Original subtitles

Narrator: BEFORE HUMANS RULED THE WORLD,

PLANET EARTH WAS A LAND OF GIANTS.

SNAKES THE LENGTH OF BUSES.

Man: I AM STILL, TO THIS DAY,

COMPLETELY AMAZED BY THIS ANIMAL.

Narrator: OCEAN KILLERS WITH JAWS

BIG ENOUGH TO SWALLOW A PERSON WHOLE.

Man: THESE JAWS WERE ABLE TO RIP OUT THIS BIG CHUNK OF CAR.

Narrator: AND PREDATORS THAT DWARF T. REX.

Man: WE'RE TALKING SOMETHING OF ENORMOUS LENGTH,

THAT COULD SLICE YOU WITH ONE MOTION.

Narrator: BUT OF ALL THE MONSTERS THAT HAVE EVER LIVED,

WHICH IS THE BIGGEST?

USING THE LATEST DISCOVERIES AND CUTTING-EDGE SCIENCE,

WE'RE GOING TO REVEAL A TOP 10 OF THE BIGGEST BEASTS EVER,

THAT HAVE WALKED THE EARTH,

SWUM THE SEAS,

AND SOARED THE SKIES.

Man: THIS IS AWESOME!

[GROWLING]

Narrator: ANALYZING THE ULTIMATE GIANT BEASTS

ACROSS THE ANIMAL KINGDOM, SPECIES BY SPECIES,

AND USING LENGTH AS OUR ULTIMATE GUIDE,

WE COUNT DOWN FROM 10.

AND FIRST ON OUR LIST IS A CREATURE YOU'D NEVER EXPECT,

A TERRIFYING BEAST,

THE BIGGEST INSECT THAT EVER LIVED.

♪

LONG BEFORE THE DINOSAURS,

A WINGED GIANT TERRORIZED THE SKIES.

♪

FLYING AT OVER 20 MILES PER HOUR

AND WITH JAWS THAT COULD CUT SMALL REPTILES TO PIECES,

ITS COMMON NAME IS... THE GRIFFINFLY.

A CLUE TO THIS ANCIENT MEGA-BUG

WAS DISCOVERED IN 1940 IN NOBLE COUNTY, OKLAHOMA.

TODAY, IT'S THE JOB OF INSECT EXPERT BRIAN FARRELL

TO TAKE CARE OF THAT CLUE,

A FRAGILE FOSSIL THAT'S 275 MILLION YEARS OLD.

Brian Farrell: THIS REALLY IS A SPECTACULAR FOSSIL.

Narrator: THIS FOSSIL IS

THE LARGEST INSECT WING EVER DISCOVERED.

Farrell: TO GET AN IDEA OF JUST HOW BIG THIS INSECT WAS,

THIS IS A REASONABLY LARGE-SIZED MODERN DRAGONFLY FOR COMPARISON.

IT'S ABOUT ONE FIFTH THE SIZE, AT MOST, OF THIS MEGANEUROPSIS.

Narrator: LOOKING AT THIS SINGLE WING,

IT'S CLEAR JUST HOW BIG THE GRIFFINFLY COULD GET.

♪

♪

IT HAD FOUR WINGS,

THE BIGGEST PAIR SPANNING TWO AND A HALF FEET ACROSS.

THAT MAKES IT SIX TIMES LARGER THAN MANY MODERN DRAGONFLIES.

IF IT WAS AROUND TODAY, IT WOULD BE A MATCH FOR A HAWK

AND SPAN THE OUTSTRETCHED ARM OF A SIX-FOOT MAN.

FROM SMALLER BUT MORE COMPLETE FOSSILS,

EXPERTS HAVE DISCOVERED THAT GRIFFINFLIES DIDN'T MERELY

LOOK LIKE TODAY'S DRAGONFLIES,

THEIR ANATOMY WAS INCREDIBLY SIMILAR,

SO IT'S LIKELY THEY BEHAVED THE SAME WAY, TOO--

AS DEADLY HUNTERS.

Hans-Dieter Sues: GRIFFINFLIES PROBABLY WOULD HAVE BEEN

AT THE TOP OF AT LEAST THE INSECT FOOD CHAIN,

AND AS THERE WEREN'T ANY REALLY LARGE VERTEBRATES AROUND,

THEY MAY HAVE BEEN ACTUALLY

THE TOP PREDATOR ON LAND, PERIOD.

Narrator: ANTHONY LEONARDO IS A WORLD EXPERT

IN DRAGONFLY FLIGHT.

HE'S UNLOCKING THE SECRETS

OF WHAT MAKES THESE FLYING ACES SUCH EXPERT KILLER BEASTS.

THEY HAVE FOUR WINGS THAT CAN BEAT INDEPENDENTLY.

Anthony Leonardo: IF YOU LOOK AT THE WINGS CLOSELY,

YOU CAN SEE THAT THEY'RE QUITE AMAZING.

THE DRAGONFLY CAN FLY FORWARDS, BACKWARDS, UPSIDE DOWN.

IT CAN ALSO PULL THESE INCREDIBLY SHARP 6-G TURNS.

Narrator: THEY ALSO HAVE EYES

WITH VIRTUALLY 360-DEGREE VISION,

POWERFUL LEGS FOR GRABBING INSECT PREY,

AND KILLER JAWS.

Leonardo: THEY HAVE THESE MASSIVE MANDIBLES

AND THESE KIND OF PINCHING CRUNCHERS,

AND THEY VERY QUICKLY CUT AND SLICE ALL THIS PREY

UP INTO LITTLE BITS THAT THE ANIMAL THEN SWALLOWS.

Narrator: BUT HOW DID THE GRIFFINFLY GET SO BIG,

AND WHY ARE MODERN DRAGONFLIES SO MUCH SMALLER?

THE ANSWER LIES IN THE WAY ALL INSECTS BREATHE.

Leonardo: INSECTS DON'T HAVE LUNGS.

ON THE OUTSIDE OF THE DRAGONFLY'S BODY

ARE LITTLE OPENINGS CALLED SPIRACLES,

AND THESE ARE LITTLE HOLES THAT OPEN AND CLOSE,

AND THEY BASICALLY ARE LITTLE PUMPS

LETTING AIR INTO THE DRAGONFLY'S BODY

AND THEN PUSHING IT BACK OUT.

Narrator: ONCE THROUGH THE SPIRACLES,

THE AIR MOVES THROUGH A NETWORK OF TUBES CALLED TRACHEA.

THIS WAY, OXYGEN IS FED DIRECTLY

TO EVERY SINGLE CELL OF THE BODY.

THE PROBLEM IS THERE ARE SO MANY TUBES,

THERE'S LITTLE ROOM LEFT

FOR THE EXTRA MUSCLE NEEDED TO MOVE A BIGGER BODY.

AND THAT'S WHAT PREVENTS TODAY'S DRAGONFLIES

FROM GETTING ANY LARGER.

SO, HOW DID THEY EVER REACH

THE MONSTROUS SIZE OF THE GRIFFINFLY?

HOW DID THEY PACK ENOUGH MUSCLE INTO THEIR BODIES

TO POWER GIANT WINGS?

ONE PALEOBIOLOGIST AT MIDWESTERN UNIVERSITY, JOHN VANDENBROOKS,

BELIEVES HE HAS THE ANSWER.

HE'S DOING EXPERIMENTS TO UNCOVER THE SECRETS

TO WHAT MAKES A BIGGER BUG.

♪

JOHN THINKS THAT GROWING BIGGER

WAS ALL DOWN TO THE AMOUNT OF OXYGEN IN THE AIR THEY BREATHED.

John Vandenbrooks: OXYGEN WAS MUCH HIGHER IN THE PAST.

TODAY OXYGEN'S ABOUT 21 PERCENT OF THE ATMOSPHERE AROUND YOU.

IN THE PAST, IT WAS AS HIGH AS 31 PERCENT.

Narrator: AN EXTRA 10 PERCENT MIGHT NOT SOUND LIKE MUCH,

BUT THAT'S 50 PERCENT MORE OXYGEN THAN WE BREATHE TODAY.

Vandenbrooks: SO, PERHAPS THAT INCREASE

IN OXYGEN IN THE ATMOSPHERE IS WHAT LED TO THE POSSIBILITY

THAT THOSE INSECTS GET AS LARGE AS THEY DID.

Narrator: TO INVESTIGATE,

JOHN DECIDED TO DO SOMETHING RADICAL--

CHANGE THE OXYGEN THE BUGS COULD BREATHE.

FIRST, HE TAKES COCKROACHES

AND BREEDS THEM AT FAR LOWER LEVELS OF OXYGEN THAN TODAY.

Vandenbrooks: IN THIS TOP CHAMBER,

WE HAVE COCKROACHES REARED UNDER LOWER OXYGEN LEVELS,

ABOUT 12 PERCENT,

AND YOU CAN SEE HOW LARGE THIS INDIVIDUAL IS.

Narrator: IT MAY LOOK LARGE,

BUT IT'S ACTUALLY SMALL FOR THE SPECIES.

JOHN THEN REARS OTHER ROACHES

AT THE OXYGEN LEVELS OF THE PAST.

Vandenbrooks: COMPARATIVELY, THE COCKROACHES REARED DOWN HERE

ARE BEING REARED IN A HIGH OXYGEN LEVEL

OF ABOUT 31 PERCENT,

AND YOU CAN SEE NOW HOW LARGE THIS INDIVIDUAL IS,

MUCH, MUCH LARGER THAN THOSE REARED

AT THE LOWER OXYGEN LEVELS.

AND IT'S EVEN MORE PRONOUNCED

IF WE'RE ABLE TO COMPARE THE TWO ANIMALS.

Narrator: THE RESULTS ARE CLEAR AND ASTONISHING.

MORE OXYGEN MEANS BUGS CAN HAVE

A SMALLER INTERNAL BREATHING SYSTEM.

Vandenbrooks: WE CAN NOW DEFINITIVELY SAY,

AS OXYGEN GOES UP,

IT ACTUALLY ALLOWS FOR THE ANIMAL

TO PUT MORE THINGS INSIDE ITS BODY,

SO IT CAN HAVE MORE MUSCLE,

AND IT CAN BECOME ONE OF THESE REALLY LARGE, VICIOUS PREDATORS

THAT WE SEE 300 MILLION YEARS AGO.

Narrator: HAD WE BEEN AROUND TO WITNESS IT,

THE GRIFFINFLY WOULD HAVE BEEN A TRULY TERRIFYING SIGHT.

THIS WAS THE BIGGEST INSECT EVER TO FLY EARTH'S SKIES,

BUT OUR NEXT BEAST IS FAR, FAR BIGGER.

FAST-FORWARD FROM GRIFFINFLY TO 27 MILLION YEARS AGO.

THEN THE SKIES WERE RULED BY A FEATHERED GIANT.

WITH WINGS AS WIDE AS A TWO-LANE HIGHWAY

AND A CRUISE SPEED FASTER THAN USAIN BOLT,

IT COULD TRAVEL TO EVERY CORNER OF THE PLANET.

[SQUAWKS]

THE EVIDENCE OF THIS GIANT FIRST CAME TO LIGHT IN SOUTH CAROLINA,

IN THE CITY OF CHARLESTON.

IN 2010, PALEONTOLOGIST DAN KSEPKA

DISCOVERS A COLLECTION OF BONES

IN A STOREROOM OF THE CHARLESTON MUSEUM.

Dan Ksepka: WHEN WE PULLED OPEN THE DRAWER

AND I SAW THIS FOR THE FIRST TIME,

IT WAS JUST ABSOLUTELY SPECTACULAR.

Narrator: LAYING THE BONES OUT,

DAN COULD SEE THIS WAS NO ORDINARY FIND.

Ksepka: IT HAS THIS SKULL WITH THESE BONY-TOOTHED JAW

THAT ALMOST LOOKS LIKE A CROCODILE.

Narrator: BUT IT WASN'T ANY KIND OF REPTILE.

WHAT DAN HAD DISCOVERED WAS THE LARGEST FLYING BIRD OF ALL TIME,

A NEW SPECIES THEY CALLED PELAGORNIS SANDERSI.

Ksepka: THIS MASSIVE ELEMENT HERE IS THE HUMERUS.

THIS IS THE FIRST BONE OF THE WING SKELETON,

SO IT'S EQUIVALENT TO THE UPPER ARM BONE IN A HUMAN SKELETON.

THIS BONE, IN PARTICULAR, IS LONGER THAN MY ENTIRE ARM,

AND SO WE HAVE A REMARKABLY LONG WING.

Narrator: THE GIANT BIRD'S BODY WAS SIX FEET LONG.

WITH A WINGSPAN OF 24 FEET,

THE LARGEST BIRD ALIVE TODAY, THE WANDERING ALBATROSS,

COULD FIT UNDER JUST ONE OF ITS WINGS.

PELAGORNIS' WINGSPAN RIVALED THAT OF A HARRIER JUMP JET.

BY MODERN STANDARDS,

IT SEEMS LIKE THIS BIRD WAS TOO BIG TO FLY.

Sues: TODAY, WE HAVE SOME LARGE BIRDS AROUND

LIKE EMUS AND OSTRICHES, BUT THESE ARE NOT FLYING BIRDS,

AND WHEN WE GO BACK INTO THE FOSSIL RECORD,

WE SEE THE SAME THING.

THERE ARE SOME TRULY ENORMOUS BIRDS,

BUT THERE'S AN UPPER SIZE LIMIT FOR WHAT YOU CAN DO AS A FLYER.

Ksepka: AND SO THIS BIRD CLEARLY BLOWS RIGHT THROUGH THAT

WHEN WE'RE TALKING ABOUT NEAR SEVEN METERS,

AND SO IT'S DEFINITELY CHEATING IN SOME WAY.

Narrator: EVERYTHING ABOUT THE SKELETON

TELLS US THIS BIRD MUST HAVE FLOWN,

BUT HOW COULD IT POSSIBLY HAVE STAYED AIRBORNE?

A CLOSER LOOK AT THE BONES PROVIDES DAN WITH A VITAL CLUE.

LIKE FLYING BIRDS TODAY, ITS BONES ARE HOLLOW AND SUPER THIN.

Ksepka: THE BONE WALL IS ABOUT A MILLIMETER THICK,

AND SO THIS ANIMAL WOULD HAVE BEEN

VERY LIGHTWEIGHT FOR ITS SIZE.

THERE'S LESS WEIGHT TO SUPPORT IN FLIGHT.

Narrator: IT RIVALED THE WINGSPAN OF A FIGHTER JET,

BUT THIS GIANT BIRD WEIGHED ONLY 48 POUNDS,

LESS THAN A THIRD OF THE WEIGHT OF AN ADULT HUMAN.

LIGHT AS IT WAS,

ONE BONE STILL CASTS DOUBT ON ITS ABILITY TO FLY.

Ksepka: THIS BONE, THE SCAPULA,

IS THE EQUIVALENT TO OUR OWN SHOULDER BLADE,

AND YOU CAN SEE IT'S, IT'S JUST SO SMALL.

IT'S ACTUALLY ALMOST COMICALLY SMALL,

AND THIS CERTAINLY REVEALS

THAT THIS BIRD WAS NOT A HIGH-POWERED FLAPPER.

Narrator: IF IT WASN'T FLAPPING ITS WINGS,

HOW DID PELAGORNIS FLY?

FLIGHT BIOMECHANICS EXPERT MIKE HABIB

BELIEVES THE ANSWER LIES WITH THIS.

Mike Habib: I AM OUT HERE TO TRY HANG GLIDING FOR THE FIRST TIME.

I'M REALLY EXCITED.

I'M HOPING THIS WILL GIVE ME SOME IDEA

OF WHAT BEING A PELAGORNIS WOULD BE LIKE.

Narrator: A HANG GLIDER HAS A SIMILAR WINGSPAN TO PELAGORNIS.

IT'S ALSO LIGHTWEIGHT, HAS A HOLLOW, TUBULAR SKELETON,

AND A LARGE RIGID WING.

Habib: THE PHYSICS DON'T CHANGE,

SO AN AIRPLANE WING OR HANG GLIDER WING

LOOKS FUNDAMENTALLY VERY SIMILAR TO AN ANIMAL WING,

EVEN THOUGH THEY'RE MADE OF DIFFERENT STUFF.

Narrator: THE ONLY WAY MIKE, OR PELAGORNIS,

COULD GET AIRBORNE WOULD BE TO RUN INTO THE WIND.

Habib: I'M HOPING THAT I RUN PROPERLY AND WE LAUNCH,

AND I DON'T HAVE TO BE LIKE ONE OF THESE PEOPLE

THAT GETS DRAGGED ALONG ON THEIR FACE.

Man: OKAY, YOU READY TO TAKE OFF?

Habib: READY TO TAKE OFF.

Man: OKAY.

Habib: THIS IS AWESOME!

AH, MAN!

THIS IS GIVING ME A LITTLE BIT OF A GLIMPSE

OF WHAT IT WOULD BE LIKE

TO BE A GIANT FLYING ANIMAL IN THE PAST.

THIS IS AN AMAZING FEAT OF ENGINEERING,

AND IT'S A GREAT WAY OF SOARING,

BUT PELAGORNIS DID A LOT BETTER.

Narrator: 27 MILLION YEARS AGO,

NATURE PRODUCED A GLIDER

THAT WAS ABOUT FOUR TIMES MORE EFFICIENT THAN THIS HANG GLIDER.

IN FACT, PELAGORNIS WAS A BETTER GLIDER THAN ANYTHING

THAT HAS EVER LIVED OR THAT TECHNOLOGY HAS EVER PRODUCED.

♪

Habib: SO, WE WERE IN THE AIR FOR A GOOD 10 MINUTES,

A NICE, LONG FLIGHT,

BUT PELAGORNIS WOULD HAVE BEEN

ONE OF THE CHAMPIONS OF LONG-DISTANCE FLIGHT,

PROBABLY COULD STAY IN THE AIR FOR WEEKS AT A TIME,

MAYBE EVEN MONTHS AT A TIME.

Narrator: STAYING ALOFT FOR LONG PERIODS

WAS ESSENTIAL FOR PELAGORNIS.

ITS BONY TEETH, IDEAL FOR CATCHING SLIPPERY FISH,

REVEAL IT WAS A SEABIRD.

Ksepka: 27 MILLION YEARS AGO,

PELAGORNIS WAS LIVING IN THIS OPEN SEA ENVIRONMENT.

PELAGORNIS COULD PROBABLY TRAVEL

ACROSS THOUSANDS OF MILES OF OCEAN WITHOUT MUCH THOUGHT.

Narrator: SO, HOW DID PELAGORNIS MANAGE

SUCH AN EXTRAORDINARY FEAT?

DAN THINKS THE CLUE MAY LIE

WITH THE MODERN MASTER OF OCEAN FLIGHT,

THE WANDERING ALBATROSS.

ALBATROSSES MAKE USE OF THE WAY AIR FLOWING OVER THE OCEANS

CAN CHANGE SPEED.

THEY PERFORM A DAREDEVIL MANEUVER CALLED DYNAMIC SOARING.

DAN BELIEVES IF PELAGORNIS WAS TO SURVIVE OUT AT SEA,

IT MUST HAVE DONE THE SAME THING.

Ksepka: SO, IF WE LOOK AT THE WAVES,

THE WIND ABOVE THE WAVES IS GOING MORE SLOWLY

THAN THE WIND HIGHER UP,

AT A HIGHER ALTITUDE ABOVE THE WAVES,

ESPECIALLY OUT ON THE OPEN SEAS,

AND DYNAMIC SOARING BIRDS CAN USE THIS TO THEIR ADVANTAGE.

Narrator: THEY SWOOP DOWN TO THE OCEAN SURFACE,

THEN PULL UP AT THE LAST SECOND.

PULLING UP GIVES A BIRD ENOUGH MOMENTUM

TO RISE UP AND CATCH FASTER MOVING AIR CURRENTS.

FLYING IN LOOPS LIKE THIS,

PELAGORNIS WOULD HAVE BEEN ABLE TO COVER VAST DISTANCES

AND SNATCH PREY OUT OF THE WATER,

WHILST BURNING VERY LITTLE ENERGY.

THIS WAS THE BIGGEST AND MOST EFFICIENT FLYING BIRD

IN THE HISTORY OF THE PLANET.

IT RULED THE OCEAN SKIES.

PELAGORNIS WAS AT THE LIMIT

OF HOW BIG BIRDS COULD GET AND STILL LAUNCH INTO THE AIR,

BUT IF YOU THINK THAT'S BIG,

COMING UP AT NUMBER 8 IS AN ABSOLUTE WHOPPER.

[GROWLING]

♪

IMAGINE WALKING INTO A MODERN ZOO

WHERE THEY'D SOMEHOW MANAGED TO RESURRECT

THE LARGEST MAMMAL TO WALK THE EARTH.

WHAT YOU'D SEE IS THIS,

20 TONS OF HIDE-BOUND FLESH,

STANDING MORE THAN TWO STORIES TALL.

EVIDENCE OF THIS ANCIENT MEGA-MAMMAL EMERGED IN 1911,

IN WHAT IS NOW PAKISTAN,

BUT TODAY, THE CLUES ARE HIDDEN IN LONDON, U.K.

PALEONTOLOGIST MIKAEL FORTELIUS IS INVESTIGATING

AN EXTRAORDINARY COLLECTION OF THE BEAST'S BONES

IN LONDON'S NATURAL HISTORY MUSEUM.

THIS COLOSSAL SKULL IS TESTIMONY TO ITS SHEER SIZE.

Mikael Fortelius: THE HEAD SITS ON A VERY LONG NECK.

THERE'S NEVER BEEN ANYTHING SIMILAR TO THIS.

Narrator: PUT ALL THE BONES TOGETHER,

AND YOU GET SOMETHING

THAT LOOKS LIKE A CROSS BETWEEN A GIRAFFE AND AN ELEPHANT.

IT'S CALLED PARACERATHERIUM.

IT WAS SO BIG, A SIX-FOOT MAN

COULD EASILY FIT BETWEEN ITS LEGS.

IT STOOD 25 FEET HIGH.

IT WAS NEARLY TWICE AS TALL AND THREE TIMES AS HEAVY

AS THE BIGGEST LAND MAMMAL TODAY, THE AFRICAN ELEPHANT,

AND 26 FEET FROM NOSE TO TAIL,

IT WAS AS LONG AS AN ABRAMS BATTLE TANK.

[ROARS]

NOW, THE OBVIOUS QUESTION HAS TO BE, WHY DID IT GET SO BIG?

BUT THERE'S AN ADDED COMPLICATION.

WHILE SOME SCIENTISTS BELIEVE

THE PARACERATHERIUM LIVED IN THICK FORESTS,

MIKAEL FORTELIUS THINKS THIS CREATURE'S HABITAT WAS HARSH...

AFFLICTED BY DRY SEASONS,

WHEN WATER WAS SCARCE AND VEGETATION SPARSE.

HOW DOES AN ANIMAL BECOME A GIANT

WHEN FOOD IS IN SHORT SUPPLY?

FORTELIUS BELIEVES THE ANSWER LIES IN THE TEETH.

Fortelius: LOOKING AT THE TEETH WILL ALLOW US TO UNDERSTAND

WHY THIS ANIMAL GOT SO VERY LARGE.

THE TEETH ARE WORN IN A WAY

THAT ONLY HAPPENS WHEN YOU'RE EATING LEAVES.

Narrator: FOR EATING LEAVES, SHEER HEIGHT

WOULD GIVE THIS ANIMAL A MASSIVE ADVANTAGE.

LIKE A GIRAFFE, IT COULD GET TO FOOD

THAT'S BEYOND THE REACH OF MOST ANIMALS.

Sues: SO, WE HAVE THESE ENORMOUS PLANT EATERS,

AND BASICALLY THEIR ENORMOUS SIZE WOULD HAVE PROTECTED THEM

FROM ANY PREDATORS THAT WERE ALIVE AT THAT TIME,

AND THEY WERE BASICALLY THE TOP PLANT EATERS

IN THEIR RESPECTIVE ECOSYSTEMS.

Narrator: SO THAT EXPLAINS PARACERATHERIUM'S HEIGHT,

BUT NOT ITS MASSIVE BULK.

FORTELIUS BELIEVES THAT A HARSH ENVIRONMENT IS THE EXPLANATION,

THAT THE ANIMAL GREW SO BIG BECAUSE OF, NOT IN SPITE OF,

ITS TOUGH SURROUNDINGS.

Fortelius: IF YOU'RE SMALL, JUST ONE DAY WITHOUT WATER

IS A TERRIBLE THING AND MAY KILL YOU,

BUT THE LARGER YOU ARE, THE MORE BUFFERED YOU ARE,

THE MORE YOU CAN DEAL WITH HARSHNESS IN THIS SENSE.

YOU CAN GO WITHOUT FOOD, WITHOUT WATER.

I THINK THAT'S WHAT WAS DRIVING THE SIZE INCREASE.

Narrator: NOT EVERYONE AGREES WITH FORTELIUS' THEORY,

BUT THERE'S NO DOUBT THAT SOMEHOW PARACERATHERIUM THRIVED.

AND IT MUST HAVE CONSUMED

VAST QUANTITIES OF VEGETATION EVERY DAY.

TO FIND ENOUGH FOOD,

IT NEEDED TO RANGE OVER HUNDREDS OF SQUARE MILES,

AND THAT MAY BE THE REASON FOR WHAT IS, PERHAPS,

THE MOST REMARKABLE THING ABOUT THIS AMAZING ANIMAL,

ITS FEET.

BIOMECHANICS EXPERT JOHN HUTCHINSON

HAS ANALYZED PARACERATHERIUM'S FOOT BONES

AND PRODUCED A 3-D MODEL.

HE'S STRUCK BY JUST HOW MUCH IT RESEMBLES THE FEET

OF ONE OF TODAY'S GIANTS-- THE RHINOCEROS.

IN FACT, WEIGHING IN AT ONLY ONE SIXTH OF ITS SIZE,

THE RHINO IS PARACERATHERIUM'S CLOSEST LIVING RELATIVE,

AND HUTCHINSON'S RESEARCH SHOWS

THAT, IN TERMS OF SIZE TO WEIGHT,

ITS FEET MUST BEAR THE HEAVIEST LOADS.

John Hutchinson: RHINOCEROS,

THE PRESSURES OF ITS FEET

ARE WAY HIGHER THAN IN A HORSE,

A HUMAN, EVEN AN ELEPHANT.

RHINOS ALREADY TODAY ARE LIVING AT AN EXTREME

IN TERMS OF FOOT PRESSURE,

AND PARACERATHERIUM SEEMS TO HAVE

PUSHED THAT EXTREME FURTHER.

Narrator: ON THE FEET OF BOTH THE RHINO

AND ITS ANCIENT COUSIN,

THERE ARE THREE GIGANTIC HOOF-LIKE NAILS.

THERE'S ALSO A FATTY PAD

DESIGNED TO ACT AS A SHOCK ABSORBER.

THE PARACERATHERIUM'S FOOT

IS PROPORTIONALLY MORE SLENDER THAN A RHINO'S,

MEANING IT HAS TO BEAR EVEN MORE STRESS.

Hutchinson: MY CALCULATIONS SUGGEST

THAT PARACERATHERIUM MIGHT HAVE BORNE

AS MUCH AS 50 PERCENT MORE PRESSURE ON ITS FEET

THAN A RHINOCEROS DOES.

Narrator: THIS WAS THE HEAVIEST MAMMAL EVER TO WALK THE EARTH,

AND JOHN'S CALCULATIONS SUGGEST ONE EXTRAORDINARY FACT.

Hutchinson: PARACERATHERIUM WOULD HAVE PUT

MORE PRESSURE ON ITS FEET

THAN AN AVERAGE TANK'S TREADS WOULD PUT ON THE GROUND.

THAT'S PRETTY STAGGERING.

Narrator: PARACERATHERIUM WAS THE BIGGEST LAND MAMMAL EVER,

AND WITH FOOTSTEPS THIS HEAVY,

YOU'D HAVE BEEN WELL-ADVISED TO STAY OUT OF ITS PATH.

SO FAR ON "WORLD'S BIGGEST BEASTS,"

WE'VE MET...

A DEADLY DRAGONFLY THE SIZE OF A HAWK,

A GIANT BIRD THE SIZE OF A PLANE,

AND A MEGA-MAMMAL TWICE THE SIZE OF AN AFRICAN ELEPHANT.

BUT NEXT UP IS AN EVEN BIGGER BEAST

THAT COULD LAUNCH INTO THE SKIES.

[GROWLING]

♪

THIS IS THE CLOSEST EARTH HAS EVER GOT

TO A REAL-LIFE WINGED DRAGON.

70 MILLION YEARS AGO, WHILE THE DINOSAURS RULED THE EARTH,

THE SKIES WERE RULED BY PTEROSAURS.

THEIR NAME MEANS WINGED LIZARDS,

AND PALEONTOLOGIST GARETH DYKE

HAS SPENT MORE THAN 10 YEARS OF HIS LIFE HUNTING THEM.

Gareth Dyke: PTEROSAURS ARE INTERESTING

BECAUSE THEY'RE THE FIRST GROUP OF VERTEBRATES

TO EVOLVE POWERED FLIGHT,

LONG BEFORE BIRDS AND LONG BEFORE BATS.

Narrator: THE HUNT HAS BROUGHT HIM TO ROMANIA,

TO THE REGION OF TRANSYLVANIA,

BETTER KNOWN AS THE HOME OF THAT LEGENDARY MONSTER, DRACULA.

Dyke: 70 MILLION YEARS AGO,

THE CLIMATE IN THIS AREA WAS MUCH DIFFERENT.

BIG ISLANDS IN A TROPICAL SEA

WITH LUSH VEGETATION,

LOTS OF ANIMAL AND PLANT LIFE, AND QUITE HIGH TEMPERATURES.

IT COULDN'T BE MORE DIFFERENT TO THE WEATHER TODAY.

Narrator: THESE RED SANDSTONE CLIFFS

HOLD A HUGE NUMBER OF FOSSILS.

AS THE ROCK ERODES, MORE AND MORE ARE REVEALED.

Dyke: SO, WHAT WE HAVE HERE

ARE SOME OF THE BONES OF PTEROSAURS

THAT WE'VE COLLECTED FROM THIS AREA IN THE LAST FEW YEARS.

THIS ONE, FOR EXAMPLE, IT'S ABOUT SIX CENTIMETERS IN LENGTH,

SO IT WOULD HAVE COME FROM AN ANIMAL

THAT WOULD HAVE HAD A WINGSPAN OF ONE OR TWO METERS, SIX FEET,

AVERAGE SIZE FOR PTEROSAURS.

Narrator: BUT THEN, IN 2008,

GARETH'S COLLEAGUES CLIMBED DOWN THE CLIFFS

AND DISCOVERED SOMETHING EXTRAORDINARY.

Dyke: THIS NECK VERTEBRA IS

FROM THE SAME PART OF THE NECK IN A GIANT PTEROSAUR.

IT'S QUITE SHORT, QUITE ROBUST,

BUT GIGANTIC COMPARED TO A NORMAL-SIZED PTEROSAUR VERTEBRA

THAT YOU CAN SEE HERE, AND YOU CAN SEE IMMEDIATELY

THAT WE'RE LOOKING AT ANIMALS OF GIGANTIC PROPORTIONS.

Narrator: WHEN THE NECK BONE WAS MAPPED

ONTO A MODEL OF A PTEROSAUR SKELETON,

IT BECAME CLEAR THAT THIS WAS ONE OF THE LARGEST MEMBERS

OF THE PTEROSAUR FAMILY EVER DISCOVERED,

COMPARABLE TO GIANT SPECIES FOUND IN THE U.S.A.

UP TO 16 FEET TALL, THESE MASSIVE PTEROSAURS

COULD STAND NEARLY THREE TIMES TALLER THAN A HUMAN,

TALL ENOUGH TO LOOK A GIRAFFE IN THE EYE.

THEIR FRONT LIMBS WERE ALSO VAST WINGS

THAT, WHEN UNFURLED, COULD STRETCH UP TO 36 FEET ACROSS,

THE SAME AS A MODERN LEARJET.

THE GIANT HEAD, WITH ITS FIVE-FEET-LONG BEAK,

SEEMS PERFECTLY SUITED TO PREYING OFF OTHER ANIMALS,

AND NO LIVING CREATURE HAS EVER HAD A LARGER WINGSPAN.

WHILE IT SEEMS OBVIOUS THAT GIANT PTEROSAURS FLEW,

THEY'RE SO LARGE,

EXPERTS HAVE PUZZLED OVER HOW THEY EVER GOT OFF THE GROUND.

WE ALREADY KNOW THAT PELAGORNIS, WITH ITS 24-FEET WINGSPAN,

WAS AS BIG AS A BIRD COULD GET AND STILL FLY.

THE DIFFICULTY OF JUST GETTING OFF THE GROUND AT THIS SIZE

PREVENTED FLYING BIRDS FROM GETTING ANY BIGGER.

SO, HOW DID A 550-POUND PTEROSAUR,

WITH A 36-FEET WINGSPAN, GET INTO THE AIR?

FLIGHT BIOMECHANICS EXPERT MIKE HABIB

HAS MADE IT HIS MISSION TO FIND OUT.

HE HAS BEEN STUDYING THE BONES

OF ONE PARTICULAR GIANT PTEROSAUR, QUETZALCOATLUS.

DISCOVERED IN TEXAS, THIS SPECIES IS OF SIMILAR GIANT SIZE

TO THE ONE FOUND IN TRANSYLVANIA.

MIKE FOCUSED HIS ATTENTION ON THE PTEROSAUR'S WING.

Habib: THIS IS THE SKELETON OF QUETZALCOATLUS.

YOU CAN SEE THE MASSIVE BONES OF THE WING.

THIS IS CALLED THE HUMERUS. IT'S THE BONE OF THE UPPER ARM.

Narrator: MIKE CONDUCTED A FORENSIC ANALYSIS OF THE BONES.

Habib: I USED CT SCANS TO LOOK INSIDE OF THE BONES,

AND I FOUND THAT MOST OF THE BONES IN THE WING

WERE VERY HOLLOW.

THE BONE WALL IS ONLY THREE MILLIMETERS THICK.

IT'S MOSTLY AIR BY VOLUME.

Narrator: THIS MAKES THE SKELETON VERY LIGHT,

BUT INSIDE THE UPPER ARM BONE,

A DENSE INTERNAL SCAFFOLD REINFORCES THE BONE,

ESPECIALLY NEAR THE SHOULDER,

AND THAT'S NOT SOMETHING YOU SEE IN A BIRD WING.

THIS BONE IS FAR STRONGER THAN NEEDED FOR FLIGHT,

STRONGER EVEN THAN NEEDED FOR WALKING.

SO, WHY WOULD THE PTEROSAUR

POSSIBLY NEED SUCH POWERFUL FORELIMBS?

THEN MIKE NOTICED ANOTHER CLUE, A GIANT GROOVE IN THE BONE.

THIS COULD ONLY MEAN ONE THING: A HUGE TENDON.

Habib: A GIANT TENDON WOULD RUN IN, ALONG THE GROOVE HERE,

AND THEN WRAP AROUND THE WING PIVOT JOINT,

AND END UP AT THE TIP OF THE WING.

THE TENDON WOULD HAVE BEEN ABOUT AS BIG AROUND AS MY WRIST.

Narrator: THE SUPER SIZE OF THIS TENDON

LED MIKE TO FORM A UNIQUE THEORY.

THE PTEROSAURS WERE USING THE TENDON'S ELASTIC POWER

TO CATAPULT THEMSELVES INTO THE AIR.

Habib: TENDONS, AND THE MUSCLES ATTACHED TO THEM,

HAVE A CERTAIN AMOUNT OF SPRINGINESS.

YOU CAN STRETCH THEM, AND THEN THEY SNAP BACK,

BASICALLY A GIANT CROSSBOW.

Narrator: MIKE USED THE SKELETON TO MODEL HOW THIS MIGHT WORK.

Habib: A GIANT PTEROSAUR LIKE THIS ONE, TO TAKE OFF,

WOULD START BY CROUCHING ON ITS BACK LEGS,

AND THEN IT WOULD UNLOAD THE LEGS FIRST,

VAULTING OVER THE GIANT WING,

AND THEN IT WOULD PUSH AGAINST THE GROUND,

USING UP ALL THAT STORED ENERGY

AND PUSHING ITSELF AS FAST AS POSSIBLE INTO THE AIR.

Narrator: THERE IS STILL ONE LIVING CREATURE

THAT USES THIS KIND OF VAULTING LAUNCH.

IT'S PLAIN TO SEE WHEN YOU WATCH A VAMPIRE BAT TAKE OFF.

BUT VAMPIRE BATS ONLY WEIGH TWO OUNCES,

SO COULD THE SAME PRINCIPLE

WORK ON THE SCALE OF A GIANT PTEROSAUR?

MIKE HAS COME TO A LOCAL FIRING RANGE TO INVESTIGATE.

Habib: SO, WHAT WE HAVE HERE IS A MODERN CROSSBOW,

AND IT'S A VERY EFFECTIVE WAY OF TALKING ABOUT PTEROSAURS.

GIANT PTEROSAURS WOULD BE STRETCHING

ITS TENDONS BY CROUCHING,

AND THE CROUCH PHASE WOULD BE MUCH SLOWER

THAN THE LAUNCH PHASE,

SO IT PUTS THE ENERGY IN SLOWLY, THEN LETS IT OUT QUICK.

SO, I'M GOING TO PUT IN THE ENERGY HERE NICE AND SLOW.

YOU'LL NOTICE THAT THE LIMBS ON THE CROSSBOW ARE BENDING.

THAT'S THE ENERGY BEING STORED IN THE FLEXING OF THE LIMBS.

THERE'S A LOT OF ENERGY IN HERE,

AND WHEN I LET IT OUT TO FIRE THE BOLT,

IT'S GOING TO GO REALLY, REALLY FAST.

Narrator: THIS CATAPULT CROSSBOW STORES SO MUCH ENERGY,

IT CAN FIRE A BOLT AT UP TO 218 MILES PER HOUR.

Habib: WOW!

IT'S A LOT OF ENERGY IN THIS BOW.

IT DOESN'T HAVE MUCH KICK,

BECAUSE IT'S REALLY WELL ENGINEERED,

BUT YOU CAN TELL THAT BOLT'S COMING OUT OF THERE REAL FAST.

Narrator: THE CROSSBOW CAN FIRE THIS LIGHTWEIGHT BOLT

HUNDREDS OF FEET THROUGH THE AIR.

Habib: NOT A BAD SHOT.

Narrator: BUT HOW DO THESE MECHANICS

SCALE UP TO A 550-POUND PTEROSAUR?

Habib: BY STORING ALL THIS ENERGY IN THIS GIANT TENDON,

BIG PTEROSAURS WOULD HAVE BEEN ABLE TO TAKE OFF LIKE A ROCKET,

LAUNCHING A MASS ABOUT THE SAME AS A GRIZZLY BEAR

INTO THE AIR IN UNDER HALF A SECOND.

Narrator: MIKE CALCULATED THE PTEROSAURS

ONLY NEEDED TO GET SIX FEET OFF THE GROUND.

THAT WOULD GIVE THEM JUST ENOUGH ROOM

TO UNFURL THEIR VAST WINGS AND BEAT FOR THE FIRST TIME.

THEN, WHEN THEY'RE AIRBORNE,

JUST LIKE GIANT BIRDS, THEY GLIDE.

THESE GIANTS WERE THE LARGEST FLYING CREATURES EVER,

BUT THEY WOULD HAVE BEEN NO MATCH

FOR THE NEXT BEAST ON OUR LIST,

A SNAKE OF ASTONISHING SIZE.

[GROWLING]

THIS IS THE STORY OF A CREATURE

THAT LOOKS LIKE IT BELONGS IN A HOLLYWOOD B MOVIE.

IT BEGINS IN 2004,

IN THE COLOMBIAN REGION OF CERREJON.

A VAST MINING OPERATION HAD EXPOSED A FOSSILIZED FOREST,

DATING TO JUST AFTER THE EXTINCTION OF THE DINOSAURS.

PALEONTOLOGIST JONATHAN BLOCH LED AN EXPEDITION TO THE SITE.

HE RETURNED WITH SOMETHING EXTRAORDINARY.

Jonathan Bloch: THIS IS WHAT WE FOUND.

THIS IS A RECOGNIZABLE VERTEBRA.

WHEN WE ORIGINALLY DISCOVERED THIS,

WE THOUGHT MAYBE IT WAS THE VERTEBRA OF A CROCODILE.

Narrator: BUT THIS WAS NO CROCODILE.

JOHN HAD IDENTIFIED THE VERTEBRA

OF THE LARGEST SNAKE EVER TO ROAM THE EARTH--

TITANOBOA.

Bloch: THIS IS THE LARGEST VERTEBRA

FROM THE BACKBONE OF A 17-FOOT-LONG ANACONDA,

WHICH IS THE MOST MASSIVE SNAKE ALIVE TODAY.

Narrator: WHEN YOU COMPARE THE ANACONDA VERTEBRA

TO THE 60-MILLION-YEAR-OLD FOSSIL,

TITANOBOA'S TRUE SIZE BECOMES CLEAR.

Bloch: THAT COMPARISON IS REALLY INCREDIBLY DRAMATIC.

IT EVEN STILL TAKES MY BREATH AWAY.

Narrator: USING THE ANATOMY OF TODAY'S GIANT SNAKES AS A GUIDE,

BLOCH'S TEAM SET OUT

TO RECONSTRUCT TITANOBOA'S SKELETON,

PIECING TOGETHER THE FRAGMENTS.

THEY CALLED IN FOSSIL SNAKE EXPERT JASON HEAD

TO VERIFY THEIR FINDINGS.

Jason Head: THE NUMBERS THAT WE KEPT GETTING

WERE SO INCREDIBLE IN TERMS

OF ITS WEIGHT AND ITS LENGTH AND ITS GIRTH,

AT FIRST I WAS SUSPICIOUS WE WERE DOING THE MATH RIGHT.

Narrator: AT TWO AND A HALF FEET ACROSS,

TITANOBOA WOULD STRUGGLE TO FIT THROUGH YOUR FRONT DOOR.

WEIGHING IN AT OVER A TON, IT WOULD BE FOUR TIMES HEAVER

THAN THE LARGEST SNAKES ALIVE TODAY.

AND AT 45 FEET, IT WOULD BE AS LONG AS A SCHOOL BUS.

Head: SO, WE'RE LOOKING AT A LOWER JAW

THAT WOULD HAVE BEEN, YOU KNOW, THIS LONG,

ABOUT FOUR TIMES THE SIZE OF A LARGE GIANT PYTHON TODAY.

TITANOBOA THEORETICALLY COULD HAVE PROBABLY OPENED ITS MOUTH

WIDE ENOUGH FOR YOU OR I TO ACTUALLY STAND IN IT.

Bloch: RIGHT.

Narrator: WHAT'S CLEAR IS THAT THIS SNAKE

WAS SIMPLY TOO LARGE TO LIVE ON LAND.

Bloch: BECAUSE IT WAS SUCH A MASSIVE SNAKE,

IT WOULD HAVE HAD TROUBLE SUPPORTING ITS OWN WEIGHT.

THIS ANIMAL PROBABLY WOULD HAVE HAD TO SPEND MOST, IF NOT ALL,

OF ITS TIME IN THE WATER.

Sues: THE ISSUES OF WEIGHT

DISAPPEAR BECAUSE THE WATER

SUPPORTS YOU,

AND THAT'S THE REASON

WHY WE HAVE SO MANY REALLY

BIG CREATURES IN THE WATER,

BECAUSE WEIGHT IS NOT AN ISSUE,

WHEREAS WEIGHT IS AN ISSUE ON LAND,

AND IF YOU DON'T HAVE LIMBS, THAT HOLDS AN ADDITIONAL ISSUE.

Narrator: IN THE WATER, IT WOULD HAVE FOUND PLENTY TO PREY ON.

Head: IN ITS ECOSYSTEM,

TITANOBOA LIVED WITH GIANT CROCODILIANS,

LIVED WITH GIANT TURTLES AND THESE GIANT FISHES,

AND IT PROBABLY COULD HAVE EATEN ALL OF THEM.

Narrator: IT'S BEEN 60 MILLION YEARS

SINCE TITANOBOA BECAME EXTINCT,

SO IT'S A LITTLE DIFFICULT TO MEET ONE NOW,

BUT, AGAIN, EXPERTS CAN USE TODAY'S SNAKES TO GET CLOSE.

THIS IS A RETICULATED PYTHON, THE LONGEST SPECIES ALIVE TODAY.

Head: THESE ARE THE CLOSEST LIVING RELATIVES TO TITANOBOA,

AND A LOT OF THEIR ANATOMY IS SIMILAR TO TITANOBOA,

AND, FROM THAT, WE INFER VERY SIMILAR BEHAVIORS--

CONSTRICTION, AMBUSH PREDATION.

IN THE CASE OF ANACONDAS, LIVING IN AQUATIC ENVIRONMENTS.

[CHOKING]

Narrator: AT THIS MOMENT IN OUR INTERVIEW,

GOLDIE THE PYTHON CHOOSES TO FLEX HER MUSCLES.

Head: THAT'S BETTER.

Narrator: THIS ISN'T AN ATTEMPT TO TREAT JASON AS PREY.

IT'S SIMPLY HER NORMAL MOVEMENT.

Head: IS SHE IN A GOOD MOOD STILL?

Narrator: BUT WHEN ACTUALLY ON THE HUNT, SHE'S DEADLY.

Head: WHEN BOAS AND PYTHONS CONSTRICT THEIR PREY,

THEY'RE PUTTING SO MUCH PRESSURE

ON THE CIRCULATORY SYSTEM OF THE PREY ANIMAL

THAT THEY ACTUALLY INDUCE A HEART ATTACK.

THEY CAN STOP THE HEART BY SQUEEZING SO HARD.

Sues: SO, IF YOU HAVE LIKE A METER-LONG BOA,

CAN REALLY ALREADY PUT QUITE A SQUEEZE ON YOU,

AND BY THE TIME YOU GRADUATE

TO, SAY, HOLDING A MEDIUM-SIZED ANACONDA, YOU KNOW,

IF THAT ANACONDA DECIDES TO CONSTRICT AROUND YOU,

IT TAKES CONSIDERABLE EFFORT TO GET IT TO CHANGE ITS WAYS.

Narrator: SNAKES HAVE BEEN RECORDED

CONSTRICTING AT 25 POUNDS PER SQUARE INCH.

DELIVERED BY A SNAKE TITANOBOA'S SIZE,

THAT WOULD EASILY BE ENOUGH TO CRUSH PREY AS BIG AS A RHINO.

TO FIND OUT WHAT THIS KIND OF FORCE LOOKS LIKE,

SNAKE EXPERT RHYS JONES IS OVERSEEING A LITTLE TEST,

USING A COLLECTION OF HEAVY MACHINERY.

Rhys Jones: WE'VE GOT AN EXPERIMENT SET UP

WHICH WILL HELP US TO TRY AND VISUALIZE

EXACTLY THE TYPE OF FORCES NEEDED

TO OVERCOME THESE HUGE PREY ITEMS.

SO, WHAT WE'VE GOT HERE, WE'VE GOT A TRUCK.

THIS IS FIXED IN PLACE.

THIS BIG YELLOW ROPE HERE IS REPRESENTATIVE OF OUR SNAKE,

AND IT'S GOT, AS YOU CAN SEE,

TWO COILS HERE AROUND THIS OIL DRUM.

THE OIL DRUM IS REPRESENTING OUR PREY ITEM.

IT'S FULL OF WATER. IT'S SEALED.

THAT'S GOING TO TAKE SOME PRESSURE

TO BE ABLE TO CRUSH THAT,

SO WE'RE GOING TO NEED MUSCLE.

Narrator: CUE A SEVEN-TON TRACTOR

WITH A 190-HORSEPOWER ENGINE.

THIS VERSUS A SEALED BARREL OUGHT TO BE A TOUGH TEST.

[CREAKING]

AS THE TRACTOR PULLS ON, THE PRESSURE PASSES 25 PSI.

THAT'S THE CRUSHING POWER OF TYPICAL CONSTRICTORS TODAY,

BUT TITANOBOA HAD FOUR TIMES THE BULK,

AND ESTIMATES SAY IT COULD PULL OFF CRUSHING FORCES

OF UP TO 110 POUNDS PER SQUARE INCH,

THE SAME PRESSURE AS HAVING AN EIGHT-TON TRUCK

PARKED ON YOUR CHEST.

Jones: LOOK, IT'S JUST SQUEEZED IT LIKE A TOY, HASN'T IT?

THAT IS JUST INCREDIBLE.

I THINK OUR SNAKE PRETTY MUCH NAILED IT, DON'T YOU?

Narrator: IT ONLY TOOK 55 PSI TO BURST THE BARREL,

HALF WHAT TITANOBOA MIGHT HAVE DONE,

BUT MORE THAN ENOUGH

TO CRUSH THE LIFE OUT OF ANY LIVING THING.

Jones: I MEAN, LOOK AT THE DAMAGE TO THIS OIL DRUM.

CAN YOU IMAGINE IF THAT TYPE OF PRESSURE WAS APPLIED TO YOU?

YOU WOULDN'T LAST TWO SECONDS.

Narrator: TITANOBOA'S PHENOMENAL CRUSHING FORCE

MADE IT THE APEX PREDATOR ON EARTH FOR 10 MILLION YEARS.

♪

[GROWLING]

TITANOBOA WAS THE LARGEST SNAKE IN EARTH'S HISTORY,

NEARLY TWICE THE WINGSPAN OF THE BIGGEST FLYING BIRD

AND ALMOST 10 FEET LONGER

THAN THE WINGSPAN OF THE LARGEST FLYING CREATURE,

BUT AS MASSIVE AS THIS PREDATOR WAS,

NEXT UP IS SOMETHING BIGGER AND EVEN MORE TERRIFYING.

AT FIRST GLANCE, THIS BEAST LOOKS LIKE A CROSS

BETWEEN A GIANT TURTLE AND A MEGA-CROCODILE.

BUT WHAT THIS SUBMARINE-SIZED SEA MONSTER REALLY WAS,

AND HOW IT BECAME APEX PREDATOR,

HAS BECOME A 100-MILLION-YEAR-OLD MYSTERY.

IN 2003, NEW EVIDENCE CAME TO LIGHT

ON THE SOUTH COAST OF THE U.K.

IF YOU'RE LOOKING FOR FOSSILS, THE JURASSIC COAST OF DORSET

IS ONE OF THE MOST FERTILE HUNTING GROUNDS ON EARTH.

KEVAN SHEEHAN HAS BEEN COMING HERE FOR MORE THAN 40 YEARS.

Kevan Sheehan: I SAW THREE PIECES

OF WHAT I THOUGHT WAS FOSSILIZED WOOD.

I GOT REALLY EXCITED BECAUSE I THOUGHT,

"WOW, THERE'S GOT TO BE MORE OF THIS,"

AND THEN, JOY OF JOYS, THERE'S THIS HUGE PIECE OF BONE STUCK.

IT'S ALMOST LIKE A METEORITE HAS GONE BANG INTO THE CLIFF.

Narrator: EMBEDDED IN THE CLIFF WERE DOZENS OF PIECES OF FOSSIL.

REASSEMBLED, THEY MADE SOMETHING INCREDIBLE--

THE MOST COMPLETE SKULL EVER DISCOVERED OF A PLIOSAURUS.

PALEONTOLOGIST RICHARD FORREST IS AN EXPERT

ON THESE ANCIENT MONSTERS.

Richard Forrest: THIS IS A GIANT KILLING MACHINE.

THIS PLIOSAUR WAS THE TOP PREDATOR.

IT WAS THE PEAK OF THE PYRAMID.

THEY WERE BASICALLY JUST BIG, POWERFUL BRUTES

THAT DEVASTATED ANYTHING IN THEIR WAY.

IT'S AN AWESOME ANIMAL.

Narrator: THE BIGGEST KNOWN PLIOSAURUS

HAD FLIPPERS NINE FEET LONG.

THAT'S LIKE A BASKETBALL PLAYER AT FULL STRETCH.

IF IT SWAM IN TODAY'S WATERS,

IT WOULD HAVE BEEN AS BIG AS A NAVAL PATROL BOAT.

THAT'S 45 FEET.

IN TERMS OF WEIGHT, IT WOULD HAVE TAKEN ABOUT 44 COMPACT CARS

TO BALANCE OUT ONE PLIOSAURUS.

[GROWLS]

THE STRONGEST BITER ALIVE TODAY IS THE SALTWATER CROCODILE,

WITH A BITE FORCE OF 1.8 TONS.

PLIOSAURUS HAD A BITE NEARLY 10 TIMES STRONGER.

IT WAS THE T. REX OF THE OCEAN.

Sues: PLIOSAURUS WERE AMBUSH PREDATORS,

SO THEY WOULD BASICALLY HAVE SPOTTED PREY,

AND THEN JUST LIKE A CROCODILE

GONE FOR SORT OF A QUICK AMBUSH,

AND THEN, OF COURSE, WITH THIS ENORMOUS MOUTH

FESTOONED WITH THESE MASSIVE TEETH,

COULD HAVE SUBDUED ANYTHING THEY WANTED TO EAT.

Forrest: WE HAVE THESE GREAT TEETH AT THE FRONT,

WHICH IS WHERE IT GRABS THE PREY.

THAT'S WHAT CATCHES IT.

THEN IT MOVES A BIT FURTHER BACK, THEN ANOTHER SET OF TEETH,

AND THESE ARE THE ONES THAT CUT THE PREY UP INTO PIECES.

THEN WE HAVE THESE TEETH, WHICH ARE HOOKED BACKWARDS,

SO ONCE THE PREY GETS TO THERE, THERE'S NO WAY OUT.

Narrator: BUT THAT THROWS UP QUESTIONS.

IF YOU'RE GOING TO BITE SOMETHING,

YOU'VE GOT TO BE ABLE TO CATCH IT FIRST.

SO, HOW DOES A 45-FEET PREDATOR

THE SIZE OF A LARGE SHIPPING CONTAINER

KEEP UP WITH ITS PREY?

THE SECRET MUST LIE IN THEIR FOUR BOAT-SIZED FLIPPERS.

THE CLOSEST MATCH TO A PLIOSAURUS FLIPPER TODAY

BELONGS TO A CREATURE FAR LESS FRIGHTENING.

PENGUINS MAY LOOK FUNNY WHEN THEY WADDLE ON LAND,

BUT UNDERWATER THEY'RE LIKE ROCKETS,

WHIZZING AROUND AT SPEEDS OF UP TO 20 MILES PER HOUR.

BIOMECHANICS EXPERT FLAVIO NOCA

IS TRYING TO UNDERSTAND

HOW THEY REACH THESE EXTRAORDINARY SPEEDS.

USING A HIGH-SPEED CAMERA,

HE FILMS PENGUINS MOVING AROUND UNDERWATER.

Flavio Noca: THIS CAMERA IS ACTUALLY ABLE

TO GO UP TO 12,000 IMAGES PER SECOND.

Narrator: THAT MEANS THAT EVERY MINUTE DETAIL

OF FLIPPER ACTION IS CAPTURED.

FLAVIO'S FOOTAGE REVEALS

THAT PENGUINS AREN'T SWIMMING WITH THEIR FLIPPERS.

THEY'RE FLAPPING THEM LIKE A BIRD.

THEY'RE FLYING UNDERWATER,

AND BY TWISTING THEIR WINGS AS THEY FLAP,

PENGUINS CAN PROPEL THEMSELVES FORWARD ON THE UPSTROKE

AS WELL AS THE DOWNSTROKE,

WHICH IS SOMETHING MOST AIRBORNE BIRDS CAN'T DO.

THE PLIOSAURUS HAD NOT TWO, BUT FOUR FLIPPERS,

AND THEY WERE GIGANTIC.

ALL SIGNS POINT TO THIS MEGA-MONSTER

BEING NOT ONLY ONE OF THE BIGGEST,

BUT ALSO ONE OF THE FASTEST PREDATORS IN THE OCEAN.

AEROSPACE ENGINEER LUKE MUSCUTT IS INVESTIGATING HOW THEY MOVED.

USING X-RAYS OF FOSSILS, LUKE HAS RECREATED

A PAIR OF PLIOSAUR FLIPPERS HE CALLS WINGS.

Luke Muscutt: PLIOSAURS WERE REALLY GOOD SWIMMERS,

AND THE AIM OF THE GAME IS TO CHASE DOWN THE PREY,

AND OBVIOUSLY TO DO THAT, YOU NEED TO BE VERY FAST.

YOU NEED TO HAVE A HIGH THRUST AND A HIGH ACCELERATION.

Narrator: BY SUSPENDING THE WINGS IN A TANK,

HE'S TRYING TO DETERMINE HOW THE FRONT AND BACK WINGS

WORK TOGETHER TO PROPEL THE PLIOSAURUS.

BLUE AND RED DYES REVEAL HOW EACH WING MOVES THE WATER.

LUKE MOVES THE WINGS TOGETHER IN DIFFERENT WAYS

AND RECORDS THE AMOUNT OF PROPULSION GENERATED.

HE NOTICES CERTAIN MOVEMENTS

HAVE A EXTRAORDINARY EFFECT ON THE BACK WING.

Muscutt: SO, INITIAL RESULTS SUGGEST

THAT THE HIND WING CAN PRODUCE A THRUST

WHICH IS ABOUT 50 PERCENT HIGHER

THAN A WING OPERATING ON ITS OWN.

Narrator: BY HARNESSING THE WAKE OF THE FRONT WING,

THE PLIOSAURUS COULD GENERATE

TWO AND A HALF TIMES AS MUCH THRUST

AS IT WOULD WITH JUST ONE SET OF WINGS.

AND THAT IS HOW THIS MEGA-BEAST

GAINED SUDDEN AND TREMENDOUS ACCELERATION.

ITS PREY WOULDN'T HAVE STOOD A CHANCE.

PLIOSAURUS IS JUST THE LATEST

IN OUR LINEUP OF THE WORLD'S BIGGEST BEASTS EVER.

SO FAR, WE'VE REVEALED GRIFFINFLY,

THE BIGGEST INSECT IN EARTH'S HISTORY.

PELAGORNIS, THE BIRD WITH THE LONGEST WINGSPAN.

PARACERATHERIUM, THE BIGGEST MAMMAL TO WALK THE EARTH.

GIANT PTEROSAURS, THE LARGEST FLYING CREATURES EVER.

TITANOBOA, THE LONGEST KNOWN SNAKE OF ALL TIME.

AND PLIOSAURUS, THE LARGEST PREDATORY MARINE REPTILE.

BUT COMING UP IS A BIZARRE DINOSAUR THAT BEATS THEM ALL.

[GROWLING]

NEW DISCOVERIES OF ONE OF THE STRANGEST DINOSAURS EVER

ARE REWRITING THE TEXTBOOKS--

A MONSTER DINOSAUR WITH VICIOUS TEETH,

CLAWS ALMOST AS BIG AS A HUMAN ARM.

Paul Sereno: WE'RE TALKING SOMETHING OF ENORMOUS LENGTH

THAT COULD SLICE YOU WITH ONE MOTION.

Narrator: AND A MASSIVE SPINY SAIL.

Nizar Ibrahim: THE SPINES ARE TALLER THAN A PERSON.

EVERY NOW AND THEN, WE COME ACROSS REALLY BIZARRE DINOSAURS.

IN MY BOOK, IT'S THE MOST BIZARRE DINOSAUR OUT THERE.

Narrator: PALEONTOLOGIST NIZAR IBRAHIM WAS ON EXPEDITION

TO THE SAHARA DESERT IN MOROCCO IN 2013.

WHEN HE SAW THE BEAST'S BONES,

HE KNEW THEY WERE SOMETHING SPECIAL.

THIS WAS A SPINOSAURUS, OR SPINE LIZARD.

IT LIVED 100 MILLION YEARS AGO.

EVERYTHING ABOUT SPINOSAURUS IS VAST.

Ibrahim: SEEING IT IN FRONT OF YOU,

YOU REALIZE, "WOW, THIS IS ONE BIG PREDATOR."

Narrator: THE SEVEN-FEET SPINY SAIL

MEANS SPINOSAURUS STANDS

MORE THAN TWICE THE HEIGHT OF A HUMAN.

AT 50 FEET LONG FROM SNOUT TO TAIL,

IT IS 10 FEET LONGER THAN T. REX.

IT'S SO BIG, IT'S THE LENGTH OF A FIRE TRUCK.

WEIGHING IN AT 22 TONS,

THIS IS THE BIGGEST PREDATOR TO EVER WALK THE EARTH.

BUT SPINOSAURUS WASN'T THE ONLY DANGEROUS DINO ON THE BLOCK.

100 MILLION YEARS AGO, THIS DESERT WAS A VAST RIVER SYSTEM

BURSTING WITH OTHER GIANT PREDATORS.

Ibrahim: I CALL IT THE RIVER OF GIANTS

BECAUSE IT WAS HOME TO GIANT FISH, GIANT FLYING REPTILES,

SEVERAL T. REX-SIZED PREDATORY DINOSAURS.

IT WAS PROBABLY THE MOST DANGEROUS PLACE

IN THE HISTORY OF OUR PLANET.

Sereno: IT'S JAM-PACKED WITH ALL THESE PREDATORS,

TO THE POINT WHERE YOU SAY, "WHAT WERE THEY LIVING ON?

WHERE WERE THE HERBIVORES TO SUPPORT THIS MANY PREDATORS?"

Narrator: IT WAS A MYSTERY.

WITH SO FEW PLANT-EATING DINOSAURS TO FEED ON,

WHAT ENABLED SPINOSAURUS TO SURVIVE HERE

AND BECOME THE BIGGEST PREDATOR OF ALL?

AS NIZAR AND HIS TEAM LOOKED CLOSER AT THE BONES,

THEY BEGAN TO FIND CLUES,

STRANGE FEATURES THAT MARKED THIS PREDATOR OUT

FROM OTHER DINOSAURS LIKE T. REX.

Ibrahim: THIS ANIMAL DIDN'T LOOK ANYTHING

LIKE T. REX OR OTHER PREDATORY DINOSAURS.

IT WAS LIKE WORKING ON AN ALIEN FROM OUTER SPACE.

Narrator: FOR STARTERS, THE TEETH WERE AN UNUSUAL SHAPE.

Ibrahim: SPINOSAURUS IS REALLY ALL ABOUT

GRABBING PREY AND HOLDING IT

IN THESE MASSIVE JAWS WITH LONG, CONICAL TEETH,

SO THESE TEETH ARE GREAT TO GRAB SLIPPERY PREY.

Narrator: AT OVER FIVE FEET LONG,

THESE JAWS WERE CAPABLE

OF SWALLOWING PREY THE SIZE OF A PERSON, WHOLE.

[SNARLING]

NEXT, NIZAR NOTICED THAT, FOR A PREDATORY DINOSAUR,

THE FRONT LIMBS WERE UNUSUALLY LONG.

THOUGH NOT ALL EXPERTS AGREE,

NIZAR BELIEVES SPINOSAURUS MAY EVEN HAVE WALKED ON THEM,

AND THE BACK FEET WERE JUST AS STRANGE.

Ibrahim: NOW, THE FEET OF SPINOSAURUS ARE REALLY BIZARRE.

TYPICALLY IN PREDATORY DINOSAURS,

THE CLAWS WOULD BE RECURVED

TO GRAB PREY AND PIN IT TO THE GROUND.

IN SPINOSAURUS, THE CLAWS ARE ALMOST FLAT,

AND THEY'RE QUITE WIDE.

IT ALMOST LOOKS LIKE A PADDLE, AND I THINK IT'S QUITE LIKELY

THAT THE FEET OF SPINOSAURS WERE WEBBED,

JUST LIKE IN MANY BIRDS OR CROCODILES.

Sereno: THIS HAS MORE TO DO WITH PADDLING AND SWIMMING

THAN RUNNING ON LAND.

Narrator: EVERYTHING WAS POINTING IN ONE DIRECTION.

THIS LOOKED LIKE A BEAST THAT HUNTED AND SWAM IN WATER.

Sereno: THIS WAS A DINOSAUR THAT WAS DOING SOMETHING

NO OTHER PREDATORY DINOSAUR WAS ADAPTED TO DO.

Ibrahim: THIS IS A RIVER MONSTER.

Narrator: THIS WAS AN EXTRAORDINARY DISCOVERY.

IT SUGGESTED SPINOSAURUS HUNTED FISH,

GIVING IT A MAJOR ADVANTAGE

OVER THE OTHER DINOSAUR PREDATORS.

BUT IF SPINOSAURUS WAS SWIMMING, HOW DID IT HUNT?

HOW COULD SOMETHING THIS BULKY

CHASE DOWN ENOUGH FAST-MOVING FISH TO GROW TO MONSTER SIZE?

TO FIND OUT, THE TEAM SCANNED THE BONES.

A CT SCANNER ALLOWED SCIENTISTS TO RECORD THE FOSSILS IN 3-D

AND SEE INSIDE THEM.

SUDDENLY, THE SKULL FROM ANOTHER SPINOSAURUS

STARTED TO REVEAL NEW SECRETS.

Ibrahim: THIS IS THE TIP OF THE SNOUT OF SPINOSAURUS.

SO, WHEN YOU LOOK AT THE OUTSIDE OF THE SNOUT,

YOU HAVE ALL THESE OPENINGS, AND IT'S REALLY UNUSUAL.

Narrator: THE CT SCAN REVEALED THAT INSIDE THE SKULL

A COMPLEX NETWORK OF TUBES RUNS FROM THE HOLES TO THE BRAIN.

Ibrahim: IT'S REALLY A NETWORK OF OPENINGS,

AND SO CLEARLY, THERE'S SOMETHING HAPPENING THERE.

THERE'S PROBABLY SOME KIND OF SENSORY FUNCTION.

Narrator: IT REMINDED NIZAR

OF SOME OF TODAY'S DEADLIEST PREDATORS--

CROCODILIANS.

[WILDEBEEST BELLOWING]

CROCS AND ALLIGATORS HAVE SIMILAR HOLES ON THEIR SNOUTS.

THEY'RE CALLED FORAMINA,

AND, FOR MANY YEARS, THEY, TOO, MYSTIFIED EXPERTS.

NEUROBIOLOGIST DAPHNE SOARES MADE IT HER MISSION

TO FIND OUT WHAT THEY WERE FOR.

Daphne Soares: WOW! AS YOU CAN SEE,

THESE ANIMALS ARE REALLY WELL ADAPTED

TO LIVING IN THE WATER.

Narrator: DAPHNE DEVISED AN UNUSUAL EXPERIMENT.

SHE PUT YOUNG ALLIGATORS INTO A TANK,

BLOCKED UP THE FORAMINA ON THEIR SNOUTS,

AND THEN TURNED OUT THE LIGHTS.

Soares: I HAVE THE ANIMALS IN COMPLETE DARKNESS

SO THEY CAN'T SEE,

AND THEIR EARS ARE COVERED SO THEY CAN'T HEAR.

Narrator: THEN, TO MIMIC THE MOVEMENT

OF SMALL PREY FALLING IN THE WATER,

DAPHNE HIT UPON USING WATER DROPLETS.

Soares: AND I'M USING WATER DROPLETS

BECAUSE THEY DON'T SMELL LIKE ANYTHING.

Narrator: WITH ALL THEIR SENSES NEUTRALIZED,

THE ALLIGATORS DIDN'T REACT AT ALL.

THEN DAPHNE UNBLOCKED JUST THE SNOUT HOLES

AND REPEATED THE DRIP TEST.

DAPHNE'S EXPERIMENT REVEALED

THAT THE OPENINGS IN THE GATOR'S SNOUT

HID PRESSURE SENSORS

THAT CAN PICK UP THE TINIEST MOVEMENTS IN WATER.

THIS SUPER SENSE GIVES CROCS

AN ASTONISHING REACTION SPEED OF FIVE HUNDREDTHS OF A SECOND,

AS FAST AS A LAMBORGHINI GEARSHIFT.

THE HOLES ON SPINOSAURUS' SKULL

LIKELY HID SIMILAR PRESSURE SENSORS.

Sereno: THIS IS THE SUPER SENSE

THAT ALLOWED SPINOSAURUS TO BECOME THE ULTIMATE PREDATOR.

Ibrahim: YOU CAN JUST IMAGINE SPINOSAURUS

PLUNGING ITS HUGE JAWS IN THE WATER

AND DETECTING MOVEMENT AND THEN CATCHING PREY.

Narrator: THIS SUPER SENSE

AND THE ABILITY TO HUNT IN WATER AS WELL ON LAND

MADE SPINOSAURUS THE BIGGEST PREDATOR TO EVER WALK THE EARTH.

BUT COMING UP, THE NEXT GIANT BEAST

IS THE BIGGEST APEX PREDATOR OF ALL TIME.

[GROWLING]

STALKING THE OCEANS

FROM 16 MILLION TO 3 MILLION YEARS AGO,

THE BIGGEST APEX PREDATOR EVER--MEGALODON.

THE NAME SIMPLY MEANS BIG TOOTH,

AND IT SEEMS TO HAVE BEEN THE MOST VORACIOUS SHARK EVER.

Stephen Godfrey: THERE WAS NOTHING THAT WAS SAFE FROM MEGALODON.

IF IT COULD CATCH IT, IT COULD KILL IT.

Narrator: MUCH ABOUT THIS GIANT REMAINS MYSTERIOUS.

BUT NEW CLUES ARE COMING TO LIGHT

IN PANAMA, CENTRAL AMERICA,

IN, OF ALL PLACES, A CEMENT QUARRY.

HERE, GIANT EXCAVATORS ARE DIGGING

THROUGH THE BED OF AN ANCIENT COASTLINE.

Catalina Pimiento: 10 MILLION YEARS AGO,

THIS AREA WAS COVERED BY WATER.

WE KNOW THAT BECAUSE OF THE KINDS OF FOSSILS WE FIND HERE.

FOR EXAMPLE, WE FIND PLENTY OF THESE SHELLS

THAT ARE TYPICAL FROM SHALLOW-WATER AREAS.

Narrator: BUT AS WELL AS SHELLS, PALEOBIOLOGIST CATALINA PIMIENTO

IS ALSO FINDING MEGALODON TEETH,

BUT THERE'S SOMETHING STRANGE ABOUT THEM.

Pimiento: THE TEETH THAT WE FIND HERE

FROM MEGALODON ARE VERY SMALL,

RELATIVE TO TYPICAL MEGALODON TEETH

THAT WE FIND IN OTHER PLACES.

I KNOW THESE ARE MEGALODON TEETH

BECAUSE THEY ARE A PARTICULAR SHAPE.

THEY ARE TRIANGULAR AND QUITE SYMMETRICAL,

BUT, MOST IMPORTANTLY,

BECAUSE OF THE SERRATIONS THEY HAVE ON THEIR EDGES.

Narrator: THERE'S ONLY ONE LOGICAL CONCLUSION.

Pimiento: THE REASON IS THAT MOST OF THEM

WERE BABIES OR JUVENILES.

Narrator: CATALINA HAS MADE AN ASTONISHING DISCOVERY,

THE FIRST EVER EVIDENCE FOR A MEGALODON BREEDING GROUND.

Pimiento: THIS AREA RIGHT HERE

IS THE FIRST NURSERY AREA FOR MEGALODON.

Narrator: BUT EVEN AMONG THESE INFANT SPECIMENS,

MEGALODON'S EXTRAORDINARY SIZE WAS STRIKING.

THE BABY'S TEETH WERE AS BIG AS THOSE OF TODAY'S DEADLY GIANTS,

THE ADULT GREAT WHITE.

Pimiento: THIS IS A MEGALODON BABY TOOTH,

AND THIS IS AN ADULT GREAT WHITE SHARK.

YOU CAN SEE HERE THAT THE BABY MEGALODON

WAS AS BIG AS AN ADULT GREAT WHITE.

SO, IMAGINE WHEN THEY BORN, MEGALODON BABIES WERE HUGE.

Narrator: THE FACT THAT CATALINA HAD TO MAKE HER DEDUCTIONS

USING TEETH ALONE ISN'T UNUSUAL.

IN FACT, ALMOST EVERYTHING THAT EXPERTS KNOW ABOUT MEGALODON

COMES FROM LOOKING AT ITS TEETH.

Godfrey: WE DON'T FIND THE SKELETONS OF MEGALODON

BECAUSE, JUST LIKE LIVING SHARKS,

THEY'RE MADE OF CARTILAGE,

AND AFTER THE SHARK DIES, THE CARTILAGE DISINTEGRATES,

BUT WE DO FIND THEIR TEETH,

AND WE CAN USE THESE TEETH TO RECREATE

WHAT THE JAWS WOULD HAVE LOOKED LIKE WHEN MEGALODON WAS ALIVE.

Narrator: WHAT THEY TELL US

IS THAT THE ADULT MEGALODON WAS A GOLIATH.

ITS JAWS ALONE WERE UP TO SEVEN FEET HIGH,

EASILY TALL ENOUGH TO SWALLOW A PERSON.

WEIGHING IN AT A WHOPPING 100 TONS,

IT WAS 100 TIMES HEAVIER THAN AN AVERAGE GREAT WHITE.

AND, AT 60 FEET LONG,

IT WAS THE LENGTH OF AN 18-WHEELER.

AND THAT JAW,

UP TO 250 TEETH LINED THE MOUTH IN SEVERAL ROWS,

WITH EDGES SERRATED LIKE A STEAK KNIFE.

Godfrey: I MEAN, THESE TEETH ARE JUST SO POWERFUL.

THE MASSIVE JAW MUSCLES THAT THIS ANIMAL HAD,

TO CLOSE THESE JAWS, IT WOULD JUST DISMEMBER

ANY ANIMAL THAT WAS ALIVE ON EARTH AT THAT TIME.

Narrator: AND STEPHEN HAS EVIDENCE

OF JUST WHAT THESE JAWS COULD DO TO PREY.

Godfrey: WE KNOW FROM THE SIZE AND SHAPE OF THIS BONE

THAT IT IS A DOLPHIN TAIL VERTEBRA.

IT'S RIGHT DOWN NEAR THE FLUKE.

THERE ARE THESE DEEP GOUGES ON EITHER SIDE.

THE ONLY WAY THAT THIS FOSSIL COULD HAVE THESE DEEP GOUGES

WAS THAT IT WAS BITTEN FORCEFULLY BY A MEGALODON.

OKAY, SO IF WE LOOK AT A MEGALODON TOOTH.

SO, THE UPPER JAW SLAMS SHUT,

FORCING THE VERTEBRA DOWN INTO THE WEDGE

BETWEEN TWO ADJACENT TEETH, DEEPLY GOUGING THE BONE

WITH SUCH FORCE THAT IT PROBABLY SEVERED THE TAIL OFF.

Narrator: EVERYTHING POINTS TO AN ASTONISHINGLY POWERFUL BITE,

AND ONE MAN WHO HAS SET OUT

TO CALCULATE EXACTLY HOW STRONG THAT BITE IS

IS SHARK BIOMECHANICS EXPERT DAN HUBER.

DAN STARTS WITH A CT SCAN

OF THE SKULL OF A MODERN GREAT WHITE.

Dan Huber: AFTER THE WHITE SHARK'S HEAD IS CT SCANNED,

WE CAN CREATE A COMPUTER MODEL OF IT.

WE CAN SEE THE LOWER AND THE UPPER JAWS HERE,

AND THEN WE CAN APPLY VIRTUAL MUSCLES TO THOSE VIRTUAL JAWS

AND RUN SIMULATIONS TO FIGURE OUT HOW HARD IT CAN BITE.

Narrator: NEXT, DAN SCALES UP TO MEGALODON SIZE.

Huber: AND IF WE APPLY THESE NUMBERS TO WHAT WE THINK

IS THE BIGGEST MEGALODON THAT'S EVER EXISTED,

ITS POSTERIOR BITE FORCE WAS ABOUT 41,000 POUNDS,

OR ABOUT 18,500 KILOGRAMS.

Narrator: THAT'S LIKE THE WEIGHT OF A GARBAGE TRUCK

PRESSING DOWN ON THE BACK TEETH.

SO, WHAT DOES A BITE FORCE OF THIS SIZE LOOK LIKE IN ACTION?

[SIREN]

TO FIND OUT, DAN IS GOING ON A MISSION.

HE'S JOINING UP WITH THE TAMPA FIRE BRIGADE,

AND A PIECE OF EQUIPMENT

THEY USE FOR CUTTING VICTIMS OUT OF CRASHED CARS--

THE JAWS OF LIFE.

Dennis L. Ponce: IT'S LIGHTWEIGHT.

IT'S REALLY EASILY DEPLOYABLE.

Huber: SO, IS THIS THING GOING TO BE ABLE TO GENERATE

41,000 POUNDS OF BITE FORCE AT THE CORNER OF IT?

Ponce: ABSOLUTELY, DAN. THAT'S EXACTLY WHERE IT'S GOING TO CUT,

SO THIS SHOULDN'T HAVE ANY TROUBLE AT ALL

WHEN WE NEED TO CUT OPEN CARS.

Huber: SO, THAT'S ACTUALLY PRETTY SIMILAR

TO WHAT WE'RE LOOKING AT

WITH THIS ANCIENT SHARK, MEGALODON.

ALL RIGHT, LET'S SEE WHAT THIS THING CAN DO.

Ponce: ALL RIGHT, LET'S DO IT.

Narrator: FIRST, DAN TRIES OUT THE JAWS ON A COW BONE,

SOMETHING SIMILAR TO WHAT MEGALODON GOT TO CHEW ON.

Huber: LET'S GO AHEAD.

[WHIRRING]

SEE, IT SPLIT THE THING IN HALF, NO PROBLEM AT ALL.

Narrator: NEXT UP IS THE CAR.

THE JAWS OF LIFE CAN DELIVER

THE SAME KIND OF BITE FORCE AS MEGALODON,

ONLY FAR MORE SLOWLY.

MEGALODON WOULD HAVE BEEN CAPABLE

OF BITING THROUGH THE CAR IN A SPLIT SECOND.

Huber: FROM THIS, WE KNOW THAT MEGALODON

COULD TEAR THROUGH ANCIENT WHALES,

WE KNOW THAT IT COULD TEAR THROUGH ANCIENT SEA TURTLES,

AND APPARENTLY IT COULD EVEN TEAR THROUGH THIS CAR.

MEGALODON WAS THE BIGGEST PREDATOR THAT'S EVER EXISTED,

AND ITS BITE FORCE WAS THE HIGHEST BITE FORCE

THAT'S EVER HAPPENED IN ANY ANIMAL

IN THE HISTORY OF THE PLANET.

Narrator: MEGALODON TOPS ALL OTHER APEX PREDATORS.

IT WAS NEARLY ONE AND A HALF TIMES THE LENGTH OF TITANOBOA.

IT WAS MORE THAN TWICE THE MASS OF PLIOSAURUS,

AND IT WOULD HAVE DWARFED SPINOSAURUS.

BUT THOUGH THIS GIANT SHARK WAS THE BIGGEST APEX PREDATOR EVER,

IT SHARED THE OCEANS WITH SOMETHING MUCH, MUCH BIGGER.

[GROWLING]

THEY ARE THE LARGEST LIVING CREATURES ON EARTH

AND THE HEAVIEST IN HISTORY.

PROPELLED BY VAST TAILS,

THEY SPEND MUCH OF THEIR TIME IN THE DEEP OCEANS.

BUT EVERY YEAR, COME SUMMERTIME,

BLUE WHALES APPEAR IN THE WATERS JUST OFF LOS ANGELES.

♪

FOR ECOLOGIST ARI FRIEDLAENDER,

IT'S AN UNMISSABLE OPPORTUNITY TO STUDY THEM.

Ari Friedlaender: YOU GET CLOSE UP TO THEM,

AND YOU START TO SEE HOW BIG THEY ARE.

YOU START REMEMBERING WHAT IT FEELS LIKE

TO BE THIS TINY LITTLE PERSON IN A PRETTY SMALL BOAT

NEXT TO THIS ENORMOUS WHALE.

IT'S KIND OF DAUNTING, YOU KNOW?

THEY'RE, THEY'RE HUGE.

Narrator: THE NUMBERS ARE AWE-INSPIRING.

THE BLUE WHALE'S SO BIG COMPARED TO A PERSON

THAT 90 OF US COULD FIT ON ITS TAIL ALONE.

ITS 200-TON BULK MAKES IT 30 TIMES HEAVIER

THAN AN AFRICAN ELEPHANT,

AND, AT 100 FEET, IT'S THE SAME LENGTH AS A BOEING 737.

SO, HOW DOES A MAMMAL GET SO BIG?

IT'S ONLY WHEN A WHALE WASHES UP DEAD ON THE BEACH

THAT SCIENTISTS GET A CHANCE TO REALLY STUDY THEIR ANATOMY.

Don Croll: NOW WE'RE IN THE RIB CAGE OF THE WHALE,

AND ON EITHER SIDE OF THE RIB CAGE WOULD BE THE LUNGS.

YOU'VE GOT THE HEART. YOU'VE GOT THE STOMACH.

Narrator: A HEART THE SIZE OF A CAR

CONNECTS TO A MILLION MILES OF BLOOD VESSELS,

ENOUGH TO REACH TO THE MOON AND BACK TWICE.

BUT THERE'S ONE FEATURE THAT'S SUPERSIZED BEYOND ALL OTHERS--

THE MOUTH.

RATHER THAN HUNTING ONE BIG ANIMAL,

BLUE WHALES USE THEIR ENORMOUS MOUTHS

TO CATCH ENTIRE SHOALS IN ONE GO.

THEY FEED ON TINY SHRIMP-LIKE CRUSTACEANS CALLED KRILL.

Croll: MANY PEOPLE THINK THAT IT'S AMAZING

THAT THE LARGEST ANIMAL THAT'S EVER EXISTED

FEED ON SUCH A TINY ANIMAL,

BUT NO BLUE WHALE'S GOING,

"OH, THERE'S A KRILL. I THINK I'LL TAKE THAT ONE."

WHAT THEY'RE DOING IS THEY'RE TRYING TO FIND

HUGE, DENSE SWARMS OF KRILL,

AND A PREY ITEM FOR A BLUE WHALE IS NOT ONE OF THESE GUYS,

IT'S THOUSANDS AND THOUSANDS

AND TENS OF THOUSANDS OF THESE GUYS.

Sues: GOING FOR THE SMALL END REALLY MAKES VERY GOOD SENSE.

THESE THINGS ARE AVAILABLE IN UNIMAGINABLE QUANTITIES,

AND YOU GET A LOT OF PROTEINACEOUS,

RICHLY PROTEINACEOUS FOOD,

BY BASICALLY GETTING A MOUTHFUL OF OCEAN WATER.

[RUMBLING]

Narrator: A WHALE'S MOUTH IS SO BIG,

IT CAN TAKE IN 220 TONS OF WATER IN ONE GO.

FOR ANYTHING ROUGHLY COMPARABLE,

YOU'D HAVE TO LOOK AT SOMETHING LIKE THIS,

THE DC-10.

A SPECIALLY MODIFIED FIREFIGHTING AIRLINER,

IT SWAPPED PASSENGER SEATS FOR A MASSIVE WATER TANK.

Rick Hatton: THIS IS THE BIGGEST TANKER

FLYING IN THE WORLD.

IT CARRIES 12,000 GALLONS OR 44,000 LITERS OF LIQUID,

WHICH IS ROUGHLY FOUR TO TEN TIMES

THE SIZE OF ANY OTHER AIRPLANE.

Narrator: USED TO FIGHT FOREST FIRES,

THE DC-10 RELEASES ENOUGH WATER TO COVER

THE LENGTH OF TEN FOOTBALL PITCHES IN JUST ONE DROP.

BUT A BLUE WHALE PICKS UP FOUR TIMES THIS MUCH WATER

IN A SINGLE MOUTHFUL.

Hatton: WE'RE VERY PROUD OF THIS MACHINE,

BUT IF THE WHALE COULD FLY, WE'D HIRE THE WHALE,

BECAUSE IT'S FOUR TIMES BIGGER.

Narrator: THE WHALE MORE THAN DOUBLES ITS WEIGHT

WITH EACH GULP,

AND WHAT FOLLOWS IS ONE OF THE WEIRDEST OPERATIONS

IN THE NATURAL WORLD.

WHEN THE WHALE OPENS ITS MOUTH TO FEED,

THE WATER PUSHES ITS ELEPHANT-SIZED TONGUE

ALL THE WAY BACK TO ITS BELLY BUTTON.

THE TONGUE IS SUPER-STRETCHY AND EXPANDS OUT,

LINING THE MOUTH AND CREATING A HUGE SAC

FULL OF WATER AND KRILL.

THEN, MOUTH CLOSED,

THE WHALE RAMS THE TONGUE FORWARD LIKE A PISTON.

IT FORCES THE WATER OUT

THROUGH SIEVE-LIKE GRILLES CALLED BALEENS,

UNTIL ONLY THE KRILL IS LEFT INSIDE.

THE ENERGY REQUIRED TO PERFORM THIS MANEUVER IS COLOSSAL.

IN FACT, IN A SINGLE DAY,

BLUE WHALES BURN UP TO THREE MILLION CALORIES,

THE EQUIVALENT OF 10,000 HAMBURGERS.

Sues: YOU KNOW, AT A CERTAIN POINT,

IT JUST SIMPLY BECOMES DIFFICULT TO BREATHE,

TO MOVE BLOOD AROUND,

TO REGULATE BODY TEMPERATURE, ALL THAT.

Friedlaender: JUST TO SATISFY

THEIR ENERGETIC DEMANDS FOR A DAY,

IT PROBABLY TAKES ABOUT A METRIC TON,

OR 1,000 KILOGRAMS OF KRILL.

Narrator: HOW DOES A CREATURE BURNING THIS MUCH ENERGY

FIND ENOUGH FOOD TO BECOME A GIANT?

THE ANSWER MUST LIE IN HOW THEY HUNT.

BUT SINCE WHALES HUNT KRILL HUNDREDS OF FEET UNDERWATER,

WITNESSING THIS BEHAVIOR

HAS BEEN ALMOST IMPOSSIBLE UNTIL NOW.

ARI FRIEDLAENDER IS USING A TAG

THAT ENABLES HIM TO SPY ON WHALES

EVEN WHEN THEY'RE DEEP BELOW THE SURFACE.

IT CONTAINS A CAMERA AND MOTION DETECTORS,

LIKE THE ONES FOUND IN A SMARTPHONE.

ALL HE NEEDS TO DO NOW IS ATTACH IT TO A 200-TON WHALE.

Friedlaender: YOU ALWAYS ARE A LITTLE NERVOUS APPROACHING THEM.

THEY'RE WILD ANIMALS,

SO YOU NEVER KNOW HOW THEY'RE GOING TO REACT.

Narrator: ARI GETS INTO POSITION.

GOT IT.

ARI RETURNS TO BASE TO TRACK THE WHALE ON HIS COMPUTER.

AS ARI PLOTS THE WHALE'S POSITION IN 3-D,

HE SPOTS SOMETHING EXTRAORDINARY.

Friedlaender: INCREDIBLY EXCITING.

UP UNTIL NOW,

WE BASICALLY THOUGHT THEY JUST WENT THROUGH THE WATER,

TAKING THESE MUNCHES, AND LUNGING,

SORT OF IN A STRAIGHT LINE,

BUT WE NOTICED THE ANIMALS DIVING DOWN TO DEPTH

AND THEN IS DOING THESE 360-DEGREE ROLLS.

THIS KIND OF ACROBATIC MANEUVERING

IS SOMETHING WE HAD NO IDEA AN ANIMAL THIS BIG COULD DO.

Narrator: IMAGES FROM THE CAMERA

REVEAL THE WHALE ROLLS

JUST BEFORE IT OPENS ITS MOUTH TO FEED.

Friedlaender: THIS IS THE MECHANISM

THAT ALLOWS WHALES TO GET SO BIG.

IF YOU'RE A WHALE, YOUR EYES ARE ON THE SIDE OF YOUR HEAD.

THEY DON'T HAVE THIS BINOCULAR VISION LIKE WE HAVE,

WHERE YOU CAN SEE DIRECTLY FORWARD,

SO, IN ORDER FOR THAT ANIMAL TO SEE ITS PREY IN FRONT OF IT,

IT KIND OF NEEDS TO ROLL ITS BODY,

SO YOU MAXIMIZE THE AMOUNT OF FOOD YOU GET,

AND YOU LIMIT THE AMOUNT OF ENERGY IT TAKES TO DO IT.

Narrator: FAR FROM JUST SUCKING UP KRILL

LIKE A 200-TON DEEP-SEA JUGGERNAUT,

IT TURNS OUT THE BLUE WHALE IS THE OCEAN'S BIGGEST ACROBAT.

SO FAR ON "WORLD'S BIGGEST BEASTS,"

WE'VE MET THE HAWK-SIZED GRIFFINFLY,

A BIRD THE SIZE OF A FIGHTER PLANE,

A MAMMAL AS BIG AS A TANK,

A PTEROSAUR THE SIZE OF A LEARJET,

A SNAKE THE LENGTH OF A SCHOOL BUS,

AN OCEAN KILLER NEARLY 50 FEET LONG,

A DINOSAUR THAT DWARFS T. REX,

A SHARK 100 TIMES HEAVIER THAN A GREAT WHITE...

AND THE LARGEST CREATURE EVER TO SWIM EARTH'S OCEANS.

THE BLUE WHALE IS VERY NEARLY

THE LARGEST BEAST THAT'S EVER LIVED,

BUT THERE'S ONE BEAST THAT'S EVEN LONGER,

AND IT TAKES THE TITLE OF WORLD'S BIGGEST BEAST.

[GROWLING]

[GROWLING]

MARCH 2015.

IN SOUTHERN ARGENTINA, IN THE REMOTE PROVINCE OF PATAGONIA,

A TEAM OF PALEONTOLOGISTS IS ON STANDBY.

[HORN HONKS]

LUCIO IBIRICU HAS BEEN WAITING FOR THIS MOMENT FOR MONTHS.

[SPEAKING SPANISH]

Narrator: INSIDE THIS TRUCK

ARE SOME OF THE BIGGEST BONES ON THE PLANET.

Lucio Ibiricu: IT'S VERY GOOD. I'M VERY HAPPY.

EVERYTHING HERE NOW.

Narrator: AND AFTER FIVE YEARS IN THE UNITED STATES

UNDERGOING SCIENTIFIC ANALYSIS, THEY'RE COMING HOME.

MORE THAN 50 CRATES HOLD THE BONES OF JUST ONE DINOSAUR.

EACH BONE IS ENORMOUS.

YET, AS BIG AS THEY ARE, THESE BONES ARE JUST A CLUE

TO A CREATURE THAT WAS EVEN LARGER,

THE BIGGEST BEAST EVER TO WALK THE EARTH.

THE JOURNEY TO THIS MOMENT BEGAN IN 2005.

LUCIO WAS PART OF A TEAM OF PALEONTOLOGISTS

PROSPECTING FOR DINOSAUR BONES.

THEY WERE IN A REMOTE AREA OF PATAGONIA KNOWN AS THE BADLANDS.

Narrator: THE ANCIENT ROCKS REVEAL THE AREA

WAS ONCE A PERFECT HABITAT FOR DINOSAURS,

BUT TODAY, THE LUSH FORESTS HAVE GIVEN WAY TO HARSH DESERT.

AS THE TEAM SURVEYED THE LAND,

ONE OF THEM CAME UPON A SMALL PIECE OF EXPOSED BONE.

Kenneth Lacovara: YOU SIT THERE, AND YOU LOOK AT THIS OBJECT,

AND YOU REALIZE THAT YOU'RE THE FIRST PERSON

TO EVER SEE THIS THING.

YOU'RE THE FIRST PERSON IN HISTORY TO KNOW ABOUT THIS.

Narrator: THEY HAD FOUND A GIANT THIGH BONE

OVER SIX FEET LONG.

Narrator: IT'S HARD TO IMAGINE,

BUT BONES OF A BEAST BIGGER THAN THIS

HAVE OCCASIONALLY BEEN DISCOVERED.

WHAT WAS REMARKABLE ABOUT THIS FIND

WAS JUST HOW COMPLETE THE SKELETON WAS.

IT TOOK SEVERAL EXPEDITIONS TO UNCOVER IT ALL.

Lacovara: AT THE END OF THREE SEASONS OF EXCAVATING THERE,

WE HAD 145 BONES.

Narrator: AND THE STATE OF THEM WAS SURPRISING.

Narrator: AT FIRST, IT WAS HARD TO UNDERSTAND

WHY THE SKELETON WAS SO WELL PRESERVED,

BUT THEN, ANALYSIS OF THE TERRAIN PRODUCED AN ANSWER.

Lacovara: IT'S EVIDENT TO US,

FROM THE SEDIMENTS THAT ENTOMB THIS ANIMAL,

THAT IT WAS POSSIBLY KILLED AND CERTAINLY BURIED

IN A STORM EVENT ALONG A RIVER

WHERE THE LEVEE BROKE ON THE FLOODPLAIN.

IT BECAME SOMETHING LIKE QUICKSAND,

AND THIS ANIMAL QUICKLY SANK INTO THIS MIRE,

REMOVING IT FROM WEATHERING AND FROM PREDATORS

AND ALLOWING IT TO HAVE

THIS EXTRAORDINARY DEGREE OF PRESERVATION.

Narrator: THE UPSHOT WAS THAT THEY WERE NOW IN POSSESSION

OF WHAT WAS EFFECTIVELY A TIME CAPSULE,

ONE THAT COULD REVOLUTIONIZE OUR UNDERSTANDING

OF THE BIGGEST BEASTS TO EVER ROAM THE EARTH.

KEN TOOK THE BONES BACK TO HIS LAB IN PHILADELPHIA.

HERE, CAREFUL CLEANING, 3-D SCANNING,

AND FORENSIC EXAMINATION ALL STARTED TO REVEAL

HOW THESE EXTRAORDINARY BEASTS LOOKED AND LIVED.

THE BEAST'S SHEER SIZE WAS APPARENT AT EVERY TURN.

Lacovara: THE SCALE JUST STAGGERS THE IMAGINATION.

THIS ANIMAL WAS 85 FEET LONG FROM HEAD TO TAIL.

IT WAS TWO AND A HALF STORIES TALL AT THE SHOULDER.

Narrator: THIS DINOSAUR WAS A NEW SPECIES,

BELONGING TO A DIVERSE GROUP

OF LARGE PLANT EATERS NAMED TITANOSAURS.

KEN NAMED HIS GIGANTIC TITANOSAUR DREADNOUGHTUS,

MEANING FEARS NOTHING.

Lacovara: DREADNOUGHTUS ISN'T GOING TO HAVE

ANYTHING TO WORRY ABOUT IN TERMS OF PREDATION.

THESE ARE BIG, NASTY, CAPABLE, VIGOROUS CREATURES

THAT DESERVE A LOT OF RESPECT.

Narrator: DREADNOUGHTUS WAS CLEARLY

A MINE OF INFORMATION FOR THE SCIENTISTS,

BUT IT HELD ONE SURPRISE WHICH RELATES DIRECTLY

TO THE SIZE OF THE VERY BIGGEST TITANOSAURS.

CUTTING INTO THE BONES, KEN STARTED TO FIND EVIDENCE

OF HOW OLD THIS DREADNOUGHTUS WAS WHEN IT DIED.

Lacovara: CAN YOU SEE HERE THESE BIG OVAL BONE CELLS HERE?

THAT'S INDICATIVE OF BONE THAT'S NOT GROWING ANYMORE,

AND THEN, AS WE MOVE TOWARDS THE OUTER EDGE OF THE BONE,

YOU'LL NOTICE THAT THAT TEXTURE CHANGES,

AND THAT IS INDICATIVE OF RAPIDLY GROWING BONE.

Narrator: AND THAT COULD MEAN ONLY ONE THING--

KEN'S DREADNOUGHTUS, THOUGH VAST,

WAS NOT FULLY GROWN.

Lacovara: WE KNOW THAT IT WAS GROWING RAPIDLY WHEN IT DIED,

SO, 65 TONS AND NOT YET DONE GROWING.

THAT MEANS THERE ARE BIGGER DREADNOUGHTUS OUT THERE.

WE DON'T KNOW HOW BIG THIS DINOSAUR COULD HAVE GOTTEN.

Narrator: BUT THEN COMES ANOTHER CLUE.

TITANOSAURS WEREN'T LIKE OUR OCEAN GIANTS

MEGALODON AND BLUE WHALE.

THEY DIDN'T START OUT AT MONSTER SIZE.

PALEONTOLOGIST GERALD GRELLET-TINNER

HAS UNCOVERED STUNNING EVIDENCE

THAT REVEALS THE LAST PIECE OF THE PUZZLE.

HE'S INVESTIGATING A SITE IN NORTHERN ARGENTINA,

AN AREA THAT WAS ONCE A HARSH VOLCANIC LANDSCAPE.

Narrator: AT THE TIME OF THE DINOSAURS,

THIS AREA WAS A GEOTHERMAL HOTSPOT,

WITH STEAMING VENTS AND HOT WATER POOLS.

GERALD HAS FOUND EVIDENCE

THAT SOME SPECIES OF TITANOSAURS CAME HERE TO LAY THEIR EGGS.

Narrator: REMARKABLY, AS BIG AS TITANOSAURS COULD GET,

THEIR EGGS WERE ONLY ABOUT THE SIZE OF OSTRICH EGGS.

BUT SOME OF THEM HAD INCREDIBLY THICK SHELLS.

Narrator: GERALD THINKS THAT THE SHELLS BEGAN THIS THICK

TO SHIELD THE EMBRYO INSIDE FROM THE GEOTHERMAL CHEMICALS,

BUT THEN THESE CHEMICALS HELPED MAKE IT POSSIBLE

FOR THE BABY TITANOSAURS TO HATCH.

Narrator: AND FOR AN INCUBATING EGG,

THE CHOICE OF THIS SITE OFFERED A MAJOR PLUS.

IT HAD CONSTANT HEAT.

BUT BABY TITANOSAURS HAD ONE BIG PROBLEM.

ONCE HATCHED, THEY WERE NO BIGGER THAN DOMESTIC CATS,

NOT GREAT IN A WORLD TEEMING WITH HUNGRY PREDATORS.

Lacovara: THERE'S A PREMIUM ON GROWTH WHEN YOU'RE ON THE MENU,

AND SO THEY GROW VERY RAPIDLY TO GET TO THE POINT

WHERE THEY CAN BE IMPERVIOUS TO PREDATION.

Narrator: AND GOING FROM THE SIZE OF A CAT

TO HAVING THIGH BONES OVER SIX FEET LONG

MEANS ONE SERIOUS RATE OF GROWTH.

Lacovara: BABY TITANOSAURS HAVE AN EARLY BURST OF GROWTH,

AND THAT BURST NEVER STOPS.

THEY JUST KEEP GROWING AS FAST AS THEY POSSIBLY CAN.

Narrator: IT SHOULD NOW BE POSSIBLE

TO PULL ALL THE CLUES TOGETHER

AND BUILD A PICTURE OF WHAT THESE BEASTS LOOKED LIKE.

STARTING WITH SCANS OF THE BONES,

KEN LACOVARA WORKS ON A 3-D DIGITAL MODEL OF DREADNOUGHTUS.

THE COMPLETENESS OF THE SKELETON

MEANS THIS MODEL IS FAR MORE ACCURATE

THAN FOR ANY PREVIOUS SPECIES OF TITANOSAUR,

AND THIS GIVES US AN AMAZING OPPORTUNITY.

WE CAN TAKE THE MODEL AND SCALE IT UP

TO MATCH THE BONES OF THE LARGEST TITANOSAUR EVER FOUND--

ARGENTINOSAURUS.

ONLY A HANDFUL OF ARGENTINOSAURUS' BONES

HAVE EVER BEEN DISCOVERED,

SO THIS MAY BE OUR BEST POSSIBLE CHANCE TO FILL IN THE BLANKS

AND SEE WHAT THE BEAST MIGHT HAVE LOOKED LIKE.

JUST HOW BIG THAT IS MUST BE SEEN TO BE BELIEVED.

Narrator: USING DREADNOUGHTUS' SKELETON AS A GUIDE,

LUCIO MAPS OUT HOW ARGENTINOSAURUS

MAY HAVE STOOD ON THIS GROUND.

ITS TAIL ALONE WOULD BE THE LENGTH OF TITANOBOA AT 45 FEET.

Narrator: ADDING ITS BODY TAKES LUCIO TO 70 FEET,

LONGER THAN MEGALODON.

Narrator: THE NECK AND HEAD IS ANOTHER 60 FEET,

GIVING A TOTAL LENGTH OF 130 FEET.

THAT'S BIGGER THAN BLUE WHALE

AND PARACERATHERIUM PUT TOGETHER.

ALL THE PIECES IN PLACE,

IT'S TIME TO REVEAL THE BIGGEST BEAST EVER TO WALK THE EARTH.

[GROWLING]

MEET ARGENTINOSAURUS, THE WORLD'S BIGGEST BEAST.

[ROARING]

Narrator: TOWERING OVER 30 FEET IN THE AIR

WITHOUT EVEN LIFTING ITS HEAD,

AND WITH A NECK LIKE THE ARM OF A CRANE,

THE BIGGEST KNOWN TITANOSAURS

WOULD HAVE BEEN A FEARSOME SIGHT.

STANDING OVER THREE STORIES TALL,

A SIX-FOOT PERSON WOULDN'T EVEN REACH

THE KNEE OF AN ARGENTINOSAURUS.

AT 90 TONS, IT LIKELY WEIGHED AS MUCH AS 11 T. REXES.

AND 130 FEET FROM TAIL TO MOUTH,

IT WAS THE LENGTH OF THE SPACE SHUTTLE ORBITER.

TITANOSAURS WERE MEGA-VERSIONS

OF LONG-NECKED, LONG-TAILED SAUROPODS.

JUST THEIR STOMACHS ALONE WERE LIKELY THE MASS OF AN ELEPHANT,

AND JUST ONE FOOT WAS BIG ENOUGH TO CRUSH 20 PEOPLE.

TO REACH THIS EXTRAORDINARY SIZE,

EXPERTS CALCULATE THAT AN INFANT ARGENTINOSAURUS

COULD DOUBLE IN MASS IN JUST FIVE DAYS.

WITH THAT KIND OF GROWTH RATE, AN EIGHT-POUND HUMAN BABY

WOULD WEIGH AS MUCH AS AN ADULT WITHIN A MONTH.

EVIDENCE SUGGESTS IT WOULD TAKE JUST OVER 20 YEARS

TO REACH 90 TONS.

SO WHAT WAS THE SECRET TO THEIR MEGA-SIZE?

HOW DID THEY EAT ENOUGH TO GROW THIS FAST?

THE ANSWER APPEARS TO LIE WITH THE ONE THING ABOUT TITANOSAURS

THAT ISN'T GARGANTUAN...

THEIR HEADS.

Narrator: DREADNOUGHTUS ONLY HAD A HEAD

AS BIG AS THAT OF A HORSE,

AND ITS SECRET LAY NOT IN SOMETHING IT DID

BUT IN SOMETHING IT DIDN'T DO.

Lacovara: THE SKULL IS BASICALLY A PLACE

TO HOUSE THE SENSORY ORGANS AND A PLANT VACUUM,

AND THAT'S THE ONLY FUNCTION THAT IT DOES.

THEY DON'T HAVE THE ABILITY TO CHEW.

Narrator: WHAT THAT MEANS IS

THAT THE BIGGEST TITANOSAURS HAD THE CAPACITY

TO CONSUME OVER TWO TONS OF VEGETATION EVERY DAY.

THAT'S ENOUGH SALAD TO FEED 40,000 PEOPLE.

Lacovara: DREADNOUGHTUS COULD STAND IN ONE PLACE

WITH ITS MASSIVE BODY AND NOT MOVE THAT BODY,

AND MAYBE SPEND AN HOUR

TAKING IN TENS OF THOUSANDS OF CALORIES,

AND THEN AT THE END OF THAT,

TAKE A FEW STEPS TO THE RIGHT AND SPEND ANOTHER HOUR OR SO

CLEARING OUT ANOTHER GIANT ENVELOPE OF VEGETATION,

SO BY EXPENDING VERY FEW CALORIES ITSELF,

IT TAKES IN MASSIVE QUANTITIES OF FOOD.

Narrator: THIS BASIC STRATEGY MADE TITANOSAURS

SOME OF THE MOST EFFICIENT EATERS OF ALL TIME,

AND IT ALLOWED THEM TO REACH MONSTER SIZE,

AND YET, AS BIG AS THEY WERE,

EXPERTS ARE CONVINCED THAT SOMEWHERE OUT THERE,

HIDDEN IN THE ROCKS,

ARE EVEN BIGGER SPECIMENS STILL TO BE UNCOVERED.

THE WORLD'S BIGGEST BEASTS

ARE GIANT CREATURES AT THE TOP OF THEIR EVOLUTIONARY TREES--

BEASTS THAT HUNT, KILL,

WALK, SWIM, AND FLY

AT SIZES THAT DWARF ALL OTHERS.

BETWEEN THEM, THEY'VE MYSTIFIED SCIENTISTS,

BROKEN THE RECORD BOOKS,

AND COLONIZED EVERY CONTINENT ON THE PLANET.