CRUSTACEANS HIGHER UP THE SHORE,

IT'S TIME TO SEAL THEMSELVES AGAINST THE ROCK

AS THEY WAIT FOR THE SEA TO RETURN.

THERE'S DANGEROUSLY LITTLE WATER,

BUT AT LEAST THERE'S PLENTY OF FOOD.

A GARDEN OF ALGAE, KEPT NEATLY TRIMMED BY GRAZING LIMPETS.

LONG-SPINED LIMPETS TEND LARGER GARDENS.

THEY USE THEIR LONG SPINES

TO MAKE SURE NO OTHER LIMPETS INTRUDE ON THEIR TURF,

BULLDOZING ANY TRESPASSERS OFF THE ROCK.

HIGH AND DRY FOR SIX HOURS,

THESE BARNACLES

TUCK THEIR FEELER-LIKE FEET INTO THEIR SHELL

AND COVER UP THE OPENING WITH THICK MANTLE,

SEALING IN WHATEVER MOISTURE THEY CAN SAVE.

LIKE THE BOMBPROOF DOORS OF A BUNKER,

THE MANTLE LOCKS TIGHT,

PROTECTING THE BARNACLE FROM THE SUN AND AIR.

THE BARNACLES SHARE THIS SHORE WITH VAST COLONIES OF MUSSELS.

THESE MOLLUSKS ATTACH TO ROCKS AS YOUNG LARVAE,

SECRETING STICKY THREADS THAT ANCHOR THEM TO COAST.

IT'S A GOOD STRATEGY FOR LIVING IN SUCH A HIGH-ENERGY ZONE.

UNTETHERED, THEY WOULD WASH AWAY.

NOW, IN THE HEAT OF THE DAY,

THE MUSSELS ARE IN SURVIVAL MODE.

THEIR SHELLS CLAMP SHUT,

PREVENTING ANY MOISTURE FROM ESCAPING.

LOCKED IN A KIND OF STASIS

THEY SURVIVE WITHOUT OXYGEN FOR SEVERAL HOURS,

LONG ENOUGH FOR THE TIDE TO RETURN.

THIS PROTECTS THEM NOT ONLY FROM THE SUN,

BUT ALSO THE PROBING BEAKS OF THE OYSTERCATCHERS.

THE OYSTERCATCHERS HAVE HAD THEIR FILL OF LIMPETS

BUT KEEP INSPECTING THE MUSSEL BED,

SEARCHING FOR ANY MUSSEL THAT IS WEAKLY ATTACHED.

THESE ONES REFUSE TO BE TAKEN.

THE OYSTERCATCHER WILL HAVE TO COME BACK LATER

WHEN THE TIDE STARTS COMING IN.

HE KNOWS THE VALUE OF PATIENCE.

WHEN THE OCEAN RETURNS,

THE MUSSELS WON'T BE ABLE TO RESIST

OPENING THEIR BUNKER DOORS -

AND THAT'S WHEN HE'LL STRIKE.

FOR NOW, HE'LL NEED TO HEAD BACK TO THE NEST.

IT'S TIME TO RELIEVE HIS PARTNER SO THAT SHE CAN FEED.

UP AT THE NEST, SHE WAITS FOR HIS RETURN.

WHEN HE GETS BACK, IT'S TIME FOR A TOUGH DECISION.

THE TIDE IS TURNING.

HUNDREDS OF MUSSELS WILL BE RIPE FOR THE PLUCKING.

IT'S A DILEMMA:

SHOULD THEY CONTINUE TAKING TURNS,

OR SHOULD THEY MAXIMIZE THESE PRECIOUS FEW HOURS

BY BOTH GOING TO FEED,

LEAVING THEIR EGGS UNGUARDED?

THEY WILL HAVE TO DEPEND ON THE DAPPLED SHELLS OF THEIR EGGS,

WHICH MIMIC THE CONTRASTS AND SHADES OF THE SHORELINE.

TODAY THEY DECIDE THE RISK IS WORTH TAKING.

IT'S TIME TO DESCEND THE ROCKY SHORE

TO THE RIPE MUSSEL BEDS.

THE TIDE IS COMING IN.

MILLIONS OF YEARS OF RISING AND FALLING SEA LEVELS

HAVE CARVED SOFT SANDSTONE INTO LEVEL PLATFORMS,

JAGGED COLUMNS

AND SMALL CHANNELS.

BETWEEN THESE OUTCROPS, IS A BROAD BEACH -

EVERY GRAIN OF SAND A PIECE OF AN ANCIENT ROCKY SHORE

WORN AWAY BY TIME.

TIME AND TIDE ARE THE GREAT POWERS OF THIS WORLD.

ONCE, THEY SHAPED IT.

NOW, THEY RULE OVER IT,

RUNNING IT ACCORDING TO A STRICT AND IMMUTABLE TIMETABLE.

THE OYSTERCATCHERS ARE NOT THE ONLY RESIDENT OF THIS SHORE

THAT HAS EAGERLY BEEN WAITING FOR THE TIDE TO TURN.

ON THESE EXPOSED BEACHES,

THE SURF ZONE IS ALSO A RICH ENVIRONMENT

FOR THOSE HUNTERS

ABLE TO WITHSTAND THE SHIFTING, ABRASIVE SAND.

IT LOOKS DESERTED,

BUT HIDDEN JUST UNDER THE SURFACE

A MINIATURE FLEET IS WAITING TO SET SAIL WITH THE TIDE.

FOR NOW,

THE ONLY SIGN OF THE ARMADA IS A MYSTERIOUS BREATHING PIPE.

BUT AS THE TIDE RISES, THEY BEGIN TO REVEAL THEMSELVES.

FINGER PLOUGH SHELLS ARE SCAVENGERS,

SCOURING THE BEACH FOR CARRION.

IT'S A LONG WAY FOR A SMALL SNAIL TO CRAWL.

SO INSTEAD,

THIS SAILOR UNFURLS ITS FOOT INTO A HANDY SAIL -

AND RIDES THE SWELL UP THE BEACH.

UNLIKE THE ROCK-BOUND LIMPETS,

THAT TAKE SHELTER FROM THE WAVES,

THESE SNAILS USE THE INCOMING TIDE TO THEIR ADVANTAGE.

THE SWELL ISN'T ONLY AN ENERGY SAVER.

IT'S ALSO TAKING THE FINGER PLOUGH SHELL

TO THE SAME PLACE IT'S WASHED ANY DEAD FISH.

ONCE THEY'VE ARRIVED,

THEIR POWERFUL SENSE OF SMELL

LETS THEM HONE IN ON THEIR JUICY TARGET.

THEIR SENSORY ABILITY IS STAGGERING,

ALLOWING THEM TO SMELL CERTAIN CHEMICALS FROM DEAD FISH

IN MINISCULE CONCENTRATIONS.

THE RAIDERS GET TO WORK QUICKLY.

THE FINGER PLOUGH SHELL

BEGINS TO SUCK UP ANY TISSUE WITH ITS DEFT PROBOSCIS.

THESE SNAILS ARE GLUTTONS.

AT A SINGLE SITTING

THEY CAN EAT UP TO A THIRD OF THEIR OWN BODY WEIGHT.

IF THEY PRESERVE THEIR ENERGY

AND STAY BURIED MOST OF THE TIME,

A FEAST LIKE THIS CAN SUSTAIN THEM FOR TWO WEEKS.

ONCE THEY'RE DONE,

THEY BURY THEMSELVES AGAIN AT THE MID-TIDE LEVEL.

THEY WAIT HERE

UNTIL THE RETREATING TIDE

CARRIES THEM BACK TO THEIR ORIGINAL HAUNTS.

ALONG THE ROCKY SHORE,

THE WAVES ARE PUSHING HIGHER AS THE TIDE CRASHES IN.

EXPOSED GULLIES AND CANYONS

ARE BECOMING CHANNELS OF SURGING OCEAN.

THE TINY BARNACLES HAVE OPENED THEIR DOORS,

SENDING OUT FEATHERY BRANCHES TO CATCH THEIR MICROSCOPIC FOOD.

THE GRANITE LIMPETS MUSHROOM OFF THE ROCKS,

TRAPPING DRIFTING ALGAE WITH THEIR STICKY FEET.

AS THE MUSSEL BEDS BEGIN TO FLOOD,

THEY START OPENING THEIR SHELLS.

BUT THIS IS STILL NO EASY MEAL FOR THE OYSTERCATCHERS.

A QUIRK OF GEOLOGY HERE

PRESENTS THE BIRDS WITH A MAJOR CHALLENGE.

ON SLOPING SHORES,

THE RISE OF THE TIDE WOULD BE RELATIVELY EVEN,

THE WATER CREEPING UP PREDICTABLY.

BUT FLAT PLATFORMS LIKE THESE

CAN BE OVERWHELMED BY THE OCEAN IN AN INSTANT.

ALL IT TAKES IS FOR A WAVE TO CREST THE EDGE,

AND THE WHOLE BED WILL BE INUNDATED.

FOR A SMALL BIRD, THESE WAVES ARE VAST AND DEADLY.

ONE WRONG MOVE,

ONE SLOW REACTION,

AND THEY COULD BE DRAGGED OFF THE ROCKS

OR SMASHED BY A WAVE.

BUT NOW THE MUSSELS ARE OPENING,

AND THE OYSTERCATCHER'S DANCE WITH DANGER BEGINS.

AS THE BIVALVES OPEN THEIR SHELLS

TO LET IN OXYGENATED SEAWATER,

THEY PROVIDE THE EASY GAP THE OYSTERCATCHER NEEDS.

THE BIRDS ARE PUSHING THEMSELVES TO THE LIMIT.

IT WILL BE SIX HOURS

UNTIL THIS BUFFET IS AVAILABLE TO THEM AGAIN,

AND THEY GORGE WHILE THEY CAN.

GOING BACK FOR ONE LAST KILL -

IS ALMOST A DEADLY MISTAKE.

FOR THESE AGILE HUNTERS,

DEATH-DEFYING STUNTS ARE PART OF DAILY LIFE

ON THE SWEEPING SHORE.

THE RISING TIDE IS SWEEPING OVER THE PLATFORMS

AND RECLAIMING ROCK POOLS -

OPENING THE WINDOWS OF OPPORTUNITY

FOR THE LURKING PREDATORS.

THE OCTOPUS HAS STRUCK.

THE CRAB'S FIERCE PINCERS

ARE NOW RENDERED USELESS BY THE OCTOPUS'S SUCKERS.

DISARMED AND IMMOBILIZED,

THE CRAB WILL NOT ESCAPE FROM THIS DEATH GRIP.

WITH A MINIMUM OF FUSS,

THE OCTOPUS GETS TO WORK ON KILLING ITS VICTIM.

IT DOESN'T TAKE LONG.

UNDER THE FOLDS OF ITS BODY AND LEGS,

ITS SHARP BEAK

IS SCRAPING THROUGH THE UNDERSIDE OF THE CRAB'S SHELL.

THE SHELL, PULLED IN HALF AND EATEN CLEAN,

IS CAREFULLY PUSHED TO ONE SIDE.

AT LAST ALL THAT'S LEFT ARE DISEMBODIED REMAINS,

AND A VERY SATISFIED OCTOPUS.

THE ARRIVAL OF HIGH TIDE BRINGS NEW SEAWATER INTO THE ROCK POOL.

THE SUDDEN RUSH OF ICY WATER MIGHT COME AS A MILD SHOCK.

BUT THESE SPECIES ARE READY FOR ANYTHING.

ALONG THIS SWEEPING SHORE,

THEY'VE ADAPTED TO COPE WITH EXTREMES -

THE HIGH TEMPERATURE AND SALINITY OF EXPOSED ROCK POOLS,

FOLLOWED BY THE SUDDEN CHANGE TO MUCH COLDER, LESS SALTY WATER.

WHILE THE TIDE IS HIGH,

THEY WILL HAVE THEIR FILL OF FRESH SEAWATER

AND FOOD SUPPLIES,

PREPARING FOR THE NEXT LOW TIDE.

THE OCTOPUS, UNRUFFLED,

GLIDES AWAY

TO EXPLORE THE CHANGED UNDERWATER LANDSCAPE.

THE OYSTERCATCHERS

HAVE SURRENDERED THE COAST TO THE HIGH TIDE.

THE CYCLE OF THE TIDES IS NEVER-ENDING,

A VAST CLOCK THAT REGULATES ALL LIFE ON THIS COAST.

FOR THIS YOUNG OYSTERCATCHER, TIME HAS MARCHED ON.

NO LONGER A CHICK,

SHE MUST NOW MAKE HER OWN WAY IN THE WORLD.

LEAVING HER PARENTS IS NOT ONLY A RITE OF PASSAGE;

IT'S ALSO A SURVIVAL IMPERATIVE:

SHE'S NOW BIG ENOUGH TO COMPETE WITH THEM FOR FOOD,

AND THE PARENTS ARE HAVING NONE OF THAT.

STILL, IN THIS DYNAMIC, EVER-CHANGING LANDSCAPE,

THERE'S PLENTY TO GO AROUND IF YOU'RE TOUGH ENOUGH.

THIS IS A WORLD IN CONSTANT FLUX,

ENDLESSLY REACTING TO THE HUGE CONTRAST

BETWEEN HIGH AND LOW TIDE.

FOR THE CREATURES THAT LIVE HERE,

IT IS A DEMANDING ENVIRONMENT

BUT ALSO ONE RICH IN FOOD.

ON THIS COAST,

NATURE HAS DEMANDED BRILLIANT ADAPTATION,

AND THESE ANIMALS HAVE MET THE CHALLENGE.

HIGH ENERGY.

HIGH EXPOSURE.

HIGH RISKS.

BUT ALL OFFER BIG REWARDS

ON THE SWEEPING SHORE.

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