All language subtitles for 2 Secrets.Of Skin

♪♪

Garrod: SKIN --

WE ALL HAVE IT,

AND SO DOES EVERY VERTEBRATE
ON THE PLANET.

IT KEEPS THE OUTSIDE OUT

AND THE INSIDE IN.

ANIMALS MAY LOOK VERY DIFFERENT
ON THE SURFACE,

BUT WE ALL SHARE
THE SAME BASIC SKIN BLUEPRINT.

I'M BEN GARROD, PROFESSOR
OF EVOLUTIONARY BIOLOGY,

AND I'M FASCINATED BY THIS OFTEN
OVERLOOKED WONDER OF NATURE.

IT'S NOT JUST A CASE
THAT HE'S HAIRLESS.

THE SKIN'S
TOTALLY DIFFERENT.

Garrod: NOW GROUND-BREAKING
NEW SCIENCE...

THIS IS REALLY
QUITE REMARKABLE.

IT SHOULD BE A GAME CHANGER
FOR SO MANY PEOPLE.

THAT SOUND --
OH, IT MAKES THE HAIR

ON THE BACK OF YOUR NECK GO UP,
DOESN'T IT?

Garrod: ...IS REVEALING
SKIN'S MYSTERIES.

IT REALLY TRANSFORMS
OUR UNDERSTANDING OF DINOSAURS.

I'M GOING TO EXPLORE
THE NATURAL HISTORY

OF THE BODY'S LARGEST ORGAN

TO SEE HOW SKIN
HAS ALLOWED ANIMALS

TO CONQUER EVERY HABITAT,

DISAPPEAR INTO
THEIR SURROUNDINGS,

AND DEVELOP
EXTRA SENSORY ABILITIES.

WE'RE EVEN DISCOVERING
THE COMPLEX ECOSYSTEM

LIVING ON OUR SKIN.

OH, JIM, THAT'S AWFUL.

[ Laughing ]
IT REALLY IS.

Garrod: IN THIS EPISODE,
I'LL FIND OUT WHY SHARK SKIN

IS COVERED
IN THOUSANDS OF TINY TEETH...

NOW, I LOVE SHARKS, BUT I'M NOT
ABOUT TO GIVE THIS ONE A STROKE.

...HOW BIRDS HAVE ADAPTED
THEIR SKIN TO RULE THE SKY...

-OOH!
-OH.

-AND DOWN HE GOES.
-ROBOCROW IS DOWN.

...AND HOW A GECKO'S SKIN
ALLOWS IT

TO DEFY THE LAWS OF GRAVITY...

HE'S ABLE TO CLING
ONTO THIS PIECE

OF VERTICAL, SMOOTH GLASS
WITH EASE.

...AS I EXPLORE HOW ANIMALS
USE THEIR SKIN

TO MOVE THROUGH
THE WORLD AROUND THEM.

I'M GOING TO REVEAL
THE SECRETS OF SKIN.

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

CAPTIONS PAID FOR BY
DISCOVERY COMMUNICATIONS

MOVEMENT IS CRITICAL
FOR THE SURVIVAL OF ANIMALS.

FISH SWIM.

MOLES DIG.

SUGAR GLIDERS LEAP.

AND HUMMINGBIRDS HOVER.

MUSCLES AND BONES MIGHT DO
A LOT OF THE HEAVY LIFTING,

BUT IT'S ADAPTATIONS
TO THEIR SKIN

WHICH HAVE ALLOWED
THESE ANIMALS TO MOVE

IN THE WAYS THAT THEY DO.

AS WE'LL DISCOVER,

SKIN IS ESSENTIAL
FOR ALL TYPES OF MOVEMENT.

♪♪

FISH ARE SHAPED THE WAY
THEY ARE

BECAUSE THEY NEED
TO BE STREAMLINED ENOUGH

TO MOVE THROUGH THE WATER

WHILE USING THE LEAST
AMOUNT OF ENERGY.

BUT ONE GROUP OF FISH HAVE TAKEN
STREAMLINING TO THE NEXT LEVEL,

WITH A SUPER HYDRODYNAMIC
SURFACE TO THEIR SKIN.

SHARKS -- SOME OF THE MOST
FORMIDABLE HUNTERS

IN THE OCEANS.

THE MAKO SHARK HUNTS SOME OF
THE FASTEST FISH IN THE SEA,

SUCH AS TUNA AND SWORDFISH...

...SO HAS EVOLVED TO BE
INCREDIBLY QUICK,

REACHING TOP SPEEDS
OF OVER 64 KILOMETERS PER HOUR.

AND AS WITH ALL SHARKS,
THEIR SKIN PLAYS A CRUCIAL ROLE

IN HELPING THEM DO THIS.

-OKAY.
-WE GOOD?

I'M AT BLUE PLANET AQUARIUM
IN CHESTER,

WHERE I'M ABOUT TO GET
VERY CLOSE TO THESE PREDATORS.

IN THIS TANK IN FRONT OF ME,

THERE ARE FIVE DIFFERENT
SPECIES OF SHARK,

ALL OF WHICH ARE INFINITELY
MORE SUITED

TO MOVING THROUGH
THE WATER THAN I AM.

ANYONE WHO'S BEEN IN A POOL
WILL KNOW

THAT MOVING THROUGH WATER

IS A LOT HARDER
THAN MOVING THROUGH AIR.

WHEN I MOVE THROUGH THE WATER
LIKE THIS,

MY BODY IS CREATING
A HUGE AMOUNT OF RESISTANCE.

AND THIS REALLY SLOWS ME DOWN.

AND IT'S BECAUSE OF THIS
RESISTANCE

THAT I CAN'T MOVE THROUGH
THE WATER VERY FAST.

BUT SHARK SKIN IS PERFECTLY
ADAPTED

TO REDUCE THE RESISTANCE
CREATED AS THEY SWIM,

AND SO THEY CAN SLIP THROUGH
THE WATER WITH RELATIVE EASE.

NOW, I LOVE SHARKS, BUT I'M NOT
ABOUT TO GIVE THIS ONE A STROKE.

BUT IF I DID, I WOULD FEEL THAT
FROM THE HEAD

TO THE TAIL IS VERY SMOOTH.

BUT FROM THE TAIL TO THE HEAD
IS ACTUALLY VERY ROUGH.

AND THAT'S BECAUSE IF YOU LOOK
AT THE SKIN OF A SHARK

IN MICROSCOPIC DETAIL,

YOU'LL SEE THEIR SKIN ARE
EFFECTIVELY COVERED

IN MILLIONS AND MILLIONS
OF TINY TEETH.

THESE DERMAL DENTICLES GROW OUT
THROUGH THE TOP LAYER OF SKIN,

THE EPIDERMIS.

THEY ARE MADE FROM A HARD
MINERAL CALLED VITRODENTINE

ON THE OUTSIDE

AND SOFTER DENTINE
ON THE INSIDE.

IT'S INCREDIBLY SIMILAR TO
THE MATERIAL

HUMAN TEETH ARE MADE FROM.

DENTICLES FORM A REGULAR PATTERN

ALL OVER THE SKIN
OF EVERY SHARK IN THE OCEANS,

WITH EACH SPECIES HAVING
DIFFERENT-SHAPE DENTICLES

UNIQUE TO THEM.

♪♪

THESE DERMAL DENTICLES
HAVE EVOLVED TO ALLOW THE SHARKS

TO SLIP SEAMLESSLY
THROUGH THE WATER.

IT MAKES THEM MORE STREAMLINED,
AND IT REDUCES RESISTANCE.

AND THIS ALLOWS SHARKS TO SWIM
NOT ONLY FAST AND STEALTHILY,

BUT BY SAVING SO MUCH ENERGY,

THEY CAN COVER HUGE DISTANCES
ACROSS OCEANS.

ALL OF THESE THINGS HAVE HELPED
TURN SHARKS

INTO VERY EFFICIENT HUNTERS.

THESE INCREDIBLE IMAGES
ARE CT SCANS OF BABY SHARKS,

PRODUCED AT
THE NATURAL HISTORY MUSEUM

IN LONDON.

THE SHARKS IN THESE IMAGES
ARE ONLY A FEW WEEKS OLD,

BUT YOU CAN ALREADY CLEARLY SEE
THE REGULAR ARRANGEMENTS

THAT DENTICLES FORM IN THE SKIN.

DR. TOM FLETCHER
FROM LEICESTER UNIVERSITY

IS AN EXPERT
ON SHARK HYDRODYNAMICS.

I'VE SEEN SOME AMAZING SHARKS
RECENTLY,

AND ONE THING
THAT REALLY THROWS ME

IS OBVIOUSLY
THEY'RE COVERED IN DENTICLES,

BUT I DON'T FULLY GET HOW
THOSE DENTICLES HELP THEM

MOVE THROUGH THE WATER
WITH SUCH EASE.

SCIENTISTS FOR YEARS
WERE PERPLEXED

BY THE ROUGHNESS
OF THESE SHARKS

AND HOW THEY WERE MANAGING
TO REDUCE DRAG SO EFFECTIVELY.

NOT ONLY ARE THE DENTICLES
QUITE ROUGH,

BECAUSE THERE ARE
LOTS OF THEM

ALL JUTTING UP
NEXT TO EACH OTHER,

LIKE WE HAVE HERE,

BUT THEY'RE ALSO VERY ROUGH
ON THE SURFACE AS WELL.

OBVIOUSLY, THESE AREN'T
ACTUAL DENTICLES.

YOU'VE HAD THESE 3D PRINTED,

AND THEY'RE MUCH LARGER
THAN REAL LIFE, YEAH?

YES, THEY'RE ABOUT 1,000 TIMES
BIGGER THAN THEY SHOULD BE.

IF YOU LOOK AT SHARK DENTICLES
IN REAL LIFE,

THEY'RE LIKE GRAINS OF SAND.
THEY'RE ABSOLUTELY TINY.

AND WHAT WE HAVE HERE IS,
WE HAVE A SECTION OF SHARK SKIN.

THESE ARE DIFFERENT SPECIES.

THIS IS A LEOPARD SHARK,
AND WE HAVE A SINGLE ONE HERE.

THIS IS PROBABLY THE FASTEST
SHARK THAT WE'VE GOT

IN OUR OCEANS TODAY.

IT'S THE MAKO SHARK.

THESE SHOW REALLY NICELY
THE MICROSCOPIC STRUCTURES

THAT ARE REDUCING DRAG.

THE KEY ARE THESE RIBLETS HERE,
THESE PEAKS AND TROUGHS

THAT WE HAVE ON THE SURFACE.

AND THE WAY THEY WORK IS
BY REDUCING THE FRICTION

OF THE SWIRLING FLUID
ABOVE THE SURFACE.

SO IF, FOR EXAMPLE,
I'M THE SHARK HERE,

AND THE FLUID'S
MOVING OVER THE SURFACE

AND IT'S COMPLETELY SMOOTH,

THAT'S A VERY LARGE AREA
FOR FRICTION TO OCCUR.

IT'S SORT OF LIKE GOING ONTO AN
ICE RINK WITH BIG SNOWSHOES ON.

IF YOU'VE GOT BIG,
FLAT SNOWSHOES

THAT ARE NICE AND SMOOTH,

ACTUALLY, YOU'VE GOT
LOTS OF FRICTION THERE,

WHEREAS AN ICE SKATER WITH
THAT THIN BLADE OF METAL

INTERACTING WITH THE ICE,
JUST LIKE THESE RIBLETS,

THE FRICTION IS MUCH REDUCED
AND YOU CAN GO MUCH FASTER.

Garrod: IN FACT, SHARK DENTICLES
ARE SO GOOD AT THEIR JOB,

THEY'RE INSPIRING A WHOLE HOST
OF NEW TECHNOLOGIES.

PEOPLE HAVE BEEN VERY INTERESTED
IN REDUCING DRAG BY 10%,

THAT'S REALLY, REALLY ENORMOUS,
AND IT CAN SAVE A LOT OF ENERGY.

IN AIRCRAFT, FOR EXAMPLE,
THEY'VE TINKERED WITH THIS,

THE UNDERSIDE OF BOATS
AS WELL.

IF YOU NEED TO MOVE A FLUID
ACROSS A SOLID SURFACE,

THEN THIS COULD POTENTIALLY
REALLY HELP.

GOOD OLD SHARKS.

Garrod:
IF YOU LOOK CLOSE ENOUGH,

YOU'LL FIND A HIDDEN
MICROSCOPIC WORLD

ON THE SURFACE
OF THE SKIN OF MANY ANIMALS,

HELPING THEM MOVE IN WAYS
WHICH OFTEN APPEAR IMPOSSIBLE.

LIKE SHARKS,

GECKOS USE THEIR SKIN
TO HELP THEM HUNT PREY.

HOWEVER, WHEN YOUR FOOD
IS AN INSECT

WHICH COULD
LAND VIRTUALLY ANYWHERE,

IT'S NOT JUST SPEED
THAT YOU NEED,

BUT ALSO THE ABILITY TO CLIMB.

AS GECKOS GO, THIS TOKAY GECKO
IS PRETTY HEAVY.

BUT STILL, HE'S ABLE TO CLING
ONTO THIS PIECE

OF VERTICAL, SMOOTH GLASS
WITH EASE.

AND AS HE SPINS AROUND,

WE'RE ABLE TO SEE
JUST HOW HE MANAGES TO DO THIS.

YOU MIGHT THINK THE SURFACE
OF GLASS IS TOTALLY SMOOTH,

BUT LIKE ALL MATERIALS,

IT'S COVERED
IN MICROSCOPIC IMPERFECTIONS.

AND THE SKIN ON A GECKO'S TOES

IS ABLE TO MAKE USE
OF THESE IMPERFECTIONS

AND STICK TO THE GLASS.

THIS IS DOWN TO
A PHYSICAL PROPERTY

CALLED VAN DER WAALS FORCE.

NAMED AFTER THE 18th CENTURY
DUTCH PHYSICIST,

IT'S A WEAK
ELECTRICAL ATTRACTION

THAT EXISTS BETWEEN
ALL MOLECULES

IF THEY GET CLOSE ENOUGH
TO EACH OTHER.

IF I WERE TO PLACE MY HAND
ON THE GLASS,

THERE ARE SO MANY RIDGES,

LUMPS, AND BUMPS,
THINGS LIKE FINGERPRINTS,

THAT THERE ISN'T ENOUGH
SURFACE AREA FOR ME

TO BE ABLE TO USE
VAN DER WAALS FORCE

TO STICK TO THE GLASS.

HOWEVER, GECKO TOES HAVE
A REMARKABLE MICRO STRUCTURE.

OUT OF THE EPIDERMIS

PROTRUDE HUNDREDS OF THOUSANDS
OF TINY FILAMENTS

MADE OF A PROTEIN
CALLED KERATIN,

THE SAME STUFF THAT MAKES
OUR HAIR AND NAILS.

THESE KERATIN FILAMENTS
ARE SO SMALL

THAT FAR MORE OF THE MOLECULES
ON THE GECKO'S TOE

COME INTO CONTACT
WITH THE MOLECULES ON THE GLASS.

THIS ALLOWS THE GECKO TO USE
VAN DER WAALS FORCE

AND ENABLES IT TO CLING ONTO
AND MOVE

UP VERTICAL SURFACES.

♪♪

FOR ANY ANIMAL TO MOVE,
THEIR SKIN NEEDS TO BE FLEXIBLE.

AND ONE SUBTERRANEAN RODENT

HAS TAKEN THIS FLEXIBILITY
TO AN EXTREME.

THE MOST INTRIGUING ANIMAL
WITH THE STRANGEST SKIN I KNOW,

LIVES IN AFRICA, UNDERGROUND,
AND IS RARELY SEEN.

NAKED MOLE RATS --

THEY'RE ALMOST BLIND
AND VIRTUALLY HAIRLESS.

AND UNTIL RELATIVELY RECENTLY,

THESE STRANGE ANIMALS
WERE A TOTAL ENIGMA TO SCIENCE.

HI, CHRIS.
-HI, BEN. HOW ARE YOU DOING?

-LOOK AT THESE LITTLE GUYS.
-YEAH.

DR. CHRIS FAULKES HAS ONE
OF THE LARGEST CAPTIVE COLONIES

OF NAKED MOLE RATS IN THE WORLD.

IT'S NOT JUST A CASE THAT
THIS LITTLE RODENT IS HAIRLESS.

THE SKIN'S TOTALLY DIFFERENT.
IT'S REALLY BAGGY.

WHY ARE THEY SO LOOSE?

HOW DOES IT HELP THEM MOVE,
FOR EXAMPLE?

WELL, WE THINK THAT IT HELPS
THEM TO PASS EACH OTHER

IN VERY TIGHT SITUATIONS.

SOMETIMES YOU GET
A TRAFFIC JAM

WITH SEVERAL ALL TRYING
TO GET PAST EACH OTHER

AND THAT LOOSE SKIN
HELPS THERE.

Garrod:
ONE THEORY IS THAT

ALMOST LIKE BEING
IN A SLEEPING BAG,

THE NAKED MOLE RATS' LOOSE SKIN

HELPS THEM WRIGGLE 'ROUND
MUCH MORE EASILY IN TUNNELS,

WHERE THERE'S VERY LITTLE ROOM
FOR MANEUVER.

IT ALSO HELPS TO HAVE LOOSE SKIN

WHEN YOU'RE LIVING WITH
THIS MANY FAMILY MEMBERS.

IN THE WILD, THEY CAN LIVE
IN SOCIAL GROUPS

OF UP TO 300 SOMETIMES.

YET, THERE'S ONLY ONE FEMALE
THAT BREEDS, THE QUEEN,

AND THE REST ACT AS EITHER
DEFENDERS OR HELPERS.

SO IT'S A BIT LIKE THE MAMMAL
EQUIVALENT OF A SOCIAL INSECT.

CRAWLING THROUGH THESE SMALL
SPACES MEANS CONSTANTLY BUMPING

OR SCRATCHING YOURSELF
ON SHARP ROCKS IN THE EARTH.

BUT NAKED MOLE RATS FEEL
LESS PAIN THAN OTHER RODENTS.

EVOLUTIONARY CHANGES TO
THE PAIN RECEPTORS IN THEIR SKIN

MEANS THAT FEWER PAIN SIGNALS
ARE SENT TO THEIR BRAIN,

MAKING THEM PERFECTLY SUITED
TO THEIR UNDERGROUND LIFE.

REMARKABLY, THEY LIVE INCREDIBLY
LONG FOR A SMALL RODENT,

OVER 30 YEARS.

34 YEARS IS THE RECORD
AT THE MOMENT.

SO IF YOU THINK OF
A SIMILARLY SIZED MOUSE,

THAT LIVES FOR ABOUT
THREE YEARS,

SO MORE THAN 10 TIMES
LONGER THAN A MOUSE.

THEY RESIST ALL OF
THE NORMAL SIGNS OF AGING.

AND THAT'S NOT EVEN
THE MOST REMARKABLE THING

ABOUT THEIR PHYSIOLOGY.

THEY ALSO RESIST
GETTING CANCER.

SO PROBABLY LESS THAN
0.3% INCIDENTS OF CANCER

COMPARED TO,
IN SOME MOUSE STRAINS,

UP TO 90% DEVELOP CANCER.

SCIENTISTS BELIEVE
THIS INCREDIBLE ABILITY

TO RESIST CANCER

COULD BE TO DO WITH
A COMPOUND FOUND IN THEIR SKIN.

THERE'S A COMPONENT IN THE SKIN
CALLED HYALURONAN,

OR HYALURONIC ACID,
WHICH ALL MAMMALS HAVE.

WE HAVE IT.

IT'S OFTEN PRESENT IN SKIN
CREAMS AND BEAUTY PRODUCTS.

NOW, NAKED MOLE RATS HAVE
A UNIQUE KIND OF HYALURONAN

IN TERMS OF SIZE
AND ITS MOLECULAR STRUCTURE.

HYALURONIC ACID IS A COMPONENT
OF THE CONNECTIVE TISSUES

WHICH FORM THE STRUCTURE
OF SKIN AND OTHER ORGANS.

AND NAKED MOLE RATS HAVE
A UNIQUE FORM OF HYALURONIC ACID

WITH A COILED MOLECULAR SHAPE.

THIS MAKES THE MOLECULE ACT
ALMOST LIKE A SPRING.

THIS GIVES THE NAKED MOLE RATS
THEIR STRETCHY SKIN

AND MIGHT BE A KEY FACTOR IN
THEIR ABILITY TO RESIST CANCER.

BUT RESEARCH INTO THIS
IS STILL AT AN EARLY STAGE.

WHETHER YOU THINK
THEY'RE UGLY OR CUTE,

WHAT'S NOT UP FOR DEBATE

IS THAT THESE SAGGY-SKINNED
MEMBERS OF THE RODENT FAMILY

ARE HELPING US UNDERSTAND

AND TACKLE SOME OF OUR
MOST DEVASTATING DISEASES.

LIFE IN CHALLENGING ENVIRONMENTS
IS OFTEN ONLY POSSIBLE

BECAUSE OF SKIN'S
INCREDIBLE VERSATILITY.

♪♪

ONE LEADING THEORY SUGGESTS
THAT A SUBTERRANEAN EXISTENCE

DROVE ONE PARTICULAR GROUP
OF ANIMALS

TO EVEN MORE
EXTREME ADAPTATIONS.

GO BACK 150 MILLION YEARS,

AND THE ANCESTORS OF SNAKES
LIVED UNDERGROUND

BUT HAD FOUR LEGS.

BUT THESE LIMBS WOULD HAVE
JUST GOT IN THE WAY,

SO OVER TIME,
THE SNAKES LOST THEM

AND EVOLVED TO PROPEL THEMSELVES
ALONG ON THEIR BELLIES.

BUT NOW, WITH THE MAJORITY OF
SNAKES LIVING ABOVE GROUND,

THERE'S ONE QUESTION
THAT HAS PUZZLED SCIENTISTS.

HOW ARE SNAKES ABLE TO GET
ACROSS FLAT SURFACES

WITHOUT LIMBS?

THE SECRET TO HOW THIS SNAKE
IS ABLE TO MOVE

LIES IN THE SPECIALLY ADAPTED
SCALES

ON THE UNDERSIDE
OF HER BELLY THERE.

[ CHUCKLES ]

AND WHILE THEY MAY LOOK VERY
SMOOTH, THEY'RE ACTUALLY

ABLE TO GENERATE
A LARGE AMOUNT OF FRICTION.

EACH BELLY SCALE IS MADE
OF KERATIN

AND POPULATED WITH
MICROSCOPIC PROTRUSIONS.

THE SNAKE CAN GRIP THE GROUND
WITH ITS BELLY SCALES

BY USING THESE PROTRUSIONS
TO CATCH ON ANY IMPERFECTIONS

ON THE SURFACE.

IT IS THEN ABLE TO PULL OTHER
PARTS OF ITS BODY FORWARD.

THE ARRANGEMENT OF THESE
TINY PROTRUSIONS IS KEY.

THEY'RE POSITIONED SO THAT WHEN
THE BELLY SCALES SLIDE FORWARD

OVER THE GROUND,
THEY DO SO SMOOTHLY.

IN ONE DIRECTION,
THE SCALE SLIPS.

IN THE OTHER DIRECTION,
IT GRIPS,

ALLOWING SNAKES TO MOVE
EFFORTLESSLY

THROUGH A RANGE OF HABITATS,

TACKLING VIRTUALLY ANY SURFACE
THEY COME ACROSS.

♪♪

THROUGHOUT EVOLUTION,

SKIN HAS USED KERATIN
IN A VARIETY OF INGENIOUS WAYS.

IT'S THE MAIN COMPONENT
OF NAILS, SCALES, AND HAIR.

BUT NONE OF THESE ARE AS COMPLEX

AS ITS REAL
CROWNING ACHIEVEMENT.

FEATHERS --

THEY GROW IN A SIMILAR WAY
TO OUR HAIR.

A SHAFT MADE OF KERATIN GROWS
OUT OF FOLLICLES IN THE SKIN,

BUT THAT'S WHERE
THE SIMILARITY ENDS.

AS THE SHAFT EMERGES FROM THE
FOLLICLE,

BRANCHED KERATIN FILAMENTS
OPEN OUT,

FORMING A FLAT SURFACE
KNOWN AS THE VEIN.

THERE ARE DIFFERENT TYPES
OF FEATHERS,

WHICH COME IN ALL SHAPES
AND SIZES.

AND IT'S THE FLIGHT FEATHERS

THAT BIRDS GROW
FROM THE SKIN ON THEIR WINGS

WHICH ENABLE THEM
TO TAKE OFF AND STAY IN THE AIR.

I'VE COME TO THE INTERNATIONAL
CENTRE FOR BIRDS OF PREY

IN GLOUCESTERSHIRE TO SEE SOME
REALLY IMPRESSIVE FLYERS.

THIS IS
A STELLER'S SEA EAGLE.

HE'S GOT
A TWO-METER WINGSPAN,

AND HE'S ONE OF THE HEAVIEST
EAGLES ON THE PLANET.

AND HE CAN DIVE FROM A PERCH
TO CATCH HIS PREY,

OR HE CAN SOAR
USING THOSE MASSIVE WINGS

TO LOOK FOR HIS NEXT MEAL.

HE'S GOT HUGE FLIGHT FEATHERS,
AND EACH ONE IS LIGHTWEIGHT,

STIFF, BUT IMPORTANTLY,
REALLY, REALLY STRONG.

Garrod: IN FLIGHT,
THE SHAPE OF A BIRD'S WING

MEANS THE AIR PRESSURE
UNDER THE WING

IS GREATER THAN THAT ABOVE.

AND IT'S THIS DIFFERENCE
IN PRESSURE

WHICH KEEPS THEM IN THE AIR.

BUT THIS IS ONLY POSSIBLE

BECAUSE OF THE WAY
THEIR FLIGHT FEATHERS WORK.

AND IF YOU TAKE ONE OF THESE
FEATHERS AND HAVE A LOOK,

YOU CAN ACTUALLY SEE
THAT ON ONE SIDE,

THERE'S JUST MORE FEATHER.

AND IT'S THIS ASYMMETRY
THAT ALLOWS HIM TO BE

SUCH AN AMAZING FLYER.

ON FLIGHT FEATHERS, ONE SIDE
OF THIS KERATIN VEIN IS LARGER.

AS A BIRD FLIES,
THIS LARGER PART OF THE VEIN

CATCHES THE AIR,
ROTATING THE FEATHERS SLIGHTLY.

THIS TWISTS THE FEATHERS
SO THEY INTERLOCK.

THIS THEN STOPS AIR PASSING
THROUGH THEM,

AND IT'S THIS THAT GIVES
THE WING LIFT AND THRUST.

THIS INTERLOCKING MEANS
THAT TOGETHER,

ALL THE FEATHERS IN THE WING
FORM A LARGE SURFACE AREA,

IMPERMEABLE TO THE AIR,

MEANING THE HIGHER PRESSURE
UNDERNEATH KEEPS THE BIRD ALOFT.

ANOTHER TYPE OF FEATHER
COMMON TO ALL BIRDS

IS THE CONTOUR FEATHER.

UNLIKE FLIGHT FEATHERS,
THE VEIN ON CONTOUR FEATHERS

IS PRETTY SYMMETRICAL.

THESE FEATHERS COVER THE TORSO,

GIVING THE BIRD
ITS AERODYNAMIC SHAPE.

FLIGHT FEATHERS
AND CONTOUR FEATHERS

SHARE AN AMAZING
MICRO STRUCTURE.

THE VEINS' FILAMENTS HAVE
INTERLOCKING BARBS

WHICH MESH TOGETHER TO FORM
AN EFFECTIVE SURFACE

FOR THE AIR TO SLIP OVER.

THIS ALLOWS CONTOUR FEATHERS
TO CREATE A STREAMLINED SHAPE

AROUND THE BIRD'S BODY.

AND THERE'S ONE GROUP
OF BIRDS OF PREY

WHICH TAKE FULL ADVANTAGE
OF THIS AERODYNAMIC FEATURE.

WHEN THEY HUNT, SOME FALCONS

CAN REACH AN ASTONISHING
320 KILOMETERS PER HOUR.

AND I'M GOING TO SEE
ONE OF THEM IN ACTION.

JEMIMA, THIS IS
A BEAUTIFUL BIRD,

AND I'VE SEEN THESE
IN THE WILD.

THIS IS A GYRFALCON, ISN'T IT?THAT'S RIGHT.

THESE ARE BUILT FOR SPEED
AND BUILT TO KILL, RIGHT?

THEY ARE. THEY'VE GOT THESE
LOVELY LONG, POINTED WINGS,

AS HAVE ALL THE FALCONS.

AND WE HAVE A SPECIAL WAY
TO SHOW YOU

HOW THIS THING DOES FLY.

SO WE'VE GONE MODERN,

AND WE HAVE A ROBOTIC CROW,
THE ROCROW.

SO WE'RE GONNA CHUCK UP A ROBOT,
GET IT TO FLY,

AND SEE IF THIS BEAUTIFUL BEAST
CAN TAKE IT DOWN?

THAT'S WHAT
WE'RE GONNA DO.

BRILLIANT.
I WANT TO SEE THIS.

♪♪

Garrod:
JEMIMA USES THIS TECHNIQUE

TO TRAIN MANY OF HER FALCONS.

THESE BIRDS TYPICALLY HUNT

AT A HEIGHT OF AROUND
300 METERS,

PERFECT FOR SWOOPING DOWN
ON THEIR PREY.

SO HE'LL HAVE TO CLIMB NOW,
I GUESS,

TO GET ABOVE THE ROBOT,
WON'T HE?

HE HAS TO CLIMB, AND THAT'S
WHAT HE'S GOT TO LEARN.

HE'S QUITE YOUNG AND NOT,
AS YET, VERY FIT,

AND IT'S A WINDY DAY
FOR HIM.

Garrod: FALCONS DIVE AT
THEIR PREY LIKE BULLETS,

OFTEN STUNNING OR EVEN
KILLING THEM IN MID-AIR.

DURING THIS DIVE,
THEIR POINTED WINGS

AND THE INTERLOCKING BARBS
ON THEIR FEATHERS

MAKES THIS FAMILY OF BIRDS

AMONG THE FASTEST ANIMALS
ON THE PLANET.

THE ROBOCROW DOESN'T
STAND A CHANCE.

Garrod: YOU CAN SEE
THOSE BIG, LONG FLAPS

FOLLOWED BY SOME REALLY QUICK,
THRUSTING BEATS THERE.

YEAH.

HE'S JUST TRYING
TO GET SOME SPEED.

AND HE DOESN'T STOP
EITHER.

WHOA!
-OOH, OOH, OOH!

GOOD BOY! OH!

HE JUST HIT --
OH, AND ROBOCROW'S DOWN.

AND DOWN HE GOES.
GOOD BOY.

AND THIS IS WHAT THEY USE
TO HUNT IN THE WILD.

WE SAW DIFFERENT TYPES
OF FLIGHT THERE,

AND THAT LAST-SECOND HIT,
USING THE FEATHERS,

USING THE WING SHAPE TO REALLY
BRING ALL THOSE THINGS TOGETHER

AND TAKE DOWN ITS PREY.

WELL, I'M ALWAYS HAPPY
WHEN NATURE TRASHES A ROBOT,

SO THAT WAS GREAT.

Garrod: FROM THE GROWTH OF
SMALL KERATIN PROTRUSIONS,

IT'S THEIR SKIN WHICH HAS
ENABLED BIRDS TO SOAR,

HOVER, DIVE, AND GLIDE THEIR WAY

TO DOMINATING THE SKIES.

BUT WITHOUT FEATHERS,
HOW DO YOU GET INTO THE AIR?

LIVING IN THE RAINFORESTS
OF AUSTRALIA AND INDONESIA,

SUGAR GLIDERS SPEND THEIR TIME
IN THE TREETOPS,

GLIDING BETWEEN BRANCHES.

THESE MARSUPIALS USE WINGS
MADE OF FLAPS OF SKIN

TO HARNESS THE POWER
OF THE AIR,

ALLOWING THEM TO GLIDE
UP TO 50 METERS.

BUT HOW THEY MANAGE TO STAY
AIRBORNE FOR THIS DISTANCE

HAS REMAINED A MYSTERY.

TODAY, THIS WILL BE TESTED
FOR THE FIRST TIME

BY DR. JORN CHENEY, A SPECIALIST
IN ANIMAL FLIGHT ADAPTATIONS.

HEY, JORN.HEY, BEN, NICE TO SEE YOU.

YEAH, YOU TOO.
WHO HAVE YOU GOT HERE?

THIS IS CHLOE.

I'VE NEVER SEEN A LIVE
SUGAR GLIDER BEFORE.

HELLO.

I'M ABSOLUTELY FASCINATED
BY THE STRUCTURE OF THEIR SKIN

BECAUSE THEY MOVE
THROUGH THE AIR,

BUT THEY DON'T FLY
IN A TRADITIONAL SENSE, DO THEY?

NO, NO, THEY'RE MORE GLIDERS
THAN FLYERS.

AND TRADITIONALLY, WE THINK
OF FLYING AS ANIMALS

THAT FLAP THEIR WINGS AND POWER
THEMSELVES THROUGH THE AIR.

GLIDERS MOSTLY GO DOWN
AND THEN SIDEWAYS.

IT'S SUPER WEIRD, BECAUSE
THAT'S NOT HOW WE FLY.

WE DON'T SEE BIRDS
FLY THAT WAY.

WE DON'T BUILD AIRCRAFTS
THAT WAY.

AND SO I'M INTERESTED IN WHY
SHE'S ABLE TO FLY SO WELL

WITH SUCH AN UNUSUAL SHAPE.

Garrod:
FOR THIS EXPERIMENT,

WE'RE AT THE SPECIALIST
FLIGHT RESEARCH CENTER

AT THE ROYAL VETERINARY COLLEGE
IN HERTFORDSHIRE.

-I'LL RELIEVE HER FROM YOU.
-THANK YOU.

CHLOE HAS BEEN HAND-REARED,
AND HER HANDLER, SIMON,

IS GOING TO HELP
WITH THE EXPERIMENT.

SO CHLOE'S GOING TO START
ON THAT PLATFORM UP THERE.

SHE'S GONNA USE THAT
AS A LAUNCH PLATFORM,

AND SIMON'S GONNA HOLD THAT
AND COAX HER OFF

TO JUMP OVER TO YOU,
JUST LIKE THAT,

WHERE YOU'LL BE
STANDING OVER THERE.

JORN HAS SET UP FOUR
ULTRA-HIGH-SPEED CAMERAS

TO RECORD CHLOE'S GLIDING.

CHLOE TAKES HER PLACE
ON THE LAUNCHPAD,

AND I DO MY BEST
TO IMPERSONATE A TREE.

Simon:
[ SMOOCHING ]

OOH, OOH, OOH, OOH, OOH.
SHE'S THINKING ABOUT IT.

OOH, OOH.

[ LAUGHS ]

PERFECT.
[ LAUGHS ]

Garrod: CHLOE GETS INTO
THE SWING OF THINGS IMMEDIATELY.

COME ON, THEN.

ALTHOUGH HER AIM NEEDS
A LITTLE WORK.

[ LAUGHS ]

THIS IS ONE OF
THE WEIRDER EXPERIMENTS

I'VE EVER DONE,
I'M NOT GONNA LIE.

OH! [ LAUGHS ]

I LOVE THAT WE'RE ACTUALLY
DOING SCIENCE

WHILST TRYING TO CATCH
A SUGAR GLIDER.

THIS IS BRILLIANT.

Garrod: IT'S THE SHAPE THAT
CHLOE'S FLEXIBLE SKIN WINGS

TAKE IN THE AIR
THAT WILL TELL JORN

A LOT ABOUT
HOW SHE'S USING THEM.

WELL DONE, LITTLE ONE.

AND IN ORDER TO SEE THIS,

HE'S CREATED A 3D MODEL OF
CHLOE'S WINGS WITH HIS CAMERAS.

WHAT HAVE THE RESULTS
SHOWN?

SO THAT BEAUTIFUL THING
IS CHLOE,

JUST THE TOP SURFACE
OF HER.

YEP.

WHAT YOU'RE ABLE TO PICK UP
FROM THIS

IS THE FULL 3D SHAPE THAT
SHE'S USING WHEN SHE GLIDES.

AND THAT'S IMPORTANT BECAUSE
THE AERODYNAMICS

ARE ENTIRELY DETERMINED
BY THE SHAPE.

BUT ALSO, SHE'S NOT FLAT.
SHE'S CURVED.

YEAH, SHE'S GOT
A LOT OF CURVATURE.

Garrod: JORN HAS WORKED OUT THAT
CHLOE'S WINGS CURVED,

OR BILLOWED,
BY A SURPRISING AMOUNT,

OVER THREE TIMES MORE THAN
THE WINGS OF A GLIDING BIRD.

ALL OF THAT BILLOWING HELPS
GUIDE THE AIR DOWNWARD

AND BACKWARD, PRODUCING LIFT.

THE MORE BILLOWING YOU GET,

THE MORE AERODYNAMIC FORCE
YOU'RE PRODUCING.

SO IF THE WING WASN'T
BILLOWING LIKE THAT,

SHE'D BE
A MUCH WORSE FLYER.

WHAT'S ALSO CLEAR IS THAT CHLOE
IS CONTROLLING THIS BILLOWING.

THE MUSCLES IN THE MIDDLE
OF THE SKIN FLAPS ARE RELAXED,

WHILE THE MUSCLES AROUND
THE EDGE HAVE BEEN TENSED.

Garrod:
SO THIS FLEXIBLE SKIN --

WE DEFINITELY DON'T SEE THAT
WITH BIRDS, DO WE?

WE DON'T SEE IT WITH BIRDS,
BUT WE DO SEE IT

WITH EVERY OTHER
GLIDING MAMMALIAN LINEAGE.

ALL HAVE,
FOR WHATEVER REASON,

CONVERGED UPON THE IDEA
OF USING SKIN AS A WING

AND THEN EMBEDDING MUSCLE
INTO IT.

AND WE'RE ABLE TO FIGURE OUT
THAT THE MUSCLE

ISN'T THE ONLY THING
SUPPORTING THE BODY WEIGHT.

THE SKIN IS ACTUALLY
DOING QUITE A BIT.

Garrod:
THERE'S STILL A LOT MORE WORK
TO DO TO REALLY UNDERSTAND

WHAT IS GOING ON WITH
GLIDING ANIMALS LIKE CHLOE.

BUT ONE DAY, JORN IS HOPING
EXPERIMENTS LIKE THIS

COULD PAVE THE WAY
FOR NEW AIRCRAFT TECHNOLOGY

USING FLEXIBLE MATERIAL
FOR WINGS.

SKIN'S ADAPTABILITY
IS UNPARALLELED.

ANIMALS HAVE USED THEIR SKIN
TO MASTER MOVEMENT

ON EVERY SURFACE, PATCH OF SKY,
AND BODY OF WATER ON EARTH.

[ SPLASHING ]

♪♪

♪♪

♪♪