♪♪
I'M LUKE TIPPLE, AND THIS
IS YOUR "DAILY BITE."
ON THIS EPISODE, WE'RE TALKING
ABOUT BABY SHARKS.
SWIMMING BETWEEN UTERI,
FULL OF TEETH,
AND CANNIBALIZING THEIR
UNBORN SIBLINGS,
TAKING SIBLING RIVALRY
TO A WHOLE NEW LEVEL.
WHEN A MOMMY SHARK
AND A DADDY SHARK FALL IN LOVE,
IT'S ABSOLUTELY TERRIFYING.
LET'S BE HONEST --
SHARK SEX ISN'T PRETTY.
IT STARTS WITH A COURTING RITUAL
WHERE THE MALE SHARK
LATCHES HIS TEETH
ONTO THE FEMALE AND TWISTS
HIS BODY AROUND HERS
IN ORDER TO ALIGN THEMSELVES
FOR COPULATION.
THE DAMAGE FROM MATING
IS SIGNIFICANT,
AND WE CAN OFTEN SPOT
MATURE FEMALE SHARKS
BY THE AMOUNT OF SCARRING
ON THEIR BODIES.
NOW IN THE BIG BLUE OCEAN,
YOU NEVER KNOW
WHEN YOU'LL RUN INTO
A SUITABLE MATE,
SO A FEMALE SHARK MAY ENGAGE
WITH SEVERAL MALES
DURING A MATING SEASON,
AND THEY CAN STORE THE SPERM
FOR MORE THAN FOUR YEARS BEFORE
USING IT FOR FERTILIZATION.
AS A GENETIC DIVERSIFICATION
STRATEGY,
THEY MAY EVEN GIVE BIRTH
TO SEVERAL MALES YOUNG.
BABY SHARKS COME INTO THE WORLD
IN ONE OF THREE
DIFFERENT WAYS --
OVIPAROUS SHARKS ARE EGG-LAYING,
AND THE MOTHERS CAREFULLY HIDE
THEIR EGGS FROM PREDATORS
SO THAT THEIR PUPS HAVE
THE BEST CHANCE OF SURVIVAL.
VIVIPAROUS SHARKS GIVE BIRTH
TO LIVE PUPS.
AND OVOVIVIPAROUS SHARKS,
WHICH MAKE UP
THE MAJORITY OF SHARK SPECIES,
THEY USE BOTH STRATEGIES.
THE EGGS ARE FORMED
AND HATCHED INSIDE THE MOTHER
BEFORE LIVE YOUNG ARE BORN
INTO THE SURROUNDING WATER.
HANDS DOWN THE CRAZIEST PART
OF THIS STORY, THOUGH,
IS THE BATTLE FOR SURVIVAL
GOING ON INSIDE THE WOMB.
SHARK EXPERT VICKY VASQUEZ
IS HERE TO DIVE INTO
WHY THIS IS SUCH
AN INCREDIBLE PHENOMENON.
SOMETHING THAT IS SUPER
MIND-BLOWING ABOUT SHARKS
IS THAT THE FEMALES CAN HAVE
TWO UTERUSES,
AND IN SOME OF
THE VIVIPAROUS SPECIES,
THOSE BABY SHARKS CAN
ACTUALLY SWIM AROUND
AND THEY CAN EVEN GO FROM
ONE UTERUS TO THE OTHER.
A RESEARCHER NAMED DR. TOMITA
WAS AT THE OKINAWA AQUARIUM
IN JAPAN
WHEN HE SAW
THE CRAZIEST THING HAPPEN
WITH THE TAWNY NURSE SHARKS.
THEY WERE ABLE TO COLLECT VIDEO
WHICH SHOWED THEM
THE TAWNY BABY SHARKS
BASICALLY SWIMMING FROM
ONE UTERUS TO THE OTHER,
AND EVEN TAKING A LITTLE POKE
INTO THE OUTSIDE WORLD
TO SAY HELLO.
AND THAT'S REALLY, REALLY COOL,
BECAUSE WE'VE NEVER HAD
ANYTHING LIKE THAT BEFORE.
SHARK REPRODUCTION
IS SUCH A MYSTERY.
WHAT WE DO KNOW
AND WHAT WE HAVE LEARNED
IS BASICALLY FROM DISSECTIONS,
BEING ABLE TO SEE
WHAT THE INSIDES LOOK LIKE
AND THEN MAKE THE APPROPRIATE
ASSUMPTIONS.
BUT WITH VIDEO, THERE'S
NO QUESTION WHAT'S HAPPENING.
THEY HAVE SONOGRAMS
SO YOU COULD ACTUALLY SEE
THAT THE EMBRYOS,
THESE BABY SHARKS WERE ACTUALLY
SWIMMING FROM ONE UTERUS
TO THE OTHER.
IT WAS REALLY ABLE TO SHOW
WHAT IT'S LIKE
FOR THESE SHARKS THAT HAVE
OOPHAGY,
WHEN THE SHARKS ARE ABLE TO
EAT SOMETHING IN THE UTERUS.
A GOOD REASON WHY
THEY MIGHT BE ABLE TO SWIM
FROM ONE UTERUS TO THE OTHER
IS PROBABLY BECAUSE
THEY GET HUNGRY.
SO THEY MIGHT EAT ALL THE LITTLE
GOBSTOPPERS OF SHARKY GOO
FROM ONE UTERUS
AND THEN FILL UP
AND THEN GO CHECK OUT AND SEE
WHAT'S LEFT IN THE OTHER ONE.
NOW, WHY ARE THEY PEEKING
THEIR HEADS OUT?
IF I WAS A HUNGRY BABY SHARK,
I ATE EVERYTHING I COULD FIND,
AND NOW I'M TRYING TO, LIKE,
PEEK OUT OF MOM
TO SEE IF THERE'S
ANY FOOD OUT THERE,
IF IT'S A SAFE TIME TO EXPLORE,
AS ADORABLE AS IT SOUNDS
TO BE A BABY SHARK,
THINK ABOUT WHAT WE KNOW
ABOUT SHARKS.
A BABY SHARK IN THE WOMB
WITH THOSE TEETH,
USING THOSE FINS,
SWIMMING AROUND
FROM UTERUS TO THE OTHER,
WELL,
IT MIGHT BE WANTING TO MAKE
A LITTLE BIT MORE SPACE
WHERE IT IS, MIGHT BE
GETTING A LITTLE HUNGRY.
THESE BABY SHARKS CAN
ACTUALLY JUMP ON THEIR SIBLINGS.
SO, AS YOU CAN IMAGINE,
THE WOMB BECOMES
A LOT MORE COMFORTABLE.
THERE ARE SHARK SPECIES
OUT THERE
WITH VERY LOW REPRODUCTIVITY.
SO, IF YOU'RE A SHARK
AND YOU'RE NOT PUTTING OUT
A LOT OF BABIES,
YOU PROBABLY WANT TO MAKE SURE
ALL OF THOSE BABIES
ARE SUPER, SUPER TOUGH.
SO BASICALLY WHAT'S HAPPENING
INSIDE THE WOMB
OF A MOTHER SHARK
IS THE SURVIVAL OF THE FITTEST
SO THAT THE STRONGEST
BABY SHARK
IS WHAT'S COMING OUT
INTO THE WORLD.
TALK ABOUT CHILDHOOD TRAUMA.
SO, FROM DAY ONE,
SHARKS ENGAGE IN A BATTLE
FOR SURVIVAL WHERE ONLY
THE STRONGEST WILL SURVIVE.
WHETHER THEIR MOTHERS
ARE REALLY GOOD
AT FINDING STRONG MATES,
ARE EXPERTS AT HIDING
THEIR EGGS,
OR THE SHARKS SURVIVE
THE GLADIATOR CANNIBAL PIT
OF THE WOMB,
EVOLUTION HAS ENSURED
THAT THE SHARKS THAT MAKE IT
TO BIRTH ARE THE STRONGEST
AND FITTEST
THEY CAN POSSIBLY BE.
MAYBE THAT'S WHAT MAKES THEM
APEX PREDATORS.
STICK WITH US
ALL "SHARK WEEK" LONG
AS WE CONTINUE TO BRING YOU THE
WILDEST DISCOVERIES IN SHARK.
IN THE NEXT EPISODE
OF THE "DAILY BITE,"
"WHEN SHARKS ATTACK."
♪♪
