Original subtitles

[Ronan] The badlands of Wyoming,

Downloaded from YTS.MX

the heart of the Old West,

hidden in these remote canyons

is a prehistoric murder scene.

Official YIFY movies site: YTS.MX

[Phil] I have never seen anything like this in my whole career,

and I've been studying dinosaurs a long time.

[Ronan] In this single square mile of desert,

lie the remains of at least a dozen dinosaur giants,

including their footprints...

-What do they eat? -...their food...

[cooing]

...and signs of a brutal, bloody showdown

...and signs of a brutal, bloody showdown

between some of the biggest creatures

that ever walked the planet.

[Phil] It's the whole package on the Jurassic world.

If you want to open up the curtains,

look back in time and say,

"What did the Jurassic look like?"

This is where you come.

[Ronan] Now, with this unprecedented body of evidence,

a crack team of world-class scientists

is carrying out an epic crime scene investigation.

Kind of the... the ultimate smoking gun.

It always puts the animal at the scene of the crime.

It always puts the animal at the scene of the crime.

[Ronan] To solve a 150-million-year-old mystery...

Why did so many dinosaurs die here?

[Ronan] The dinosaur dig site is an hour by truck

[Ronan] The dinosaur dig site is an hour by truck

from the nearest town.

It's called the Jurassic Mile.

And its location is so secret,

it's known only to a handful of paleontologists.

[woman] [indistinct]

[Victoria] Welcome, guys.

I think we got a pretty good game plan for today.

So, Taylor, safety, weather.

On site, it's gonna be about 110 degrees Fahrenheit.

If you got to work for five and take a 10-minute break,

the dinosaurs have been here for millions of years.

the dinosaurs have been here for millions of years.

They can last 10 more minutes.

[Ronan] This remote corner of the Wild West is a harsh

and inhospitable place.

Extreme summers and brutal winters

mean there's just a tiny window,

when people can work out here.

We have a relatively short dig season,

about six to eight weeks usually,

and that is mostly due to Mother Nature.

And it's wet out here.

The roads become impassable and then extreme heat too.

[Ronan] But since 2017,

an international team of scientists,

led by The Children's Museum of Indianapolis

has endured the summer heat.

Intent on peeling back the layers of rock,

inch by inch...

To reveal a lost world, when today's arid desert

was covered by lush Jurassic Forest.

[Ronan] The Jurassic Mile lies within a vast rock bed

[Ronan] The Jurassic Mile lies within a vast rock bed

called the Morrison Formation,

which spans 12 Western states

and is one of the richest deposits

of dinosaur fossils on Earth.

Nestled in the far north of Wyoming's Bighorn Basin,

it's a one-of-a-kind sight, even for seasoned experts.

So far, over 3000 bones have been unearthed,

including skeletons of 10 sauropods,

including skeletons of 10 sauropods,

remains of at least five predatory allosauruses,

and parts of a Stegosaurus.

This year, the team is unearthing so many fossils

that it's struggled to keep on.

[Jennifer] This site is the gift that keeps on giving.

We've got large theropod coming out over there.

We've got this very exciting, articulated tail

We've got this very exciting, articulated tail

from a sauropod coming over here.

[Ronan] Paleontologist, Dr. Jennifer Anne

manages the dig site.

[Jennifer] As you can see, it's all hands on deck.

There's a lot of pressure

to get done as much as possible.

You really want to see what's there.

You want to get it out of the ground.

[Ronan] But digging up fragile fossils is a gamble.

After 150 million years in their safe,

After 150 million years in their safe,

rocky tomb,

every bone is at the mercy of the elements

from the moment it's exposed.

Wyoming's wild weather could destroy

vital clues in a matter of days.

The day has barely begun for Prof. Phil Manning,

one of the lead scientists here,

and he's already been called

and he's already been called

to check out a potential new dinosaur.

[Phil] What have you got?

So, I was cleaning up the wall

for the stratigraphic column

and found this nice big limb bone right here--

[Phil] Ooh.

Can I have that?

Wow.

[man] It's a bit cracked--

Oh, it's going into that, it's going in, it's going in.

[Ronan] Another bone means another chance

to solve the mystery of why so many dinosaurs died here.

to solve the mystery of why so many dinosaurs died here.

[Phil] Some sites you find bones.

Some you find tracks,

and some you find fossil plants

or other creatures that lived at the time of the dinosaurs.

Here, you find everything.

That's what makes this site so important.

[Ronan] First question for Phil.

What kind of dinosaur did this bone belong to?

Well, it, it's definitely a limb bone.

-[woman] Yeah. -There's no question on that.

And it's from a big animal.

So judging by the... the depth and the size of this,

we're probably dealing with a sauropod dinosaur.

we're probably dealing with a sauropod dinosaur.

[Ronan] These huge plant-eating reptiles

dominated the Jurassic Wild West.

At least 24 different kinds roamed the forest,

including the famous diplodocus

and brachiosaurus.

Sauropods were the biggest creatures

ever to walk the planet.

Sauropod dinosaurs really were the giants of the Jurassic,

at over 90 feet in length.

That's like putting three Greyhound buses end to end.

The next could be over 25 feet in length

and their tails twice as long as that.

[Ronan] At the far end of the site,

another huge bone is now Phil's biggest problem.

This is a massive shoulder blade

This is a massive shoulder blade

from this vast sauropod dinosaur.

[Ronan] He believes this fossil could be a crucial key

in understanding how some of the dinosaurs

might have died here.

[Phil] Hopefully, by close of play today,

we can lift this thing.

It will move for the first time

in 150 million years.

[Ronan] It's not just the bone itself he's interested in,

the way it's buried and even what's hidden beneath it

could all help to answer the question.

But to reach that evidence, Phil has to dig up the bone.

But to reach that evidence, Phil has to dig up the bone.

To protect the crime scene,

Phil needs to stabilize the bone

inside a protective jacket.

[Phil] You cannot flip the bone this big

without having a nice bandage

holding everything in or hugging it.

[Ronan] Just like a cast on a broken limb,

this mixture of plaster and burlap

should hold everything together.

But it's extremely heavy.

And how much do you reckon is the weight, Peter?

Two, three hundred pounds.

Yeah.

A mere 200, 300 pounds.

A mere 200 to 300 pounds of dinosaur.

And that's just the scapula.

[Ronan] It's the riskiest part of the whole job.

[Phil] At some digs, you can see

these horrific situations

where bones or even whole skeletons

have been lifted up and the jacket utterly fails.

And the animal then sort of turns to dust

and drops out of the underside of the jacket.

That's the worst-case scenario.

-[man] Oh, we can... -[man] Keep moving.

[man] Keep going. Can you touch it there?

Yeah. Just checking, it's flat. Go for it.

[man] Do you want to put a couple of chisels under there?

-The long chisels? -[man] Yeah.

[man] One, two, three.

[man] Keep going, keep going, keep going.

Nice one.

Woo-hoo.

Ho-ho, look scapula.

That's amazing.

That's beautiful.

There... there you go.

There... there you go.

Six foot four.

When we talk about our own height,

we think of like, "I'm five foot nine."

This bone is a little over six feet.

So standing next to me,

this is the length of the bone.

[laughing]

[Ronan] Keeping the bone in one piece

isn't the only good news.

Underneath it, Phil has struck gold,

a jumble of different fossils, including parts of a tree.

[Phil] You've got a complete mash of bones

[Phil] You've got a complete mash of bones

and plants and trunks washed together,

creating this complete mess, basically.

[Ronan] To Phil's trained eye, it all points to a potential

cause of death being swept away

by a fast flowing river.

[Phil] Large chunks of rock

being dragged along the bed of the river.

That means the river is in flood to pick up,

move big chunks of rock along.

And if you ever look at a river,

where there's a log-jam and piled up logs,

um, this is the sort of structure

that would have caught the bodies of these dinosaurs.

that would have caught the bodies of these dinosaurs.

[Ronan] Phil reckons that a river flowed here

150 million years ago.

Oh, yes.

Oh, that's beautiful.

Looks like a trunk and some branches coming off.

[Ronan] And he thinks that a violent storm

once turned it into a death trap

for at least one dinosaur.

It ended up in a watery grave,

washed in with a huge flood deposit.

[Ronan] But did the dinosaur drown

or was it dead before the flood?

Phil can't be sure,

but there was certainly water here

and lots of it.

Could this be the reason

so many dinosaurs came to visit the site?

Lower down the hill,

the team has discovered more evidence of water.

Ripples like geological fingerprints,

preserved in mud, that may once have lain

preserved in mud, that may once have lain

at the bottom of a very shallow pool.

These ripples didn't form yesterday.

They formed 150 million years ago,

when there was a few millimeters of water

covering what was this mudflat.

[Ronan] Phil thinks this was not a dangerous river,

but a life-saving watering hole.

So like this pond-like environment, shallow water,

the wind was blowing,

the surface of the water creating

these beautiful ripple marks.

[Ronan] It could have drawn dinosaurs to drink here

[Ronan] It could have drawn dinosaurs to drink here

in huge numbers.

If you go to a waterhole today on the savanna of Africa,

you will see a lot of animals

drinking at the side of that waterhole.

It's a very, very busy place.

[Ronan] Dr. Victoria Egerton wants to find out

if the area was some kind of sauropods' Garden of Eden,

if the area was some kind of sauropods' Garden of Eden,

an oasis of plentiful food.

You can see the bits of fossil give things a light--

[Ronan] It's the kind of evidence

that's usually very hard to find.

But once again,

the Jurassic Mile is different.

Not only do we get some really awesome dinosaur bones,

but we get plants.

This is incredibly rare.

It is a treasure trove of information for the Jurassic,

It is a treasure trove of information for the Jurassic,

not just about the dinosaurs,

but about the environment that they lived in as well.

[Ronan] Uncovering these secrets from the remote past

is what brings Victoria back here year after year.

What I enjoy most about paleontology

is that it's storytelling.

You're recreating this environment

and trying to understand how these animals live

and what the world looked like.

[cooing]

[Ronan] Victoria finds plant fossils everywhere.

It's clear evidence that this area was green and lush,

but in a way that was very alien to us.

During the Jurassic,

the plants and landscape was pretty different.

We had no flowering plants.

That means no fruits, no vegetables, and no grass.

You're gonna eat what's available.

Everything from ferns to cycads,

Everything from ferns to cycads,

as well as lots and lots of conifers

like monkey puzzle trees.

[Ronan] She soon finds evidence of a water-loving weed

called horsetails.

That's really nice.

So, right here, if you look at this one,

what we have here is Equisetum or horsetail.

And you can see the stem right there.

And we've got some little tiny leaves attached.

[Ronan] There may be plenty of them,

but they're tough and hard to digest.

but they're tough and hard to digest.

If this was all there was to eat,

how did these giant dinosaurs get enough nutrition?

Did these sauropods starve to death?

[Ronan] High in the Wyoming desert,

a dinosaur graveyard is emerging from the ground,

and a team of scientists is investigating

the scene of the crime.

They want to know what killed these Jurassic giants.

[Phil] Wow.

[Ronan] So far, the team has found

the fossilized remains of 10 dead sauropods,

huge, long-necked dinosaurs

like diplodocus and brachiosaurus,

like diplodocus and brachiosaurus,

along with evidence of their strictly herbivorous diet.

These super-sized animals had appetites to match,

but only tough, low-nutrition plants to sustain them.

Was the Jurassic Mile

too popular as a dinosaur diner?

Did they run out of food, too weak to move on

to the next life-saving Eden?

[Ronan] The answer may come from living animals.

[Ronan] The answer may come from living animals.

These enormous reptiles are giant tortoises.

Together with birds and crocodiles,

they form a group of animals

that are the closest living relatives to dinosaurs.

Biologist, Dr. Stephen Blake and wildlife vet,

Dr. Sharon Deem

have been researching these animals for 12 years,

both here at the zoo

and in the animal's natural habitat

on the Galapagos Islands.

on the Galapagos Islands.

[Stephen] All right.

See how big this one is.

Here we go.

[Ronan] They're investigating

how tortoises maintain a healthy diet.

Here in the zoo, the tortoises are treated

to a daily vegetable buffet.

But in the wild, it's a very different story.

In the wild, the tortoises have to,

uh, eat both low-quality forage and lots of it.

[Ronan] Just like Jurassic sauropods,

[Ronan] Just like Jurassic sauropods,

the tortoises can survive on poor-quality food

that would be unable to support other large animals

because a cocktail of bacteria

in their gut helps to break it down,

extracting precious nutrients locked inside.

[Sharon] They can really get a lot of energy,

calories, minerals, vitamins

out of food that may be less, less quality

than it would be for someone like us.

[Ronan] But they're eating strategy

[Ronan] But they're eating strategy

leaves them with the same problem

as our sauropods.

Even with their specialist digestion,

their food is so low in nutrition

that they need to eat huge quantities.

Eventually, they eat everything in sight.

In the dry season, on the Galapagos,

the lowlands receive no rainfall

and are very dry and become very desert like.

There's very little food around.

[Ronan] Sharon and Steve decided to find out

how they get around this problem.

By fitting GPS trackers

to a group of Galapagos tortoises,

what they discovered was a huge surprise.

As their own graphic model reveals

when they run out of food,

hungry giant tortoises go on a hike.

Well, nobody knew tortoises migrated, within six months,

we realized that this phenomenon was real.

we realized that this phenomenon was real.

When the food runs out in the lowlands,

they moved to a higher ground.

[Sharon] Giant tortoises go from the lowlands,

where the food quality is low to the highland,

where they have a... what we call a salad bowl of choices.

[Ronan] Slowly clambering more than six miles

through volcanic boulder fields,

its equivalent to a human walking

from New York City to Philadelphia.

[Stephen] Tortoises are not known for their sprinting abilities.

[Stephen] Tortoises are not known for their sprinting abilities.

Having said that,

they're a lot more mobile than people

give them credit for.

[Ronan] Finding enough food throughout the year

is a major challenge for big animals.

As they grow larger, so does their need to feed.

We always say giant tortoises need a lot of food,

but you imagine a sauropod

needs a colossal amount of food,

so they got to move and to get out

of one habitat into another.

You've probably got to move a long way,

maybe hundreds of miles.

It's the same evolutionary solution

It's the same evolutionary solution

to the same problem.

[Ronan] As food supplies withered in the Jurassic dry season,

the watering hole

could have been a vital rest stop

on the way to higher, greener ground.

But sauropods were many times bigger than giant tortoises.

How can we know if they were just as mobile?

Animal movement expert, Prof. Bill Sellers,

is trying to find out if sauropods

weighing up to 80 tons

were capable of making long journeys.

He's discovered extraordinary evidence

that could help to answer that question.

Super-sized dinosaur footprints.

I'm interested in how dinosaurs moved.

And one of the best pieces of evidence we have

about dinosaur movement is footprints.

about dinosaur movement is footprints.

[Ronan] These fallen rocks

were once a patch of fine sand,

higher up the hill, and baked into them,

are the tracks of a sauropod

that walked by 150 million years ago.

You can see the toe marks here and you can see

the base of the foot in some detail

'cause they have rather cylindrical feet

that stick into the ground.

[Ronan] Just one preserved footprint is a precious find.

But a trackway of multiple prints

is an information goldmine.

If we actually go higher up the cliff,

we can start to find other footprints.

So, here, we have another sauropod footprint,

and it's been cut in half here.

This is almost certainly from the same, um,

the same trackway as that.

[Ronan] From the pattern of the footprints,

Bill can use a finely-tuned computer program

to find out how this leviathan walked.

to find out how this leviathan walked.

We can take measurements from things

like the length of the stride and the size of the foot,

and then we can use that to produce a scaled

model of the dinosaur we think made the tracks.

We have put on the muscles

that we expect to find for an animal this size.

And then, we can use the computer simulation

to try and make it actually walk in

the trackways that we'd measured.

[Ronan] Best of all, Bill's program can calculate

[Ronan] Best of all, Bill's program can calculate

the dinosaur's top speed.

It's surprisingly high.

Diplodocus didn't dawdle.

These guys can walk at about 7.5 meters per second

simply because they can walk with really long legs.

So, in fact, um, it's quite fast.

[Ronan] At more than 15 miles an hour,

sauropods were as swift as Olympic athletes.

And easily capable of the long journey

to summer-feeding grounds.

Along the way,

stopping off at the Jurassic Mile,

like a roadside diner,

for life-saving food and water.

So, if it wasn't starvation

or exhaustion that killed all these giants, what did?

[cooing]

[Ronan] Phil is eager to find out.

[Ronan] Phil is eager to find out.

He's sifting carefully through the death site

in search of clues.

But approaching clouds are a warning

that should never be ignored.

Bad weather is bad news for fossils,

and many of the most crucial new discoveries

are also the most delicate.

Ripples in the sand, footprints,

Ripples in the sand, footprints,

and fragile plant fossils could be destroyed overnight by heavy rains.

[Phil] This is the first time they've seen the light of day

for 150 million years.

If the weather hits before the bones are out of the ground,

it's a potential disaster.

[Ronan] Jen's team rushes to protect the fossils,

but the rain can quickly cut off the site.

They need to make their escape.

Nice weather for ducks.

The storm is coming. We got to go.

The storm is coming. We got to go.

Go, go, go.

[Ronan] Now all that protects this open grave

are a few layers of plaster and tarpaulins.

Phil can only hope it's enough.

[Ronan] In the high desert of Wyoming,

a mysterious dinosaur boneyard

is emerging from the rock after 150 million years.

Up here, conditions change fast.

And last night, a ferocious storm battered the site.

The lightning show that that one put on was really amazing.

I've never really seen

I've never really seen

lightning that widespread and constant.

[Ronan] Storms can destroy crucial evidence

that could solve the mystery

of what killed these dinosaurs.

First job of the day is to check for damage,

starting with a mound

where Phil's spotted signs of bone

from an unidentified dinosaur.

It's a pain when the site gets wet

'cause it means you start picking up bone

and stuff on your feet and that damages the site.

and stuff on your feet and that damages the site.

[Ronan] But the team is in luck.

All the evidence is intact.

Phil's investigation can continue.

So far, the team has found the fossilized bones

from 10 sauropods.

Giant dinosaurs like diplodocus and brachiosaurus

that dominated the Jurassic landscape.

They're trying to reconstruct this prehistoric crime scene

to figure out why so many of them died here.

Victoria is examining some very special bones

from another sauropod dinosaur.

They reveal an ancient link

between dinosaurs and modern birds,

which could provide the best evidence yet

of what killed these giant beasts.

What we have is the neck bone

and curving into this one

and getting smaller as we go this way.

[Ronan] There could be as many as 15 of these sauropod neck bones

containing crucial clues.

containing crucial clues.

With a tiny head on the end of a 20-foot neck,

sauropods looked like

one of nature's great mistakes.

Imagine having to hold your arm out

and hold a giant rock,

and that's what you have to do the rest of your life.

Your muscles would get really tired.

[Ronan] Their long necks look almost impossible to hold up.

But to get around this problem,

sauropods had a surprising evolutionary secret

sauropods had a surprising evolutionary secret

hidden inside their necks.

Sauropod dinosaurs are some of the weirdest animals

ever to have walked on the planet.

And the adaptations

that these organisms evolved over

millions of years to become so big are fascinating.

They are the walking suspension bridges

of the fossil world.

[Ronan] But new research reveals this secret

may have occasionally been their undoing.

At the Museum of the Rockies,

sauropod expert, Dr. Cary Woodruff

is investigating a collection of fossils,

unearthed from another site in the Morrison formation.

This is from a long-necked dinosaur

that we discovered, and we named this animal, Dolly.

It gets that name after country Western singer,

It gets that name after country Western singer,

Dolly Parton.

So Dolly was alive about 150 million years ago.

[Ronan] Examining Dolly's neck bones,

Cary spotted a clue that gives

an unprecedented glimpse into the life and death of this dinosaur.

Well, if we look at a normal sauropod vertebra here,

you see the bone along these areas

is incredibly smooth

and sometimes almost glassy like.

But I knew something was special about Dolly

But I knew something was special about Dolly

because as soon as I looked at those same areas,

we see that rough and wrinkled bone

and even coming outside of some of those sockets

are this weird,

almost broccoli-like irregular bone growths.

[Ronan] The growths appeared

on several of Dolly's neck vertebrae.

Puzzled, Cary shared his discovery

with colleagues around the world.

I literally took a picture of these features

and posted it on social media

and said, "What the heck are these?"

[Ronan] One reply was from a veterinarian,

who recognized these marks as a serious bone infection.

And the only way they could explain the infection

was by a respiratory disease that normally affects birds.

The group answer was, "Holy cow,

we've never seen a respiratory infection in a dinosaur before."

[Ronan] Cary wondered how a bird lung disease

could affect Dolly's bones.

The answer lies in the surprising way

The answer lies in the surprising way

that sauropods solve the problem

of holding up their massive necks.

Paleontologists think sauropod chests

held large chambers called air sacs.

They kept the lungs constantly supplied with oxygen.

Smaller tube-shaped air sacs

ran all the way along the neck,

surrounding the bones

and filling their hollow cavities.

This may be the secret

This may be the secret

to how sauropods held up their long necks.

Taking the place of dense bone,

the air-filled tubes made them light enough to lift.

Modern birds

are distant descendants of dinosaurs,

and birds too have air sacs.

They reduce weight enough to allow for flight,

but they have a big downside.

They increase birds' risk of serious infection.

We were able to hypothesize that Dolly had air sacculitis,

We were able to hypothesize that Dolly had air sacculitis,

and that respiratory infection,

the air sacculitis was so bad

that it actually caused a secondary bone infection.

[Ronan] Using modern CT-scanning technology,

Cary can work out

just how advanced the infection was.

[Cary] Dolly would have had labored breathing,

probably sneezing and nasal discharge,

and, basically, the same symptoms

that we think of that we've all had

with the cold or flu or pneumonia.

with the cold or flu or pneumonia.

[Ronan] The scans reveal that Dolly's air sac infection

had spread deep inside the bones,

causing illness far more serious than a cold.

Here we have a case, from 150 million years ago,

of an individual dinosaur that was sick.

And it was so sick, it probably died

from that illness.

And I think those are

the closest thing to time machines

we'll ever get these little windows

and literally moments in the life of a dinosaur.

[Ronan] Were the dinosaurs at the Jurassic Mile

victims of their own design and died of disease?

So far, Dolly's are the only sauropod bones

discovered with this type of infection.

Until similar evidence is found at the Jurassic Mile,

the team will need to keep looking

for other potential killers.

The answer may soon be at hand.

Back on site,

Jen has unearthed another spectacular discovery

that may be the lead they're looking for.

[Ronan] This new find revealed

that the long-necked sauropods

weren't the only visitors to this watering hole.

And the others may have had murder on their mind.

In the Wyoming Badlands,

a 150-million-year-old crime scene

is emerging from the ground.

A team of paleontologists is trying to figure out

how 10 giant sauropod dinosaurs

met their end right here.

Investigations have revealed that some of the dinosaurs

may have been killed in sudden floods

and also that their neck-lightening air sacs

and also that their neck-lightening air sacs

could risk severe infections.

Now, Jen may have discovered a major new suspect...

A skeleton that reveals the long-necked sauropods

weren't the only visitors to this watering hole.

Right here, we have a large theropod.

We've got back, we've got hip,

all the way back to a lovely tail.

[Ronan] Lying just feet away from the emerging tail bones

of a plant-eating sauropod,

of a plant-eating sauropod,

her diggers have uncovered

the backbone of a ferocious carnivore.

Jen thinks this may be a skeleton

of the apex predator of the Jurassic Wild West,

Allosaurus.

[Ronan] Eighty million years before T. rex,

allosaurus was the king of the Jurassic Frontier.

[cooing]

[Ronan] It attacked its prey with razor sharp,

serrated teeth and powerful grasping arms.

serrated teeth and powerful grasping arms.

So was this watering hole the site of a bloody clash

between predator and prey?

And since both bodies fell here,

who came out on top?

To find out, Jen needs to study this apex predator.

That means getting it out of the ground

intact to look for signs of violence.

But it's lying in a bed of super hard rock.

We've actually broken rock saws

and crowbars on this.

So it's gonna take some special kinds of equipment.

[Ronan] They've had to bring in an air-powered mini jackhammer

to chip away at the stone.

The first thing is just like feeling the vibrations

and feeling a bit scared

that you have something powerful in your hand.

[Ronan] This tool brings its own danger.

'Cause the scribes are powerful enough

to go through sandstone, they, of course,

are powerful enough to go through the fossil.

are powerful enough to go through the fossil.

[Ronan] It's painstaking work.

Just one slip could shatter a 150-million-year-old relic,

ruining the evidence of what killed this dinosaur.

Jen's crack team is starting to make up time.

But the badlands don't always play fair.

Out of nowhere,

squalls are whipping up sand and dust

into an abrasive blast.

into an abrasive blast.

[woman] Yeah, it's got to come down now, guys.

[woman 1] Okay.

[woman] We got to move towards Jen and Liz.

Yeah, back this way.

There's another dust devil coming over, so.

[Ronan] Dust devils can create winds up to 60 miles an hour.

[woman] Can we get some help, guys?

Thank you.

[Ronan] Every fossil exposed to the winds is in danger

from this sudden sandblasting storm.

[woman] Welcome to Wyoming.

Raise for a second.

Yeah, yeah.

Yeah, yeah.

We're hanging on.

Moving.

Let your fingers hold in.

[woman] [indistinct]

Ooh, another one coming.

Out of nowhere.

[screaming]

Ooh.

[Ronan] Six years of work is at the mercy of the wild weather.

But it's getting dangerous

and they need to make a run for cover.

Next morning, Jen arrives on site early

to assess the damage.

Come on, buddy.

How'd you survive?

Ooh.

Oh, thank God. You look good.

This fossil is already very exposed,

so it could have gotten a lot of abrasion damage.

Looks like maybe one piece broke.

So, uh, that's the only thing that broke.

That's good.

[Ronan] They've had a lucky escape,

but Jen isn't going to take any chances.

Another dust storm could hit any time.

They quickly cover the exposed bones in protective plaster.

And as soon as the jacket is set...

Yeah.

Yeah, well, I think, I think this one's going to be tricky.

...it's time to get them out of the ground.

First, they need to flip the jacket over.

First, they need to flip the jacket over.

[Jennifer] What I'm gonna have you do

is, if you all of a sudden can't reach anymore,

I'm here to help pull this part

because we have the femur and all that there,

so we have to be careful.

[Ronan] But there's a chance the bones will fall out

as they leave the surface, destroying precious evidence.

[Jennifer] Phil's got the middle, Rachel's got this side.

We're flipping it towards me.

Things are gonna fall, probably.

Don't freak out.

We'll just cry later.

Okay, Rachel, go.

-[Rachel] Are we ready? -We are ready.

-[Rachel] Are we ready? -We are ready.

Three, two, one.

Let's go. Go, go, go, go.

Go, go, go, go, go, go, go, go, go!

Oh, my God. That worked.

Ah! Ah!

-Yes. -[Ronan] They've done it.

The jacket has held firm.

Oh!

Oh, my God.

I thought so much was gonna fall out.

[woman] I thought everything is gonna fall out.

[woman] Yay!

[Jennifer] Boom, that's how you flip an allosaurus.

It looks pretty darn good.

[Ronan] Jen's allosaurus could be the chief suspect

in a multiple sauropod murder mystery.

But was this predator powerful enough

and fast enough to kill an 80-foot giant

that they now know

was as fast as an Olympic athlete?

[Ronan] High in the desert of the Old West,

a team of scientists

is unearthing a remarkable story,

frozen in time for 150 million years.

They're discovering evidence of an epic showdown

between predator, prey,

the fearsome allosaurus and the gigantic sauropod.

Their Jurassic crime scene places allosaurus

as the main suspect in a case of dinosaur murder.

as the main suspect in a case of dinosaur murder.

But was it up to the task?

Biomechanics expert,

Pasha Van Bijlert wants to find out.

He's investigating if allosaurus

could catch a fleeing sauropod.

He's pioneering a new method of calculating dinosaur speeds

with a detailed computer model,

based on the size of their bones

based on the size of their bones

and the bounce of their tails.

Potentially, it might have been able to run very fast,

but we don't know yet.

[Ronan] He's found the ideal specimen

to answer the question.

Its leg bones are perfectly preserved.

Right now, I'm measuring the left tibia,

which is the left shin bone.

It's about 23.5 inches.

[Ronan] Pasha soon has all the measurements he needs

to see how this predator moves

to see how this predator moves

for the first time in 150 million years.

And to find out if allosaurus had the pace

to catch a speedy sauropod.

It's actually a bit more work than I would have liked.

Right.

[Ronan] Bill Sellers is teaming up with Pasha

after discovering that sauropods

could move at 15 miles an hour,

as fast as Olympic athletes.

Bill has researched the top speeds

of different predatory dinosaurs

of different predatory dinosaurs

in past studies.

You have these wonderful pointy sources,

but we did a T. rex and allosaurus,

various other theropods.

We came up with top speeds

from this of about 8 meters per second for the T. rex.

Uh, so, it's the slowest.

And then, just over 10 meters per second for the allosaurus.

[Ronan] Using his models,

Bill estimated that both predators

might be able to run at nearly 20 miles an hour.

But he discovered a big problem for big T. rex.

But he discovered a big problem for big T. rex.

It was only when we started looking at the bone loading

that the really high speeds on the T. rex seemed unlikely

because, as you know, when you run faster,

you put more stress on the bone.

[Ronan] Bill concluded that if T. rex tried to run,

it would break its own legs.

At best, it could manage

little more than a 10-mile-an-hour walk,

not even enough to catch a sauropod at full tilt.

not even enough to catch a sauropod at full tilt.

But can Pasha's prototype model

reveal whether allosaurus was fast enough

to catch a speeding sauropod?

Allosaurus was further away

from T. rex than T. rex was from us.

So there are bound to be

many differences between these animals.

[Ronan] His research takes into account

the built-in bounce of allosaurus' tail.

He's shown that their tails had a natural rhythm

like a pendulum,

and he believes that if they stepped in time

with that rhythm, they could walk much faster.

with that rhythm, they could walk much faster.

We treated the entire tail as this big

rod suspended by springs.

And if you find the natural frequency of this,

um, I think this gives you a good idea

of the step frequency.

So, it's much more sort of pogo-stick-type locomotion,

relying on elastic storage.

[Ronan] With all the data entered into Pasha's test model,

his allosaurus quickly gathers speed...

And runs at an astonishing 25 miles an hour.

And runs at an astonishing 25 miles an hour.

Compared to T. rex,

allosaurus was like a thoroughbred racehorse.

It could easily outpace

a retreating sauropod like diplodocus.

The team has shown that sauropods and allosauruses

both visited this watering hole

and allosaurus had the speed to run down

the giant herbivores.

But maybe it wasn't just about speed,

But maybe it wasn't just about speed,

it was about surprise too.

If so, how could a three-ton allosaurus

creep up on a sauropod

and launch an attack without being noticed?

To answer that,

scientists are studying living animals.

At Whipsnade Zoo in England...

Dr. Beth Mortimer

Dr. Beth Mortimer

and Dr.Tarje Nissen-Meyer

are researching animal senses.

Hopefully, they would come through the fence here

and we can pick up the vibrations--

Hopefully.

[Ronan] Beth and Tarje want to find out

how today's biggest land animals

detect threats like approaching predators.

In particular,

they want to see whether elephants

can use a special sixth sense,

which tunes in to seismic vibrations

in the ground.

in the ground.

How far away do you think

we'll be able to pick up the elephants?

Huh, completely depends on what they're doing.

Let me try here.

[Ronan] Elephants are the modern-day equivalent

of the Jurassic's giant sauropods.

[Beth] The reason we studied elephants to start off

with is because of their size.

Because elephants are really large,

they're generating a lot of motion in the ground,

kind of mini earthquakes, if you like,

kind of mini earthquakes, if you like,

just as they're moving around.

[Ronan] So, the way they detect threats may shed

light on the way their ancient counterparts did.

Ground vibrations are almost undetectable to humans,

but can be picked up by elephants through

special sensors in their feet.

We've got sensors that are embedded

in our skin, uh, which can detect vibrations,

um, and elephants have a large number

of these types of sensors on their feet.

[Ronan] Beth and Tarje use a geophone,

[Ronan] Beth and Tarje use a geophone,

a sensor that can detect ultra-low vibrations.

-[Tarje] The audible sound, are you recording them? -[Beth] Yes.

We got the elephant coming over here,

so we're just picking up, uh, the vibrations that she's making.

[Ronan] In her fieldwork in Kenya, Africa,

Beth has shown that seismic senses

are a vital part of an elephant's defensive system.

Her team records seismic ground vibrations

Her team records seismic ground vibrations

made by humans.

When these vibrations are played back to elephants,

they are able to interpret them

as dangerous and quickly retreat.

Elephants are not alone in tuning into this infrasonic world.

Beth and Tarje have studied this kind of seismic detection

in a number of different animals.

And Tarje thinks that one making vibrations

And Tarje thinks that one making vibrations

as large as a sauropod would also evolve to detect them.

[Tarje] So, we know many examples in the animal world

that use seismic sensing.

So, it's... I think, the best assumption to...

to think, well, if there's a signal, um,

why shouldn't they use it?

[Ronan] It's likely these giants could have detected

seismic signals from a very long way away.

[Beth] Essentially, the bigger they are,

the larger distances over which they can communicate.

So, if you have a larger dinosaur source

So, if you have a larger dinosaur source

that might be generating a vibration

through the ground, in theory,

that's then information that could be propagating over larger distances.

[Ronan] Just like their giant modern-day equivalents,

Jurassic sauropods would most likely be alerted

to any approaching allosaurus by the quaking ground,

signaling every step the predator took

and make their getaway long before they were in any real danger.

and make their getaway long before they were in any real danger.

But allosaurus may have had one more

evolutionary trump card to play.

In Montevideo, Uruguay, Doctors, Nicolas Benech

and Ernesto Blanco are researching

how predators like allosaurus could fool their prey's defense systems.

They visualize seismic waves as ripples on the surface of a water tank.

They visualize seismic waves as ripples on the surface of a water tank.

[Nicolas speaking]

[Ronan] In their test, sauropod's round-shaped feet

cause vibrations to spread out equally in all directions.

But predators like allosaurus had triangular-shaped feet.

And when they took a step, most of the vibrations

traveled out to the sides.

The waves ahead of them were much weaker.

[Ernesto speaking]

[Ernesto speaking]

[Ronan] The scientists believe this effect gave predators

like allosaurus a crucial advantage.

Their sauropod prey couldn't tell how close they were,

which meant they could launch a lethal lightning attack.

[Ernesto speaking] [cooing]

[Ronan] It points the finger of suspicion back

at allosaurus, but it's circumstantial evidence.

To finally prove the sauropods at the Jurassic Mile were its victims,

the team needs to place these predators right next to their prey.

And back on site, Phil believes

he may have found clear-cut evidence that does just that.

Oh, look at that.

Beyond ridiculous. It's beautiful.

[Ronan] A whole host of dinosaur footfalls

preserved in Jurassic mud, including one filled in

with rock in the exact shape of the dinosaur's foot.

[Phil] These are the coolest thing on the whole site.

They're good ones.

[Phil] We've got footprints literally all over this whole surface.

[Phil] We've got footprints literally all over this whole surface.

These are some of the best trackways I have seen in the Jurassic.

They're absolutely beautiful.

[Ronan] Dinosaur footprints are every bit as rare as dinosaur bones,

but to find both in the same place is rarer still.

It's what makes the Jurassic Mile so special.

And it shows Phil, these animals did come to the same place,

maybe even at the same time.

From these shallow depressions,

we got both the hind feet

and the forefeet of these big plant eaters.

and the forefeet of these big plant eaters.

Right next to it, there are huge tracks

of a big predator,

which I think is pretty nice.

That's behavior.

Kind of the, the ultimate smoking gun.

It puts the animal at the scene of the crime.

[Ronan] Phil's evidence puts the predator

and prey together in the same place.

But if they were here at the same time,

a giant like diplodocus would not have gone down without a fight.

So, the team wants to know, is there any evidence of a struggle?

So, the team wants to know, is there any evidence of a struggle?

Did diplodocus battle for its life?

In the wilds of Wyoming, a dinosaur dig site

like no other was being unearthed.

It tells the story of a giant sauropod

facing off against the deadly predator, allosaurus.

Fossil evidence has put the hunter at the scene of the crime.

But was it really responsible for the deaths

of the giant herbivores,

or were sauropods able to defend themselves?

or were sauropods able to defend themselves?

Lower down the hill, Jen's team has found clues

of what could be a defensive weapon.

The first bones of an enormous sauropod tail.

[Jennifer] One of the very interesting discoveries

we have of this year that was only found a couple of days ago.

So, we've got a tail going into the wall.

So, this is something we really want to focus on this year.

[Ronan] A sauropod's tail could exceed 25 feet

in length and weigh 5,000 pounds.

in length and weigh 5,000 pounds.

Right now, we have one, two, three, four,

five, six, seven is poking out.

They can have about 80 bones in just the tail.

[Ronan] The tail was more than five feet thick

at the base and tapered down to the thickness

of a pencil at the tip.

[Jennifer] And the good news is they're getting larger.

They're going from the size of my pinky to something

that's gonna be like serving plate size.

[Ronan] For decades, paleontologists have wondered

[Ronan] For decades, paleontologists have wondered

why sauropods had such long whip like tails.

Was it part of their defensive armory?

In Seattle, Washington, a team is trying to find out.

They're headed up by tech pioneer, Dr. Nathan Myhrvold.

[Nathan] I was always fascinated by dinosaurs as a child.

And ever since the discovery of the sauropod dinosaurs,

people wondered what was this enormous tail for.

people wondered what was this enormous tail for.

[Ronan] Nathan's company specializes in solving

scientific mysteries by thinking outside the box.

To decipher the riddle of the sauropod tail,

they came up with this.

[Nathan] So, this is a physical model of a tail

of a sauropod dinosaur.

Specifically, it's an exact replica of an apatosaurus

that's in the American Museum of Natural History.

that's in the American Museum of Natural History.

So... So, this is a one-quarter scale model.

So, it's around 12-feet long.

[Ronan] Even without any soft tissue,

the lightweight aluminum construction

is as close to the real thing as Nathan's engineering team can create.

The scale mass is correct within less than a percent.

So, it's very accurate.

[Ronan] Now, it's time to see what this model can do.

[Ronan] Now, it's time to see what this model can do.

Immediately, Nathan detects a problem with the fine,

delicate tip of the tail.

[Nathan] There are dinosaurs that use tails

as defensive weapons, and they almost always have clubs or spikes

or something really nasty on the end to get something with.

The trouble is the end of it is really skinny,

it's less than a garden hose.

It didn't seem plausible to me that they were a weapon.

[Ronan] He believes the tail wasn't designed for fighting.

Instead, he wonders if they may have had

Instead, he wonders if they may have had

a much less violent purpose, communication.

Nathan believes the tail's shape could make it perfect

to act like a bullwhip.

Cracked with enough force to create a sonic boom.

So, in the same way that a human can pick up

a bullwhip and with a very ordinary arm can make it crack,

I think this would require a negligible amount of energy

in the sauropod's part.

[Ronan] High-speed cameras record the tail in action.

[Ronan] High-speed cameras record the tail in action.

So, here, we are moving the tail.

And what's gonna happen is that tail...

this part here will get flipped up, and boom,

there it gets flipped up and that would be the sonic boom.

[Ronan] Nathan calculates that the tip of the tail

exceeds 760 miles per hour, faster than the speed of sound.

Scaled up to sauropod size,

the sonic boom it will create may have traveled for miles.

the sonic boom it will create may have traveled for miles.

It would be as loud as

the guns on a big battleship going off,

an enormous cannon.

Kaboom!

[Ronan] Nathan thinks sauropods may have used their tails

to get a dinosaur date.

[Nathan] I think it's a good chance

that they used this amazingly loud noise

that they create with their tails

as a form of competition.

You know, "Kaboom! See?

I can really crack my tail."

I can really crack my tail."

And then, the next guy says, "Oh, yeah, you heard that?"

Kaboom.

[Ronan] Nathan doesn't claim his is the only answer

to the mystery of the sauropod's tail.

[Nathan] Just a question of, okay,

what does the mathematics say?

If we do an accurate engineering model,

what is the answer?

The answer comes out, of course,

that it cracks supersonically. [cooing]

[Ronan] If they didn't use their tails as weapons,

their only real defense against attacking

their only real defense against attacking

Allosauruses was their size.

So, at more than 10 times the weight of its alleged assailant

was a sauropod just too big for an allosaurus to bring down.

This missing piece of the predatory puzzle

could change everything.

Allosaurus may not have hunted alone.

Victoria is examining evidence that could solve that mystery.

[woman] Yeah.

[Victoria] Hey, guys. What you got?

Hey.

[Ronan] Inside this large stone slab are the jumbled

remains of several allosauruses.

Within this block, we have at least two,

maybe three allosaurus.

We've got a leg bone here and then another leg bone up there.

And one is significantly smaller than at least one other one.

So, the smaller one was probably a juvenile.

So, the smaller one was probably a juvenile.

[Ronan] Victoria thinks it's no coincidence

that several predators are buried together here.

If they died together,

it may mean they lived together in family groups.

That raises the possibility that they hunted in packs

to take on more massive prey.

[Victoria] To take down one of those sauropods

would have been incredibly difficult

because they're 10 times

or more than the size of these allosaurus.

or more than the size of these allosaurus.

So, the question is, would the allosaurus

have tried to take down an adult?

And if they did, they would probably

have to do it together and work as a pack.

[Ronan] Hunting in packs would give allosaurus

a much better chance of bringing down a 16-ton sauropod.

But to nail this predator as the killer,

the team needs evidence of a murder weapon.

the team needs evidence of a murder weapon.

[Jennifer] These are marks left from teeth,

from the meat-eating dinosaurs.

So, we're kind of finding the...

the bullet wound and the bullet.

[Ronan] At a secret location in Wyoming,

the scene of a Jurassic murder mystery

is revealing an astonishing array of fossil evidence.

Clues that could solve the mysterious deaths

of 10 giant sauropod dinosaurs.

Chief suspects, a marauding pack of allosauruses.

[indistinct chatter]

[Ronan] Now, Jen is looking for a smoking gun.

Nice parallel scraping looking lines into it.

[Ronan] She's an expert on ancient injuries in fossilized bones...

and she's found something that puts an allosaurus pack

as the prime suspects in at least one giant dinosaur death.

These are marks left from teeth, from theropods,

so, the meat-eating dinosaurs'

tooth marks are decent size.

So, it could be an allosaurus.

So, one of our...

our main culprits for who's snacking on our sauropod here.

[Ronan] Many of the sauropod bones here at the Jurassic Mile

are scarred with scrapes from predator teeth.

And there's even stronger evidence lying just nearby.

[Jennifer] So, Victoria found this lovely tooth here

[Jennifer] So, Victoria found this lovely tooth here

from a theropod, a meat-eating dinosaur.

And it's probably an allosaurus.

So, we're kind of finding, like, the...

the bullet wound and the bullet.

[Ronan] These razor-sharp, serrated teeth

were highly specialized, flesh-tearing tools.

And like, modern crocodiles, allosaurus would constantly replace them.

So, you could lose a couple of teeth in one meal.

Some of these guys are still fairly sharp

when you pop them out of the ground,

even though they're millions of years old.

even though they're millions of years old.

Holding a tooth from an allosaurus, every time I do it,

I still have that little kid go hee-hee, hee-hee,

inside, and it...

it's, it just reminds me of one of the reasons

why I got into paleontology.

[Ronan] And there's not just one tooth alongside

this sauropod skeleton.

[Jennifer] We have at least

50 teeth from this site.

We've got a lot of nibbling going on.

You know, what's, what's the reason?

Is it that everybody came in for one big feast?

So, the family is coming over for Sunday roast kind of deal.

So, the family is coming over for Sunday roast kind of deal.

[Ronan] Skeletons of multiple allosauruses buried together

and dozens of teeth from different animals.

This evidence could add up to a feeding frenzy

by a whole pack of predators.

But this theory opens up a new mystery.

Only the most intelligent of modern animals

are capable of coordinating pack hunting.

So, did allosaurus have the smarts to team up against its prey?

So, did allosaurus have the smarts to team up against its prey?

To find out, paleontologists need to get inside its head.

In Athens, Ohio...

Prof. Larry Witmer has amassed

one of the world's most impressive collections

of dinosaur skulls and casts, which he uses to study

their brain anatomy.

their brain anatomy.

This is the skull of allosaurus,

a very famous specimen known as Big Al.

I mean, just looking at the skull, we can tell a lot.

[Ronan] Larry uses a CT scanner to look inside skulls.

[Larry] CT scanning has revolutionized our field,

but we can actually look through the bone.

[Ronan] The scanner measures differences

in density and builds up a 3D model of the internal structure.

[Larry] We can actually work our way back

to where that brain would be.

And so, we can actually see the brain cavity.

It looks kind of small inside this really big skull.

[Ronan] This relatively small brain cavity in a large skull

is common amongst dinosaurs.

This is why some scientists have wondered if dinosaurs were dumb.

But Larry believes that size isn't everything.

So, we now know that brain size is important

and how big your brain is relative to your body.

What we've discovered is that actually the structure

of the brain itself winds up being potentially

even more important.

even more important.

[Ronan] Larry wants to know what's going on inside

an allosaurus' brain.

To find out, he's turning to birds.

Birds are the direct descendant of dinosaurs like allosaurus.

And just like their ancestors, they have very small brains.

But that doesn't stop them from being clever,

versatile hunters and even using tools.

Birds, it turns out, have pretty remarkable cognitive ability,

something we've discovered, um, and really in the past 10 or 15 years.

something we've discovered, um, and really in the past 10 or 15 years.

[Ronan] The secret of a bird brain success

is in its compact structure.

[Larry] They actually have a huge number of neurons

in that brain, but they're smaller

and packed together, much more tightly than what we see in mammals.

[Ronan] By cramming more brain cells into a small space,

they have greater thinking power

than was ever thought possible.

Larry's scans revealed that allosaurus brains

Larry's scans revealed that allosaurus brains

had some strikingly birdlike features.

We used to look at a brain like this and sort of say, like,

"Well, there's probably not a whole lot going on here."

But the reality is allosaurus probably

had much greater cognitive abilities

than what we would have ever thought in the past.

[Ronan] This could have made it a sophisticated hunter.

Perhaps even capable of working in teams

to bring down a 16-ton sauropod.

[Larry] Was allosaurus able to solve problems,

[Larry] Was allosaurus able to solve problems,

was it able to defeat the defenses of...

of the prey species and be an effective predator

because it was smart?

Was it capable of things like cooperative hunting?

You know, 15 years ago, we would have said,

"No, absolutely not."

But now we're kind of going, "Maybe."

[Ronan] Fossil evidence from the Jurassic Mile,

together with research from around the world

is building a compelling case that

is building a compelling case that

pack hunting allosauruses might have been responsible

for the deaths of the super-sized sauropods

buried at the site.

But before they settle on this solution,

Jen's team has one more lead to investigate.

One that could blow the whole case wide open.

At a secret location in Wyoming,

the scene of a Jurassic murder mystery,

a crack team has unearthed an astonishing array of fossil evidence.

The chief suspect is a pack of marauding allosauruses.

But did these ferocious predators really

have the upper hand in this showdown?

Jen is trying to find out.

She thinks that allosaurus may well have shared

many behaviors with successful modern predators.

[Jennifer] It's just remembering

that dinosaurs are animals.

Because we didn't get to observe these animals,

we have to use what we, we can observe in nature today

to understand what went on in the past.

[Ronan] Nature follows rules that stretch over the eons of time.

And less than 150 miles away in Yellowstone National Park

And less than 150 miles away in Yellowstone National Park

live predators that seem to have a lot

in common with allosaurus, gray wolves.

They, too, are intelligent pack hunters

and are often dwarfed by their prey.

The 2,000-pound American plains bison

is the wolves' most dangerous quarry,

even when they're working as a pack.

But according to brand new research,

the predators are smart enough to avoid a risky hunt.

the predators are smart enough to avoid a risky hunt.

Like in summer, bison rutting season,

males fight to the death over mates.

Wolves wisely wait it out.

And when opportunity knocks, switch up their behavior from hunter to scavenger.

A bison is more than ten times the size of a wolf,

just like allosaurus, matching up to a sauropod.

[Jennifer] We've got very large sauropods

that can get up to 90 feet long.

that can get up to 90 feet long.

In this landscape of giants, the allosaurus

is a little guy compared to everybody else.

[Ronan] And to Jen, it's likely allosaurus

may have shared wolves' cautious approach.

If this is the case, her team may not be looking

at evidence of a murder here.

[Jennifer] And so, we've got a lot of these little marks from the teeth.

But if it happened right before it died,

right after it died, that gets to be a more of a CSI question.

right after it died, that gets to be a more of a CSI question.

[Ronan] To expert eyes, the injuries

on the sauropod skeletons will look different

if they were caused by scavenging or frenzied attack.

But it's almost impossible to tell in the field.

The remains will need a careful autopsy.

For that, the bones must be taken away for cleaning and preparation,

which means an 1800-mile journey

which means an 1800-mile journey

to one of the most specialized facilities on the planet.

Research Casting International is a world leader

in assembling dinosaur skeletons.

They're working on two complete sauropods

from the Jurassic Mile.

There you go.

-Like this? -All right. Tilt towards Jamie a little.

Yeah.

Yeah.

[man] Okay.

[Ronan] They're destined to become the centerpiece

of the brand new dinosphere exhibit

at the Children's Museum of Indianapolis.

With the bones cleaned and mounted,

it's the first opportunity for Phil and Victoria

to examine them properly.

Oh, wow.

[Phil] That... that is awesome.

[Ronan] Phil is looking for the telltale signs

[Ronan] Phil is looking for the telltale signs

of careful butchery by an intelligent scavenger.

[Phil] You get back to the lab and you've removed

all of this caked dirt and mud.

You can suddenly see the wood for the trees.

[Ronan] On the cleaned bones, bite marks are clearly visible.

[Victoria] The predatory dinosaur tried to bite it

multiple times, or maybe other predatory dinosaurs

also tried to take off a little bit of meat as well.

[Ronan] But the location and nature of these marks

[Ronan] But the location and nature of these marks

leaves Phil certain they're not the result of a frenzied kill.

He thinks they're too measured and precise,

like the cuts of a butcher's knife.

[Phil] The animal was deliberately going for the joint capsules.

It's trying to pop the joint capsules

with its sharp teeth 'cause those capsules

are incredibly strong and that...

that enables the animal then to remove a chunk of tail.

And that's fascinating. That's not just feeding.

Feeding would have bite marks all over the vertebrae.

Feeding would have bite marks all over the vertebrae.

[Ronan] Phil is convinced these aren't the signs of a killing blow.

But probably happened long after death.

[Phil] This fossil shows evidence of a predator.

But probably from scavenging, we can see

what is very precise bite marks,

which were associated with behavior.

That was really hard to work out in the field,

but here it's clear as day.

[Ronan] The team is building a theory.

[Ronan] The team is building a theory.

One hundred and fifty million years ago,

a group of allosauruses

took advantage of an unmissable scavenging opportunity.

They expertly picked apart a mountain of free meat,

left after a sauropod died here.

But if the apex predator of the Jurassic

didn't kill the giant herbivore, what did?

To solve this mystery once and for all,

the team needs to find evidence of some other cause of death.

the team needs to find evidence of some other cause of death.

But with only days left before the site closes down for the winter,

the tough rock of the badlands is holding them up.

We have concrete hard rock, where the bones

have been embedded in some of the toughest rocks

I've ever come across.

[Ronan] They throw everything at it.

[indistinct chatter]

[Phil] Rock is winning.

[Phil] Rock is winning.

But we have another trick up our sleeve,

and it's a rather large jackhammer

which we can attach to the front of the bobcat.

[Ronan] It's a risk.

Big machinery can destroy fragile bones,

but it's their only chance to get at the fossils

beneath this rock and potentially

to solve the mystery of the dinosaur deaths

before the season ends and evidence is lost.

Phil hopes to claw back precious time,

but his hope doesn't last long.

but his hope doesn't last long.

Pieces are shaking off of this thing.

It looks like it's leaking right here.

So, we're losing hydraulic fluid.

Think one of the seals is gone.

[Ronan] The team now has a big problem.

Let's call the bobcat place.

-Oh, yes. -I'll do it now.

[Ronan] Until a replacement part arrives,

they'll have to dig by hand.

In the badlands of Wyoming, a boneyard of giant

dinosaur fossils is seeing the sky again after 150 million years.

And a team of world-class paleontologists is racing

to finally figure out what killed them all.

After an exhaustive investigation,

they're running out of time.

Their dig season is almost over

Their dig season is almost over

and a vital piece of heavy machinery has broken.

Leaking from this thread, which I don't have a way to tighten it.

[Ronan] They've had an anxious night,

but there is finally some good news.

So, a new part.

[Ronan] The vital replacement seal

for their jackhammer has arrived.

We can plug our breaker back up over there

and get through this really thick piece of sandstone

that has been causing trouble for us for the past few days.

that has been causing trouble for us for the past few days.

[grunting]

[Ronan] It's a big relief.

Now the team can get on with building their final case.

The team has found evidence here of a fast-flowing river

that may have swept some of the dinosaurs to their death.

And clues to a deadly infection that could have felled them.

They've investigated whether there was a standoff

They've investigated whether there was a standoff

between giant sauropods and a pack of predatory allosauruses.

But autopsies have convinced them

that the herbivores were probably scavenged after death.

So, with more than a dozen dinosaur deaths

to account for, how did they die?

With the hard rock now cleared away,

Phil is searching for evidence of what could have killed

the sauropods, if they weren't victims of the Jurassic's

the sauropods, if they weren't victims of the Jurassic's

apex predator, allosaurus.

And he's found a new clue right next to the skeleton

of one of the giant sauropods.

Here, a pool of water created ripples in the sand

150 million years ago.

At different times in the life of this pond, it dried out.

And you can see when the water shallowed

that the wind was blowing the surface of the water

creating these beautiful ripple marks.

creating these beautiful ripple marks.

[Ronan] Phil thinks this pond often shallowed out in the dry season.

But that in extreme dry seasons,

something more dramatic happened.

The pool dried up completely.

And it looks like the water continued drying up

to a point where we got a cracked surface,

literally desiccation cracks.

[Ronan] For Phil, these faint cracks

in the mud are a vital clue.

[Phil] It's such an extreme event,

it got incredibly hot and dry, and this whole area dried out.

This animal was looking for the place

where it knew it could find water and couldn't.

And it's days ended here in a dried out pond.

[Ronan] Phil believes he's solved the mystery

of why so many sauropod skeletons are buried here.

His theory is that the Jurassic Mile was home

to a watering hole, where many sauropods passed

to a watering hole, where many sauropods passed

on their way between feeding grounds.

But just like an extreme wet season could flood it,

an extreme dry season could turn it into a wasteland.

When that happened, some dinosaurs arrived

too late for food and water, instead finding only a fetid mud pit.

too late for food and water, instead finding only a fetid mud pit.

They succumb to thirst and starvation, dying right here.

And Phil believes this explains

why so many allosauruses were here, too.

The carcass was rotting away and it would have stunk to high heaven,

and was probably a signal for all predators

and scavengers around the landscape

and they'd have come here for a free meal.

[Ronan] But for at least one allosaurus, whose bones

lie a few feet from this sauropod,

this may have been the last meal it ever ate,

which leaves one final mystery to solve,

what killed this ferocious predator?

Jen may have found an answer at last.

To her expert eye, the bones of this allosaurus

To her expert eye, the bones of this allosaurus

reveal something about life in the Jurassic.

It was incredibly dangerous, even for apex predators.

They're the kings, if you will, of the Jurassic.

When you have all these different animals living together,

you're gonna have different conflicts.

This is the kind of world that the allosaurus is living in.

[Ronan] Most allosaurus bones here have scars

from serious injuries and infections that affected them in life.

Just as they are for predators today,

Just as they are for predators today,

hunting injuries were common and there was always competition for meat.

Allosauruses tend to be a pretty beat up lot.

You're dealing with big preys, there's also other

allosauruses and other meat-eating dinosaurs they have to interact with,

they have to defend territory, they could probably be fighting over a mate.

[Ronan] Sometimes, these injuries

could be very serious.

The bones already excavated from this allosaurus

have made her wonder if it may have suffered a broken leg.

have made her wonder if it may have suffered a broken leg.

[Jennifer] This is where I saw a split down the femur.

And so, right on what looks to be maybe a fracture,

so an injury, didn't look like it got to heal too much.

It was starting to heal, but it didn't get all the way there.

[Ronan] With such an injury, this allosaurus

would have been at a big disadvantage in the hunt,

or if challenged by another large predator.

[Jennifer] Probably wasn't gonna be sprinting

after healthy animals.

So probably it's scavenging, but it...

So probably it's scavenging, but it...

it definitely found a way to...

to live at least a couple of weeks more.

[Ronan] Maybe this allosaurus had made its final journey.

Attracted here to feast, injury,

mud and ferocious rivals may have proved too much

and it died right next to its last meal.

As the season changed and the rains returned,

As the season changed and the rains returned,

its remains were lost below the water.

Predator and prey entombed together

for 150 million years.

Jen has found this crucial evidence in the nick of time.

It's the last day of the summer's dig season.

Phil and the team are wrapping and protecting any exposed bones.

Phil and the team are wrapping and protecting any exposed bones.

[Phil] Don't have it taut. Remember? There should be no...

Yeah, no tension.

[Phil] No... no... That's it. No tension.

[Ronan] Until they return next year,

they want all evidence to be safe against the harsh Wyoming winter.

[Phil] You're protecting the fossils

from the extreme weather conditions

that persist here in winter,

can get down to -37 or more, it's pretty terrifying.

[Ronan] There are still some major finds to cover.

[Phil] There's so much bone that's been exposed.

This is the last day, everyone's stressed.

[Ronan] So, it's all hands on deck.

[Bill] We just, we want a few longer ones

just so we can wrap them absolutely all the way around.

It makes it stronger.

[Ronan] And with one final push, time is up.

[Ronan] And with one final push, time is up.

At the Children's Museum of Indianapolis,

the completed dinosaur skeletons

from the Jurassic Mile are finally resurrected after 150 million years.

from the Jurassic Mile are finally resurrected after 150 million years.

[Jennifer] Dinosaurs are so bizarre.

They're the closest things we have to like

mystical beasts, but they're real.

[Ronan] For those left in the ground,

silence will return for another long winter.

But the team will be back.

I think the Jurassic Mile will yield

hundreds of dinosaurs over the next 20, 30, 40 years.

[Ronan] They may have solved this particular murder mystery.

[Ronan] They may have solved this particular murder mystery.

But this extraordinary place has many more secrets to unearth.

I've been very lucky to chase dinosaurs

around the globe for the last 30 years,

but I've never found a site like this one.

I mean, it... it could keep 100 paleontologists busy for 100 years.

[Ronan] For many years to come,

this remarkable site will continue

to give these scientists a unique window

into a long lost world.

into a long lost world.

The Jurassic Mile is dinosaur country.