I'M LUKE TIPPLE, AND THIS IS YOUR "DAILY BITE."

SHARK WEEK HAS BEEN HOME TO SOME OF THE GREATEST

SHARK DISCOVERIES OVER THE YEARS,

AND TODAY, WE'RE TAKING A LOOK

AT THE YEAR'S BIGGEST BREAKTHROUGHS --

FROM THE RE-EMERGENCE

OF A PREVIOUSLY THOUGHT-EXTINCT SPECIES

TO NEVER BEFORE SEEN BEHAVIORS.

LET'S DIVE IN.

FORREST GALANTE HAS MADE IT HIS LIFE'S MISSION

TO SEARCH FOR EXTINCT ANIMALS.

AND THIS YEAR, HIS TEAM FOUND UNDENIABLE EVIDENCE

THAT A HIGHLY ADAPTIVE SPECIES

HAS POSSIBLY JUST BEEN SMART ENOUGH TO EVADE HUMAN CONTACT

SINCE THE '70s.

THE PONDICHERRY SHARK HAS BEEN CONSIDERED EXTINCT FOR YEARS.

BUT THE FISHERMAN IN THE INDIAN OCEAN BEGAN REPORTING SIGHTINGS

OF A STRANGE SHARK THAT MATCHED ITS DESCRIPTION.

Galante: GUYS, LOOK AT THIS. I'M NOT EVEN KIDDING. LOOK.

Narrator: FORREST RECEIVES THE NEWS ABOUT JESSICA'S FIND.

A FISHERMAN CAUGHT TWO SHARKS

MATCHING THE DESCRIPTION OF THE PONDICHERRY.

JESSICA TAKES A SMALL CLIPPING OF THE FIN,

AND SHE ALSO REMOVES A TOOTH.

THESE SAMPLES WILL BE SENT BACK TO THE LAB FOR GENETIC TESTING

AND IT WILL BE SEVERAL DAYS

BEFORE THEY CAN POSITIVELY IDENTIFY THIS SPECIES.

JUST WHEN IT SEEMS ALL IS LOST,

FORREST RECEIVES THE RESULTS OF THE GENETIC TESTS

TAKEN FROM THE SPECIMEN FOUND IN THE FISHING VILLAGE.

Galante: I'M, LIKE, ON THE EDGE OF MY SEAT.

THE WHOLE TEAM'S HERE.

JESSICA: Yeah.

ARE YOU 100% SURE?

-Yeah. -SWHOOOOOOOOO!

[ LAUGHS ]

WE HAVE THE GENETIC PROOF.

THAT IN ITSELF WILL REMOVE THE ANIMAL

FROM THE EXTINCT SPECIES LIST

AND PLACE IT ON THE CRITICALLY ENDANGERED LIST.

♪♪

LAST YEAR ON SHARK WEEK,

ANDY CASAGRANDE DISCOVERED WHAT APPEARED TO BE

TWO BROTHER SHARKS PROWLING THE OCEANS TOGETHER

AND HUNTING AS A TEAM.

THIS YEAR, HE DOVE FURTHER INTO THE MYSTERY

AND UNCOVERED SOME OF THE MOST UNPRECEDENTED

SHARK BEHAVIOR EVER CAPTURED ON CAMERA.

WE FOUND THESE TWO SHARKS, AND I SWEAR TO GOD,

HAVE TO BE BROTHERS.

THEY SWAM THE SAME, THEY ACTED THE SAME,

ROUGHLY THE SAME SIZE, MATCHING BIRTHMARKS.

Dr. Ferrara: THESE TWO SIBLINGS ARE STAYING TOGETHER.

TO MY KNOWLEDGE,

THAT'S NEVER BEEN DOCUMENTED BEFORE FOR WHITE SHARKS.

Narrator: ANDY CASAGRANDE AND HIS TEAM

HAVE FOUND THE SHARK BROTHERS,

STILL SWIMMING SIDE BY SIDE AFTER 14 MONTHS.

Casagrande: THIS IS INCREDIBLE!

THEY'RE CIRCLING THE UNDERWATER DRONE.

THIS IS STRATEGY, NOT MINDLESS PREDATION AT ALL.

Narrator: WHILE ONE DISTRACTS FROM IN FRONT,

THE OTHER MAKES A MOVE.

THE BROTHERS DEMONSTRATE A STRATEGY

SIMILAR TO LAND-BASED PACK HUNTERS.

THEY MAY HAVE BEEN USING THIS TECHNIQUE ON ANDY

WHEN HE FIRST FOUND THE BROTHERS TOGETHER MORE THAN A YEAR AGO.

IT'S PRETTY AMAZING.

DUDE.

SEALS DON'T STAND A CHANCE.

NO WAY. NOT AGAINST THE BROTHERS.

THESE ARE DEFINITELY GREAT WHITE SHARK BROTHERS.

IT MAKES SENSE TO ME BIOLOGICALLY

AND JUST COMMON SENSICALLY

THAT GREAT WHITE SHARKS WOULD HAVE BROTHERS AND SISTERS

AND THEY LIKELY HANG OUT WITH EACH OTHER,

HUNT WITH EACH OTHER, LEARN FROM EACH OTHER.

THEY HAVE FAMILIES.

ON "THE LAWS OF JAWS," A HIGHLY SKILLED DIVE TEAM

HAS PUT THEIR LIVES ON THE LINE TO PROVE AND DISPROVE

REAL-LIFE SHARK ENCOUNTERS

TO DETERMINE WHAT REALLY INFLUENCES SHARK BEHAVIOR.

THIS YEAR, PAUL DE GELDER WENT TO THE ABSOLUTE EDGE OF DANGER,

DIVING UP CLOSE AND PERSONAL WITH SHARKS

WITH ACTUAL BLOOD IN THE WATER TO PROVE ONCE AND FOR ALL

WHETHER SHARKS HAVE A TASTE FOR HUMAN BLOOD.

De Gelder: WE'VE BEEN TAUGHT THAT SHARKS CAN SMELL A DROP OF BLOOD.

IF YOU HAVE A SMALL CUT,

THEN THEY'RE GONNA BE ATTRACTED TO YOU.

♪♪

BUT SO MUCH ELSE ABOUT THE SHARKS HAS BEEN

A PRECONCEIVED NOTION THAT'S UNTRUE.

MAYBE THIS IS, TOO.

Narrator: PAUL WILL BE 50 YARDS FROM THE SAFETY OF THE BOAT

WITH JAMIN AND NICK BELOW.

IN THE FIRST PART OF THE TEST,

PAUL WILL RELEASE THE HUMAN BLOOD

IN A CLOUD AROUND HIMSELF.

THEN, IN THE SECOND HALF OF THE TEST,

FISH BLOOD WILL BE POURED INTO THE WATER.

IF THERE IS A RESPONSE TO EITHER,

HE'LL THEN NEED TO GET HIMSELF TO SAFETY.

THE STAGE IS SET TO TEST THE FIRST PHASE OF THE EXPERIMENT.

A SHADOW APPEARS.

Nick: HERE COMES A TIGER.

THE SHARKS HAVE ABSOLUTELY NO REACTION TO THE HUMAN BLOOD.

WHEN YOU FIND OUT THAT SOMETHING THAT'S COMMONLY BELIEVED

IS TOTALLY FALSE, IT'S AMAZING.

SO YOU JUST LEARN THIS NEW FACT, YOU PUT IT IN YOUR TOOLKIT,

AND THEN YOU MOVE ON TO THE NEXT ONE.

♪♪

SHARK WEEK HAS MADE A HUGE IMPACT

ON PROTECTING THESE VULNERABLE SPECIES,

PERFORMING IMPORTANT WORK

THAT HAS HELPED PASS LEGISLATION AROUND THE WORLD.

DON'T MISS THE REST OF THIS YEAR'S INCREDIBLE DISCOVERIES,

ALL AVAILABLE TO WATCH ON DISCOVERY GO.