Original subtitles

♪♪

Dr. Guttridge: According to folklore here, there's a legendary hammerhead

That stalks the seven mile bridge,

And it's an absolute monster.

Man #1: I've seen him countless times.

Man #2: That thing's hammer is six, eight feet wide.

Man #1: He's just so much bigger than any of the other sharks.

Narrator: Deep in the heart of the florida keys,

In the shadows of the iconic seven mile bridge...

♪♪

Lives a monster.

They call him big moe.

These stories date back 30-plus years.

So if this legend is true,

We could be dealing with a huge hammerhead

That is 50 years of age.

Narrator: Scientists believe big moe

Could be the largest hammerhead on the planet

And that he's a member of an entirely new species of shark.

It might sound a bit far-fetched,

But in fact, we have some data that suggests

That this might actually be true.

And we're gonna discover something really unique

About a cryptic, secretive new species of hammerhead.

We want to get to the truth

Behind this huge, great hammerhead.

Narrator: To unravel the mystery of big moe...

Man: Hammer, hammer!

Narrator: ...Two teams of researchers embark

On an expedition around the florida keys.

Man: I just saw something massive.

Narrator: This mission could lead to the discovery

Of a new mega hammerhead species.

Oh! Get this out of my way!

-- Captions by vitac -- www.Vitac.Com

Captions paid for by discovery communications

Narrator: In 1912, a bridge was built connecting mainland florida

To the then undeveloped wilds of the florida keys.

It's called the seven mile bridge.

And just as this overseas highway

Dramatically changed the economy of florida,

Its physical structure also transformed

The underwater world beneath the bridge.

Today, this artificial reef superhighway

Is home to monster sharks.

Dr. Guttridge: Every single one of these pylons is growing life on it,

Is like a mini ecosystem in itself.

It's provided additional habitats

For loads of different species,

Because there's quite a bit of shadowing

That's caused by the big structures.

This is an opportunity for the biggest predators

To rest in those shadow areas

And essentially launch attacks from there.

♪♪

Mcdonnell: You've got miles of these bridges.

They act as an artificial reef, so things can grow on them.

Fish are attracted to it, and these bridges as these barriers

Between the gulf of mexico and the atlantic ocean,

So you have these two rich ecosystems that merge here.

Dr. Hammerschlag: I think that big moe is using this bridge

To ambush something like a tarpon

That is moving between the gulf of mexico

And the atlantic ocean.

Narrator: Beyond his use of the bridges,

Big moe is also defined by his massive size.

Great hammerheads rarely grow to be longer than 12 feet

Or weigh more than a thousand pounds,

But numerous reports of big moe

Estimate his length at around 20 feet

And his weight at nearly a ton.

And recently, the dna of two massive male great hammerheads

Caught near seven mile bridge

Revealed something incredible about their genetics.

Their common stock dna structure

Didn't match any other hammerheads in the region.

This sparked the theory that specimens like big moe

And these outliers might belong to a new species of shark

Known as the keys hammerhead.

Could there be the keys great hammerhead?

That's what we want to find out.

Narrator: If the keys hammerhead is real,

It could be the ultimate predator.

Like other hammerheads,

They would possess nearly 360-degree vision

So they could see in almost any direction.

But that's not all.

Their extra wide cephalofoils

Would spread their ampullae of lorenzini

Over a greater surface area.

These special sensory organs allow them to zero in

On weak electrical signals generated by prey.

♪♪

To find out if they exist,

The teams will collect dna samples

From great hammerheads in the region

And have them analyzed by shark geneticist david portnoy.

Hey, dave, how are you doing?

Good. How are you guys?

We're ready for action.

David portnoy is a leading geneticist in the u.S.

When it comes to sharks, he's the man you go to.

So, guys, the idea is that these really big hammerheads

Could be this unique evolutionary lineage.

We need tissue from the real big ones.

You know, maybe there's something to this ecosystem

That is attracting them and keeps them coming back here.

Good luck.

Alright, man. Thanks so much.

Talk soon.

♪♪

Alright, here we go, the game plan.

This map really allows you to kind of visualize

The scale of these bridges.

You know, they're connecting all these different keys.

There's so many places for these hammerheads to use.

Quite a lot to work with here.

I would suggest that we probably split up --

You know, divide and conquer

To cover as much ground as we can

To try to find these big hammers.

I cannot wait to get in the water

And see if I can find big moe.

No competition at all.

Definitely not a competition, neil, okay?

Yeah. I mean, this is a team effort.

Nobody's keeping score, but we're definitely keeping score.

♪♪

My plan is to start at bahia honda bridge.

This is where big moe was last seen,

And this is the hot spot.

♪♪

If a great hammerhead comes in, I'm gonna sneak in,

Deploy my biopsy, take a sample, and leave it with a tag.

♪♪

These bridges are a unique habitat.

There's strong current. There's visibility issues.

There's pylons everywhere.

There's a lot of things that can go wrong,

So we need maneuverability.

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Narrator: The team encounters their first monsters.

Goliath grouper can reach lengths of up to eight feet long

And weigh nearly 1,000 pounds.

This makes them some of the biggest fish in the ocean.

♪♪

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Tarpon are known for traveling

In these massive schooling packs,

Using safety in numbers

To protect themselves from predators.

Their sudden appearance under the bridge

Is a promising sign for the research team.

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Nurse sharks are bottom feeders

Known for their powerful, suction-like jaws.

They use these to crush prey like lobsters and crabs

That they find on the seafloor.

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Coming up, the teams explore the amazing underwater habitats

Of the keys after the sun goes down.

And later...

Man: Whoo!

Narrator: ...They come face to face

With the biggest hammerhead in shark week history.

Narrator: In key west, florida,

A massive hammerhead called big moe

Stalks the waters under seven mile bridge.

Two teams of researchers believe this beast

Could be a brand-new hammerhead species

That's larger than any other on the planet.

[ thunder crashes ]

To test their theory,

Marine biologist tristan guttridge

Dives a big moe hot spot to obtain a genetic sample.

And he's about to get his first shot

At a groundbreaking discovery.

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Narrator: After an hour in the water,

The team heads back to the surface.

And while they didn't succeed in getting a genetic sample,

The appearance of a great hammerhead under the bridge

Is a promising start to the mission.

Dr. Guttridge: Just got back off an epic dive,

And I actually saw a huge hammerhead...

I can hear your heart thumping through the walkie-talkie here.

I took a shot, but the shark was kind of turning

As I tried to get a genetic sample,

And it just bounced straight off.

But there's definitely big sharks that use that bridge.

♪♪

Narrator: On the other side of big moe territory,

Neil adopts a different strategy to find the legendary shark.

Let's get the bait in the water. Let's do it.

Narrator: He and laura are deploying baited buoys from the surface

To attract great hammerheads.

If one takes the bait,

They'll move in for a genetic sample alongside the boat.

I'll work the tag if you're gonna do the biopsy.

Yep. Hopefully we can see who's related to who

And what the interconnectedness is of the populations.

The genetic work will actually allow us to determine

Is there a big moe,

Is there something unique

About the keys great hammerhead,

And try to get an understanding

About the population of great hammerheads

That are using the seven mile bridge.

Narrator: In addition to the buoys,

The team also deploys a bruv,

Or baited remote underwater video,

So they can spy on big moe's territory

When they're not around.

Alright, laura, turn on the camera.

1, 2, 3.

♪♪

Narrator: Shortly after dropping their bruv,

One of neil's baited buoys goes on the run.

♪♪

Dr. Hammerschlag: Bucco put us on top.

Let's see if we can get a look.

We've got a shark on this buoy.

Fingers crossed it's big moe.

♪♪

-Wow. -Holy moly. -Gosh.

That's a tarpon-eating bull shark.

Narrator: The baited buoys capture a bull shark.

Not the target species they are looking for,

But an impressive specimen nonetheless.

Dr. Hammerschlag: Get the bolt cutters, send him on his way.

Narrator: This powerfully built and stocky species.

Are pound for pound some of the strongest sharks on the planet.

♪♪

Dr. Hammerschlag: Careful!

Narrator: When caught on the line,

This makes them notoriously aggressive.

♪♪

You know, about that night dive we're gonna do under the bridge,

I really hope we don't bump into one of those bull sharks.

Yeah.

♪♪

With the light beginning to fade,

They retrieve their bruv.

Oh, yeah. Alright. Awesome.

Okay.

Let's check it out.

Alright. Let's see what we got here.

Alright.

I got an octopus.

Octopi like this have highly evolved brains

So they can operate their eight tentacles independently.

This makes them

Some of the most intelligent animals in the ocean.

♪♪

Oh! Look at the octopus go.

Zipped out of there. He took off.

Whoa-ho-ho!

That's crazy. A huge hammerhead.

That is awesome!

Came and, like, sucked it right up.

♪♪

The bruv captures a massive great hammerhead

That could be over 12 feet long.

That is so crazy.

While this great hammerhead

Isn't as large as the one reported in big moe sightings,

It's further proof

That the bridge is a hot spot for these monster sharks.

♪♪

Back at bahia honda bridge,

Tristan and his team deploy a new strategy --

Shadowing local fishermen.

-Alright! -Yeah!

Dr. Guttridge: Local fishermen come here

To target the huge spawning tarpon run.

And if one of them hooks up on a tarpon

And they happen to see a big hammerhead,

We're hoping that we'll be able to come in and tag that shark.

[ indistinct shouting ]

Man: Whoa!

-Hammer, hammer! -Hammerhead. Big hammer.

Right, there it is. Get that bait out.

Get that bait out.

♪♪

-There it is. -Wow!

Narrator: To their surprise,

This hammerhead happens to be a familiar face.

It's the exact same hammerhead

That tristan missed his shot at under the bridge.

Dr. Guttridge: It's got that acoustic tag,

And also the satellite tag trailing off the dorsal fin.

♪♪

The dorsal fin has got like a cut in it, as well.

♪♪

It's coming in.

About 60 feet behind us.

About 40 feet, 20 feet...

15 feet.

I need to get this sample.

♪♪

Aah! Missed it.

God.

Man: Alright, here we go. Turning right back on the bait.

Dr. Guttridge: Oh, he spun on that. Wow!

♪♪

Okay, that's it. -Come on, man.

♪♪

Coming in hot.

♪♪

Oh, oh!

Oh, god!

♪♪

Narrator: Coming up, neil encounters a monster in the making.

♪♪

And later, the results from the genetic samples

Reveal something extraordinary.

That is crazy.

Narrator: Around the bridges of the florida keys,

Shark scientist neil hammerschlag

And tristan guttridge are tackling the mystery

Of a legendary shark named big moe.

With a possible size of more than 20 feet long

And weighing nearly a ton, big moe is an outlier.

And this means he could be part

Of a new subspecies of hammerhead.

To find out, researchers have to obtain dna samples

From great hammerheads in the region.

-It's coming back again, guys. -Coming back in.

Dr. Guttridge: Right. This time I'm getting it.

Narrator: And right now one is showing tristan's team

Who owns the water.

-Oh, no! -Coming in hot.

Get this out of my way, guys!

♪♪

-No! -Oh!

♪♪

Man: Oh...

-You alright? -Yeah.

Dr. Guttridge: That was crazy.

Okay. It's coming in.

I've got the shark!

-That's it. -Nice.

-Whoo! -Alright!

♪♪

Nice, dude. Yes.

That is awesome. Look at that.

Perfect sample.

So we know this hammerhead uses the bridge.

We've seen it a couple of times now.

It has a satellite tag on it, an acoustic tag on it.

Now we have a genetic sample.

We can reach out to the collaborators,

And we can learn more about these animals.

That was awesome. Whoo!

Narrator: Tristan's obtained the first genetic sample of the mission.

But the team soon has another opportunity heading their way.

It's coming in now. It's coming in.

Narrator: A second. Even larger great hammerhead

Appears off the stern of the boat.

Dr. Guttridge: It's a big shark -- 12, 13 foot.

Pull it in, pull it in, pull it in.

Man: It's coming right in on the bait.

♪♪

Dr. Guttridge: Perfect positioning.

That's it, that's it, that's it, that's it.

Yes. -Nice!

Man: Oh!

-I got it! Yes! -Whoo!

♪♪

Dr. Guttridge: We just had two different great hammerheads,

Both females, coming right up to the side of the boat.

Narrator: The team succeeded in getting an acoustic tag

On the second great hammerhead, which will allow them

To track its movements around the bridges.

Dr. Guttridge: That was incredible.

I just had a 14-foot great hammerhead

Up on the back of the boat.

I'm two for two underneath the bridges,

And I'm not really sure what to say.

It's just been a crazy, crazy day.

Alright, man, well, we'll keep you posted

When we get up from the dive.

Wish us good luck.

Alright. Over now.

Alright, laura, set up for the night dive.

Let's do it.

As the sun sets, the researchers want to capitalize

On the spike in hammerhead activity.

For neil and laura,

That means preparing for a night dive around seven mile bridge.

Dr. Hammerschlag: I would love to see a hammerhead.

Narrator: Numerous studies prove that large sharks

Use the cover of night to ambush prey

If big moe's in the area,

It's possible he's most active after the sun goes down.

♪♪

-So you're ready? -I'm ready. Are you ready?

-Born ready. -Alright. Let's get it done.

♪♪

♪♪

This strange animal is known as a snake eel,

And it belongs to a family of fish

That can grow to be more than seven feet long.

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The yellow ray is a distant cousin of sharks,

And the beautiful patterns of their scales

Provides them with the perfect camouflage

As they hunt along the seafloor.

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Neil and laura remain on high alert,

While just a 10-minute boat ride away,

Tristan and his team

Prepare for their own plunge into the darkness

Around one of the largest shipwrecks in the region.

Dr. Guttridge: There's one called the vandenberg,

Which is like a 400-foot, old wartime ship.

It's just a few miles offshore.

And it could be an important staging ground

Or navigational tool

For these hammerheads coming in from the gulf.

Narrator: As the team prepares for the dive,

A promising sight appears near the boat.

-It's a hammerhead. -Wow!

Dr. Guttridge: There's a hammerhead on my boat right now.

Right now.

Narrator: With the hammerhead circling nearby,

The team scrambles to get into the water.

Dr. Guttridge: Okay, guys, you guys go ahead.

[ thunder crashes ]

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Narrator: Just like the bridges, the wreck forms an artificial reef

That's a magnet for sea life.

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Dr. Guttridge: Oh!

Man: You guys seen any of these sharks?

There's quite a few behind the boat,

Up on the surface.

♪♪

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Narrator: The swarm of bull sharks suddenly disappear.

This could be a sign that a larger predator lurks nearby.

♪♪

Narrator: Off the florida keys,

Shark scientists neil hammerschlag

And tristan guttridge are on a mission

To determine if a legendary hammerhead called big moe

Belongs to a new species of shark.

♪♪

And because they hunt at night,

The teams are searching for them in the dark.

Right now, just off the vandenberg shipwreck,

Tristan and his team have spotted something massive.

♪♪

This hammerhead is at least 16 feet long,

Placing it within big moe's weight class.

But it's too far away to obtain a sample.

♪♪

Running low on air, they have no choice

But to head back to the surface.

♪♪

[ indistinct conversations ]

Dr. Guttridge: Whoo-hoo-hoo! Man: What a dive.

I know. I saw you turn suddenly

And shine your light on the big hammer.

Intense.

I don't know whether it's big moe,

But I am absolutely exhausted.

♪♪

Failing to obtain samples

From either of the hammerheads spotted at night,

The teams are desperate for a new lead.

Dr. Hammerschlag: Awesome. We'll be there immediately, alright?

Just hang tight.

We just got a call on the radio

That someone hooked up with a small great hammerhead.

If this shark is as small as we think it is,

It could be within its first two years of life,

Suggesting that this spot might even serve as a nursery ground

For the great hammerhead shark --

Something that hasn't been identified,

To my knowledge, anywhere else in the world.

We're going to get a genetic sample,

See if that shark was potentially born in the area

And related to big moe.

♪♪

That's amazing.

Beautiful, little shark.

Mcdonnell: That's the smallest hammerhead I've ever seen.

♪♪

Dr. Hammerschlag: My guess, it's about 2 years old, maybe less.

Really hope we're able to get a sample from this one.

Be absolute gold.

Narrator: For neil and laura, the clock's ticking.

They can only keep the hammerhead on the line

For a short period of time

Before they have to release it to ensure its safety.

Dr. Hammerschlag: We're ready. Alright. Let's go, guys.

♪♪

Man: To your right, to your right.

Narrator: To safely handle the shark,

They must secure it with a tail rope.

Neil and laura quickly attach an acoustic tag,

But the little shark

Isn't giving up a genetic sample so easily.

♪♪

Neil regains control of the baby shark

By putting it into tonic immobility.

Man: There you go.

Narrator: This is a hypnotic-like state that's generated

By touching its ampullae of lorenzini.

With the shark relaxed, laura moves in for the genetic sample.

♪♪

Dr. Hammerschlag: Alright, guys.

♪♪

Oh, yes! Oh, my god, that was amazing.

That was so crazy.

That tag is gonna last -- I don't know --

Half a decade, so if this is a nursing area,

We'll know about it.

Yeah, come back. Come back.

We were just able to sample and tag a baby great hammerhead!

That's amazing news.

Narrator: Even though they haven't obtained a genetic sample

From a specimen in big moe's weight class,

This juvenile could grow up to be another monster shark.

And this makes its dna just as valuable as any others.

Holy crap.

Dr. Guttridge: We've got a fisherman who's fishing for tarpon,

And as they were trying to relay in, they saw a big hammerhead.

What we're hoping will happen is the hammerhead might come in

And try and take it off him, and that's when we can

Intercept, place a tag, and biopsy

And get that information that we've come for.

-One on! -One on!

Man: There's the hammer right here!

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Man: What?!

Dr. Guttridge: One of the biggest hammerheads

I've ever seen -- 17 feet, hard to tell.

Massive!

♪♪

-There he is. -There he is.

Narrator: This massive 17-foot-long shark

Is exactly the type of hammerhead

The teams have been looking for.

Man: Whoo-hoo!

Narrator: Its dna could contain the answer as to whether or not

There's a new species of hammerhead in the florida keys.

Man: It's right here.

[ indistinct shouting ]

Man #2: Come on now! Yes!

Alright!

♪♪

I got the tag in, but I didn't get the biopsy.

I didn't get the tissue.

Narrator: Tristan succeeds

In getting a tracker on the hammerhead,

But the most important piece of data

Is hidden in the shark's dna.

Thankfully, this tarpon

Is keeping the hammerhead in the area.

A tarpon like this can weigh as much as 280 pounds.

A healthy snack that provides this hammerhead with the energy

It needs to stay at the top of the food chain.

Dr. Guttridge: No way I could miss out on getting a genetic sample

From an animal of that size.

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Narrator: Off seven mile bridge, a huge 17-foot-long

Great hammerhead has emerged from the deep.

I got the tag in, but I didn't get the tissue.

Narrator: A genetic sample might reveal

If there's a new subspecies of hammerhead in the keys.

But to ensure he has a clean shot,

Tristan guttridge has to free dive alongside the shark.

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♪♪

The hammerhead reappears on the seafloor,

Devouring the tarpon it caught at the surface.

This could be tristan's best chance to obtain the sample.

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Man: Alright, he's back here.

Dr. Guttridge: I think I got it.

I think there's enough on the end of that.

[ cheering ]

We just tagged the biggest great hammerhead

I've ever seen in my life.

It was massive, probably close to 17 feet long.

We got a tracking device in it. We got a genetic sample.

And now we can learn more about how it's connected

To the population of great hammerheads in this region.

If it wasn't big moe, then it was definitely big moena.

[ laughter ]

It was massive. It was incredible.

And we now have some analysis to do.

Narrator: As the field team's mission comes to a close,

The genetic samples they obtained are sent

To the lab for analysis.

The results will help the team determine if sharks like big moe

Belong to a new species of mega hammerhead.

♪♪

-Hey, dave. -Hey, dave. How are you doing?

Hey, guys, good to see you again.

A lot happened in the field.

I saw the biggest hammerhead I've ever seen in my life.

Dr. Hammerschlag: Yeah, and we saw the smallest hammerhead

We've ever seen in our life.

Dr. Guttridge: We did exactly what you asked.

What have you got for us?

Okay, so we've been able to take the samples

That you provided from the field,

And you guys are not going to believe the results.

They're really interesting.

Of the specimens analyzed,

We discovered that some of them are actually related.

That is unbelievable.

That's so crazy.

Dr. Portnoy: And most of those relatives

Were adult siblings captured in the same area.

But sometimes we capture them years apart from one another.

That is crazy.

What's so amazing about this is hammerheads

Can travel thousands of miles,

So they can essentially go wherever they want.

But for some reason, they appear to be favoring habitat

Around south florida.

Dr. Hammerschlag: Yeah, this is amazing.

The fact that we can identify siblings

In such a small dataset opens up so much more.

Dr. Portnoy: Well, I think it indicates

That they're displaying site fidelity.

Narrator: Site fidelity means these sharks frequently return

To a specific area for important parts of their life cycle,

Like mating, pupping, and to feed.

Dr. Portnoy: It's possible that big moe is, in fact,

One shark that's reappearing at the bridge every year

Because it's such a productive habitat.

Narrator: The numerous eyewitness reports of big moe,

Combined with the evidence that many hammerheads in the region

Are related, leads to a new possible theory.

Big moe might be just one member of a huge family of sharks

That call the bridges of the florida keys home.

And while there could be a new species of hammerhead

Somewhere out there, more data is needed.

Hammerhead! It's a massive hammerhead!

Dr. Guttridge: Because it's such a highly migratory species,

There's a tendency for all of us to think that these animals

Just travel all over the place randomly.

But we're beginning to learn that they show repeatability

In where they go.

And we think there might be a genetic structure

That's underpinning this behavior.

Mcdonnell: I'm saying it now.

I think big moe is actually big moena.

I think that that might just be a really massive female

That is stalking these bridges.

So girl power.

Dr. Hammerschlag: The great hammerhead shark is an animal

That we know so little about.

Yet it's so important because they are a species

That is globally endangered.

Narrator: While there's still a lot to learn about large

Great hammerheads like big moe,

The teams' efforts have brought them one step closer

To solving the mysteries behind some of the greatest sharks

In the ocean.