Original subtitles

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NARRATOR: WHEN YOU SEE THIS SYMBOL, YOU KNOW YOU'RE

WATCHING TELEVISION THAT IS EDUCATIONAL AND INFORMATIONAL.

THE MORE YOU KNOW ON NBC.

DYLAN: HI, EVERYONE, I'M DYLAN DREYER.

GET READY TO EXPLORE A HIDDEN WORLD ON "EARTH ODYSSEY".

TODAY, WE'RE TAKING A DEEP DIVE INTO THE WEIRD AND WONDERFUL

WORLD OF CRUSTACEANS.

WE'LL CATCH A RARE GLIMPSE AT WHAT MAKES THESE CREATURES COME

APART AT THE SEAMS.

AND LATER, A HIGHLY SKILLED FISHERMAN SHOWS US THEIR

BUILT-IN NAUTICAL NET.

ON THE OCEAN FLOOR, WE'LL SEE A TAG TEAM OF TOP-NOTCH HUNTERS

ENJOYING A MEAL, BUT WE START IN CALMER WATERS, WHERE THE MOST

FAMOUS CLASS OF CRUSTACEANS TAKES CENTER STAGE.

ALL OF THIS AND MORE ON TODAY'S EPISODE OF "EARTH ODYSSEY".

[MUSIC]

THE WORLD'S OCEANS ARE HOME TO A WEALTH OF STRANGE CREATURES;

HOWEVER, NONE MAY BE AS UNIQUE OR ALIEN AS ONE UNUSUAL GROUP:

CRUSTACEANS.

THESE INCREDIBLE ANIMALS WERE A COMPLETE MYSTERY TO HUMANS FOR

CENTURIES.

EVEN TODAY, THEY'RE STILL SOME OF THE MOST INTRIGUING WONDERS

UNDERWATER.

CRUSTACEANS CAN BE FOUND EVERYWHERE.

CRABS, FOR INSTANCE, MEET ON ROCKS BETWEEN THE LAND AND

THE SEA.

BUT THEY ONLY EMERGE BRIEFLY FROM THEIR FAVORITE PLACE.

SEVERAL MILLION YEARS OLD, THIS GROUP IS A BRANCH OF THE

KINGDOM ANIMALIA, WHICH CONTAINS ABOUT 50,000 SPECIES, MOST OF

WHICH ARE AQUATIC.

IT ISN'T ALWAYS EASY TO OBSERVE THEM IN THEIR NATURAL

ENVIRONMENT BECAUSE THEY HIDE IN HOLES AND CRACKS DURING THE DAY.

THESE ANCIENT ANIMALS LIVE IN EVERY REGION OF THE WORLD...

...FROM THE SEA'S SURFACE TO DEPTHS OF THOUSANDS OF FEET.

THEY VARY IN SIZE FROM WELL UNDER AN INCH TO MORE THAN TEN

FEET FOR THE JAPANESE SPIDER CRAB, THE LARGEST KNOWN

CRUSTACEAN IN THE WORLD.

THEIR CLASSIFICATION IS VERY COMPLEX.

THERE ARE BRACHIOPODS, SO NAMED BECAUSE THEY HAVE GILLS ON THEIR

FEET, SUCH AS ARTEMIA, WHICH BREATHE BY TAKING IN OXYGEN FROM

THE WATER THROUGH THEIR FEET...

...OR CIRRIPEDES, SUCH AS BARNACLES, WHOSE DISTINCTIVE

FEATURE IS THAT THEY SPEND THEIR ENTIRE LIFE ATTACHED TO THE SAME

PLACE.

THERE ARE MANY SUBCLASSES, TOO.

THE ONE WE ARE INTERESTED IN IS MALACOSTRACA, AS IT CONTAINS THE

ORDER DECAPODA, WHICH INCLUDES THE WORLD'S BEST-KNOWN

CRUSTACEANS.

DECAPODS, SO NAMED BECAUSE OF THEIR TEN LEGS, INCLUDE

CRUSTACEANS SUCH AS SHRIMPS, CRAYFISH, CRABS,

AND SLIPPER LOBSTERS.

AND WITHIN THIS GROUP, THERE ARE SWIMMING CRUSTACEANS AND

WALKING CRUSTACEANS.

SOME, LIKE LOBSTERS, SLIPPER LOBSTERS, AND CRAYFISH HAVE A

VERY LONG, WELL-DEVELOPED ABDOMEN ENDING IN A TAILFIN...

...WHILE OTHERS, SUCH AS HERMIT CRABS, HAVE

ASYMMETRICAL ABDOMENS.

AND LASTLY, THERE ARE THOSE THAT ARE ROUNDER WITH A SMALL ABDOMEN

OFTEN FOLDED UNDER THE THORAX, LIKE SPIDER CRABS AND CRABS.

BUT THIS GROUP IS NOT AS SIMPLE AS IT SEEMS.

THERE ARE MANY OTHER SUBCLASSES, SUCH AS AMPHIPODS, REPRESENTED

BY THESE SKELETON SHRIMPS...

...OR ISOPODS, REPRESENTED BY PARASITES.

CRUSTACEANS COME IN ALL SORTS OF SHAPES AND COLORS AND VARY FROM

ONE EXTREME TO ANOTHER.

SOMETIMES THEY LOOK ALMOST UNREAL.

WHILE ALL THESE CREATURES BELONG TO THE SAME GROUP, THEY CAN BE

WILDLY DIFFERENT, SOME LIVING IN THE SEA, OTHERS IN FRESH WATER,

LIKE HERE.

CRAYFISH EVOLVED FROM PRIMITIVE MARINE ANCESTORS, LIKE ALL ITS

RIVER AND LAKE-DWELLING FELLOWS.

MAKING AN APPEARANCE IN ALMOST EVERY BODY OF WATER ON EARTH,

CRUSTACEANS ARE EVERYWHERE.

COMING UP, WE'LL SEE SOME CRUSTACEAN GYMNASTICS THAT END

IN THE SPLITS.

AND IN THE DEPTHS OF THE SEA, THIS CRAB HAS AN UNLIKELY TOOL

FOR FAST FISHING.

PLUS, A CREATURE AS CURIOUS AS THEY ARE COLORFUL.

THIS AND MORE WHEN "EARTH ODYSSEY" RETURNS.

.

NARRATOR: WE NOW RETURN TO THE MORE YOU KNOW ON NBC.

[MUSIC]

DYLAN: OUT OF THE APPROXIMATELY 50,000 SPECIES OF CRUSTACEANS,

THEY ALL SHARE ONE DEFINING CHARACTERISTIC THAT ALSO MAKES

THEM SO UNIQUE: THEIR EXTERNAL SKELETON, MORE COMMONLY REFERRED

TO AS A SHELL, OR CARAPACE.

IN FACT, THEY GOT THEIR NAME FROM THIS CARAPACE, BECAUSE THE

WORD "CRUSTACEAN" COMES FROM THE LATIN "CRUSTA", WHICH MEANS

CRUST, OR HARD SHELL.

THIS HARD EXTERIOR IS NOT MADE OF ONE SOLID PIECE, AS THIS

WOULD MEAN THEY COULDN'T MOVE.

MOVEMENT IS POSSIBLE THANKS TO THE ARTICULATION BETWEEN THE

DIFFERENT PARTS.

BUT IF THIS SHELL IS RIGID, HOW DO THEY GROW?

MOLTING.

MOLTING IS THE PROCESS BY WHICH THEY GROW, AND WHAT MAY LOOK

LIKE JUST A DEAD CRUSTACEAN IS IN FACT AN EMPTY SHELL BEING

CARRIED ALONG BY THE WAVES.

MOLTING INVOLVES THE SHEDDING OF THE OLD SHELL AND REGENERATION

OF THE NEW ONE.

CRUSTACEANS MOLT BECAUSE THEIR OLD SHELL HAS BECOME TOO SMALL.

SO, IT HAPPENS FREQUENTLY WHEN AN ANIMAL IS YOUNG AND THEN LESS

SO AS IT GROWS OLDER.

IT IS ALMOST IMPOSSIBLE TO OBSERVE A CRUSTACEAN MOLTING

BECAUSE IT USUALLY OCCURS WHEN NO ONE IS LOOKING, AT NIGHTFALL.

THEY USE THE COVER OF DARKNESS TO HIDE SINCE THEY ARE

ESPECIALLY VULNERABLE.

BEING ABLE TO SEE THE MOLTING PROCESS IS EXCEPTIONALLY RARE.

SHOT IN AN ARTIFICIAL ENVIRONMENT, THIS RECORDING

CATCHES THE ENTIRE PROCESS.

FIRST, THE OLD SHELL BECOMES DETACHED.

THEN THE ANIMAL BEGINS TO SHED IT.

SHEDDING OCCURS THANKS TO THE ANIMAL'S TYPICAL BEHAVIOR.

IT MOVES RHYTHMICALLY AND INFLATES ITS BODY AS MUCH AS

POSSIBLE, OFTEN BY SWALLOWING WATER.

THE OLD SHELL TEARS ALONG THE WEAKEST POINTS, AND THE ANIMAL'S

MOVEMENTS ENABLE IT TO SHED THE OLD SHELL AND STRETCH THE NEW

SHELL FULLY.

AFTER MOLTING, THE ANIMAL IS SOFT; AND THEREFORE, IT'S EASY

PREY FOR PREDATORS.

IT TAKES SEVERAL DAYS FOR THE NEW SHELL TO HARDEN AND FORM A

PROTECTIVE LAYER.

MOLTING ENABLES CRUSTACEANS TO REGENERATE MISSING LIMBS.

IN OTHER WORDS, THEIR LEGS CAN GROW BACK.

ALL THAT THIS WOUNDED LITTLE CRUSTACEAN HAS TO DO IS WAIT FOR

THE NEXT MOLT TO REGAIN THE USE OF ALL ITS LIMBS.

MOST CRUSTACEANS HAVE EYES, AND SOME OF THEM DESERVE

SPECIAL ATTENTION.

THEIR EYES HAVE MANY FACETS, SOMETIMES SEVERAL HUNDRED.

THEY DON'T HAVE KEEN VISION, BUT THEIR EYES MOVE QUICKLY, WHICH

ENABLES THEM TO DETECT MOVING SHAPES.

SOME DEEP-SEA SPECIES WHICH LIVE IN TOTAL DARKNESS HAVE PRICKLES

INSTEAD OF EYES.

20-20 VISION, THE MANTIS SHRIMP HAS THE BEST EYESIGHT IN THE

MARINE WORLD AND MAYBE EVEN THE ANIMAL KINGDOM.

ITS EYES PIVOT INDEPENDENTLY AND WILL ALLOW IT TO SEE IN

EVERY DIRECTION.

EACH EYE IS DIVIDED INTO THREE SECTIONS, EACH WITH ITS OWN

PUPIL.

THIS EYE SEES THE SHAPE, DISTANCE, AND DEPTH OF OBJECTS.

IT'S BASICALLY 3D VISION AND ONE OF THE MOST IMPRESSIVE

ADAPTATIONS IN THE WILD.

WHEN WE RETURN, WE CONTINUE OUR EXPLORATION OF THE CRUSTACEAN

WORLD WITH THIS UNIQUELY FIERCE FISHERMAN, AND WE'LL HEAD TO THE

SHALLOWS TO SEE A HARLEQUIN HUNTING PARTY, ALL COMING UP ON

"EARTH ODYSSEY".

.

NARRATOR: WE NOW RETURN TO THE MORE YOU KNOW ON NBC.

[MUSIC]

DYLAN: WITH WAVES, TIDES, AND CURRENTS CONSTANTLY SHIFTING THE

LANDSCAPE OF UNDERWATER ENVIRONMENTS, MOST AQUATIC

ANIMALS HAVE BECOME EXPERTS IN MOBILITY.

WITHOUT ANY BONES IN THEIR BODIES, GETTING AROUND FOR

CRUSTACEANS REQUIRES ITS OWN UNIQUE ABILITY.

THEY MAY NOT BE AS FLUID OR AS GRACEFUL AS THEIR FISH OR MAMMAL

COUNTERPARTS, BUT THEY ARE ODDLY VERSATILE IN THE WATER.

CRUSTACEANS MOVE MAINLY THANKS TO THEIR APPENDAGES, OR LEGS,

ALWAYS MANY, ALWAYS IN PAIRS.

THESE LEGS GIVE THEM A DISTINCTIVE GAIT.

IT'S JERKY, SLIGHTLY UNBALANCED, AND NOT VERY ELEGANT.

BUT THESE LEGS AREN'T JUST MADE FOR WALKING.

THEY CAN ALSO BE USED FOR SWIMMING.

THAT'S THE CASE WITH SHRIMP.

THEY SWIM SO QUICKLY AND ELEGANTLY, THAT IT LOOKS AS IF

THEY'RE FLYING.

THE LEGS ALSO SERVE AS PINCERS.

AS WELL AS ITS HUGE CLAWS, THE PORCELAIN CRAB HAS MORE

SOPHISTICATED APPENDAGES.

LIKE NETS, IT UNFURLS ITS FEATHERY, FAN-LIKE MOUTH PARTS.

THIS INGENIOUS SYSTEM ENABLES IT TO FILTER THE PLANKTON

IT FEEDS ON.

THESE DIFFERENT FUNCTIONS HAVE ONE PURPOSE, FEEDING.

MOST CRUSTACEANS ARE CARNIVOROUS, EVEN THOUGH ALGAE

SOMETIMES ENTERS THEIR DIGESTIVE SYSTEM.

THEY ARE OFTEN OPPORTUNISTIC AND EAT DEAD AS WELL AS LIVE PREY.

THE SMALLEST FEED ON PLANKTON, OR DECOMPOSING PARTICLES.

POWERFULLY ARMED, THE LARGEST PREFER LIVE PREY, LIKE FISH OR

MOLLUSKS.

HOWEVER, CRUSTACEANS ARE CONSUMMATE SURVIVORS EVEN WHEN

FOOD IS SCARCE.

SOME, SUCH AS LOBSTERS, ARE ABLE TO SURVIVE WITHOUT FOOD FOR

SEVERAL MONTHS.

ONE MORE REASON THIS FASCINATING CLASS OF ANIMALS HAS BEEN ABLE

TO ROAM THE EARTH FOR MILLIONS OF YEARS.

COMING UP NEXT, FOR THESE COLORFUL CRUSTACEANS, IT TAKES

TWO TO FIND A MEAL.

THIS AND MORE WHEN "EARTH ODYSSEY" RETURNS.

.

NARRATOR: WE NOW RETURN TO THE MORE YOU KNOW ON NBC.

[MUSIC]

DYLAN: THE MAJORITY OF CRUSTACEANS THAT AREN'T MOBILE

ARE WHAT'S KNOWN AS FILTER FEEDERS.

THAT'S TO SAY THEY ABSORB TINY THINGS.

BARNACLES, FOR INSTANCE, GATHER PARTICLES OF PLANKTON BY

CONSTANTLY FILTERING THE WATER.

THESE SMALL, BARELY VISIBLE CRUSTACEANS OFTEN FIND

THEMSELVES INVADED BY CORAL, AND THEIR HARD PART IS NO LONGER

VISIBLE.

HERE, LESS COLONIZED, IT'S EASIER TO SEE THEM FEEDING.

BARNACLES CAN LIVE NEAR THE SURFACE BETWEEN THE AIR AND

WATER.

WHAT YOU MIGHT THINK AT FIRST GLANCE ARE SHARP BUMPS ON THE

ROCKS ARE ACTUALLY LIVING CREATURES.

THESE ANIMALS HAVE CALCIUM PLATES

WHICH CAN BE PULLED TOGETHER.

THIS HERMETIC SEAL PREVENTS THE BARNACLES FROM DRYING OUT, AND

IT MEANS THEY CAN WITHSTAND LONG PERIODS OUT OF THE WATER.

THEY ALSO NEED SOMETHING ON WHICH TO ATTACH THEMSELVES, EVEN

SOMETHING LIVING.

ALWAYS IN PAIRS, HARLEQUIN SHRIMPS FEED EXCLUSIVELY ON

STARFISH.

WITH THEIR PINCERS, THEY HAVE CUT OFF AN ARM AND ARE TAKING IT

AWAY TO EAT.

THIS STARFISH IS LUCKY.

THE SHRIMP DIDN'T KILL IT, AND ITS ARM WILL SOON GROW BACK.

LESS THAN A HALF-INCH IN LENGTH, SKELETON SHRIMP ARE THE ONLY

CRUSTACEANS ABLE TO STAND UP BY ANCHORING THEMSELVES WITH THEIR

REAR LEGS.

THEY CAPTURE THEIR PREY WITH THEIR MUCOUS-SECRETING ANTENNAE,

A THICK AND VISCOUS SUBSTANCE.

THIS MUCOUS PARALYZES THE PLANKTON LARVA AND SMALL

INVERTEBRATES THEY FEED ON.

BUT TO FEED, SOME SHRIMP HAVE ADOPTED A DIFFERENT TECHNIQUE.

THEY OFFER THEIR SERVICES IN WHAT ARE KNOWN AS

CLEANING STATIONS.

THEY REMOVE OTHER CREATURES' PARASITES.

AND THOSE WHO MIGHT HAVE BECOME PREDATORS IF IT WASN'T FOR THIS

INDISPENSABLE REMOVAL FUNCTION, OPEN THEIR EARS AND MOUTHS WIDE,

WHERE THE CLEANER SHRIMP WORK UNDISTURBED.

IT'S A FINE EXAMPLE OF SOLIDARITY AND MUTUAL TRUST,

ANIMALS HELPING EACH OTHER THRIVE IN THE WILD.

FOR EVERY SPECIES OF ANIMAL, SURVIVAL IS A UNIQUE ENDEAVOR.

EACH HAS THEIR OWN INDIVIDUAL TRAITS THAT GIVE THEM THE BEST

CHANCE TO SUCCEED, AND CRUSTACEANS ARE NO EXCEPTION.

THESE WEIRD, YET WONDERFUL OCEAN WANDERERS OFFER A NEW

PERSPECTIVE OF WHAT IT MEANS TO THRIVE IN THE WILD.

THANKS FOR JOINING ME TODAY, AND I HOPE TO SEE YOU FOR THE NEXT

ADVENTURE ON "EARTH ODYSSEY".

[MUSIC]