Original subtitles

[James Cameron] The Ocean...

the last frontier on earth.

So much is unexplored and unexplained.

To change that...

a kickass team of insanely talented specialists is

setting out to push the frontiers of what we know

about our oceans.

[Zoleka Filander] Oh my gosh.

[James Cameron] Zoleka Filander, deep sea scientist.

[Zoleka Filander] Being a deep-sea researcher means

having front row tickets to the best movie that everybody

wants to watch.

[James Cameron] Melissa Márquez...

[Melissa Márquez] Straight ahead, 12:00.

[James Cameron] Shark biologist.

[Melissa Márquez] We just saw what no one has seen before.

[James Cameron] Eric Stackpole...

[Eric Stackpole] Scan now!

[James Cameron] Ocean tech innovator.

[Eric Stackpole] I love building tools that allow us

to see things in ways we've never seen before.

[gasps]

[James Cameron] And Aldo Kane...

[Aldo Kane] This is insane.

[James Cameron] Former Royal Marine; special ops.

[Aldo Kane] It doesn't get any more cutting-edge

exploration than this.

[James Cameron] Their secret weapon...

...the OceanXplorer.

The most technologically advanced research vessel

ever built.

There's never been a more urgent need to understand

our ocean and the animals that call it home...

Because their lives and ours depend on it.

This time, the team's following one of the ocean's

most unique predators.

[Matt Smukall] Hammer, hammer, hammer...

[James Cameron] To discover the superpowers.

[Eric Stackpole] Look at the size of him!

[James Cameron] Of the great Hammerhead.

[theme music plays].

[James Cameron] The team is powering through the

Atlantic Ocean off the eastern seaboard of the USA.

[Pilot] Green light green deck we're lifting.

[James Cameron] Firing up the OceanXplorer's armory of

cutting-edge gear.

[helicopter whirring]

They're on a mission to search out one of the strangest

sharks in our oceans and one of the most recognizable

animals on the planet.

[helicopter whirring]

[Eric Stackpole] That's what we're looking for.

[James Cameron] The great hammerhead.

These sharks haven't changed for millions of years.

They are one of evolution's most eccentric creations.

But why would nature select for a head shaped like

a stealth bomber?

Science suggests: Improved agility and

enhanced electro sensor capabilities

make this shark one of the most specialized in the ocean.

[♪ intimidating music]

Hammerheads are found off the coast of Virginia to the North

and Louisiana to the West.

But highly sensitive to temperature,

every winter they migrate to the warmer waters of Florida.

We think the sharks are navigating this journey,

by following the earth's magnetic field.

This field generated by our planet's molten core,

creates the magnetic north and south poles.

It's believed that hammerheads can tune into this and use it

like we'd use a compass.

But as a mariner, I know even one degree out and you're

soon miles off course.

So how do great hammerheads navigate so accurately

across this vast ocean?

With the hope of finding an answer...

The team is in Florida.

Their plan, to attach a camera tag to a hammerhead.

[Aldo Kane] Welcome aboard.

[James Cameron] They're joined by

marine ecologist Erin Spencer.

[Aldo Kane] Here he is, welcome aboard.

Let's go.

[James Cameron] And shark biologist Matt Smukall.

[Erin Spencer] Everyone ready to tag some sharks?

[engine rumbling]

[Matt Smukall] Hammer!

[Erin Spencer] Hammer!

[James Cameron] The only way to catch a hammerhead is with

a baited line.

It might look stressful, but these sharks are tough,

and their wellbeing is the team's top priority.

[Matt Smukall] Get out of the way guys, get out of the way.

Alright. Coming up.

Neutral, neutral, neutral.

Go for dorsal.

[Aldo Kane] I have the dorsal.

[James Cameron] The team works fast to take vital measurements.

[Eric Stackpole] 80 to caudal.

[Matt Smukall] 180 to caudal. 180 caudal.

186 for fork length.

[Zoleka Filander] 186.

[Matt Smukall] Check the sex Erin, remember sex.

[James Cameron] They attach a tracking tag.

[Erin Spencer] Alright, it secure?

[James Cameron] And release the shark in under 5 minutes.

[Aldo Kane] It's a physical task holding onto that

main dorsal fin.

You know it's amazing but it's, like it's a live animal and

it's, you know you, you are fully tuned, you're focused.

[Matt Smukall] We have 30 seconds to release.

You guys on tail count it down.

[Eric Stackpole] 3,2,1...

Tail's loose.

[Erin Spencer] Looking good, swimming off.

[Matt Smukall] Alright, Nice job guys.

Nice job.

[Aldo Kane] How many hammers have you worked up like this?

[Erin Spencer] So we've worked up quite a number of hammers

but it's the first time we've been able to put out a

video tag with our speed sensor.

And so hopefully we're gonna get some good footage to also

match up maybe with some of that speed data.

[James Cameron] The tag is designed to fall off

within 24 hours.

[Matt Smukall] What's that just, at like 11:00?

[Erin Spencer] See that floating?

[Matt Smukall] Is that the tag?

[Aldo Kane] Look how small that is in the water.

[Erin Spencer] Whoa. We have a tag!

So you're gonna see what the shark sees, are you ready?

You can see him turning to look left and right.

[Aldo Kane] That's amazing getting that perspective of

the head moving.

[Erin Spencer] We're moving up towards the surface.

And he's right at the surface,

you can see the water patterns at the surface.

Now we're back towards the bottom down to about 80 meters.

[Matt Smukall] It looks like that's a choice to either be

up at the surface or down, it's not just like a wandering.

[Zoleka Filander] You're actually right, cos like if

you look closely, we can actually see this up and down

movement of the shark, and it,

it resembles a yo-yo pattern.

And it looks like it happened 20 or 30 times.

And I'm just wondering, why would the shark be using

so much energy intentionally moving up and down?

Do you think it has something to do with its magnetic sense?

[James Cameron] For a shark, the earth's magnetic field is

clearest at the surface.

But the seafloor also has local magnetic fields created

by geological formations.

It's believed that hammerheads yoyo up and down to create a

virtual magnetic map.

This map allows them to plot a more accurate course.

So that they can eventually find their destination

hundreds of miles away.

Some hammerheads are content wintering in Florida,

but others keep going.

Crossing the Gulf stream into the Bahamas.

And eventually, even pinpointing the tiny island group of Bimini.

Following in the wake of the great hammerheads,

The OceanXplorer sets sail.

[James Cameron] Matt's been studying hammerheads in Bimini

for years, and knows the best place

for Eric to meet the locals.

[Eric Stackpole] Ok, let's do it.

[Matt Smukall] Ready.

[SCUBA breathing]

Alright.

[James Cameron] This feeding station attracts more than

just Hammerheads.

[Matt Smukall] Bull shark!

So those are the sharks that

you know have a pretty bad reputation.

[Eric Stackpole] Looks like a shark that means business.

[Matt Smukall] Eric.

Hammer hammer, hammer.

Look at the size of him.

He must be at least 12 feet long.

I just need to keep telling myself they don't eat people,

they eat stingrays.

[Eric Stackpole] So do you recognize this shark?

[Matt Smukall] Yeah this is Atlas.

He's one of the regulars around Bimini.

And he's been coming back at least 6 or 7 years.

[Eric Stackpole] So he's an old friend.

Maybe he recognizes you as well.

[bubbles]

Seeing Atlas return to this island year after year

is incredible.

I mean it's a tiny little speck in a big ocean,

but you don't get that ability without having some

crazy navigation skills.

But I guess that's evolution in action.

[James Cameron] Thanks to Matt's research, we know

hammerheads like Atlas keep coming back to Bimini.

But it's only 7 miles long.

Even with geomagnetic navigation, finding this place

is a longshot.

So how do these sharks get here?

Could they be using other senses to help guide them in?

Zoleka wants to map the seafloor using the

OceanXplorer's sonar.

In the hope it uncovers an answer.

[computer beeps]

[clicking]

[Zoleka Filander] The sea floor in this area has never

been mapped to this resolution before, and so I'm really

hoping we pick up on some anomalies.

Different features that can give insights as to how these

hammerhead sharks are coming here to Bimini.

[James Cameron] The ship scans for 12 hours straight,

mapping this area for the very first time,

and generating detailed images

of what lies beneath the surface.

[Eric Stackpole] Wait so this has got to be exaggerated relief

right, I mean these are really sharp features

that we're seeing here.

[Zoleka Filander] It's not exaggerated.

[Eric Stackpole] This is actually what it looks like?

There's huge, tall pillars

sticking out of the bottom of the ocean?

[Zoleka Filander] Yeah. Yeah. This is very exciting.

[James Cameron] The sonar reveals a labyrinth-like terrain

hidden on the ocean floor.

[Eric Stackpole] These are meter marks, it's 100 meters.

So that's like a 300-foot tower.

I mean, I'm just trying to picture that standing up

from the bottom of the sea.

[James Cameron] These towers are the height of the

Statue of Liberty.

[Aldo Kane] This is off the west coast then?

[Matt Smukall] Right on the, right on the drop off to

the gulf stream.

[Erin Spencer] Is this what you thought, is this a surprise?

[Matt Smukall] We didn't know this was there.

There's a lot going on there, that's really exciting.

[Zoleka Filander] It would be great to do a sub dive and

to get like some visuals on what's there, you know.

We always go out to find the known unknowns, but we stumble

on the absolutely unknowns,

like something we've never seen before.

[James Cameron] To discover if these towering outcrops could

be influencing the great hammerhead's navigation,

Zoleka and Matt take a dive into the deep.

[Zoleka Filander] This is real, real exploration.

No idea what we are getting ourselves into.

[SO] Bridge, SO that's Neptune off deck.

[Bridge] Copy that!

[splashing]

[Pilot] Ah Roger SO.

SO, this is Neptune, venting now.

[SO] Venting now.

[James Cameron] The sub team will be accompanied by the

remotely operated vehicle.

Controlled from the surface it sends up live pictures

from the seafloor.

[Pilot] Control, control.

This is Neptune, passing 500 meters.

Descending.

Depth under keel 21 meters.

Over.

[SO] Roger.

[Aldo Kane] Where these pinnacles are is, is right in

the gulf stream and that gulf stream is, is cranking north

the whole time there's no rest there.

[Pilot] That's a strong current.

[James Cameron] The Gulf stream is the fastest ocean current

in the world, running up to five miles per hour.

And 1600 feet down

the deep dive team is feeling its force.

[Pilot] Zoleka can you see?

[Zoleka Filander] I can't see much.

[James Cameron] The strong current is picking up sediment

and visibility is reduced to near zero.

Conditions us sub pilots refer to as "off-nominal".

Out of the gloom.

[Pilot] Ah man, that's massive.

[James Cameron] A towering pinnacle.

[Zoleka Filander] Oh this is so beautiful.

[Pilot] Control, this is Neptune.

Intention is start working up wall, over.

[SO] Roger, walking up wall.

[Eric Stackpole] Oh my gosh.

[Matt Smukall] A mountain underwater.

[Pilot] Shark port side.

[Matt Smukall] Oh yeah.

There it is there, night shark.

Oh came right under the...

came darting under the uh...

[Zoleka Filander] There it is. Port.

[Matt Smukall] Ah.

He darted off pretty quick.

[Zoleka Filander] Yep.

[Pilot] We are at the top.

[Zoleka Filander] Ah look at this.

[Pilot] Control, control this is Neptune.

We are at the top of the first pinnacle.

Depth 408 meters.

[Zoleka Filander] The minute we got to the top,

it was beautiful.

Absolutely stunning.

[Pilot] Guys do we wanna move to the next pinnacle?

[Matt Smukall] Yep. Yep.

[James Cameron] Now the sub and ROV teams begin to survey

the pinnacle field, looking for sharks.

[Matt Smukall] Oop little shark here.

[Pilot] Oh yeah.

[James Cameron] A dusky smooth hound.

[Erin Spencer] Ohh. Look, shark, shark, shark.

[James Cameron] And a Tiger shark.

Just like Atlas, tiger sharks must cross hundreds of miles

of open ocean to find their way to Bimini.

And this complex field of pinnacles could hold the key

to getting them there.

[Aldo Kane] When I'm navigating, I don't just use a map

and compass to find out where I am.

I use other senses like sight to look for landmarks and

that's what we think sharks are doing but with smell.

[James Cameron] As water from the Gulf stream hits the

towering pinnacles, nutrient rich water is forced to the

surface, creating distinctive 'scent trails'.

Sharks like Atlas, with their powerful sense of smell,

are able to detect these scent trails and follow them,

like an underwater signpost pointing straight to Bimini.

The discovery of this vast pinnacle field could finally

answer how these sharks locate this tiny group of islands.

But once here, does this unique adaptation give them

any other advantages?

The team meets in the mixed reality lab to investigate.

[Aldo Kane] I notice just how huge that cephalofoil is and

then underneath it how,

how small in comparison the, the mouth is.

[Matt Smukall] You can tell they're just not designed to

take down massive prey but what they are designed to do

is actually chase down rays or smaller sharks and use that

big cephalofoil, almost sometimes pin down the animal

and then that that mouth is right underneath there and

they could potentially, you know, bite off one of the

wings of a stingray and kind of incapacitate it.

[Eric Stackpole] But also they're a sensing machine right?

They've got all these um, you know sensing olfactory glands,

they can detect electrical signals from fish and

I imagine that's got to be useful?

[Matt Smukall] Yeah, and and having all of those senses

spread out over a wider area can probably help them hone in

on certain things like a stingray that's buried

under the sand.

[Zoleka Filander] So it's the spread out array that's making

the Hammerhead sharks such an accurate hunter?

[Matt Smukall] Absolutely.

That's what allows them to be such an efficient predator.

[boat motor rumbling]

[James Cameron] To observe the shark's hammerhead in action

Aldo and Matt are going out with a camera tag designed

to give them a view rarely seen.

[Aldo Kane] 1, 2, 3 go.

[James Cameron] But to attach it, first they must get

up close and personal with the hammerheads.

[Aldo Kane] She is big.

These sharks are huge.

They can be up to 900 pounds and when you're in the water,

they are all around you.

You need your head on a swivel.

But with this mask you get quite a lot of tunnel vision.

Shark coming in your right.

[Matt Smukall] Alright here we go.

[♪ dramatic music]

[Aldo Kane] Here she comes.

Almost, almost.

Coming in again.

Ah man that's on.

[Matt Smukall] Yeah that one looked like it went

on really well.

Topside, topside.

If you copy, that's successful deployed tag.

[♪ peaceful music]

[James Cameron] After eight hours, the tag releases.

And once retrieved, the footage is ready to view.

[Matt Smukall] You know you can actually just see what a

nice view these cameras are giving us of what the shark's

actually doing in that habitat.

[Zoleka Filander] He's got his head down, and scanning

back and forth.

It looks like it's hunting.

[Matt Smukall] He's cruising along relatively calm,

probably looking for some prey there.

[Zoleka Filander] Yeah they generally cruise at

five miles per hour and they can burst to like 20 miles per hour.

Look he's picking up speed.

He must have gotten his eyes on something.

With its wide-angle field of view, this camera tag reveals

where the great hammerhead is hunting.

[Matt Smukall] That little strip along the the reef where

you kind of have the convergence of two habitats.

You have the the seagrass flats coming to meet the

the reef area.

That is the area that they're using most of the time and

probably hunting in both of those types of habitats.

[Zoleka Filander] Yeah.

[Eric Stackpole] Is this, this is night-time now.

[James Cameron] Even in the pitch-black waters of the night,

using its electro sensors, this hammerhead...

[Zoleka Filander] Fish.

[James Cameron] Can still detect prey.

[Zoleka Filander] Whoa.

He senses the fish and goes precisely at it.

He's sensing the electric field, or vibration.

This network of sensors that you find along this broad head.

[James Cameron] No luck this time.

But the team has gained key information on where

the hammerheads are hunting.

[seagulls cawing]

[boat engine rumbling]

[James Cameron] Eric and Matt head out,

their destination: the seagrass flats of Bimini.

[Eric Stackpole] It's amazing because this is a really

shallow area.

I, I wouldn't have expected hammerhead sharks to come

around here.

[James Cameron] These shallows are home to the hammerheads'

favorite prey, the southern stingray.

[Matt Smukall] Look at all the stingrays.

But see how they're all right up close up to the shore?

[James Cameron] These waters offer the rays protection,

and a place to hide.

Too shallow for most predators.

But not the great hammerhead.

It's a shallow water specialist.

And these rays carry the scars.

[Matt Smukall] You can see right there at the base of her tail.

She actually no longer even has a barb.

So you can imagine that might be from a shark coming in and

biting off a section of that tail.

[James Cameron] Now they know what and where the hammerheads

are hunting, the team sends up the Helo.

[helicopter whirring]

If the aerial crew can capture footage of a hunt,

the team on the ship

will see how the hammerhead is uniquely

adapted to life in these shallows.

[helicopter whirring]

[helicopter whirring]

[James Cameron] The aerial crew returns with footage to share.

Once again the shark is head down looking for prey

[splashing]

and this time it finds it.

[Erin Spencer] The tail movement is wild.

[Eric Stackpole] Oh!

[Erin Spencer] Oh yeah.

[Eric Stackpole] Look how quick it can turn.

[James Cameron] To lock on this stingray, the hammerhead

attacks from the side.

[Zoleka Filander] These waters are only one meter deep,

it's really well adapted for hunting in these shallow waters.

[Matt Smukall] As the water starts murking up she's still

able to use all her other senses beside sight to keep

tracking that ray down.

[splashing]

[Eric Stackpole] In this visibility it must be using its

electro receptors to detect the electrical signal from the ray.

[Zoleka Filander] This is so wild!

[splashing]

[Erin Spencer] This is really a gem of an encounter.

[Zoleka Filander] Oh, hectic!

Look at those sharp turns.

[splashing]

[splashing]

[Matt Smukall] The shark is trying to pin that ray down

whereas the ray's trying to come up to the surface.

Which is basically the safest spot because the mouth is

actually on the underside of that shark.

[splashing]

[Eric Stackpole] The hammerhead is making much

tighter turns than I would have pictured possible for an

animal that size.

You know maybe even the cephalofoil is useful as, as

being a sort of extra control surface to help it get those

tighter turns.

[Matt Smukall] It does shows you how powerful and agile

they are.

[Eric Stackpole] I mean the hammerhead is like a perfect

ray hunting machine.

[Matt Smukall] Right there.

[Erin Spencer] Yeah, yeah, yeah, yeah.

You can see the instant that, that ray is captured.

[James Cameron] Rarely filmed in its entirety, the hunt

lasts nearly four minutes.

A long arduous battle of attrition, finally won

by the great hammerhead.

[Eric Stackpole] It's the ultimate shark

for this environment.

[♪ dramatic music]

[James Cameron] In their time following the great hammerheads,

the team has deep dived into the world of

this mysterious creature.

[Aldo Kane] The great hammerhead has a sixth sense.

Opening up a magnetic map, leading it across the ocean

and that is just incredible.

[James Cameron] They've revealed hidden landscapes

on the ocean floor.

[Eric Stackpole] Oh my gosh.

[Zoleka Filander] Absolutely stunning.

Every single time we scan the seafloor, we find something

that we never knew existed,

and these are the sort of clues that help us

solve the greatest ocean mysteries.

[James Cameron] And they've captured images that offer

a rare insight into the lives of these

little-understood creatures.

[Eric Stackpole] I mean the camera tag got us right in there

and we got to spend a day watching what the

shark does from its perspective.

[helicopter whirring]

[James Cameron] The team was able to study hammerheads here

because the Bahamas is a shark sanctuary.

But elsewhere in our oceans,

great hammerheads are critically endangered

and they need our protection.

We have to do all we can to safeguard the future of this

extraordinary species.

[♪ peaceful music]