Jurassic Sharks

- Deep below the ocean's surface... -OK, do it.

...lies the remnants of a forgotten past.

It's like going in a time machine. This is a marine biologist's dream.

- Before the age of dinosaurs... -What is that?

...the seas were ruled by monster prehistoric sharks.

This is truly nightmare fuel.

Super predators with terrifying adaptations.

Structures off their head that looked like anvils,

head spines, scissoring jaws.

These sharks were like nothing seen today.

Formidable predator that you did not want to get in front of.

Now teams of scientists from around the world...

-Might have something. -What you got?

...will scour the darkest depths...

This thing is a monster. It's huge.

...digging for evidence in unlikeliest places.

-That's from a 50-foot shark. -Things really are bigger in Texas.

To resurrect the strangest, biggest...

...and most fearsome...

...Jurassic sharks.

Sharks are among the oldest living marine species on the planet.

Sharks are older than trees themselves.

They've been ruling the oceans for hundreds of millions of years.

Before dinosaurs controlled the land and air,

the oceans were full of prehistoric predatorial nightmares.

We're talking about sharks that were larger than white sharks.

Massive hyper-predatory sharks with a lot of weird body styles.

But not all of these sharks survived for long.

Deadlier predators or mass extinctions

mean that these predators only reigned for a small era

before the next one came along.

In the shadow of Mount Fuji, Japan,

marine biologist Austin Gallagher is spearheading an expedition

to an ancient canyon thousands of feet below the surface.

Suruga Bay is the deepest bay in Japan

and it is the perfect location to study ancient sharks.

It's like going in a time machine.

Once an ancient marine battleground,

Suruga Bay is filled with bizarre creatures

and survivors of that forgotten era.

It's home to species like the frilled shark,

ghost shark and the goblin shark.

Species that used to swim alongside these Jurassic sharks.

These living fossil sharks are the last links

between the present and the past.

Living fossil is a species that exists today

that shows traits of a much more ancient early design.

Traits that were common millions of years ago.

Finding these living fossil sharks will help us better understand

what this ancient battleground looked like,

allowing us to bring these extinct Jurassic sharks

through animation like never before.

I think that this bay was home

to some of the most insane-looking super predators

that ever lived in the oceans,

like the scissor-tooth and the buzzsaw shark.

Two absolute killing machines,

the scissor-tooth and buzzsaw sharks were 25-foot monsters

with nightmarish jaw adaptations

that have baffled scientists for generations.

Nothing like that exists today.

Completely bizarre and unfamiliar to us in the modern world.

There's so little that's known about these prehistoric sharks.

So we're looking for living shark species

that would've swam alongside them

that can prove they were here and tell us more about them.

Austin is setting out with his research partner

and deep-sea expert Yuuki Watanabe.

-We've got a shark. -Kitefin shark!

The team has pulled up a four-foot shark,

a survivor of the ancient past.

Really cool.

Kitefin sharks are deep-water shark species

that have adapted to living at depth.

But I've never seen a live specimen up close.

So this is just an amazing shark.

Yeah, look at this tail.

It's elongated and it looks like a kite,

and this is why this shark is called kitefin shark.

Many of the prehistoric sharks that we see today

show a very elongated, almost snake-like body.

And as sharks continued to evolve and the tail started to change

and it started to make more of a shape

of a classic fin that we see today.

The kitefin shark is a perfect example of an ancient shark

that is in the middle of evolution, in the middle of this change.

-Look at the teeth. Really sharp. -Yeah. Those teeth are sharp.

So definitely capable of biting

and taking big chunks of flesh out of species.

I'm always interested by the eyes of this shark.

Green, big and like a jewel.

Adaptations are key

for the long-term survival of any species.

Their eyes has a different ratio of rods and cones

that gives them the advantage of seeing in pitch black.

The kitefin's eyes aren't their only deep-sea adaptation.

It is also the largest known shark to exhibit bioluminescence,

which researchers believe it uses

to see on the sea floor while hunting

as a way to blend into the ocean from below.

All right, let's get it back in the water.

As we explore deeper waters,

I'm really hoping we see sharks with even stranger adaptations,

which will teach us so much more about these Jurassic sharks

and help us bring them back to life.

Halfway around the world,

marine biologist Kesley Banks

is searching for extinct super predators

in an unexpected location.

We're in the middle of Texas, about 600 miles from the Gulf.

When people think of Central Texas, this is what they think about.

But what they don't think about

is this was actually the bottom of the ocean at one point.

The land now known as Texas has dramatically changed

over hundreds of millions of years.

Once the Western Interior Seaway,

a body of water that divided the continental US,

Texas has seen multiple eras of oceanic super predators,

some of which left evidence of their existence.

-Hey, Ron. How are you? -Hey, how are you doing? I'm well.

I'm here to meet with my friend Ron. He's a paleontologist.

So if anyone has the answer to what ruled the prehistoric sea, it's him.

Welcome to the Texas perineum.

What we call Texas today,

and pretty much all over the Earth's land masses,

have been slowly shifting around

ever since they first formed over four billion years ago.

All of this sedimentary rock here

would've once been an ancient sea floor.

It was teeming with prehistoric life.

This land is brimming with reminders of the ocean that once was

and all of the amazing creatures that lived in it.

So the water's gone, but the sharks are still here.

The sharks are still here. If you know where to look for 'em.

Over the past few years,

fossilized teeth from over 20 different ancient shark species

have been discovered in Central Texas.

These seem, morphologically, like modern-day sharks.

This one kind of looks like a...

-a very large mako tooth. -I'll take your word for it.

I've not encountered a mako shark before, but I'm sure you have.

I have. Like, I would... If you were to put this in my hand,

in size, you know, that's very similar to a mako tooth.

-Does it actually look like that? -They do. They're very pointed.

That's not a mako, but this one is around...

80 to 90 million years in age.

-And it's from Central Texas. -That's impressive.

We've had a selection of things. Turns out there were a lot.

There's quite a bit of diversity, different kinds of fossil sharks

preserved in these rocks in Texas.

We find them throughout the rocks across this region.

What's neat is all these rocks, they still preserve these remains.

You can go out and dig them up today and find a remarkable diversity.

For instance, we'll even find

some of these rarely preserved bones of the skull.

Unlike a lot of other sharks, they actually mineralized

some of the bones of their skulls and jaws.

Usually shark skeletons are terribly preserved.

You don't usually find them.

-And this is the jaw? -That is a left lower jaw.

-A left lower jaw. -Actually flip it.

There we go.

That's the jaw joint in the back.

-Oh, cool. -Yeah. So there you go.

-Exactly. -Perfect.

One of these fossil sharks...

A lot of these specimens are anywhere from 300 million

to, say, 270 million years in age.

This was a golden age of sharks.

This was a time when sharks

reached their maximum diversity and abundance.

They started adapting to all sorts of different opportunities

and evolving different body structures, new kinds of teeth,

new kinds of swimming, new kinds of tails.

And the most successful designs make it through

and the rest would go extinct.

Using these fossilized teeth,

I'm trying to find the largest and the baddest shark

that ruled the waters of Texas 300 million years ago.

At its time, the largest predatory animal on the planet

would be the Texas super shark.

We're talking about sharks that would be larger

-than the truck you drove in here on. -Oh, my gosh.

Reaching up to 30 feet long,

the Texas super shark was larger than modern-day white sharks.

It was a savage killing machine

that ruled the oceans 300 million years ago.

Discovered in 2015,

it dramatically changed our understanding

of ancient predators of the area.

No-one thought sharks were that large that long ago.

That's roughly a 300-million-year-old fossil.

-Oh, my gosh. -Teeth are very distinctive.

Early shark teeth usually had multiple cusps.

Each one would've been a batch of points

to slam down on and hold slippery prey.

Even with defense mechanisms,

smaller sharks were no match for the super shark.

That thing had a mouthful of needles.

Great for piercing prey, holding it, ripping it to shreds back in the day.