World's Biggest Bull Shark?

Oh my God.

You're in a bad spot. I know, Guys, get up.

The chance encounter, with a giant!

Maybe the largest alive.

That's the biggest bull shark I've ever seen!

And evidence of more super sized bull sharks!

Two bull sharks, there's two bull sharks.

Lurking just beneath the surface.

Close to shore.

That's a big shark.

Close to people.

Hold on to it!

Now, a team is on the trail of a family of hungry giants.

This is military grade technology.

That is epic.

This is the hunt.

Big bull shark down there!

For the world's biggest bull shark!

Florida's East Coast is one of America's

most popular destinations for beach going vacationers.

But there are also year round residents.

Just beneath the surf.

Florida's warm coastal waters are a hotbed for sharks.

Including one of the most dangerous, the bull.

Bull sharks are the deadliest sharks in the world after

great whites and tigers.

Adult bulls average around seven and a half feet long.

But there is one bull shark that may be queen of them all.

The amazing thing about the wild is you never know

what you're going to encounter and no two days are the same.

For marine biologist Dr. Neil Hammerschlag,

no day stands out more than May 27, 2012.

Neil and his team of researchers head out to study

the health and numbers of bull sharks in South Florida.

It was a normal trip; I was out with my students doing

our ongoing surveys of sharks.

This is a nice piece of Barracuda, only the freshest meats!

Uh, 75 feet of monofilament, a weight,

200 foot of line, so it takes it down to the bottom, and a float.

Alright, clear!

The University of Miami team gives average sized bulls,

like this one, the usual check up for science.

If I feel where its jaw is, it can't bite me.

So, I'll stay right behind it because it's a good gripping point.

They keep it safe by continually pumping water

through its gills so it can breathe.

Are we good on everything else data wise?

Here I have a biopsy and in this one here I have a

the fin clip sample so I'm just labeling those.

The grad students takes samples from one bull after another.

170! 170 FL! Get the total length as well.

Suddenly, all the smaller sharks disappear.

You're in a bad spot. I know, you guys.

Get off! I need you guys to get off...

And all of sudden, one of the lines became very difficult to

bring in and I knew we had something big on it.

I had no idea how big.

The whole team feels it;

They are in the presence of greatness.

This is insane.

A special shark.

Okay, don't lean back.

This animal was very hard to bring up here.

A couple of times she just ran off.

And no one could hold her.

The largest bull shark ever caught was 771 pounds,

the scientists estimate that this one is bigger.

How much would you say that fish weighs?

At least 800 pounds.

There's no way is weighs less than 800 pounds.

Bull cutter. Bull cutter.

Can someone take a picture of this?

The typical adult bull shark is in the seven foot range.

This one, just over nine feet.

I think she's 1,000 pounds.

That's my personal opinion.

They discover she's a healthy strong female.

And her extraordinary girth has her tipping the scales.

196.

It's time to take tissue samples for DNA and

draw blood from this amazing animal.

Okay, got it. Fresh blood sample here.

So now we have our blood sample from this huge bull shark;

You can see the dark and richness of that blood.

To reach this size,

she must be around 30 years old,

no one knows for sure if they get any older.

No one has seen anything like her in the

United States in decades.

Alright guys we have a loose fish.

Loose fish, fish is not secured to the boat by...

It's possible that they've got their hands on

the largest living bull shark in the ocean.

Okay, hold on, I'm gonna use this pump to pull her out.

They release her no worse for wear.

It's like those wrestlers who are all neck.

And it was just like...

I couldn't even see its eyes,

because there was just meat around it!

She disappears into the depths.

But not before Neil and his team give her a name that befits her size.

They call her Big Bull.

In all the years of surveying sharks including

hundreds of bull sharks, I'd never seen bull shark

anywhere near that size.

The photos taken of Neil with Big Bull go viral.

She captures the imagination of millions the world over.

No one thought the ocean had giants like this anymore.

It was incredible that we captured one of the

largest specimens ever recorded!

But it also showed us how little we actually know about bull sharks.

They could only guess how she got this big,

the range of her territory,

and whether she's given birth to more giants like her.

Until now.

Eight years later there's more.

Big bull sharks are showing up all along Florida's coastline.

Fishermen notice first.

Oh my gosh, what a monster.

160 miles from where Big Bull was first captured.

That's a giant bull shark.

Then divers report large bulls by a shipwreck.

Now scientists wonder if Big Bull has ushered in

a new wave of giant sharks.

Could this big momma have spawned a new generation of behemoths?

In humans, there are traits associated with

being big or size that are hereditary.

They're passed down from parent to offspring.

And I wouldn't be surprised if the same thing applies in

sharks that are hereditary, that could be contributing to

the sheer size of Big Bull.

It's time to find out if Big Bull is still here,

and if other big sharks are her pups.

The goal of this trip is to gather more information

that allows us to understand how and why she got so big,

and ultimately figure out whether there's even a

bigger bull shark out there.

If Big Bull is still out here,

and the mother of a large family,

it may cause concern for beach goers.

Shark attacks in the areas just north of here have

increased 37% in that last ten years.

Bull sharks are crucial for a healthy ocean and

they are near threatened,

so a slew of big bulls would give

the species hope for the future.

Neil is rooting for the sharks and he's not alone.

Shark conservationist and former Royal Marine Commando, James Glancy,

joins the marine biologist for a chance to make history.

Florida is a really special to me because it's

where I first learned to dive as a kid in the '90s and

I saw my first bull shark on that trip,

and that gave me my passion for sharks and the ocean.

So it's incredible to be back here using the military skills

that I've developed over my career to support shark science

and to go out and find the world's biggest bull shark.

But the conditions are not ideal.

Well the sun is out today but the swell is huge.

It's gonna be an interesting dive.

Ripping currents, deep water, poor visibility, plus bull sharks?

They head to where divers have seen big bulls,

near a wreck site just two miles off shore.

This was a drug smuggling ship,

seized by the coast guard and sunk here 20 years ago.

Now it's habitat for fish of all kinds.

And for bull sharks, a seafood buffet.

If Big Bull is here, she would have grown close to an inch a year

and now be an incredible ten feet in length.

Yeah, we are on the wreck right now, yeah.

James sets up his camera to check the size of sharks.

I've got my camera rigged up with two lasers;

that's gonna help us measure the sharks.

Problem is, bull sharks can come in a pack.

When you get more than five or six bull sharks,

they get more of a pack mentality.

They are an incredible predator that understands

where our sensory systems are.

They know how to use stealth, how to use ambush to try and

get close to you.

Whoa. Look at that!

This is some great shark habitat.

We've got a really strong current in here.

It's a little dicey.

Lots of shark food around here.

We got a shark.

There we go.

I think that's a bull shark.

About thirty feet away.

It is a bull.

And it's not alone.

Watch your left!

More and more show up.

Suddenly, they're surrounded.

Neil and James search a shipwreck for the

megashark Big Bull, and other large bull sharks that

may be her descendants.

Neil, you okay?

I'm good over here.

Bull sharks have a pack like mentality and

swarm around possible food.