Original subtitles

When you go out looking at rocks that are

millions of years old,

you never know what you’re going to find.

As we came through a little clearing,

I spotted a rough looking bone.

Yep, this is the spot right here.

Where it all began.

One bone after the next revealed itself.

This was the Holy Grail.

Finding a dinosaur bone tells us

only part of the story.

There’s so much more to these amazing creatures

than just their skeletons,

which leaves the movies with a lot of artistic license.

The colors are made up,

a lot of the behavior is made up.

But now, remarkable new fossil finds

are opening a window on the prehistoric world

as never before.

Technology is allowing us to answer questions

that were previously unanswerable.

We get to make dinosaurs move again for the first time

in millions of years.

And we can figure out their color.

And even how they lived.

Can recent discoveries force us to

put aside the movie magic

and finally see dinosaurs as they truly were

when they ruled the Americas?

I think that we're closer to uncovering

the truth of the age of dinosaurs than we've ever been.

Fact is stranger than fiction.

My first exposure to the dinosaurs was

probably The Flintstones.

.

Which is not a very accurate portrayal of dinosaurs.

You know, like all kids,

I was sort of immersed in this dinosaur culture.

I've always been fascinated by the biggest, the smallest,

the highest flying, the lowest diving.

That's where you really start to learn the

limits of evolution.

I wanted to find creatures that were among the largest

to ever walk the face of the earth.

Usually the largest dinosaurs are also among the worst

preserved because it's so hard for a creature that size,

the size of a house, to become a fossil.

There is a group of plant eating dinosaurs called

Titanosaurs that we know relatively little about.

So I was very attracted to finding one of those.

'How do you find a dinosaur?'

It's the number one question I get asked.

The world is geologically mapped.

And so to find dinosaurs you have to find rocks from

the Triassic, the famous Jurassic or Cretaceous period.

I'm looking for the green colors

that are cretaceous aged deposits,

rocks that are at least 66 million years old.

There are some rocks here but this is the Congo basin,

too many plants here.

Northern Patagonia, rocks are the right age but

quite a bit of work has been done here.

But here down in Southern Patagonia we have everything

that I was looking for.

Patagonia is an amazing place.

Vast sweeping landscapes.

Sometimes it's called "Fin del Mundo",

the end of the World.

It's the last stop before Antarctica.

To get to this site from the US is a six airport trip and

then once you're there, you have to get Jeeps and

you have to navigate up very rough dirt roads.

No other paleontologists had been working within

maybe 1,000 kilometers.

This is the field area and you get yourself on the ground

and you walk and you just look for bones

sticking out of the rocks.

That year in 2004 we were about a month into the expedition

and we hadn't found anything that I would say

was really great.

So at this point, the pressure's on.

You start to worry.

We had a week left.

And then finally we found something.

A piece of bone exposed.

It had weathered out of a cliff-face,

so it was super easy to excavate.

So, it doesn't take us long before we uncovered a very,

very large femur.

2.2 meters long, that's about seven feet one inch long.

We know that we're looking at one of the largest

dinosaur bones that had ever been seen.

This was an incredible result.

But where are the rest of the bones?

We dug and dug and dug around there but there wasn't another

bone to be found.

But still, that told us giant dinosaurs lived here and that

was enough for us to know that we had to come back

to this place.

A year later, I was ready for a return expedition

but I needed a bigger team.

And I called up my friend, Matt Lamanna.

This was somewhat of a professional gamble,

I would say, for Ken.

Ken, in a lot of ways was putting all of his eggs

in one basket.

I think that there was some pressure upon arrival

that second year in 2005.

You know, we're not there for, you know,

for a month long vacation in the desert.

We're there to find dinosaurs.

On the first morning I was

prospecting for bones,

and saw a dinner plate sized piece of bone exposed

in the desert.

I GPSd the location,

I give it a field number, and I move on and,

I start to prospect for some other sites.

This is 2005 so I put on my iPod...

.

And put on some heavy metal.

And I walked basically up the side of a mountain, you know,

thinking that I was going to find the next big thing.

But, I turned around when I got to the top of the mountain,

and I saw my three Argentine colleagues,

Marcelo Luna, Lucio Ibiricu and Gabriel Casal,

all kind of gathered around this spot,

that didn't really look like it was much of anything.

And so I go down there because they're lingering there.

Maybe they'd found something interesting.

I returned to the spot where I'd found the

bone and I saw something astonishing.

They have about a half of a leg bone exposed,

half a femur.

The bone is six foot three long.

So we knew we had a giant Titanosaur.

And soon other bones start appearing.

When we began to excavate the tail it was really

a thing of beauty.

It was articulated,

meaning the bones were still touching each other like

they were in life.

We started to see that this was giving us our best window yet

into the anatomy of the largest creatures to walk the planet.

To protect the bone in transport we wrap it with

bandages of burlap and plaster.

This is what we call jacketing the bones.

We had excavated about 200 square meters of rock,

as hard as concrete.

After four more really grueling field seasons,

so that’s five years,

we end up with 70% of the skeleton from the neck down

which was almost three times more complete than the

next best preserved super giant.

We had this huge creature,

maybe the most massive dinosaur ever discovered.

Where does this thing rank compared to

other giant Titanosaurs?

There's an equation you can use based off of modern animals

that allows you one way to calculate an estimate of the

weight of an extinct animal,

using the circumference of the upper arm bone,

the humerus and the femur,

the thigh bone.

But for most of these dinosaurs,

they don't have the fossil remains so the weight is more

of a guess.

But, we have the two bones that we need.

Now we have the key to understanding the mass of

this great creature.

We start to do the math.

We know this individual is one of the largest ever discovered.

Is it the largest?

When we finally did crunch the numbers,

the number that came out was something like 59 metric tons,

65 short tons that we use here in the U.S.

Which was mind boggling to me.

An animal that's 65 tons

is the mass of 13 African elephants,

the most massive land animal for which we can

calculate a weight.

This was a very exciting and very tantalizing result.

Our next question was, is this a new species of Titanosaur?

The only way to find out was to study it in minute detail.

I loved dinosaurs so much,

by the time I was 13,

I was volunteering at our local dinosaur museum.

That's when I started hearing whispers of this giant dinosaur

that was coming from the edge of the world.

You know, it was, "It's the biggest dinosaur".

Really?

Okay, I'll believe it when I see it.

And we went into the basement,

when we opened the door and saw 300 containers,

all with bones.

It was way more than I ever could have expected.

I was a fossil preparator

and my job was to extract the bones out of the rock,

so we could examine them in close detail.

We didn’t know whether it's a new species,

So we had to look for novel features in its skeleton.

You’re making maybe a dime size of progress a day.

But little by little,

day after day it all starts coming together,

it’s really slow but I love it.

.

To establish a new species of dinosaur,

you have to see at least one feature in its bones that

hasn't been seen in any other dinosaur.

Eventually, after three years,

we have the full skeleton just laid out on every table top.

The 30 foot tail was laid out along one wall and down

part of a next.

The humerus standing by the door.

Now we could see the 77 million year old skeleton

it all its glory and finally work out what it was.

We began to get a full set of measurements.

This animal would have been 85 feet long that's almost

the size of a basketball court.

At the shoulder it would stand 2 stories high.

This was an immense animal.

Now based on all our lab work,

we could see that it had unique features that hadn't

been seen in any other dinosaur.

So, this was a new species of Titanosaur.

Now we need a name.

What would this animal have to fear in its landscape?

Essentially nothing.

And I come up with the name Dreadnoughtus,

which means fears nothing.

The first chance we got, we ran outside,

screamed it as loud as we could Dreadnoughtus!

It was like the best feeling, it’s such a cool name.

Now we had identified this dinosaur

as a new species,

but we still had so many questions about how an animal

so large could live.

The largest animals today are the whales.

They don't have to contend with walking on land.

And it really sparked in me this question of how is this

animal moving?

All the parts that would tell us everything that we need to know,

like muscle, cartilage, tendons, don't preserve.

You can’t just open up a book and look up

the muscles for a new dinosaur.

We have to discern those from the bones themselves.

The big limb bones are six foot two,

about 800 pounds.

We can't move that and try and figure out how it moved.

So our solution was to go digital.

We used a 3D scanner

to capture all the bones.

This was one of the first dinosaurs to be

captured in a 3D scan,

and this opened up avenues of investigation that

would have been impossible by using the real bones.

So this area right here,

that is a palm-sized muscle scar.

Which means the muscle was pulling on this part

of the bone so much that it left an imprint.

Now with these scans we could begin to

reconstruct Dreadnoughtus.

It enabled us to have these 3D bones that we can easily

manipulate in a virtual environment and do our

biomechanical experiments with.

One of my colleagues, Kristyn Voegele,

has mapped out those muscle scars,

attached virtual muscles to test how these dinosaurs move.

Let's contract this muscle,

let's contract this muscle and we'll see what the limb does.

So we're actually letting the anatomy inform us

about its life.

Our analysis of its largely complete skeleton helped us put

flesh on the bones of this amazing creature.

First, we could see that the bones themselves were big and

strong it could easily walk on land.

There's really nothing like these creatures on

the planet today.

But, there was one strange anomaly in the tail

that puzzled us.

Underneath each of the tail vertebrae was a pair of bones

that were hanging down and instead of tapering to a point

like they do in other dinosaurs they flare out into

this big paddle for muscle attachment.

It was housing these hugely powerful muscles that would go

from its leg to its tail.

When we looked at it carefully we realized that

these muscles would have provided powerful leverage

in the tail.

We thought, oh, if they pull on this fast enough,

that's going to hurt.

It's not only that it was so big that nothing wanted

to eat it.

It was that it was weaponized in the case that

something did try.

This was something we hadn’t seen

before in Titanosaurs.

This was a tail that could kill or maim the largest predators.

I think in comparison to other Titanosaurs Dreadnoughtus looks

like about the toughest that I've ever seen.

I think that plant eating dinosaurs

probably are often made out to be these, you know,

like sort of gentle giants.

But we're starting to understand that just eating

plants does not, by nature, make you docile.

I think it's time to recast these giant animals as

the surly beasts that they were.

Look out meat eating dinosaurs because you do not want

to mess with a Dreadnoughtus!

We put virtual flesh on Dreadnoughtus to

visualize dinosaurs more clearly.

Up in Canada another discovery has got even closer

to seeing dinosaurs as they really were.

For me, fossils tell us that there’s

more to the world than what we see today.

There’s this huge buried past.

Normally when we go looking for them,

we’re only looking at the surface.

But, sometimes we get a helping hand from miners,

who are used to digging down far deeper than we would ever

dream of doing.

So, it's no surprise that every once in a while they’re going

to bump into something.

One day out of the blue I received a set of photos from

Suncor, a mining company working in northern Alberta.

They’d found something they suspected might be a fossil and

they wanted to know if we could identify it for them.

And that was our start to dealing with this mystery

animal from the far north.

Two days later myself and a technician were on a plane.

Fort McMurray exists in the middle of nowhere

in northern Alberta

where they're digging out bitumen soaked sand.

We were driven out to a site.

Initially all we saw was a few broken fragments.

We were told where it happened and when it happened.

I was digging right in this area right here

with my shovel.

I could see some really big slabs with that big around of,

with that really distinctive pattern.

I’ve never seen anything come down the bank that had this

distinctive uniform pattern to it before.

When Shawn Funk made the initial discovery

it was hit by the excavator bucket

and it shattered into pieces.

And the technician, Darren Tanke said,

what if it's a dinosaur?

And then all the pieces started to make sense,

and we knew this was going to be a big deal.

So, if it was a dinosaur,

what kind was it?

Most of it was still stuck up in the cliff face,

completely encased in hard rock.

But when we looked carefully at the clues,

we could begin to imagine what sort of animal it could be.

All we could see was this cross section in the cliff.

Then I began to see a shape of where the body was.

Then we knew this was not your typical dinosaur fossil.

We could see bony plates exposed,

so we knew we were dealing with an armored dinosaur.

We noticed the arc of the armor was curving upwards.

So that meant this dinosaur was lying on its back.

This is curved.

It was all rather puzzling.

The rocks that we were finding this fossil material

in are early cretaceous,

are about 110, 112 million years old.

And at this time, this place was a shallow inland sea.

It would be underwater.

This thing's on its back on the seabed.

But, this, it's a land animal.

It's not evolved to be in water.

And then you start to wonder, well,

how did it get washed out to sea?

The only way to find out more would be to get it out

of the rock.

But to try and dig it out would risk the collapse of

the whole cliff.

We were under major time pressure.

We were told we had three weeks to get this thing out.

We couldn't start from the cliff face.

We had to come down from the top.

So, they got one of their best shovel operators.

Some of them could do brain surgery,

they're so good with the bucket.

It’s peeling off very, very well.

Ooh, stop.

Stop!

We had most of it exposed and it looked like a

giant grey lumpy potato.

This large, seemingly bombproof mass had resisted being struck

by a giant excavator and having a kilometer of rock piled on it

for tens of millions of years,

so the thinking was that this thing could withstand

being lifted in one go.

You look at that big grey lump and you'd have no idea that

there's an absolute treasure sitting there.

All we had to do is lift it up and plop it on the back

of the truck.

No one had ever done this before.

So, no one knew really what to expect.

I’m like the expectant father here.

They got their best hoisting and rigging people,

started to lift it.

There we go, come on baby.

They said sorry we broke your dinosaur.

We only just started to move the dirt and she let go.

Yeah, she didn’t take much pressure.

The question now was,

how were we going to salvage this?

Getting a fossil out of the ground is just

the end of the beginning.

We quickly saw that we'd lost nothing.

It came out in convenient chunks instead of one epic

five ton block.

We now had to remove the rock from around the fossil and

reveal what this animal was.

So, we needed someone with experience and who had the

delicate touch but also had the muscles to shift these blocks.

Dinosaurs are basically like

real life monsters.

And I've been interested in dinosaurs since I was

five years old.

Because I'm good working with my hands,

I wanted to become a preparator of fossils.

So, what I’m doing right now is slowly removing away paper-thin

layers of rock away from the bone’s surface using a pin vice.

This will go on for many many hours, if not days.

.

Usually when we work with specimens,

we just work with the actual bones themselves.

But as I removed the rock

I started to find sections of black,

I was amazed.

This wasn’t just bone,

it was actual fossilized dinosaur skin,

something that hardly ever survives, and if it does,

it’s usually just small patches.

The biggest challenge was basically finding where all the

skin was and kind of knowing where to stop.

Sometimes it’s really distinctive,

kind of a very black in color,

and other times it kind of fades out.

You don't want to start digging too deep of a hole

trying to find something that’s not quite there.

Mark was just the person to do that.

It takes special skill to go from this unbelievably hard

rock to something that's instantly soft and delicate.

We have the skin over most of the surface.

So, it's kind of like mummified,

even though it's not a true mummy.

Once I had finished preparing all the blocks,

my next task was to reassemble them.

When you start putting those pieces together and

the shape of this dinosaur begins to emerge,

that's when it really became exciting.

It became like a three-dimensional jigsaw puzzle.

Now we could finally identify

what kind of dinosaur we had.

It's built like a tank.

It's covered head to toe in body armor.

It has a narrow muzzle and it has big shoulder spikes

and that could only mean it's a nodosaur.

It was a plant eater and it lived about

110-112 million years ago.

This was a new type of nodosaur,

one that had never been seen before,

and this meant we could give it a new name.

The name of the dinosaur is

Borealopelta markmitchelli.

Named after little old me.

.

It’s just fantastic.

This specimen has taken about five and a half years

of my life.

Now it looks like a sleeping dinosaur.

It’s absolutely magical how it turned out.

One of the things that makes this dinosaur

unique is that

it's preserved in three dimensions with all that skin.

Beautifully preserved,

but are there details that it reveals that we

didn't know before?

I was brought onto this project to help figure this out.

Given that the skin is so well preserved

it held a tantalizing possibility,

to find out the color of this animal.

The colors either in children's books or in documentaries,

were largely just estimates.

Estimates based on modern animals.

A lot of dinosaurs are portrayed as

sort of basically greens or grays.

We don't know the colors of extinct

animals because the pigment molecules don't preserve.

It takes exceptional conditions to preserve skin and even

better conditions to preserve any traces of the

chemistry of that skin.

This is a fragment from Borealopelta and

this dark grey is the fossilized skin.

We sent a small sample of this for geochemical analysis.

Using mass spectrometry,

we could find out if any organic compounds

were preserved in it.

Those organic compounds can tell us about

some of the pigments that were there originally.

More than five years after we found Borealopelta,

we were on the cusp of knowing whether or not its skin was

preserved well enough to tell us its color, and finally,

we got the news.

The results of the geochemistry revealed that one of the

common organic compounds was a compound called Benzothiazole,

which is a breakdown product of

the reddish brown pigment, pheomelanin.

The color was definitely a big surprise.

I think there's only been a couple other cases when that's

ever been done.

It was very exciting to see how these

animals actually looked.

You almost don't need to use your imagination

to reconstruct it.

It's the best-preserved armored dinosaur

in the world

because it was preserved in the better conditions found at sea.

But, that presented us with our final puzzle.

We have this odd situation where we have this

animal that lived on land, but it's preserved in what was an

inland sea quite a ways from where the coast would have been.

So, what was this animal doing in the middle of the sea

in the first place?

We could see right from the first day we were

in the field it went to the seabed upside down,

and it hit the seabed with such force in the cliff we

could see the impact crater.

And the question is,

how does this happen and why does it happen?

Large animals when they die,

bacteria start right away to digest their bodies and these

animals fill up with gas and they become bloated.

For many years I've been studying how animals float.

So, I have this program I wrote to test these ideas.

It takes basic physics, and it lets you take a body,

put it in water, you can see what happens.

Let's try a body that's full of gas and you can see it becomes

unstable and then it starts to roll and then very quickly

it rolls over.

And this happened every time without fail.

And since they're full of gas, they're extremely light.

And that allows them to be transported great distances

just by floating.

It's called bloat and float.

Fortuitously, our floating carcass got swept out to sea.

Eventually the gases burst,

the body loses all buoyancy and goes bonk onto the seabed.

And there was so much energy of it going down great clouds

of sediment would have quickly covered it over.

And so it was quickly sealed away from

the air and scavengers.

That's why it's so well preserved.

We were finally able to fill in missing pieces

about how dinosaurs actually looked.

Learning how they behaved from bones alone can be even harder.

But, sometimes a site reveals discoveries so remarkable it

changes the way we view an entire species.

Most tourists travel half way around the world

to see the red rocks here.

But the grey rocks can be beautiful in my opinion.

And I'm probably biased because I know that the grey

means there's fossils in them.

I jokingly refer to the area as "50 Shades of Grey" because

that's basically what you've got.

I’ve been making this commute for 22 years

and it never gets old.

When I first started we had no idea what we would find

at the end of this drive.

I know there are dinosaurs out there, but where are they,

and what will they tell us?

Essentially we have 2 million acres,

and the middle million we knew virtually nothing about.

It was just one giant question mark.

As district paleontologist,

it was my job to find some answers.

We had actually planned to meet a crew of volunteers coming up

to dig on a hadrosaur site.

But, flash floods the previous night had basically taken out

the road and made it so they couldn't come in.

So, I had Mike Knell with me, who was a turtle expert,

and I had Katja Knoll, my intern with me.

Now what? What are we going to do today?

I remembered that there was this place nearby that had lots

of fossil turtle fragments and off we went to this turtle site.

Previously a really beautiful river turtle

has been excavated there.

So, we took him out there and walked that whole area.

We expected to find more turtle fossils.

So, what we saw instead came as a complete surprise.

The deluge had actually caused some erosion and

created a little gully.

As we came through a little clearing,

I spotted something that had just been exposed by

the recent rains.

It was fairly large, about the size of my fist.

It was a rough looking bone.

You immediately run through a catalogue of shapes

in your mind, you're thinking, what is this?

This is so familiar. Have I seen this before?

It had this unusually rugged,

rough texture on it and the texture to me suggested that

I really have something here.

I don't quite recall what he actually screamed.

It was maybe just grunts. I can't remember.

Or something really crude.

Hey! Guys!

You want to go and check because when Alan screams,

it's, it may be something.

.

And it turned out to be something pretty amazing.

I think we've got a Tyrannosaur, guys.

.

And then there was lots of high fiving and whooping and

hollering and dancing around,

because that just doesn't happen every day.

It's pretty mind blowing to know that you're

the first person to ever lay eyes on it.

Tyrannosaurs are relatively rare.

We kept digging and by the end of the day

we'd uncovered 50 bones

We were wondering,

how much more can there possibly be?

How extensive is the site?

After the first day's excavation,

we came back with a larger crew.

We had groups of people out there pretty much

four or five days a week.

Everybody was sitting in the singeing sun for 8 to 10 hours.

As we worked, we were astounded to see that there

didn’t seem to be an end to the bones coming from the site.

We expanded the quarry out to about 100 square meters.

The largest bone bed that we'd ever documented.

It became clear that the bones were a complete chaotic mass,

that they were just a jumble that looked like they'd been

randomly rolled and tossed out like dice.

But, there was something even more remarkable here.

We kept finding bones that were very clearly

belonging to tyrannosaurs of different sizes.

We're now certain we had

not just one tyrannosaur

but at least two individuals at the site.

And then we started seeing more parts of skulls and

more toes that indicated we had more than two individuals.

By that time all of our minds were totally blown.

.

We did not expect this.

It's not uncommon to find a mass death sites for

prey animals that perhaps lived in large herds,

but for a predator,

like a tyrannosaur, it's just so incredibly rare.

Everybody always imagined Tyrannosaurs as being those

lone mavericks.

I mean, it is almost unthinkable to find a

tyrannosaur mass death site.

How many tyrannosaurs were at that site and why were

they all together?

Of course, everybody knows about Tyrannosaurus Rex and

everybody thinks they're cool but Tyrannosaurs are in a fairly

large group and T Rex is only one representative.

The fossils had been encased in burlap and plaster jackets.

And the first thing we needed to know was what kind of

tyrannosaur was inside.

It's kind of like opening a really cool package for

Christmas, yeah, mmm-hmm.

In order to be able to identify an animal with confidence you

really have to be able to look at the elements of the skull

because there are slight variations between

all the species.

This is a jaw of a not fully grown tyrannosaur from our site.

I would venture to say it is probably the most iconic part

of a tyrannosaur.

In this instance it's a little bit smaller than the jaw you

would expect from Tyrannosaurus Rex.

Tyrannosaurus Rex's jaw was significantly larger and

the teeth were also significantly more massive.

The tyrannosaurs that we found at our site is perhaps

a completely new kind.

The tyrannosaurs that we found are

76 million years old.

They're older cousins to the famous T-Rex.

Very similar in appearance,

but about three quarters to two thirds scale.

We're talking about some of the largest terrestrial carnivores

that ever lived on our planet.

Now we knew what kind of dinosaur

we were dealing with,

there was a big question we needed to answer next.

Just how many individuals do we have at this site?

We knew we had all these toe bones of varying sizes.

We had a really big one and we had a really tiny one

that was obviously another individual.

And then we had sort of inbetweeners.

We compare, just exactly how many left feet are present

in the collection.

The pattern slowly emerges.

Oh, ok I've got one left foot.

Okay, I've got two left feet.

Oh, my gosh, here's a third left foot,

then finally a fourth, now five.

There you have it, you've got a baby,

you've got teens and you've got a fully grown adult.

Oh, my gosh.

We've got an entire pack.

We were forced to face the question,

was this a social group?

Was this even a family group?

Tyrannosaurs were always perceived as

being solitary predators.

But, after spending months separating the skeletons out,

we finally knew for sure that we had five individuals.

The big question is, how did they all end up together?

There are just two possibilities,

either they all died separately in different areas and they

were flushed in by some big river system,

or they all just died together.

When we inspected rock samples

from the site,

it became clear this whole area used to be a lake.

So, we think a flood drowned them

and washed them into the lake.

But, how could we be sure our tyrannosaurs had actually died

together rather than just being washed in from different places

by coincidence or accumulating there over time?

What do we have in our toolkit that can answer this question?

The geochemist on the project, Celina Suarez,

had a eureka moment.

She's like, we can study the rare earth elements.

As animals decompose in the sediment rare earth elements

get incorporated into their skeletons as they're initially

turning into fossils.

They're a fingerprint.

They will show us whether or not these bones were buried

together from the get go.

So, we, of course, sampled the bones and voila.

They all had the exact same rare earth fingerprint.

So, they definitely died in the same lake at the same time.

The chances of individual tyrannosaurs all ending up

together are almost nil.

And the age spread almost screams or mandates,

interpreting it as a family.

These had died together and been buried together.

Which brought us back to the bigger idea,

that this was a social animal.

Scientists and popular culture alike have viewed Tyrannosaurs

essentially as these lone killers functioning at the

level of a crocodile or an alligator.

But what if that’s not right?

What if everything we thought we knew about tyrannosaur

behavior is in fact wrong?

The only reason large predators start forming groups is to

guarantee success of taking down large dangerous prey.

And then the question begs itself,

could these have been pack hunters?

Had anyone else come across something like this before?

There is this other site in North America, in Canada.

"Lethal Albertosaurus was a family man!"

"Fossils found at Dry Island Buffalo Jump

suggest this predator hunted in packs."

And then I heard that there had been another mass mortality

site in Montana.

These events represent a capture of tyrannosaur behavior.

So, now we've got three sites in North America with three

different species of tyrannosaurs,

all of which are relatively closely related to T Rex.

Perhaps T-Rex would have engaged in similar behavior.

Paleontologists often use bones to learn about anatomy,

but these sites tell us something about how the

dinosaurs actually lived.

It is really amazing to see how we're

starting to put more of

sort of a face on this creature that everybody just

kind of knows about but really doesn't know a lot about.

If they all, in fact, belong to the same family unit,

it could be very important to understand the

dynamics of Tyrannosaurs.

So, they were social, not just as families,

but also as hunters.

I think finds like these are challenging the idea that

tyrannosaurs were not that intelligent.

They may in fact have actually been able to

co-operate during hunts.

The idea now that we've got the largest killing machine

that ever walked on dry land now with the smarts of a

wolf and the complexity to pack hunt, um, it's terrifying.

We're certainly in a renaissance.

Technology is allowing us to tease ever greater detail out

of the fossils that we find.

Discoveries that paleontologists

are making now

are going to change the way that dinosaurs are portrayed

in popular culture.

We are approaching truth.

Let’s give these dinosaurs the gravitas

that they have well-earned.

Captioned by Cotter Media Group.