Original subtitles

♪♪

Narrator: ANIMALS...

DO THE MOST INCREDIBLE THINGS.

[ GOAT BLEATS ]

LIKE THIS...

AND THIS.

I BET YOU'RE WONDERING, "HOW DO THEY DO THAT?"

WE'RE REVEALING ANIMALS' BIGGEST SECRETS, LIKE...

HOW DO CATS ALWAYS LAND ON THEIR FEET?

HOW DO BUTTERFLIES CREATE SUCH BEAUTIFUL WINGS?

AND DOES THIS WEIRD-LOOKING CRITTER HOLD THE KEY

TO A LONG DISEASED-FREE LIFE?

THESE WONDERS AND MORE ON...

--Captions by VITAC-- www.vitac.com

CAPTIONS PAID FOR BY DISCOVERY COMMUNICATIONS

SCIENTISTS HAVE WRESTLED

WITH SOME OF THE GREATEST MYSTERIES OF THE UNIVERSE.

HOW DID IT ALL BEGIN?

CAN WE GO FASTER THAN LIGHT?

AND JUST WHAT IS GRAVITY?

Man: AAAAAH!

Narrator: BUT THERE'S ONE PROBLEM THAT SEEMS TO DEFY

THE FUNDAMENTAL LAWS OF PHYSICS.

HOW DO CATS ALWAYS LAND ON THEIR FEET?

DOMESTIC CATS ARE THE NATURAL ATHLETES OF THE PET WORLD.

THEY COULD TAKE ON THE FASTEST PEOPLE AROUND

WITH A TOP SPEED OF 30 MILES PER HOUR.

THEY CAN JUMP AS HIGH AS SIX TIMES THEIR BODY LENGTH.

THAT'S LIKE A HUMAN LEAPING A THREE-STORY BUILDING.

BUT THE CAT'S ABILITY TO TWIST IN MID-AIR

AND PUT FOUR FALLING PAWS ON THE GROUND

IS ITS MOST IMPRESSIVE FEAT.

HOW DO THEY DO IT?

WELL, CREDIT THE CAT'S AMAZING, BENDABLE SPINE.

AS THE CAT FALLS, IT DOES SOMETHING EXTRAORDINARY.

THE CAT BENDS ITS SPINE SO MUCH THAT IT CAN SEPARATE

THE MOVEMENT OF ITS FRONT HALF FROM THE REAR HALF.

THE FOUR-LEGGED CONTORTIONIST TUCKS ITS FRONT PAWS IN

AND AT THE SAME TIME, PUSHES ITS BACK LEGS OUT.

THIS MAKES THE FRONT END SPIN FASTER,

JUST LIKE AN ICE SKATER PULLING IN HIS ARMS,

WHILE THE REAR LEGS TWIST BACK FOR A PERFECT LANDING.

BOTH WILD AND DOMESTIC CATS HAVE 30 VERTEBRAE

IN THEIR SPINES, COMPARED TO OUR 24,

WHICH MEANS THE CAT'S SPINE HAS THE ABILITY TO TWIST FURTHER.

AND THE LIGAMENTS THAT JOIN THE CAT'S VERTEBRAE

ARE SOME OF THE STRONGEST AND SPRINGIEST

IN THE ANIMAL KINGDOM.

IT'S THIS ELASTICITY THAT ALLOWS CATS TO CORK-SCREW

THEIR BODIES IN OPPOSING DIRECTIONS.

IF WE TRIED THIS, EVEN AFTER A LIFETIME OF YOGA,

WE'D BREAK OUR BACKS.

THE CAT'S AMAZING TALENT IS CALLED

THE "SELF-RIGHTING REFLEX."

BUT CATS AREN'T BORN WITH IT.

IT STARTS APPEARING IN KITTENS WHEN THEY'RE 3 WEEKS OLD.

BY SEVEN WEEKS, THEY'VE NAILED IT.

THIS INCREDIBLE FELINE INSTINCT IS LEFTOVER FROM WHEN CAT'S WILD

ANCESTORS LIVED IN THE TREES, WHERE BALANCE, AGILITY,

AND A QUICK ESCAPE WERE ESSENTIAL FOR SURVIVAL.

AS IS ANOTHER LIFE-SAVING SKILL.

CATS CAN SLOW THEIR DESCENT DOWN BY STRETCHING OUT ALL FOUR LEGS.

THIS MAXIMIZES DRAG ON ITS FALLING BODY.

JUST LIKE A PARACHUTE.

THE CAT'S INCREDIBLE ABILITY HELPS THEM SURVIVE FALLS

FROM AS HIGH AS 32 STORIES UP.

HUMANS FALLING THAT FAR WOULD REACH A TERMINAL VELOCITY

OF 120 MILES PER HOUR, MAKING DEATH ALMOST CERTAIN.

BUT THAT PARACHUTE POSE CUTS THE CAT'S SPEED IN HALF,

DOWN TO A SURVIVABLE 60 MILES PER HOUR.

SO, CATS REALLY HAVE MASTERED THE PHYSICS OF FALLING.

[ TIGER GROWLS ]

[ CLOCKS TICKING ]

IT'S ONE OF LIFE'S SAD TRUTHS, THAT FROM THE MOMENT WE'RE BORN,

THE CLOCK STARTS TICKING.

AND AS WE AGE, MUSCLES LOSE STRENGTH, BONES WEAKEN,

AND OUR IMMUNE SYSTEM CAN'T FIGHT DISEASE AS EASILY.

[ GUN FIRES ]

BUT IMAGINE IF YOU COULD HAVE THE BODY OF A 20-SOMETHING,

WELL INTO YOUR RETIREMENT YEARS?

SOUNDS LIKE SCIENCE FICTION, BUT HIDDEN UNDERGROUND

IN THE PLAINS OF EAST AFRICA IS AN AMAZING ANIMAL

THAT COULD HOLD THE SECRET OF A LONG, DISEASE-FREE LIFE.

WHY DON'T NAKED MOLE RATS AGE?

NAKED MOLE RATS AREN'T MOLES OR RATS.

IN FACT, THEIR CLOSEST RELATIVES ARE PORCUPINES AND CHINCHILLAS.

BUT THEY ARE NAKED, APART FROM ABOUT 100 WHISKER-LIKE STRANDS,

BUT LET'S NOT SPLIT HAIRS.

THESE NOT-SO-PRETTY MAMMALS LIVE IN COLONIES OF UP TO 300.

THEY SPEND THEIR WHOLE LIVES UNDERGROUND IN NARROW TUNNELS

THAT CAN STRETCH AS FAR AS THREE MILES.

YOU'D THINK LIVING IN LIGHT-LESS TUNNEL CONDITIONS,

SOMETIMES WITH VERY LITTLE OXYGEN

WOULD ADD UP TO A SHORT LIFE SPAN,

BUT THE TUNNELS MAY BE THE REASON FOR A LONG ONE.

DR. CHRIS FAULKES FROM THE UNIVERSITY OF LONDON

HAS BEEN STUDYING THESE INCREDIBLE RODENTS

FOR MORE THAN THREE DECADES.

Faulkes: THEY LIVE AN INCREDIBLY LONG TIME FOR A SMALL RODENT.

THEY LIVE ABOUT 10 TIMES LONGER THAN A SIMILARLY SIZED MOUSE.

Narrator: A MOUSE IN CAPTIVITY LIVES ABOUT FOUR YEARS,

BUT NAKED MOLE RATS LIVE AS LONG AS 35 YEARS OR MORE.

FOR THEIR SIZE,

THEY ARE ONE OF THE LONGEST LIVING ANIMALS ON EARTH.

NAKED MOLE RATS ARE REALLY AMAZING.

THEY HAVE ALMOST SUPER HERO QUALITIES.

THE AMAZING THING IS, NOT ONLY DO THEY LIVE A LONG TIME,

BUT THEY HAVE A LONG HEALTH SPAN,

SO THEY STAY HEALTHY WELL INTO THEIR VERY OLD AGE.

THIS IS REALLY LIKE AN 80-YEAR-OLD HUMAN HAVING

THE BODY OF A 30-YEAR-OLD.

Narrator: SCIENTISTS BELIEVE THEY HAVE DISCOVERED THE REASON

THESE HARDY LITTLE RODENTS ARE ABLE TO STAY HEALTHY

AND LIVE SO LONG.

MOLE RATS PRODUCE A KIND OF QUALITY CONTROL CHEMICAL

THAT CONSTANTLY REPAIRS THEIR DNA.

IT'S SO EFFECTIVE, NAKED MOLE RATS HARDLY EVER GET CANCER.

THEIR GENES RELEASE A SUPER-SUGAR THAT KILLS OFF

MULTIPLYING CELLS AND STOPS ANY TUMORS FROM GROWING.

BUT THESE FOREVER YOUNG CREATURES AREN'T JUST IMMUNE

TO THE RAVAGES OF OLD AGE.

THEY'RE PERFECTLY ADAPTED TO THEIR HOSTILE ENVIRONMENT.

WITH SO MANY MOLE RATS LIVING IN SUCH CRAMPED CONDITIONS,

OXYGEN CAN DROP TO DANGEROUSLY LOW LEVELS

THAT WOULD TRIGGER BRAIN DAMAGE IN HUMANS

AFTER JUST THREE MINUTES.

BUT AMAZINGLY, THE MOLE RAT ALTERS ITS METABOLISM

IN A WAY NO OTHER ANIMAL CAN,

DOING SOMETHING ONLY KNOWN IN PLANTS.

IF OXYGEN IN A TUNNEL BECOMES DANGEROUSLY LOW,

THE MOLE RAT CELLS STOP USING THE OXYGEN AND METABOLIZE

A TYPE OF SUGAR, FRUCTOSE, INSTEAD.

THEN THE MOLE RAT FALLS INTO A KIND OF SUSPENDED ANIMATION.

THE HEART RATE DROPS FROM 200 BEATS PER MINUTE TO JUST 50.

AND IT CAN STAY IN THIS STATE FOR UP TO 18 MINUTES.

AS SOON AS THE MOLE RAT SNIFFS THAT THE OXYGEN IN THE TUNNEL

HAS RISEN, IT POWERS BACK UP.

[ SNAKE HISSING ]

AND THE MOLE RAT'S GOT ANOTHER SECRET TO A LONG LIFE --

SUPER-SKILLS TO EVADE PREDATORS.

AS THEY'RE SO FANTASTICALLY ADAPTED TO LIVING

IN THESE SMALL TUNNELS, A CONSEQUENCE OF THAT

SEEMS TO BE THAT THEY'VE EVOLVED THIS ABILITY

TO MOVE FORWARD AND BACKWARDS, ALMOST WITH EQUAL EASE.

Narrator: IN FACT, THE MOLE RAT IS THE ONLY ANIMAL THAT CAN RUN

AS FAST BACKWARD AS IT CAN FORWARD

AND IS BORN OUT OF NECESSITY.

Faulkes: IN THE WILD, THEIR MAIN PREDATOR IS A SNAKE.

WHILE MOST ANIMALS FACING PREY OR A THREAT

COULD PROBABLY TURN AROUND AND RUN AWAY,

IF A SNAKE GETS DOWN INTO THE TUNNEL,

THE NAKED MOLE RATS CAN ACTUALLY RETREAT AND RUN AWAY BACKWARDS.

Narrator: SO, THE SECRET TO EVERLASTING LIFE?

ACT LIKE A PLANT AND RUN BACKWARDS.

[ DUCKS QUACKING ]

COMING UP, WHY AREN'T ALL PUPILS ROUND...

...HOW BEAUTIFUL BUTTERFLY WINGS ARE BORN...

AND WHAT HAPPENS TO TINY, HALF-OUNCE BIRDS WHEN IT RAINS?

Narrator: VIRTUALLY EVERY ANIMALS ON EARTH

HAS A PAIR OF MUST-HAVE ORGANS.

EYES DO THE AMAZING JOB OF GATHERING LIGHT

TO SEE OUR WORLD.

BUT WHEN IT COMES TO THE HOLE THAT LETS LIGHT INTO THE EYE,

THE PUPIL, THAT'S WHERE EYES GO OFF THE RAILS.

THERE ARE SLITS, CRESCENT SHAPES, SOME ARE EVEN W's.

SO WHY AREN'T ALL PUPILS ROUND?

EVEN THOUGH ANIMALS USE THE SAME SUNLIGHT AND MOONLIGHT

TO SEE THE WORLD AROUND THEM, THE SHAPE OF THEIR PUPILS

DETERMINES WHAT KIND OF VIEW THEY GET.

[ SCREECHING ]

MANY MAMMALS, LIKE LIONS, DOGS, AND HUMANS, HAVE ROUND PUPILS.

THE CIRCULAR SHAPE MAXIMIZES THE AMOUNT OF LIGHT ENTERING THE EYE

AND LETS THE EYES FOCUS ON A LARGE AREA.

BUT OTHER PUPIL SHAPES ARE MORE SPECIALIZED.

ANIMALS THAT HUNT AT NIGHT, LIKE CROCODILES AND CATS,

NEED PROTECTION FROM STRONG SUNLIGHT IN THE DAYTIME.

SO, BY DAY, NOCTURNAL PREDATORS' PUPILS SHRINK

TO NARROW VERTICAL SLITS.

AS IT GETS DARKER, THE SLITS EXPAND UP TO 135 TIMES,

TO ALLOW MORE LIGHT IN, TURNING FROM THIS TO THIS.

OUR ROUND PUPILS CAN ONLY MANAGE A 15 TIMES CHANGE.

AND WHEN THEY NEED TO HUNT IN DAYLIGHT,

NARROW, VERTICAL PUPILS FOCUS

ON WHAT'S DIRECTLY IN FRONT OF THEM.

THE BLURRY OUTLINE HELPS WITH PERCEPTION OF DEPTH,

LETTING THEM CALCULATE THE EXACT DISTANCE TO THEIR PREY

BEFORE THEY POUNCE.

BUT THE STRANGEST EYES BELONG TO THE CREATURES OF THE DEEP.

GIANT SQUID HAVE THE BIGGEST EYES ON THE PLANET.

EACH IS THE SIZE OF A HUMAN HEAD.

BUT THERE'S ANOTHER UNDERWATER EYE THAT'S EVEN MORE AMAZING,

AND IT BELONGS TO THE CUTTLEFISH.

IN THE DARK, CUTTLEFISH HAVE ROUND PUPILS

TO MAXIMIZE THE AMOUNT OF LIGHT THEY CAN DETECT,

BUT WHEN THE SUN PENETRATES THE WAVES,

THE PUPIL TURNS INTO A "W."

SCIENTISTS THINK THIS W-SHAPED PUPIL

LETS CUTTLEFISH SEE CLEARLY UNDERWATER.

AS LIGHT PASSES THROUGH THE OCEAN,

IT GRADUALLY GETS ABSORBED BY WATER.

THE DEEPER YOU GO, THE DARKER IT GETS.

THIS CREATES UNEVEN LIGHT THAT MAKES IT HARD

FOR HUMAN EYES TO FOCUS

AND IS PART OF THE REASON OUR UNDERWATER VISION IS BLURRY.

BUT THE CUTTLEFISH'S PUPIL SHAPE FIXES THIS PROBLEM.

THE "W" LETS IN MORE LIGHT FROM THE DARKER AREA BELOW

AND LESS FROM THE BRIGHTER ABOVE.

THE RESULT, LIGHT GOING INTO THE EYE IS EVEN.

AND THAT TURNS A NORMALLY FUZZY VIEW OF THE OCEAN

INTO ONE WITH CRYSTAL-CLEAR DETAIL.

PROOF THAT WHEN IT COMES TO PERFECTING THE EYE,

WE HAVE SOMETHING TO LEARN.

SO, YOU COULD SAY, IN THIS LESSON, WE'RETHE PUPILS.

COMING UP, THE MIRACLE TRANSFORMATION OF NATURE'S

WINGED MASTERPIECES.

AND HOW DO TINY HUMMINGBIRDS STAY AIRBORNE IN A RAINSTORM?

Narrator: BUTTERFLIES CAN GROW AS LARGE AS A FOOTBALL,

OR AS SMALL AS A THUMBTACK.

SOME FLY SO FAST, THEY CAN OUTPACE A RACEHORSE.

MORE THAN 17,000 SPECIES OF BUTTERFLY LIVE ON

SIX CONTINENTS, AND THEY'RE ALL LIVING WORKS OF ART.

AND FOR THE FIRST TIME,

WE HAVE THE CHANCE TO SEE THE ARTIST AT WORK.

HOW ARE BUTTERFLY WINGS CREATED?

EVERY BUTTERFLY SPECIES HAS A UNIQUE

AND DISTINCTIVE WING PATTERN,

AND THESE INCREDIBLE MARKINGS ARE VITAL FOR SURVIVAL.

THE CALIGO, ALSO KNOWN AS THE OWL BUTTERFLY,

HAS FALSE EYES THAT MIMIC PYGMY OWLS.

MIMICKING A PREDATOR HELPS SCARE OFF OTHER PREDATORS,

SO SCIENTISTS KNOW THESE INCREDIBLE WING PATTERNS

ARE USEFUL.

BUT WHAT THEY HAVE STRUGGLED TO FIGURE OUT

IS HOW THE COLORS AND PATTERNS ARE CREATED.

AT THE UNIVERSITY OF CALIFORNIA IN BERKELEY,

KYLE DeMARR AND HIS TEAM

ARE USING A REVOLUTIONARY TECHNIQUE

THAT FINALLY GIVES SCIENTISTS A WINDOW INTO WING FORMATION.

LITERALLY, A WINDOW.

WE HAVE A NEW TECHNIQUE THAT ALLOWS US

TO PEER INSIDE OF THE PUPA.

Narrator: IT INVOLVES PERFORMING SOME MICROSURGERY

ON AN ANAESTHETIZED CATERPILLAR

THAT'S ABOUT TO TRANSFORM INTO A BUCKEYE BUTTERFLY.

SO, OUR TARGET HERE IS TO REMOVE WHAT WE CALL THE IMAGINAL DISC,

AND THIS IS WHAT WILL BECOME THE FOREWING OF THE BUTTERFLY.

Narrator: BY HARMLESSLY REMOVING THE IMAGINAL DISC,

A SECTION ON THE SIDE OF THE PUPA

WILL BECOME A TRANSPARENT WINDOW.

OKAY, SO NOW THAT OUR INCISION HAS BEEN MADE,

WE CAN POP HIM BACK INTO HIS CONTAINER OVER HERE.

AND HE'LL WAKE UP AND BE GOOD TO GO AND EATING

AND MUNCHING LEAVES IN AROUND 10 OR SO MINUTES.

Narrator: A DAY-AND-A-HALF LATER,

THE CATERPILLAR HAS FORMED A CHRYSALIS

AND THE WING IS VISIBLE THROUGH THE WINDOW.

AND BEHIND AN OUTER MEMBRANE,

THOUSANDS OF COLORLESS SCALES BEGIN TO GROW ACROSS IT.

ZOOMING IN, EACH SCALE IS A SINGLE LARGE CELL,

70 TIMES THINNER THAN A SHEET OF PAPER.

ALL ARE MADE OF CHITIN,

THE SAME MATERIAL FISH SCALES ARE MADE OF.

SURPRISINGLY, FOR ONE OF THE MOST COLORFUL CREATURES

ON EARTH, THESE WINGS HAVE NO COLOR AT ALL.

SO, WHAT IS GOING ON?

INCREDIBLY, WITH THE GROUNDWORK OF THE WING COMPLETE,

THE BUTTERFLY'S UNIQUE GENETIC BLUEPRINT TRIGGER COLORS

INSIDE THE CHRYSALIS.

THE THOUSANDS OF INDIVIDUAL SCALES ARRANGE THEMSELVES

LIKE PIXELS ON A TV TO FORM CIRCLES, LINES,

AND OTHER SENSATIONAL SHAPES.

BROWN, YELLOW, AND BLACK SCALES ARE COLORED

BY THE PIGMENT MELANIN,

THE SAME PIGMENT THAT GIVES OUR HAIR AND SKIN ITS COLOR.

AND AS THE WINGS FLAP, THE ANGLE OF THE SCALES CHANGE.

THIS MEANS DIFFERENT COLORS ARE REFLECTED TOWARDS US,

MAKING WINGS APPEAR TO SHIMMER AND CHANGE COLOR IN AN INSTANT.

AND THE SCALES' COMPLEX STRUCTURES

PERFORM EVEN MORE VISUAL TRICKS.

EACH SCALE IS MADE UP OF TINY LAYERS WITH AIR POCKETS

IN BETWEEN.

THE MULTIPLE LAYERS INCREASE HOW MUCH LIGHT IS REFLECTED BACK,

SUPERCHARGING THE WINGS' VIBRANCY.

THE RESULT IS A DISPLAY OF NATURAL BEAUTY,

UNLIKE ANY OTHER ANIMAL ON EARTH.

COMING UP, THE SECRET POWER OF NATURE'S TINIEST BIRD.

♪♪

Narrator: FOR THE SMALLEST BIRD IN THE WORLD,

A RAINDROP HITS LIKE A TWO-POUND LIQUID CANNONBALL.

FOR HUMMINGBIRDS, GETTING AIRBORNE WITH HUNDREDS OF DROPS

SMASHING ON TO THEM SEEMS LIKE AN IMPOSSIBLE CHALLENGE.

BUT THESE LITTLE GUYS HAVE A SECRET SKILL.

HOW DO HUMMINGBIRDS FLY IN THE RAIN?

THERE ARE MORE THAN 300 SPECIES OF HUMMINGBIRD.

SOME ARE JUST TWO INCHES TALL AND WEIGH LESS THAN A PENNY.

BUT THEY'VE GOT BIG HEARTS.

REALLY BIG HEARTS.

IN FACT, SCALED UP TO HUMAN SIZE,

THEIR TICKERS WOULD BE AS BIG AS A MELON.

THEIR HEART PUMPS BLOOD TO THEIR HUGE WING MUSCLES,

WHICH POWER THEM RIDICULOUSLY FAST AT 80 FLAPS PER SECOND.

THESE ACES CAN OUT-MANEUVER EVERY OTHER BIRD ON EARTH.

BUT TO FUEL THEIR FLYING SUPERPOWER,

HUMMINGBIRDS NEED NECTAR EVERY 10 MINUTES, OR THEY'LL PASS OUT,

AND THEY MUST KEEP FINDING FLOWERS...

[ THUNDER CRASHES ]

...EVEN IN THE FIERCEST STORM.

AT U.C. BERKELEY, AN ANNA'S HUMMINGBIRD

FROM WASHINGTON STATE IS GOING TO SHOW HOW

SHE PULLS OFF THIS INCREDIBLE FEAT.

WHEN SHE'S DRY, THIS HUMMINGBIRD WEIGHS LESS THAN HALF-AN-OUNCE.

BUT UNDER A SPRINKLER, WITH WATER CLINGING TO HER FEATHERS,

SHE NOW WEIGHS MORE THAN DOUBLE THAT.

SO, HOW'S SHE GOING TO GET AIRBORNE?

OKAY, SO, DOGS SHAKE WHEN THEY'RE WET, TOO,

BUT THE SPEED OF THE HUMMINGBIRD SHAKE

MEANS THE FORCES ACTING ON HER HEAD REACH 14 Gs.

A HUMAN WOULD PASS OUT AT 5 Gs.

SPECIAL OIL STOPS THE WATER STICKING TO HER FEATHERS

AND ALLOWS ALMOST ALL OF IT TO BE SHAKEN OFF

IN LESS THAN A SECOND.

NOW, LIGHT AGAIN, THE HUMMINGBIRD NEEDS TO FEED.

FEEDING IN THE RAIN, SHE REDUCES THE NUMBER OF RAINDROPS

SMASHING INTO HER WINGS BY USING SHORT, SHALLOW FLAPS.

BUT SHALLOW FLAPS MEAN LESS LIFT,

SO SHE INCREASES HER FLAPPING RATE 19%.

AND WHEN SHE GETS WET AGAIN, SHE DOES SOMETHING AMAZING.

THE HUMMINGBIRD MAKES THAT 14-G POWER SHAKE IN FLIGHT.

NO OTHER BIRD HAS THE AERODYNAMIC CONTROL

TO DO THIS IN MID-AIR.

SO, ALL THIS TINY FLIER HAS TO DO

IS SHAKE OFF THE EXCESS WEIGHT, AND SHE'S GOOD TO GO.