Supersize Crocs

ROM WHITAKER HAS SPENT THE PAST 40 YEARS WORKING AMONG BIG REPTILES.

IT DWARFS MY HAND.

THIS IS LIKE A DINOSAUR FOOTPRINT.

IN THE 1970s, WHEN INDIA'S CROCODILE POPULATION WAS ON THE BRINK OF EXTINCTION, ROM FOUNDED THE COUNTRY'S FIRST REPTILE PARK.

HIS BREEDING PROGRAM CHANGED THE CROCODILE'S FUTURE.

IF IT COMES THIS WAY, JUST GET READY TO JUMP.

TODAY, ROM'S MISSION TAKES HIM OUTSIDE HIS PARK.

DRIVEN BY THE MEMORY OF A 21-FOOT CROCODILE SKIN DI SCOVERED IN PAPUA NEW GUINEA, ROM WANTS TO KNOW IF MONSTER CROCODILES STILL EXIST IN THE WILD.

Whitaker: MY WORRY IS, HAVE WE SELECTIVELY WEEDED OUT, HAVE WE SHOT OUT THE GIANT GENE?

ARE THERE ANY MORE 20-FOOT CROCODILES LEFT IN THE WORLD?

ROM WILL SEARCH THREE CONTINENTS IN PURSUIT OF THIS ELUSIVE ANIMAL.

THERE SHE GOES.

IF HIS HUNT FAILS, THEN IT'S POSSIBLE THE CLOSEST THING WE HAVE TO LIVING DINOSAURS HAS DISAPPEARED FOREVER.

BUT IF THIS CROCODILE CONSERVATIONIST SUCCEEDS, THEN PERHAPS SUPERSIZE CROCS WILL ROAM THE EARTH AGAIN.

(Epic Music) Narrator: EVERY CONTINENT HAS ITS DRAGON MYTHS.

LEGENDS OF THESE GREAT REPTILIAN BEASTS DATE BACK TO THE DAWN OF CIVILIZATION.

TODAY, THE MYTH AND LEGEND IS MADE FLESH AND BLOOD IN THE LAST OF THE GIANT CROCODILES.

THEY ARE THE CLOSEST THINGS WE HAVE TO LIVING DINOSAURS.

TO THIS VERY DAY, THESE COLD-BLOODED BEASTS STILL HAUNT OUR DARKER NIGHTMARES.

AND THE FEAR AND FASCINATION THEY INSPIRE REMAINS ROOTED IN OUR PSYCHE.

AND FOR GOOD REASON.

EVERY YEAR, THERE ARE STILL HUNDREDS OF CROCODILE ATTACKS WORLDWIDE.

FOR CROC CONSERVATIONIST ROMULUS WHITAKER, FASCINATION TURNED INTO A LIFELONG OBSESSION WHEN, AS A CHILD, HE SAW THE SKULL OF A 40-FOOT PREHISTORIC CROCODILE.

[ CROCODILE CALL ] [ Laughing ] THIS IS IT.

THIS IS DINOSUCHUS.

YOU KNOW, THIS TAKES ME BACK, I HAVE TO ADMIT IT, 50 YEARS.

WHEN I WAS A KID, LIVING IN NEW YORK, MY MOTHER USED TO TAKE ME TO THE AMERICAN MUSEUM OF NATURAL HISTORY.

AND I'VE GOT A FEELING THIS IS PERHAPS WHAT SORT OF KICK-STARTED ME INTO THE WHOLE REPTILE THING.

Narrator: FOSSIL CROCODILES ARE ALMOST IDENTICAL TO TODAY'S LIVING SPECIES.

IT'S A BODY PLAN THAT HAS BARELY CHANGED SINCE BEFORE THE DINOSAUR ERA.

Whitaker: I KNEW, PROBABLY EVEN AT THAT TENDER AGE, THAT THERE WERE LIVING DINOSAURS, SO TO SPEAK, IN THE FORM OF CROCODILES.

AND I REALLY DO BELIEVE THAT'S WHERE IT ALL STARTED.

Narrator: ROM MOVED TO INDIA AS A BOY, AND IN THE EARLY 1970s, WHEN HE REALIZED THAT CROCODILES HAD BEEN HUNTED TO THE BRINK OF EXTINCTION IN INDIA, HE SET UP THE COUNTRY'S FIRST REPTILE PARK IN MADRAS.

WITH HIS BREEDING PROGRAM, ROM'S HANDS-ON APPROACH HAS HELPED TURN AROUND THE FATE OF INDIA'S THREE SPECIES OF CROCODILES -- THE NOTORIOUSLY AGGRESSIVE SALTWATER CROCODILE, THE SMALLER MUGGER CROCODILE, AND THE WEIRD-LOOKING GHARIAL.

WE'RE GETTING THESE GHARIAL EGGS OUT, BECAUSE THE NESTS HERE, THEY WILL ACTUALLY START DRYING OUT WHEN YOU GET A VERY HOT SUMMER HERE.

IF SHE COMES THIS WAY, JUST GET READY TO JUMP.

Narrator: ALTHOUGH NOT USUALLY DANGEROUS TO HUMANS, WHEN ITS NEST IS THREATENED, THIS 12-FOOT GHARIAL CAN BE AS AGGRESSIVE AS ANY OTHER BIG CROC.

TODAY, THE CROC BANK FLOURISHES, AND NOW ROM HAS A NEW MISSION.

WHEN HE DISCOVERED THAT 21-FOOT SKIN IN NEW GUINEA, HUNTING LEGEND DISSOLVED INTO ZOOLOGICAL FACT.

THAT DAY, ROM CAME WITHIN TOUCHING DISTANCE OF THE DINOSAURS OF HIS CHILDHOOD.

BUT AFTER OUTLIVING THE DINOSAURS, HAVE THE LAST OF EARTH'S GIANT REPTILES NOW BEEN WIPED OUT BY US?

Whitaker: MY WORRY IS, HAVE WE SELECTIVELY WEEDED OUT, HAVE WE SHOT OUT THE GIANT GENE?

ARE THERE ANY MORE 20-FOOT CROCODILES LEFT IN THE WORLD?

Narrator: IT CAN TAKE 80 YEARS FOR A CROC TO REACH SUPERSIZE.

WHEN THE MODERN AGE OF RIFLES ARRIVED IN THE LAST CENTURY, YEARS OF TROPHY-HUNTING SWEPT AWAY ALMOST ALL THE MATURE MONSTER CROCS.

ONLY THE WILIEST AND MOST REMOTE OF BEASTS SURVIVED THIS GLOBAL CROCODILE GENOCIDE.

FINDING OUT IF THESE GIANT CROCS STILL EXIST IS NOT ONLY VERY IMPORTANT TO ME.

THERE'S A REALLY GOOD REASON FOR THIS.

Narrator: IF ANY MONSTER CROCS DO STILL EXIST, THEN THAT MEANS THERE'S STILL THE HABITAT OUT THERE TO GUARANTEE THEIR FUTURE.

TODAY, IN MANY AREAS, CROCODILES HAVE BEEN PROTECTED FROM HUNTERS FOR NEARLY 30 YEARS, AND SO ROM HAS DECIDED IT'S TIME TO SET OUT TO FIND ANOTHER GIANT.

CROCODILES ARE INCREDIBLY SUCCESSFUL ANIMALS.

THEY ARE THE LARGEST AND MOST INTELLIGENT REPTILES ON EARTH TODAY.

AND THE KEY TO THEIR SUCCESS IS A BODY PLAN THAT IS OVER 200 MILLION YEARS OLD.

YET, DESPITE THE GREAT GULF OF EVOLUTIONARY HISTORY THAT SEPARATES US FROM THESE ANCIENT REPTILES, ON THE INSIDE, WE SHARE A REMARKABLY SIMILAR BODY DESIGN.

THERE IS A SPINE RUNNING THE LENGTH OF THE BODY, FOUR LIMBS WITH FIVE DIGITS, A CENTRALLY PLACED PAIR OF LUNGS, AND A FOUR-CHAMBERED HEART.

IT'S OFTEN CONSIDERED PRIMITIVE, BUT THE CROCODILIAN BODY PLAN IS POWERED BY A PHYSIOLOGY THAT IS AS COMPLEX AND ADVANCED AS ANY ANIMAL ALIVE TODAY.

IT'S A TIMELESS DESIGN CLASSIC, PROTECTED BY A LAYER OF REPTILE ARMOR PLATING.

BONY DISKS CALLED OSTEODERMS RUN THE LENGTH OF ITS BACK...

WHILE A TOUGH REPTILIAN SKIN SEALS THE WHOLE PACKAGE TOGETHER.

TODAY, THERE ARE 23 DIFFERENT CROCODILIANS, FOUND ON ALMOST EVERY CONTINENT.

BUT MOST SCIENTISTS BELIEVE ONLY SEVEN SPECIES HAVE THE POTENTIAL TO APPROACH ANYWHERE NEAR 20 FEET.

AND FINDING ONE WILL ONLY BE HALF THE BATTLE.

PUTTING A TAPE MEASURE ON A 20-FOOT, ONE-TON WILD REPTILE IS THE REAL CHALLENGE.

THE STAR ATTRACTION AT ROM'S CROC BANK IS A 36-YEAR-OLD, 16-FOOT SALTWATER CROCODILE KNOWN AS "JAWS."

Whitaker: IF THERE'S ANY WAY WE'RE GOING TO BE ABLE TO ESTIMATE THE SIZE OF CROCODILES IN THE WILD, IT'S BY FIRST ESTABLISHING THE RATIO BETWEEN THE HEAD AND TOTAL LENGTH OF A CROCODILE HERE.

THINGS LIKE THE WIDTH OF THE TAIL SCALES, ALL THE KIND OF LITTLE MEASUREMENTS WHICH WE'RE GOING TO BE HAVING A LOT OF FUN WITH IN THE WILD.

HERE'S A CONTROLLED CIRCUMSTANCE, SO WE CAN DO EVERYTHING JUST RIGHT.

AND JAWS, HOPEFULLY, WILL COOPERATE THROUGHOUT.

Narrator: ALONG WITH HEAD LENGTH, THESE CLUES, LIKE BODY WIDTH AND FOOT SIZE, MAY BE THE ONLY MEASUREMENTS ROM CAN GET IN THE WILD.

Whitaker: AS LONG AS YOU KEEP HIS INTEREST WITH FOOD, YOU CAN DO ALMOST ANYTHING TO HIM -- ALMOST ANYTHING.

OKAY, 77 MILLIMETERS.

Narrator: HE'LL USE JAWS AS HIS MODEL TO HELP PREDICT THE SIZE OF A WILD CROCODILE.

Whitaker: OKAY, THE IDEA IS TO TRY TO GET HIM TO STRAIGHTEN OUT A LITTLE BIT HERE.

COME ON, FATSO.

HE OBVIOUSLY NEEDS EXERCISE.

GETTING A BIT JOWLY IN HIS OLD AGE.

OKAY.

GOOD, GOOD-SIZED CROCODILE.

ONE, TWO, THREE, FOUR, FIVE, SIX, SEVEN, EIGHT, NINE, TEN -- HOLD IT, HOLD IT.

Narrator: ROM RAISED JAWS BY HAND.

BUT AT THIS SIZE, HE CAN NEVER BE TRUSTED.

Whitaker: 3.6 METERS -- NOW, IT'D BE, OF COURSE, MORE SCIENTIFIC TO FLIP JAWS OVER AND DO A REALLY PROPER SNOUT-TO-, UH... [ Laughing ] THAT LENGTH, BUT WE'RE NOT GOING TO FLIP HIM OVER TODAY.

HE'D MORE LIKELY FLIP US OVER.

NOW, THE THING THAT KIND OF MESSES ME UP IS THE FACT THAT THE RATIO OF A CROCODILE'S HEAD TO ITS TOTAL LENGTH WAS SUPPOSED TO BE ABOUT 1.1 TO 7.

BUT IN MEASURING JAWS'S HEAD AT ABOUT 22 1/2 INCHES, HIS LENGTH IS OVER 16 FEET.

AND THAT'S MORE LIKE A RATIO OF 1 TO 8.5.

Narrator: DESPITE THIS VARIATION, SKULL SIZE IS OFTEN THE ONLY RECORD OF GIANT SPECIMENS SCIENTISTS HAVE, SO THEY'VE DEVELOPED A FORMULA TO ESTIMATE BODY SIZE FROM HEAD LENGTH BY SIMPLY MULTIPLYING BY A FACTOR OF AROUND 7 1/2.

BUT, ALTHOUGH CROCODILES GROW THROUGHOUT THEIR LIVES, THIS RELATIONSHIP BETWEEN SKULL AND BODY GETS DISTORTED WITH REALLY BIG CROCS, WHICH TEND TO PUT ON MUCH MORE IN BULK THAN LENGTH.

THIS IS THE KIND OF THING WE'RE GOING TO HAVE TO BE WORKING WITH AND ADJUSTING, AS WE GO AROUND AND MEET WILD CROCODILES -- AS IF IT WASN'T DIFFICULT ENOUGH ALREADY.

Narrator: ROM IS NOW IN ORISSA, IN EASTERN INDIA, WHERE, ACCORDING TO THE GUINNESS BOOK OF RECORDS, THE WORLD'S BIGGEST CROCODILES CAN BE FOUND.

THE LOCAL MAHARAJA, PRINCE SHIVENDRA, IS THE GRANDSON OF A FAMOUS CROCODILE HUNTER.

Whitaker: WHAT A SIGHT!

YOU KNOW, 1976 IS WHEN YOUR GRANDFATHER SHOWED ME THIS.

SO THIS GUY, FROM WHAT I UNDERSTAND, WAS A MAN-EATER -- OR A WOMAN-EATER, MOSTLY.

OH, YES, MORE THAN 30 PEOPLE, OUT OF WHICH I THINK 20-PLUS WERE WOMEN.

WE HAD A WHOLE TABLE OF ALL THE BANGLES AND ANKLETS THAT CAME OUT OF HIS STOMACH.

Narrator: IT'S CLAIMED THAT THIS ENORMOUS 80-YEAR-OLD SKULL CAME FROM A 23-FOOT SALTWATER CROCODILE KILLED IN A NEARBY RIVER.

Whitaker: IT'S 73.3.

Narrator: IT'S BELIEVED TO BE ONE OF THE LARGEST CROCODILE SKULLS IN THE WORLD.

Whitaker: AND WE TAKE THE WHOLE WIDTH... 45.

Narrator: HISTORICALLY, GIANT CROCS WERE ONCE FOUND HERE.

SO ORISSA IS A GOOD PLACE TO BEGIN HIS SEARCH.

ALTHOUGH WEIGHING LESS THAN 1% OF TOTAL BODY WEIGHT, CROCODILE BRAINS ARE HIGHLY COMPLEX AND HIGHLY EFFICIENT.

IN APPEARANCE, SCIENTISTS BELIEVE THEY HAVE FAR MORE IN COMMON WITH THE BRAIN OF A LARGE, MEAT-EATING DINOSAUR THAN OTHER LIVING REPTILES.

AND, WITH A GOOD MEMORY AND A PROVEN ABILITY TO LEARN, THEY ARE CONSIDERED THE MOST INTELLIGENT REPTILES ALIVE TODAY.

A SKULL THIS BIG IS A NATIONAL TREASURE.

Whitaker: IT'S HEAVY, ISN'T IT?

Narrator: BASED ON THE JAWS/SKULL RATIO, IT WAS AT LEAST 20 FEET, POSSIBLY MORE.

BUT IT DIED OVER 80 YEARS AGO.

SO, IN THE MYRIAD OF WATERWAYS THAT SURROUND THE MAHARAJA'S PALACE, ROM GOES IN SEARCH OF ANOTHER MONSTER.

Whitaker: WE'VE SEEN THE GIANT SKULL, AND NOW I'M BACK IN BHITARKANIKA FOR THE FIRST TIME SINCE 1976.

BACK IN THOSE DAYS, WELL, I PROBABLY COUNTED 10 OR 12 CROCODILES IN A WHOLE NIGHT'S SEARCHING.

AND I'M ALREADY UP TO 50 AND COUNTING.

Narrator: DESPITE THE NIGHTTIME NUMBERS, IT'S ONLY BY DAY THAT ROM WILL HAVE ANY CHANCE OF ASSESSING THEIR SIZE.

THE BEST TIME TO GET A GOOD LOOK AT CROCODILES IS IN THE MORNING, WHEN THEY BASK ON THE RIVERBANK.

BUT A LOCAL HEAT WAVE IS NOT HELPING.

IT'S ACTUALLY TOO HOT ON LAND, AND FOR NOW, THEY PREFER THE COOLER WATER.

WE'RE GETTING TO THE TIME OF YEAR WHEN THE MORNING IS WARMING UP FAST.

THEY WANT TO GET UP AND GET WARM, BUT RIGHT NOW, THE WATER TEMPERATURE AND EVERYTHING IS MUCH HIGHER THAN, LET'S SAY, A MONTH AGO, IN JANUARY.

IT'S GOING TO DEPEND A LOT ON LUCK, HOW MANY CROCS WE SEE.

Narrator: THERE ARE SOME BIG TRACKS ON THE MUD BANK.

FROM WHAT HE'S LEARNED FROM JAWS, IT'S AN OPPORTUNITY TO MAKE A GUESS AT THE SIZE OF THE ANIMAL THAT LEFT THEM.

Whitaker: WOW!

THIS IS SOME HEFTY FOOTPRINT.

IT'S 17.5 INCHES, THE HIND FOOT.

Narrator: THAT MAKES IT BIGGER THAN JAWS.

I DON'T KNOW IF I'D SWIM IN THIS WATER.

THERE ARE A HECK OF A LOT OF CROCODILES, AND ALTHOUGH I'M NOT GENERALLY SORT OF FRIGHTENED OF CROCODILES, PER SE, I'M REALLY DISAPPOINTED THAT WE HAVEN'T SEEN ANY CROCS THIS MORNING YET.

YOU'D THINK THAT ONE WOULD WANT TO COME OUT AND WARM UP A LITTLE BIT, AT LEAST.

Narrator: ROM NEEDS TO BE CAREFUL.

CROCODILES ARE PRIMARILY AMBUSH PREDATORS, RELYING ON SHORT BURSTS OF SPEED, LAUNCHING THEMSELVES AT NEARLY 30 MILES PER HOUR OUT OF THE WATER, TO SURPRISE THEIR PREY.

AND THE KEY TO THIS AMBUSH STRATEGY IS THE ABILITY TO SLOW DOWN THEIR METABOLISM AND STAY SUBMERGED AND MOTIONLESS UNDERWATER.

AND THAT DEPENDS ON HAVING ONE OF THE MOST ADVANCED HEARTS IN THE ANIMAL KINGDOM.

LIKE US, THEY NEED A FOUR-CHAMBERED HEART TO SEPARATE THE HIGH BLOOD PRESSURE OF THE BODY FROM THE MORE DELICATE LUNGS, WHERE AIR IS ABSORBED.

BUT WHAT MAKES THEIR CROCODILIAN HEART UNIQUE IS A SPECIAL VALVE THAT ALLOWS THEIR BLOOD FLOW TO BYPASS THE LUNGS ALTOGETHER.

COMBINE THIS WITH UNIQUE BLOOD CELLS THAT HAVE A SUPER-EFFICIENT CAPACITY FOR OXYGEN TRANSMISSION, AND YOU HAVE AN ANIMAL THAT CAN LIE FOR UP TO TWO HOURS UNDERWATER WITHOUT TAKING A SINGLE BREATH.

THAT'S THE SPOT.

OH, OKAY.

Narrator: BEFORE ROM LEAVES BHITARKANIKA, HE RECEIVES A REPORT OF A 20-FOOT GIANT NEARBY.

[ MEN SPEAKING INDIAN LANGUAGE ] Narrator: UNFORTUNATELY, IT'S DEAD AND BURIED.

BUT ROM IS STILL EAGER TO TAKE A LOOK, JUST TO SEE IF IT'S AS LONG AS CLAIMED.

Man: THERE IS A BONE.

Whitaker: YEP, IT STINKS, TOO.

YEAH, THERE'S THE SKULL.

THE SKULL IS THERE.

Narrator: AFTER ALMOST A YEAR UNDERGROUND, ONLY THE BONES REMAIN.

Man: OH, MY GOD.

Man: MOLAR TOOTH.

Whitaker: NOW YOU REALLY GET TO SEE THEM NICELY BECAUSE THERE'S NOT ALL THAT SKIN AND SORT OF GUM AROUND THEM.

Narrator: THE COMPLETE SKELETON WOULD HAVE MEASURED OVER 17 FEET.

IT'S NO MONSTER CROC, BUT IT'S A SIGN THAT MAYBE THE GIANTS HAVEN'T ALL BEEN WIPED OUT IN ORISSA.

UNTIL THE WEATHER CHANGES, IT'S TIME TO MOVE TO THE COOLER NORTH, TO A WILDLIFE SANCTUARY NEAR THE NEPAL BORDER.

THE ORISSA SALTIES MAY CLAIM THE WORLD RECORD, BUT ROM KNOWS THAT INDIA ALSO HAS ANOTHER POTENTIALLY GIANT CROCODILE SPECIES THAT COULD BREAK THAT 20-FOOT BARRIER.

IT'S THE GHARIAL.

THESE ARE AMONG THE WORLD'S MOST ENDANGERED CROCODILES, ALTHOUGH THEY POSE ALMOST NO THREAT TO HUMANS, SINCE THEY FEED ALMOST EXCLUSIVELY ON FISH.

PUTTING A TAPE ON THIS ANIMAL IS OUT OF THE QUESTION.

EVEN WITHOUT THE DANGER, IT'S SIMPLY TOO SHY OF PEOPLE.

BUT ROM HAS ANOTHER METHOD UP HIS SLEEVE.

OKAY, ROM, MOVE 10 FEET FORWARD.

MOVE TWO FEET DOWN THE BANK.

Narrator: THE TRICK IS TO FIND THE EXACT SPOT WHERE THE GHARIAL WAS LYING.

OKAY, YOUR FEET ARE JUST ABOUT WHERE HIS GHARIAL WAS.

YOU MAY WONDER WHY I'M DOING THIS.

BUT I'M EXACTLY SIX FEET TALL.

180 CENTIMETERS.

AND WITH MY SIZE AS THE RELATIONSHIP BETWEEN THE SIZE OF THE GHARIAL, AND WHAT WE'VE DONE ON THE OTHER BANK IS TAKEN EXACT AND PRECISE PHOTOGRAPHS OF THIS AREA, WE'RE GOING TO BE ABLE TO CALCULATE THE SIZE OF THE GHARIAL ACCURATELY.

Whitaker: WE'VE GOT TWO ROMS HERE.

TWO ROMS DON'T MAKE A RIGHT.

IN THIS CASE, TWO ROMS MAKE 12 FEET.

BUT WE'VE GOT PART OF THE ANIMAL'S TAIL IN THE WATER, ANOTHER AT LEAST TWO FEET, POSSIBLY MORE.

Man: IT'S A THREE-ROM GHARIAL.

[ LAUGHTER ] Narrator: AND NOW, SOMETHING A LITTLE MORE PRECISE.

AT OVER 16 FEET LONG, IT WAS EVEN BIGGER THAN ROM EXPECTED.

Whitaker: I THINK I'M REVISING MY OPINION.

I'M GOING TO LISTEN TO PEOPLE A LITTLE MORE -- LESS SKEPTICALLY, LET'S SAY.

AND FINALLY CONFIRM IT WITH THIS KIND OF METHODOLOGY.

I'M DEFINITELY CHANGING THE WAY I LOOK AT SIZES OF CROCODILES.

Narrator: ROM HAS NOW ESTABLISHED A WAY TO MEASURE CROCS REMOTELY.

AND IF THOSE RUMORS OF BIG CROCS ARE TRUE FOR INDIA, WHAT ABOUT THE REST OF THE WORLD?

Whitaker: WELL, I'VE BEEN DOING QUITE A BIT OF RESEARCH ON THIS.

AND IF WE'RE GOING TO FIND THE GIANT CROCODILE, WE'RE PROBABLY GOING TO HAVE TO LOOK AT THE NILE CROCODILE IN AFRICA AND THE SALTWATER CROCODILE THROUGHOUT THIS VAST CHUNK OF ASIA.

THAT'S A PRETTY BIG CHUNK OF TERRITORY.

I THINK I REALLY HAVE TO MAKE SOME CALLS AND NARROW THIS DOWN A LITTLE BIT FURTHER.

SIMON, HOW ARE THINGS IN BORNEO, MATE?

HOW IS SOUTH AFRICA?

Narrator: WITH OVER 30 YEARS' WORTH OF CONTACTS, IT'S TIME TO TAP INTO ROM'S GLOBAL CROCODILE NETWORK.

AH.

REALLY?

Narrator: BUT HE'LL STILL NEED TO BE WARY OF FISHERMEN'S TALES.

22?

[ Laughing ] THAT IS ENORMOUS, YEAH.

"ALL LINES ARE BUSY."

4 1/2 FEET ACROSS.

WOW.

THAT'S GIANT.

ARE THEY THINKING THAT THIS IS THE CROCODILE THAT HAS TAKEN A FEW PEOPLE OVER THE LAST COUPLE OF MONTHS?

HELLO.

HELLO.

HELLO.

[ LAUGHING ] GOOD, GOOD.

GOOD TALKING WITH YOU.

SEE YOU.

Narrator: ROM'S BEST LEADS ALL POINT TO NORTHERN AUSTRALIA AND THE SALTWATER CROCODILE.

BUT THERE'S ONE AFRICAN SPECIES THAT, IN TERMS OF SHEER SPECTACLE, HAS NO COMPARISON.

FOR DECADES, FILMMAKERS HAVE CONVERGED ON THE GRUMETI RIVER TO FILM THE AWESOME AMBUSH POWER OF THE NILE CROCODILE.

BUT HOW BIG DO THESE GREAT REPTILES REALLY GET?

AH, LOOK AT THIS!

YOU KNOW, WHEN YOU'RE TALKING ABOUT GIANT CROCODILES, YOU CAN'T IGNORE AFRICA.

AND THIS IS WHY I'M HERE IN SOUTHERN ETHIOPIA, ON THE EDGE OF THE RIFT VALLEY.

THIS IS LAKE CHAMO.

AND I'VE BEEN TOLD THAT THIS IS THE PLACE THAT CONTAINS THE MOTHER LODE OF GIANT NILE CROCODILES.

Narrator: LAKE CHAMO LIES ALMOST 4,000 FEET ABOVE SEA LEVEL AND COVERS OVER 200 SQUARE MILES.

ROM'S ODDS ON FINDING A GIANT ARE IMPROVING.

THESE BIG NILE CROCODILES LOOK UNGAINLY ON THE BANK...

THERE IT GOES.

Narrator: BUT IN THE WATER, THEY'RE LITERALLY IN THEIR ELEMENT AND ABLE TO CONTROL THEIR BUOYANCY LIKE A SUBMARINE, EVEN SWALLOWING STONES FOR FINE-TUNING.

63, 64.

Whitaker: I'M STARTING TO BELIEVE WHAT THEY SAID ABOUT LAKE CHAMO NOW.

Narrator: ROM'S FIRST PORT OF CALL IS A RIVER MOUTH KNOWN LOCALLY AS "THE CROC MARKET."

WOW.

LAST NIGHT THERE WAS A HEAVY RAIN UP IN THE MOUNTAINS, AND THE WATER IS POURING DOWN HERE, MUDDY WATER, BRINGING WITH IT FISH AND OTHER STUFF, AND THAT'S WHY THE BIRDS ARE ALL HANGING AROUND HERE.

AND OBVIOUSLY WHY THE CROCS ARE HERE, TOO.

I'VE COUNTED, WHAT, ABOUT 62 -- NOW 63.

JUST IN THIS SMALL AREA HERE.

AND SOME OF THEM ARE REALLY BIG.

PREDICTABLY, THE BIGGER ONES ARE MORE WARY, AND THEY SORT OF PUSHED OFF, LEAVING THE SMALLER ONES STILL BEHIND.

THIS IS JUST AN INCREDIBLE SIGHT.

I'VE NEVER SEEN ANYTHING LIKE IT IN MY LIFE.

129.

130.

173 CROCS IN TWO HOURS.

[ LAUGHING ] Narrator: ETHIOPIA'S LAKE CHAMO CLEARLY HAS A GOOD POPULATION OF LARGE CROCODILES.

BUT WILL ANY REACH THAT MAGICAL 20-FOOT MARK?

TO FIND OUT, ROM IS GOING TO TRY OUT ANOTHER HIGH-TECH MEASURING STRATEGY -- LASER RANGE-FINDING BINOCULARS.

COMBINED WITH DATA FROM A DIGITAL PHOTOGRAPH, THESE ENABLE THE ESTIMATION OF BODY LENGTH AT A DISTANCE.

OVER 16 FEET.

THIS ONE IS EVEN BIGGER, OVER 17 FEET.

AND 16 AGAIN.

IT'S NOT COMPLETELY PRECISE, BUT IT'S A PRETTY GOOD GUIDE.

ROM IS HEADING FOR A SMALL, UNINHABITED ISLAND IN THE MIDDLE OF THE LAKE.

THE DAY IS HEATING UP, AND THE CROCS ARE LOOKING TO MAKE THE MOST OF THE MORNING SUN.

UNLIKE MAMMALS, CROCODILES ARE COLD-BLOODED, AND THEY NEED TO ACTIVELY REGULATE THEIR BODY TEMPERATURE.

THEY DO THIS BY BASKING IN THE SUN BY DAY AND THEN SPENDING THE COOLER NIGHTS SUBMERGED, WHERE THEIR BODY TEMPERATURE DROPS MORE SLOWLY.

THE NEXT DAY, THE CYCLE BEGINS ALL OVER AGAIN.

THE BIGGER THE CROCODILE, THE LONGER IT CAN STORE HEAT, AND SO THE GIANTS DON'T NEED TO BASK AS MUCH AS THE SMALLER ONES.

IT'S ANOTHER REASON WHY THEY'RE HARDER TO SPOT.

BUT THIS NARROW STRETCH OF GRAVEL IS A GOOD OPPORTUNITY FOR A SIZE COMPARISON.

ROM IS GOING TO TRY OUT HIS GHARIAL METHOD AGAIN.

BUT IT'S NOT JUST THE CROCODILES HE NEEDS TO WATCH OUT FOR.

LAKE CHAMO SUPPORTS A HEALTHY HIPPO POPULATION, TOO.

THESE CAN BE MORE DANGEROUS THAN THE CROCODILES.

OUR COMPUTER IS CALCULATING A SIZE COMPARISON.

IT GIVES A ROM COUNT OF 1.5.

THAT'S NINE FEET.

THERE WERE BIGGER CROCS ON THE BANK, BUT THEY'RE NOW HANGING AROUND OFFSHORE.

AND ROM IS UP AGAINST ANOTHER PROBLEM -- WHILE LARGE CROCS STILL LIKE TO HAUL OUT OF THE WATER TO REGULATE TEMPERATURE, SCIENTISTS HAVE NOW CALCULATED THAT ALL THE SUPERSIZE ONES NEED TO DO IS EXPOSE THE LENGTH OF THEIR BACK, LIKE A REPTILIAN ICEBERG.

AS WELL AS BEING AN EFFICIENT RESERVOIR FOR HEAT, A LARGE BODY CAN ALSO BE A FOOD STORE.

IT'S THOUGHT THAT A DECREASE IN THEIR METABOLISM ALLOWS SOME REALLY BIG CROCODILES TO LAST FOR OVER A YEAR WITHOUT FOOD.

AND WHEN THEY DO FIND SOME, THEIR STOMACHS ARE SO ACIDIC, THEY CAN EVEN DIGEST BONE.

THIS ENERGY-EFFICIENT BODY PLAN, ALONG WITH THEIR AQUATIC HABITAT, MAY BE ONE OF THE REASONS WHY CROCODILES SURVIVED WHILE THEIR DINOSAUR COUSINS DIED OUT.

BUT NOW, SOME 65 MILLION YEARS LATER, ROM KNOWS THAT TODAY, SURVIVING HUMANS IS THEIR GREATEST CHALLENGE.

AT 4,000 FEET ABOVE SEA LEVEL, NIGHTS ON LAKE CHAMO ARE UNUSUALLY COOL.

SO, IN THE EARLY MORNING, ROM IS HOPING THAT EVEN THE GIANTS WILL BE TEMPTED TO HAUL OUT.

Whitaker: WHOA!

I'M GETTING MIGHTY CLOSE.

Narrator: BUT BASKING ISN'T THE ONLY REASON CROCODILES LEAVE THE WATER.

I COULD HAVE ALMOST TOUCHED HIM!

[ LAUGHING ] SO THIS IS SO OBVIOUSLY A NESTING BEACH, BECAUSE ALMOST EVERYWHERE YOU LOOK, THERE'S A DEEP PIT AND THE REMAINS OF THE EGGSHELLS.

HATCHING SEASON WAS ALREADY A COUPLE OF MONTHS AGO.

SO ALL WE'RE GOING TO SEE HERE ARE THESE REMAINS.

AND THE FEMALE CROCODILE WILL ACTUALLY TAKE THE EGGS IN HER MOUTH AND GENTLY ASSIST THE BABY TO HATCH.

AND THEN CARRY THEM TO THE WATER.

LOOK AT THIS.

THIS IS THE HIND FOOT.

JUST, IT DWARFS MY HAND.

THIS IS LIKE A DINOSAUR FOOTPRINT.

IT'S MASSIVE!

Narrator: HEADING OUT OF THE NATIONAL PARK, THEIR LOCAL GUIDE LEADS THEM TO ANOTHER RIVER MOUTH, WHERE IT WAS SAID AN 18-FOOT CATTLE-EATER WAS SHOT JUST A FEW DAYS AGO.

HE'S SEEN TWO BASKING ON THE OPPOSITE BANK.

THE NOISE OF THE NESTING WEAVER BIRDS PROVIDES COVER.

BUT WITH HUNTING STILL ABOUT HERE, THESE CROCODILES ARE VERY WARY.

ROM NEEDS TO BE CAREFUL.

THERE'S NO GUARANTEE THE HUNTER ACTUALLY SHOT THE ONLY 18-FOOT CATTLE-KILLER.

FINALLY, THEY ARRIVE AT A SMALL, SECLUDED BAY THAT, AT A DISTANCE, APPEARS TO BE FULL OF LARGE CROCODILES.

BUT EVEN AT OVER 300 YARDS AWAY, THE CROCODILES' KEEN EYES SPOT THEM.

OH, SHUCKS.

Narrator: COULD THIS BAY BE HOME TO A MONSTER CROC?

A REAL GIANT EMERGES FROM THE REEDS, AND WITH HIS LASER RANGE-FINDERS, ROM CAN CALCULATE ITS SIZE.

BUT THERE ARE STILL SOME LEFT ON THE BANK.

SO ROM IS GOING TO TRY ANOTHER SIZE COMPARISON.

Man on radio: KEEP WALKING, KEEP WALKING.

KEEP -- HIGHER, HIGHER, HIGHER.

AND LIE DOWN.

ACCORDING TO THE COMPUTER SCAN, THE BIGGEST HERE WAS ABOUT 14 FEET.

BUT AT THE END OF THE BAY, SOME BIGGER CROCS HAVE ALSO HAULED OUT.

Rom: JUST WALK SLOWLY TOWARDS THOSE TWO BITS OF WOOD ABOVE THEM, KEEP ALONG AT THAT LEVEL, WITH YOUR HEAD TOWARDS THE END OF THE SPIT, PLEASE.

Narrator: IT'S ANOTHER BIG CROC, 15 FEET, AT LEAST.

BUT FINDING THAT SUPERSIZE CROC ON THE SHORE IS STILL PROVING ELUSIVE.

BEFORE HE LEAVES ETHIOPIA, ROM HAS ONE LAST LOCATION TO CHECK OUT.

Whitaker: MAN!

AS IF WE NEEDED ANY MORE EVIDENCE, THIS IS REALLY HANDS-ON.

LET ME JUST GET A QUICK ONE HERE.

67 CENTIMETERS -- THAT MAKES THIS POSSIBLY THE LARGEST NILE CROCODILE SKULL IN THE WORLD.

Narrator: AND IT COULD HAVE COME FROM AN ANIMAL ALMOST 20 FEET LONG.

Whitaker: WE HEARD ABOUT THE LAKE CHAMO CROCODILES.

AND THE NILE CROCS HERE GROW BIGGER THAN ANYWHERE ELSE.

THIS IS CLINCHING EVIDENCE.

HAVING SEEN THE BIG ONES IN THE LAKE, WHICH WERE PRETTY HARD TO MEASURE, ADMITTEDLY, NOW WE CAN CONFIRM IT.

BUT THERE'S MUCH MORE RECENT EVIDENCE OF A REALLY HUGE CROC, OVER 18 FEET LONG, WHICH WAS SHOT NEAR THE LAKE JUST TEN DAYS AGO.

Narrator: SO, AT OVER 18 FEET, ROM HAS ESTABLISHED THE NILE CROCODILE AS THE NUMBER-TWO IN THE WORLD.

NOW IT'S TIME TO GO AFTER NUMBER ONE.

AND THAT WILL LEAD HIM TO THE VAST WILDERNESS OF THE AUSTRALIAN OUTBACK, ALMOST 1,000 MILES FROM WHERE HE FOUND HIS RECORD-BREAKER ALL THOSE YEARS AGO.

BEFORE HE HEADS OUT INTO THE BUSH, ROM IS GOING TO MEET AN OLD AUSTRALIAN RECORD-BREAKER WITH LOCAL CROC BIOLOGIST ADAM BRITTON.

HEY.

CROCODILE SKULLS ALL OVER.

MUST BE AN OLD DINO.

WELL, WE HEAR YOU'VE GOT A VERY LARGE CROCODILE SKULL HERE.

DO YOU MIND IF WE CHECK IT OUT?

THE SKULL IS OVER THERE.

OKAY, IT'S OVER THERE.

THANKS, MAN.

WHOA.

MAN!

THAT'S FANTASTIC.

LET'S DO A REAL QUICK MEASUREMENT.

WELL, WE'VE GOT 68.8.

WOW!

THAT IS THE BIGGEST SKULL IN AUSTRALIA, AS FAR AS WE KNOW.

MAN, I'M FINISHED MEASURING SKULLS.

I MEAN, WE'VE GOT TO PUT A TAPE ON A REAL, LIVE 20-FOOT CROCODILE.

OKAY, WELL, LET'S GO AND CATCH ONE.

Narrator: IT'S PROOF THAT 30 YEARS AGO, AUSTRALIA, TOO, WAS HOME TO 20-FOOT-PLUS CROCODILES.

BUT WHAT ABOUT TODAY?

ALONG THE ADELAIDE RIVER, WHERE THAT GIANT WAS KILLED, CROCODILES ARE NOW RENOWNED FOR APPROACHING BOATS, ESPECIALLY IF THEY'RE OFFERED A SMALL SNACK.

ROM WON'T GET A BETTER CHANCE TO MEASURE A LIVE CROC.

HERE WE GO.

Narrator: CROCODILE NUMBERS IN AUSTRALIA ARE ON THE INCREASE, RISING FROM JUST 3,000 OR SO AT THE END OF HUNTING IN THE 1970s TO ALMOST 90,000 TODAY.

BUT IS 30-ODD YEARS LONG ENOUGH FOR GIANTS TO GROW?

OR ARE THOSE BIG GENES REALLY LOST?

THESE TIDAL CREEKS ARE NOW HOME TO A MONSTER CROCODILE KNOWN AS "MARRAKAI."

BUT HOW BIG IS HE?

WITH THE FLOODING CAUSED BY A RECENT TROPICAL CYCLONE, ALL THE CROCODILE TERRITORIES HAVE BEEN DISTURBED.

AND YET ANOTHER GIANT IS PROVING ELUSIVE.

[ SPLASHING ] OH!

THERE SHE GOES.

THAT'S AMAZING.

Narrator: STILL, THERE ARE PLENTY OF OTHER CROCS AROUND FOR ROM TO DEMONSTRATE JUST HOW BOLD AND AGILE THE SALTWATER CROCODILE IS.

NOW, WE DON'T WANT TO TEASE THIS CROCODILE, BUT I WOULD LIKE TO GET A BETTER LOOK AT HIM.

COME ON, ALL THE WAY UP, ALL THE WAY UP.

THEY'VE GOT THIS AMAZING CAPACITY TO CLIMB INTO THE AIR BECAUSE OF THEIR FANTASTIC TAIL STRENGTH.

OKAY, IF THIS IS SIX FEET, AT LEAST TWO MORE FEET BEYOND THERE.

OH!

[ LAUGHTER ] OH, YOU GOT IT, YOU GOT IT!

OH, YOU GOT IT.

OH!

OH!

WHOA!

ALL RIGHT!

STRAIGHT OUT.

Narrator: CROCODILES ARE KNOWN TO JUMP CLEAR OF THE WATER FOR ROOSTING FRUIT BATS AND OTHER PREY.

SO WHAT WE'RE SEEING IS SIMPLY MAN-INDUCED NATURAL BEHAVIOR.

FAR DOWNSTREAM, ROM SPOTS WHAT COULD BE A LARGE CROCODILE ON A DISTANT BANK.

BUT THIS IS NOT THE PLACE TO LIE DOWN IN THE NAME OF SCIENCE.

SALTIES ARE JUST TOO UNPREDICTABLE.

TIME FOR A MORE CONVENTIONAL MEASURING TECHNIQUE.

ROM HAS BROUGHT A 22-FOOT MEASURING POLE.

IT'S THE PERFECT YARDSTICK FOR ESTIMATING THE SIZE OF A GIANT SALTIE.

BUT ROM KNOWS THAT AT JUST NINE FEET, THIS ONE IS A LONG WAY SHORT OF THAT 20-FOOT MARK.

Whitaker: OKAY!

IT'S ABOUT TIME YOU PICK ME UP!

Narrator: IS IT SIMPLY TOO SOON TO FIND ANOTHER GIANT?

ROM HAS ONLY ONE LEAD LEFT -- THE BULLO RIVER STATION, 200 MILES DEEPER INTO THE OUTBACK.

HALF-A-MILLION ACRES, 9,000 HEAD OF CATTLE, AND ONE BIG, MONSTER CROCODILE.

HERE, THERE HAVE BEEN REPORTS OF A 22-FOOT-PLUS SUPERSIZE CROC THEY'VE NAMED "BULLO."

BUT ROM IS, ONCE AGAIN, SKEPTICAL.

AN ANIMAL THAT SIZE WOULD BE THE LARGEST EVER MEASURED, BY AT LEAST TWO FEET.

THE LOCAL RANCHER, FRANZ, FLIES ROM OUT TO WHERE THE GIANT WAS LAST SIGHTED.

THIS IS A BIG RIVER DOWN HERE, THE VICTORIA.

IT'S HUGE.

FRANZ, WHERE DID YOU SEE THE REAL BIG ONE?

JUST OUT THERE, AT THE MOUTH, ON THIS SIDE OF THE BANK.

I'LL STAY UP HIGH -- THERE'S SOMETHING SITTING THERE.

IT CERTAINLY LOOKS LIKE A CROC.

IT'S INTERESTING, WHY HE WAS SO FAR AWAY FROM THE WATER.

Narrator: THEN ROM SPOTS SOMETHING ELSE, ON ANOTHER BANK.

FRANZ, JUST STRAIGHT AHEAD OF US NOW, I THINK I SAW ONE ON THE BANK THERE, BUT IT WAS SHADY, SO I -- ON THE OTHER SIDE?

Narrator: IT'S LONG SINCE GONE IN THE RIVER, BUT IT'S LEFT BEHIND A PERFECT IMPRINT OF A LARGE CROCODILE.

BUT HOW BIG?

LOOK AT THAT!

[ Laughing ] THIS, ESPECIALLY!

YOU CAN SEE EVERY SCALE.

LET'S SEE WHAT WE GOT.

OKAY, CALL THAT THE END OF IT.

I'M NOT GOING TO GET THIS ALL MUDDY FOR THIS ONE.

16 -- 16 AND A BIT.

16 AND A BIT.

IT'S A BIG CROCODILE.

IT IS.

HOW LONG WOULD THAT HEAD BE?

YOU GOT YOUR TAPE MEASURE THERE?

MIGHT AS WELL CHECK THESE JOWLS, ANYWAY.

THAT'S AT 67.

Whitaker: THAT'S JUST THE BEST CROC PRINT I'VE EVER SEEN IN MUD ANY TIME, EVER.

YOU CAN SEE THE -- LOOKS LIKE SOMEONE PUT HIM THERE AND PICKED HIM UP.

THE SCALES, YOU CAN COUNT THEM HERE.

SO WHEN YOU SAW THE REAL BIG ONE, THE GIANT CROC'S TRACK -- IT WAS HERE, ON THE SAME BEACH.

IT WAS THE SAME BEACH AND IT WAS THE SAME KIND OF TRACKS?

SIMILAR PRINT, YEP.

IT WAS FACING AWAY FROM THE WATER, IT LIFTED ITS HEAD UP, AND IT WENT IN.

YEAH.

AND THAT JUST LAID THE ROPE OUT ON IT.

UM, 16, SO THAT WOULD COME ABOUT DOWN TO HERE.

[ LAUGHING ] AND IT'S JUST LIKE -- AND A HELL OF A LOT WIDER.

Narrator: WHAT FRANZ MEASURED WAS AN ALMOST IDENTICAL CROCODILE PRINT, BUT SIX FEET LONGER, AT JUST OVER 22 FEET.

WHEN I FIRST HEARD THE STORY, I'LL BE REAL HONEST WITH YOU, FRANZ, I SAID, "SOUNDS LIKE ANOTHER ONE OF THOSE 'CROCS BIGGER THAN THE BOAT.'"

BUT YOU GOT ME CONVINCED FOR SURE, NOW.

MY BOAT IS NOT EVEN 40 FOOT, SO THAT'S EASY.

[ BOTH LAUGH ] THAT CONVINCES ME.

IT REALLY DOES.

Narrator: IT'S TRULY AN ASTONISHING SIZE, AND ROM WILL HAVE TO TAKE FRANZ'S MEASUREMENT OF A 22-FOOT MONSTER CROC SERIOUSLY.

WE'VE FINALLY ARRIVED WHERE THE ACTION IS.

I MEAN, WE'VE SEEN GATORS 12, 13 FEET LONG, WE'VE SEEN GHARIAL UP TO 16 FEET.

WE'VE SEEN SALTIES CLOSE TO 16 FEET.

BUT, YOU KNOW, WHEN YOU WANT TO CATCH A MONSTER CROCODILE, A SUPER CROCODILE, YOU NEED A SUPERSIZE TRAP.

OKAY.

AND WE'RE OFF.

Narrator: A CROCODILE THAT SIZE CAN POSE A SERIOUS THREAT TO BOTH MAN AND BEAST.

FRANZ HAS CONSTRUCTED HIS VERY OWN SUPERSIZE TRAP TO CAPTURE AND RELOCATE THE GIANT CROCODILE.

AND THAT'S THE CROCODILE CHOCOLATE?

THAT'S THE CROCODILE CHOCOLATE.

AND IT REALLY SMELLS, TOO, MAN, IT HANGS IN THE WATER FOR A COUPLE OF DAYS... THAT SHOULD BE GOOD.

Whitaker: BUT IS THERE SOME IDEA THAT YOU'VE GOT A BIG ONE HERE?

Franz: MIGHT BE SOME HERE NOW.

YOU DON'T SEE THEM, BUT THEY MAY BE WATCHING US.

[ Laughing ] YEAH, I'M SURE.

Narrator: WITH THE TRAP NOW SET, ROM HEADS TO A NEARBY FRESHWATER BILLABONG IN SEARCH OF ANOTHER RECORD-BREAKING CROCODILE.

SALTWATER CROCODILES AREN'T THE ONLY CROCS AT BULLO RIVER.

THERE'S ANOTHER VERY INTERESTING SPECIES HERE.

AND YOU DON'T NEED A 20-FOOT-LONG STEEL TRAP TO CATCH HIM, EITHER.

ALL YOU NEED IS ONE OF THESE.

WHOA, AN AUSTRALIAN FRESHWATER CROCODILE, BUT WITH A DIFFERENCE -- THIS IS A FOUR-FOOT-LONG CROCODILE.

AND IT COULD BE 25 OR 30 YEARS OLD.

AND IT'S A CANDIDATE FOR BEING THE WORLD'S SMALLEST CROCODILE.

OKAY, NOW, LET'S GET A GOOD LOOK AT THIS GUY.

SO THIS IS A PYGMY FRESHIE.

LOOK AT THOSE TEETH AND THAT NARROW SNOUT.

HE'S A REAL FISH EATER.

HE REMINDS ME OF MY OWN GHARIAL.

HE CAN TEACH US A LOT ABOUT HOW CROCS GROW TO SUPER SIZES.

HERE, WITH THE LIMITED RESOURCES IN THIS MINERAL STREAM, HE DOESN'T HAVE ENOUGH TO GROW BIG.

WHEREAS A BIG SALTWATER CROCODILE DOWN IN THE RIVER HAS PLENTY OF RESOURCE, PLENTY OF FOOD TO GROW TO A SUPER SIZE.

SO IT'S NOT JUST ABOUT GENES.

IT HAS EVERYTHING TO DO WITH ENVIRONMENT.

OKAY, LET'S SEE IF WE CAN GET HIM BACK TO HIS WARM POOL.

MOST PEOPLE DON'T THINK OF CROCODILES AS HIGH-SPEED RUNNERS, BUT DID YOU SEE THAT GALLOP?

THAT WAS PROBABLY ABOUT 10 MILES AN HOUR.

OH!

DID YOU SEE THAT?

Narrator: THESE SMALLER FRESHWATER CROCODILES USUALLY LIVE JUST OUT OF REACH OF THE SALTIES.

AND THEIR EXTRAORDINARY GALLOPING IS AN ESCAPE RESPONSE MANY SMALLER CROCODILES CAN PERFORM.

WHOA!

SINCE MANY LARGER CROCODILES CAN BE CANNIBALS, THIS TECHNIQUE GIVES THEM A CHANCE TO ESCAPE -- ON LAND, AT LEAST.

Whitaker: WOW!

Narrator: IT'S ROM'S LAST DAY AT THE BULLO RIVER STATION.

HE MAY HAVE ENCOUNTERED ONE OF THE WORLD'S SMALLEST CROCODILES, BUT WHAT HE'S REALLY HERE TO DO IS TO TRY AND COME FACE TO FACE WITH THE WORLD'S LARGEST.

LIKE AFRICA'S LAKE CHAMO, THE BULLO RIVER MAY BE A LAST REFUGE FOR THE GIANTS.

ROM HAS NOW SEEN PLENTY OF BIG CROCS AT 16 OR 17 FEET.

BUT IN CROC YEARS, THESE ARE RELATIVE YOUNGSTERS.

THEY WERE PROBABLY BORN AFTER HUNTING ENDED, AND ARE LIKELY TO BE LESS CAUTIOUS THAN THE REALLY OLD GIANTS HE'S COME ALL THIS WAY TO FIND.

BUT IT'S GOOD NEWS.

WITH POPULATIONS RECOVERING IN AUSTRALIA, THESE COULD BE THE NEXT GENERATION OF MONSTER CROCS.

AND WHAT ABOUT THE BULLO GIANT THAT FRANZ SAW?

THERE'S STILL NOTHING IN THE TRAP, AND IT MAY BE WEEKS BEFORE ANY CROC SPRINGS IT, LET ALONE A 22-FOOT SUPERSIZE MONSTER.

THEN ROM SPOTS SOMETHING ON A DISTANT BANK.

IT'S A HUGE CROC, FAR BIGGER THAN ANYTHING HE'S SEEN BEFORE.

BUT IT'S QUICKLY OUT OF SIGHT.

THAT'S A BIG ANIMAL.

YOU GET A VERY GOOD, CLEAR IDEA OF THE WIDTH OF THE BELLY SCALES.

Narrator: FRANZ PUTS ROM DOWN NEAR THE MUD PRINT FOR A CLOSER LOOK.

IT'S LEFT BEHIND A HUGE SLIDE ON THE BANK.

CAN HE GET ANY EVIDENCE?

ANY REAL PROOF OF THE SIZE OF THIS GIANT REPTILE?

WITHOUT LEAVING BEHIND A CLEAR PRINT, IT'S HARD TO IMAGINE HOW MASSIVE THIS CROCODILE WOULD REALLY BE.

BUT IF IT WAS THE BULLO GIANT, IT COULD BE TWO FEET LONGER AND AT LEAST HALF A TON HEAVIER THAN THE RECORD-BREAKER ROM MEASURED ALMOST 25 YEARS AGO.

I WAS WONDERING WHETHER HE WAS GOING TO BE IN THE BUSHES.

[ Laughing ] THAT'S WHY I CREPT FROM BEHIND.

THOSE TRACKS ARE INCREDIBLY IMPRESSIVE.

I'VE NEVER SEEN ANYTHING LIKE IT.

YEAH, I CAN REALLY BELIEVE YOU GOT SOME REAL MONSTER CROCODILES HERE.

Narrator: ALTHOUGH ROM HAS NOT FOUND HIS GIANT, WHAT HE'S SEEN IN AUSTRALIA HAS GIVEN HIM HOPE.

HE'S FOUND A REAL CHANGE IN OUR ATTITUDES TOWARDS THESE MAGNIFICENT REPTILES.

THE TRAP REMAINS EMPTY.

BUT RON HAS SEEN ENOUGH TO BELIEVE THAT THERE ARE STILL GIANT CROCS LEFT OUT THERE.

AND AS LONG AS THERE ARE HABITATS WHERE THEY CAN GROW IN PEACE, IN 20 YEARS OR SO, GIANT REPTILES MIGHT ONCE AGAIN ROAM THE EARTH.