Original subtitles

(triumphant music)

North America's Atlantic Coast

is a magnet for sea creatures.

(water splashing)

Strange and giant beasts seem to appear

when summer begins.

Some are old friends,

but others are elusive.

What are they hunting?

And why are they here?

A special team, armed with revolutionary cameras,

plans to spy on these secretive sea monsters.

Their discovery may change the way

we think about the ocean forever.

(upbeat music)

(peaceful music)

It's summer in the cold Atlantic,

and from Canada to the northeastern United States,

the ocean is quickly warming up.

In Cape Cod, Massachusetts,

both locals and visitors take to the sea.

Few suspect that huge sea creatures can suddenly show up

anywhere, at any time.

(dramatic music)

Now a team of investigators plans to find and follow

the mysterious beasts.

There's been a shark sighting,

so Captain Bryan Treadwell heads to the spot.

It's very difficult to spot them in these conditions,

but this time of year, they congregate in this area,

and they always come up to the surface,

where we generally can see the shark's dorsal fin,

maybe a little bit, sometimes a lot.

Depends on the size of the fish.

The team scans the sea for signs of the shark.

They quickly spot something.

(whale spouting)

But as they get closer,

they realize it's a huge fin whale.

Nearby, a smaller minke whale surfaces.

(water splashing)

Cape Cod draws humpbacks too.

(lighthearted string music)

All of the whales are enjoying this balmy sea,

but they're not here for fun.

During summer, this part of the Atlantic

is full of food for the big whales.

The Labrador Current sends nutrient-rich water

from the north.

More bounty rises from the depths to the surface.

And the Gulf Stream brings warm water from the south.

An explosion of phytoplankton results

when the sun further heats the sea.

Tiny zooplankton feed on microscopic plants,

so their numbers also increase.

This is the banquet that the great whales come to devour.

The team believes that their elusive quarry

also comes to feed in these waters.

They're searching for a unique dorsal fin

that belongs to a very rare shark.

There it is.

Then the captain spots something.

(dramatic music)

The creature heads straight towards the boat.

Judging by the distance from the dorsal fin

to the tail fin, this is a behemoth.

It's a basking shark!

(man speaking in foreign language)

(peaceful music)

It's one of the giants they've been hunting,

a 30 foot long basking shark.

Its pointy snout is trailed

by very large dorsal and tail fins.

As the shark leisurely cruises through the sunlit water,

it's easy to see how it got its name.

This one's swimming so slowly

that it just might be possible to film it underwater.

Get in, get in, get in, go on!

There's no time to waste.

(men yelling)

(dramatic music)

It looks even bigger through the camera lens.

But the shark doesn't stick around for long,

and it's much faster than it looks.

It's taken days of searching

for this few seconds of footage,

but the research team's appetite has been whetted.

They want more.

(men chattering)

(peaceful music)

But days and nights pass without another sighting.

It's time for plan B.

(triumphant music)

With the help of pilot George Breen,

they scan the water for their elusive quarry.

An aerial view should enable them to spot a shark,

even if the creature's submerged.

The small plane and the boat head out together.

Yeah, that sounds about it.

You'll get better conditions this way, lot better.

If the pilot spots a shark,

he'll transmit the location to the researchers on the boat.

The plane begins its search

where the basking shark was seen days ago.

Now I gotta find a real one.

He does.

It's definitely a basking shark.

Yeah, just off your bow, about a mile off your port bow,

and I got a shark here,

maybe 10 or 20 degrees to port.

All right, we got one shark a mile off our starboard bow,

coming right 20 degrees to starboard.

How big is it, over.

It's a big shark, and it's on the surface,

and it's swimming towards the south, towards the south.

Big one, very good.

Big shark, all right, copy that.

Be there about three minutes.

Roger that, roger that.

I'll keep you covered.

The team needs a small boat

that's easy to maneuver

in order to get close to the shark.

(tense music)

(radio chatter)

Basking sharks can be very shy,

and they don't want to startle their quarry.

They're going around, coming around.

Yes, yes.

But this shark seems to have

a plan of its own.

Look at that, whoa.

(man speaking in foreign language)

(peaceful music)

This 25 foot basking shark

appears willing to offer our cameras

the opportunity to get rare footage

while it literally basks in the sun.

Its conical snout is similar to man-eating sharks,

but this animal only eats tiny plankton.

Basking sharks open their giant mouths

to inhale water full of microscopic food.

Five gill slits draw in food-rich sea water,

strain it through the rake-like rows,

and then eject the filtered water back out.

As the shark swims,

water is forced into its mouth and through its gills.

It's an efficient way to feed near the surface.

A powerful blade-like tail propels the creature,

while its large dorsal fin acts like a stabilizer.

This undulating movement might be an indication

that the beast is about to feed.

But this time, the cameramen are out of luck.

In no time at all, the shark vanishes.

The team has spent a bit of time

with this elusive creature,

but they need more help.

Kirsten McGovern mounts cameras on animals

in order to study their behavior.

And you think this is fine?

Dr. Gregory Skomal is an expert

in shark behavior.

Big white sharks that we never got another shot at.

Oh man.

(upbeat music)

This special camera also measures

depth, water temperature, and speed of the animal

while recording video.

But first, they've got to mount it on a basking shark.

After being submerged in the sea water for 24 hours,

this metal attachment will dissolve.

Once the camera detaches,

the scientists can retrieve it on the surface.

This particular instrument can tell us

what depth the shark is at,

and it's gonna tell us about water temperature

and water chemistry,

so we'll get really, really good observations

from the point of view of the shark,

and what it's doing, that's important.

A basking shark shows up

and seems approachable.

He's turning south on us here.

That sucker's being nice and cooperative though.

Here he is right here, it's one right here.

Yeah, that's him.

Is that him?

Dr. Skomal needs to attach the camera

behind the dorsal fin,

where it will least affect the shark's movement.

Think we got him.

(peaceful music)

As the shark swims away,

they see the camera right where it should be.

Now they have 24 hours before they can get it back.

When dawn breaks,

they follow the camera's signal and find it floating.

(man speaking in foreign language)

Yeah (laughs).

Now, the results.

Look at that, yeah, that's interesting.

(peaceful music)

These may be the first images ever captured

with a camera mounted on a basking shark.

The large fin on the screen is the dorsal fin.

The head is at the back of the screen,

and the shark is going deep.

The shark's rough skin is also clearly visible.

Look at him.

That's the lampreys.

There's a lot of them on there, you can see.

They're a parasite.

Lampreys use sucker-like mouths

filled with teeth to feed on the shark's mucous membrane.

They leave white scars when they drop off.

I think it must annoy the shark,

and as far as I'm concerned, a vile beast.

Then, a surprise.

What's that all about? (Kirsten laughs)

What is that all about?

(dramatic music)

(water splashing)

Wow, that's never been filmed before, a full jump,

I mean, a jump out of the water,

this kind of surface behavior,

not from the perspective of the animal itself.

They watch it in slow motion.

The enormous basking shark leaps out of the water.

Dr. Skomal believes the shark was trying

to rid itself of the camera.

And it may be doing it thinking that we're a lamprey.

I wanna get rid of this thing on my back,

and I might wanna get rid of those things too,

which are eating my flesh. (Kristen laughs)

But that may very well have been a breach.

I mean, that's spectacular.

You couldn't hope for, and it held.

Other vital information was recorded

with the device.

(peaceful music)

The vertical axis represents water depth,

and the horizontal axis, time.

This basking shark stayed 2 1/2 hours

at the depth of 450 feet,

where it's a chilly 40 degrees.

The camera captured images of abundant zooplankton,

just at the thermocline,

where the temperature abruptly changes.

There goes the theory

that these sharks feed only at the surface.

Dr. Skomal believes the creature found this deep plankton

and devoured it.

The prey animals may also be scattering more vertically

so the shark is in a surge pattern trying to get back on it,

whereas during the daylight hours,

they may form very dense bands that the shark is exploiting.

This confirms that the sharks

can feed in deep water,

but still relax at the surface.

Perhaps they come up when they need to get warm again.

This time of year and this part of the world,

we know that the water column here is stratified,

meaning it's much colder, deeper, than it is at the surface,

it's very warm at the surface.

They're a cold-blooded fish, like most fish species,

that they don't warm their body temperature internally,

so when they go down into cold water,

their bodies get cold and they need to come up

into warm water, spending time in the warm surface waters,

and therefore basking.

By traveling between cold and warm water,

basking sharks fully enjoy the sea's summer bounty.

They aren't alone.

Another sea monster appears during the summers

off the Nova Scotia coast in Canada.

(peaceful music)

By August, this part of the Atlantic is

even richer with food than Cape Cod.

Leatherback sea turtles are unchanged

since the time of the dinosaurs.

This one weighed over a ton.

They're the largest sea turtles in the world,

and they're very rare.

Dr. Michael James has been studying

the giant turtles for over 16 years.

Welcome to Neil's Harbor, welcome.

The team needs his expertise

to find a leatherback.

How's the weather today?

The weather is good.

It looks like the sea is gonna become a little flatter

this afternoon.

Despite their great size,

leatherbacks are rarely seen today.

But sometimes, during summer, they come here.

After only an hour at sea, they spot something.

Yeah, there it is.

Yeah, (mumbles) staying there.

It was up for a breath.

The mystery creature is elusive,

but then a fin appears.

It's not a leatherback, it's an ocean sunfish.

There are several sunfish in the area,

which could be a clue on the whereabouts of the sea turtles.

These ocean giants like the same food.

See that calm water there?

The turtle was right in front of the boat.

It came up for a breath.

It takes practiced eyes to spot a turtle.

(man murmuring)

The team slowly moves the boat closer,

just as the creature raises its head for a breath.

(peaceful music)

This adult is about six feet long.

Instead of a hard, bony shell,

this turtle is covered by oily, leather-like tissue.

Deep ridges on the shell prevent

the heavy turtle from tilting.

This leatherback uses its huge fin-like front paddles

to vanish into the depths.

Canada's government prohibits

approaching the turtles underwater,

so the team must deploy a robot-bearing camera.

This will prevent the turtle from being startled.

(water splashing)

(peaceful music)

The leatherback stays around,

gliding through the water with ease.

Its spindle-shaped body is designed for speed.

The robot cam keeps up with the turtle near the surface,

but not when the beast dives.

They need a different camera,

one that can follow the animal anywhere.

Dr. James has just the toy.

(upbeat music)

Like the device used on the basking shark,

this one will record data as well as video.

Suction cups will keep it attached to the turtle.

Even if it only sticks for a short time,

they hope it will capture clues

as to what the leatherback is doing.

They'll have a very short window to attach the camera

when the turtle surfaces to take a breath.

Dr. James gets ready.

Oh, I can't reach it.

(men murmuring)

But it's a miss.

(men laughing)

(men murmuring)

He needs to try again.

This time, he cleans the turtle's back

so the suction cups can stick securely.

Perfect.

(dramatic music)

Well, I'm gonna give it my best.

And it works.

(peaceful music)

He goes for a second leatherback.

Once again, this one sticks too,

while the turtle carries it down to the depths.

After two hours, the camera has been released,

and the team tracks its signal.

(device beeping)

Guys, you see (mumbles)?

They have no idea what's been recorded.

Look, look, look, look.

Here it comes, here comes the jellyfish.

(men chatter excitedly)

Turtle's turning its head.

(mumbles) one more time, pointing, pointing.

Om, nom.

(man laughs)

(peaceful music)

The camera recorded an epic dive

by a leatherback turtle.

As the beast descends, something appears in the distance.

It's a jellyfish, one of the leatherback's favorite foods.

For two hours, this turtle dines exclusively on jellies.

It's a strange diet.

Jellyfish are mostly water and not very nutritious.

A big turtle needs to consume lots of jellies to survive.

(triumphant music)

The strategy for leatherbacks as a species

is to feed on a jellyfish

and eat lots and lots of them a day,

so yes, they don't have a particularly high nutrient value,

but if you feed constantly on them,

almost like a conveyor belt,

all day during daylight hours,

you're gonna gain enough nutrition to make a go,

and what we've discovered is that, these turtles up here,

they'll gain as much as a third of their body weight again

while they're feeding up here.

Dr. James does hands-on research

with leatherbacks in the area too.

They capture turtles on the surface with a large net,

measure, and weigh them.

This female is seven feet long.

89, 590, 588, 587, five.

She weighs an incredible 1,300 pounds.

(upbeat music)

The process allows us to get a good look at her mouth,

and it's a jellyfish-shredding machine.

Behind her parrot-like beak are spines

which go all the way down to her stomach,

tearing the jellies apart the whole way down.

After the turtle swallows its prey,

the hapless jellyfish travels down a lethal conveyor belt.

During digestion, excess water is sent the other way.

With a belly full of jellies,

this turtle is enjoying the warm surface water.

In this part of Canada,

they spend their summers eating to their hearts' content.

Leatherback turtles evolved physically and behaviorally

to eat unpopular prey.

Perhaps it's their secret to millions of years of survival.

Then the researchers get a big surprise.

(mumbles) nesting animal, these are very deep troughs,

and when they're up here--

While they're examining a turtle,

they recognize one of their own tags.

It was placed on the animal in Trinidad in the Caribbean.

Holy cow, it has Trinidad tags! (laughs)

T48599.

T means--

Trinidad.

That's Trinidad.

Amazingly, this turtle swam over 3,000 miles

from the Caribbean to Nova Scotia.

Trinidad and Tobago, a twin island country in the Caribbean,

is one of the world's most important

leatherback nesting sites.

This beautiful sandy beach is

where a sea turtle drama unfolds.

During the night, in early summer,

female leatherbacks come ashore.

They're heavy, and it's hard work.

This turtle was born on this beach nearly 30 years ago,

returning only every few years for a short visit.

When she finds a spot she likes,

she digs a hole using her hind flippers.

The deeper she digs, the safer her eggs will be.

Then she deposits about 80 eggs.

It's almost as difficult to cover the nest

as it is to dig it.

The mother turtle doesn't wait around

to see her babies hatch.

She belongs in the sea,

and she'll head towards Canada.

Her eggs stay buried for almost two months.

(lighthearted music)

Then, it's time for the tiny turtles to emerge.

They immediately head for the water.

But before they reach the safety of the sea,

they face a gauntlet.

Hungry birds are waiting.

Only a few lucky hatchlings will get past them.

(peaceful music)

Those that do make it begin a life adrift,

feeding on small jellyfish

while growing into their flippers.

It may take 30 years before they're mature enough

to begin their own journey north.

They'll pass Cape Cod during the summer,

when whales of all kinds are enjoying the warm water.

These warm seas are

where the basking sharks plunder plankton.

One day, something strange happens.

(men speaking in foreign language)

A giant basking shark swims over to the inflatable.

The shark seems relaxed, and inspects the small boat.

It's a close encounter of the shark's choice.

Then the basking shark turns away.

(peaceful music)

Then it happens again.

(men speaking in foreign language)

Another basking shark approaches the boat.

(man whistles)

Wow.

It's as though these beasts

are searching for something.

The team wonders if the sharks are mistaking

their boat for another shark.

More sharks appear,

with both male and female sharks spending time

close to the researchers.

Some are slightly aggressive.

An open mouth could be an early sign of courtship.

Other species of sharks bite each other's fins while mating.

It's a provocative new theory,

but the creatures remain mysterious.

You know, they're shrouded in mystery.

We don't know anything about their reproductive biology,

where mating behavior occurs,

where they give birth to their young.

We know they travel these great distances,

and we only learned that in recent years.

That's relatively new information.

(upbeat music)

Dr. Skomal does know

that the basking sharks head south in the fall.

By winter, some travel as far as South America.

This makes them a cosmopolitan migratory species,

constantly seeking warmth and food.

No one knows where they give birth.

These giants keep their secrets close.

During summer in the Atlantic,

along the North American coast,

we have a brief and lucky window to get to know them.

Sunny water gives rise to a glorious buffet

that draws many monsters from far away.

Leatherback sea turtles devour jellyfish with abandon.

(peaceful music)

Basking sharks enjoy the warm water

while diving deep to satisfy their appetite.

It's all here for them, and for other giants too.

We're learning more about their mysterious habits

every summer,

and more about our seas from these giants of the oceans.

(triumphant music)