Original subtitles

Pantagonia in southern Argentina.

Like many detective stories, this one began by chance. The

shepherd stumbled across the tip of a huge bone poking out

of the ground.

Experts from Pantagonia's premier paleontological

museum confirmed it was part of a dinosaur.

But they didn't realize at the time what a

truly extraordinary one it would prove to be.

Dinosaurs of many kinds roamed all over these lands in the

southern end of South America during what's known as the

Cretaceous period between 66 and 145 million years ago.

The largest were plant eaters known as sauropods, and the

largest of them were the Titanosaurs.

Giant Titanosaur bones are comparatively rare,

so very little is known about these dinosaurs.

This new discovery could change all that.

Like many people, young and old, I'm fascinated by

dinosaurs. So the chance to join this investigation is just

too good an opportunity to miss. Oh, well, I'd love to have

a go. I'm sure they'd like it. Of course, it's the giants in

particular that capture the imagination.

The first sauropods to appear on Earth were comparatively

small creatures. This is the cast of the thigh bone of one

of them. It's not even as big as my thigh bone. But after

about 20 million years, some had become pretty big. This is

a thigh bone from one of those creatures. But then, after

that, our giant appeared. This is its thigh bone. It's the

largest ever found.

Coming across such a bone in your backyard must

be quite a shock. Just ask farm owner Alba Mayo.

I don't have many sheep, but I have a dinosaur.

We're surprised. We're like shocked. Apparently,

it's a unique specimen, because of its size.

Before long, the whole team of fossil-hunting

scientists arrives and starts work.

The thigh bone proves to be 8 feet long, the longest ever found.

It's preserved in extraordinary detail. And detail will be

critical to this creature's life. It's forensic examination

that will follow.

The research team soon turn the site into a vast quarry.

It proves to be one of the biggest dinosaur finds of the century.

Bone after bone emerge from the rocks.

We just found another bone right here. We wasn't expecting

it at all. We just found another bone right here. Let's

start digging and find it. Until recently, giant titanosaurs

have only been known from a dozen bones. And our team have

already found more than 10 times as many.

Dr Diego Pol is the chief paleontologist leading the

investigation. If you really want to know what a really

gigantic dinosaur looked like, this quarry here has the

potential to answer that question. And that's really

exciting for us. It's really impressive. When you stand by

one of these bones, you really feel tiny. With so much new

evidence, there is a chance of discovering all

kinds of new facts about the mysterious titanosaurs.

It's like a paleontological crime scene. It's a really

unique thing that you will not find anywhere else in the

world.

Patagonia's harsh weather makes uncovering the fossils

exhausting, but it also endangers the newly exposed fossils.

With a lot of damage from the rain, so we need to protect

the bones that are at risk. I'm really concerned that this

already has some cracks. If the bones aren't

protected, tiny details on their surface could be lost.

To protect the bones, they're covered with, of all things,

wet toilet paper and plaster of Paris. It's like putting a

plaster cast on a broken leg.

There's a rush to get them back to the museum

to begin examining them in minute detail.

A new road has been specially built to enable

them to be transported without too much jolting.

Once at the museum laboratory, the detailed detective work begins.

It's a chance to start putting flesh on bones. There's some

really big muscle that's going on here. This animal was so

big that it certainly needed really powerful muscles

and really strong attachments into the bones.

This is a giant vertebra, one of the bones of the spine, and

it's a very important find. That's because it's likely to

provide crucial evidence for identifying the species of our dinosaur.

Despite weighing up to half a ton, these fossils are surprisingly fragile.

It's all rather nerve-racking. One bone like

this has already cracked in half without warning.

And so this is the position as it was in life with the

centre of the backbone there. Then this is the crest on the

top. Right, right, and this belongs to the middle part of

the thorax. What about here? About that. Many more weeks of

detailed examination will be needed before the backbones reveal all their secrets.

Surprisingly, perhaps, one of the first things the team is

able to deduce about our titanosaur is its weight. That's

because after finding the thigh bone, they discovered

another huge bone from the front leg, a humerus.

By measuring the circumference of each of these leg bones,

it's possible to estimate how much weight they could

support. Let's see how much...

79.

79? Wow. I'm not sure how that translates to body weight.

Yeah, around 70 tons or even more, probably. Wow. That's

really big. It's amazing. That evening, Dr

José Luis Caballido checks his calculations.

Until now, Argentinosaurus was the heaviest known dinosaur. Ours already looks bigger.

Could this mean it was the largest animal ever to walk the

Earth? Could it also be a new species? We can't be sure yet.

The rocks of Patagonia, so bare of vegetation, also contain

astonishing evidence of how titanosaurs began their lives.

I've now come nearly 500 miles north from our Patagonian

dinosaur excavation to a place called Alcomajuevo. This is

the largest dinosaur nesting ground yet discovered. The

remains of their eggs and their nests are wherever I look.

In fact, it's quite difficult for me to take

a step without walking on a dinosaur eggshell.

Over thousands of years, the wind and the rain have cleared

away the soft rock that once enclosed these fragments. And

they can tell us quite a lot about how titanosaurs

reproduced. Careful excavation has shown that these

dinosaurs laid eggs in clutches of up to 30 or 40 at a time.

They would have looked rather like these replicas because

they lay on the surface of the ground, not covered by soil,

but in a shallow depression. Sometimes, though, remains of

vegetation have been found in some nests which suggest that

the dinosaurs might have used rotting leaves to help with

the incubation. The dinosaur that laid these eggs here were

medium size. Our dinosaur that we're excavating probably

laid eggs as big as that. I'm shown around by Dr Luis

Chiape, who with his team discovered this remarkable site.

Dinosaur eggs here were laid on an old river plain. Then

the river flooded and covered the unhatched eggs, preserving

them in mud. You see, you know, many eggs... Oh, yeah. ..for

kilometres and kilometres. Here's a nice one. Oh, that's a

huge beast. Yep. And this is the actual surface of the egg? Yes. Astounding.

Do you suppose they could have been coloured like bird's

eggs? They may. Maybe they were off-white. We can't tell,

really. Yeah. Well, we can see all the tiny pores on the

surface. And the texture, right? Yeah. What a beautiful

piece. You must admit, it's pretty romantic. I think it's

incredible. I think it's absolutely extraordinary. And I

must put it back where I found it. Thank you. Oh! The

fragments can tell us quite a lot about how the dinosaurs

nested. But some, amazingly, can do even more than that.

All these examples have something quite special. But this

one is my favourite. And what you can see is a very large

patch of baby dinosaur skin. How wonderful. Well, it's

extraordinary. And this is not just an impression. This is

the mineralised skin. It is. Yeah. Astounding. Luis Quiape

has dozens of complete eggs in his museum, and he allows me

to examine some of his most precious specimens for myself.

There are many other remarkable things in these astonishing

time capsules. This one has got perfectly clearly the limb

bones.

Here is a skull. That's the orbit of the eye.

There's the lower jaw. There's the snout.

This one also has a skull, but on the tip of the snout you

can see a little spike, which is like the egg tooth that a

bird embryo has to help it crack itself out of a shell.

And here is a replica of what the complete, uncrushed shell must have looked like.

With all these details, it's possible to

imagine how a baby titanosaur entered the world.

To get an idea of how these youngsters might have lived, we

can compare them with their closest living relatives, birds.

Rather like baby ostriches, a young titanosaur

would have been able to walk soon after hatching.

They may well have gathered into groups to give

some safety from predators, as young ostriches do.

Microscopic analysis of dinosaur leg bones show rings,

rather like tree rings, and these indicate that titanosaurs

grew very swiftly early in their lives. And they could have

lived for some 50 years, plenty of time to become enormous.

The team now has 150 bones of our titanosaur, enough to

get an idea not only of its weight, but also its height and

length. Now the plan is to build a life-size

reproduction of the complete skeleton.

But it's a challenge to find a place big enough to house an

animal that is 121 feet long, over three times the length of

a school bus. But Diego thinks he's found one. It's an old wool warehouse.

One, two, three, four, five, six, seven, eight. We have been

looking for a place that is big enough to feed our dinosaur.

This seems to be it. This is a warehouse that we could use.

Not only in terms of the length, this is 70 meters long, but

also very important in terms of the height. So we need a

place not only long, but really high. It really needs a

little bit of decoration, but I think we'll do it. It's going to be awesome.

Putting the skeleton together will help us understand

the particular challenges of being such a giant.

So next, an international team of skeleton builders arrive

to scan the bones, ready to make a 3D computer model of each

of them.

Extraordinarily accurate 3D scanning allows images of the

bones to be placed in a virtual reality world, so they can

now be examined from all points of view without needing eight people to lift them.

One of the mysteries surrounding our dinosaur is how could

an animal as big as it was actually move about? The computer

data allows us to put our dinosaur leg bones together in

3D and then compare the arrangement with what we know about

living animals.

Elephants are the largest land animal alive today.

They, like titanosaurs, have to move their massive bodies

around without their bones shattering under the enormous

weight.

I've come to meet Professor John Hutchinson here at ZSL

Whipsnade Zoo. He's studied elephants for many years and has

joined the team that's investigating the internal workings

of our titanosaur. We have about a one meter long pressure

-sensitive mat out there with several thousand sensors in

it and it's telling us in very high resolution what the

pressure on an elephant's foot is like. We can see on the

elephant's foot here, oh, there she goes. Oh yeah, great.

Oh, that was a perfect one. The pressure hits the ground,

rolls over and then pushes off with its toenails. So we can

see there are some hot colors or reds and oranges on the

toenails of an elephant's foot indicating high pressure and

then some cooler colors back toward the heel pad in greens

and light blue. That's low pressure, so elephants are

supporting most of their weight on their toenails that

pressure gets transmitted up to their toe bones and then up

to their wrists and ankles and so forth.

John's analysis suggests that our titanosaur's legs, like

those of an elephant, were placed vertically beneath the

body like strong massive columns.

This arrangement transmits the weight to the toes and then

spreads the force using fatty pads in the back feet as shock

absorbers. But our titanosaur had one other

adaptation to help them walk, one that elephants lack.

A clue to this can be seen on the giant thigh bone. Hey,

how's it going? Good, good. Ben Garrard specializes in

reconstructing skeletons and he's joining the team to look

at the bones in detail. Marks on them show clearly where the

muscles were attached. So that's halfway down the femur,

isn't it, that big lump there for these massive muscle, I

guess, tendon attachments. This lump is where a huge muscle

was attached to the femur. The other end of this muscle was

connected to bones like these in the tail. It's this

connection that helped our dinosaur to walk. They've got so

much strength and so much rigidity up there, they actually

use their tails to help move, to help their propulsion. So

they had massive muscles and tendons from... Help? Yeah,

so the movement of the tail actually pulled the hind legs

backwards and then released them forward. Oh, I see. I must try that sometime.

The largest lizard alive today, the Komodo dragon, has a

similar adaptation. The swing of their tail helps their back

legs move more efficiently.

Of course, our dinosaur was different, not least because it

weighed over 500 times more. And that makes John Hutchinson

suspect that it would have had to deal with another problem,

one also faced by passengers on long-haul flights. Pressure

in the legs of big animals is a really big problem. If blood

stays down there too long, it's going to pool and die. Much

like airline socks that humans use, large animals again

and again have evolved very thick elastic skin around their

lower limb that helps to keep that pressure very high.

Actually, I can empathise. I have to wear those same kind of

stockings to get my arm back up my long legs. Time to thank

our helpful elephant. You're a lovely thing. Yes. Oh, you

want one of these too? OK. Here you go. Thanks. Thanks, pal.

That's all I've got. A giant animal like an elephant also

needs a huge heart to pump blood around its body. And so did our titanosaur.

Its heart must have been immense.

From our new detailed knowledge of the skeleton, John

Hutchinson has calculated that it was more than six feet in

circumference.

It probably weighed 230 kilos, and would have had to

shift 90 litres of blood with a single beat. There's one.

And it would have had to repeat that beat every five seconds. There it goes again.

Weighing more than three grown men, it would have been extraordinarily powerful.

And in order to pump blood around the body at high pressure

and then into the delicate lungs at a lower pressure, it's

thought that our titanosaur's heart had four

chambers, more like that of a bird than a reptile.

So a powerful heart pumped the blood to the extremities

of the body, but how did the blood get back?

As in an elephant, a combination of fatty foot pads and

tight skin are thought to have forced the blood from its

legs all the way back to its heart.

Toronto, Canada, and the world's biggest dinosaur-making factory.

The team is building a life-size skeleton of this vast

creature to be unveiled in Diego's warehouse in Argentina in

six months' time.

First, they have to turn all the information

from the 3D scans into each individual bone.

State-of-the-art robots carve moulds from polystyrene

so that the bones can be cast in fibreglass.

Up until now, the fossil bones have been the main focus of

the dig, but the rock that surrounds the fossils also holds

important information. The nature of the layers of rock in

which these fossils lie can tell us a great deal about how

they got to be where they are and how old they are. Some of

these layers are volcanic ash, which must have come from a

volcano erupting every now and then somewhere in the neighbourhood.

And this ash around the bones can tell us how old the

fossils are. Scientists work out that all these fossils

dated from the Cretaceous period, but better than that,

they dated them precisely to 101.6 million years old. In an

investigation of this scale, sometimes the most important

information comes not from the most eye-catching evidence,

but from quite tiny details. Here is

something that I really hoped the excavation was going to find.

It's a tooth, and it's tiny compared with the size of the

huge animals from which it came. Teeth can tell you a huge

amount about an animal, and if you look at the tip, you can

see that it has been worn into two facets, one on either

side, and that tells us that this tooth engaged with the

teeth on the other side in that alternate way like that, not

head-on, but one on either side. So this animal, like a pair

of scissors, just nipped off the vegetation on which it was

feeding, enormous though it was, just nipped off little

leaves. And here are fossils of some of the different kinds

of plants on which it might have fed.

Psycats, ferns, and conifers.

One thing these plants have in common is that they're all

very fibrous and hard to digest. To get enough nutrients

from such poor quality foods, our titanosaur

would have had to eat them in vast quantities.

A descendant of one of the most important plants in the

world, one of these plants still grows in Patagonia today.

200 million years ago, when South America, Australia, and

Antarctica were all joined together to form a supercontinent

called Gondwana, a particular kind of vegetation was

dominant. They were conifers. They continued to survive to

100 million years ago when our titanosaurs were roaming the

land, and a few still survive today. Here, in the foothills

of the Andes, is one of them, the monkey puzzle tree, called Oricaria.

Trees like Oricaria show that the dinosaurs must have had

another problem. These conifers, apart from being poor

quality fodder, can grow to over 130 feet in height. They

would have been out of reach for many animals, but not our

titanosaur.

Here, boys, come on.

It's pretty clear why a long neck is useful for a land

-living animal. It enables it to reach vegetation that's

growing high up on the top of trees that other ground-based

animals couldn't reach. And it must have been much the same

for titanosaurs, except we know from the fossils that the

titanosaur's neck was very, very much longer. And that

enabled it to sweep its head in a great wide arc, and even

to reach between two tree trunks that happened to be growing

close together to get other vegetation. What about that?

This enormous reach would have saved our titanosaur a lot

of energy. It only needed to move its neck to feed, not its

whole body.

But how did it eat enough of this poor quality food to

survive? Elephants face a similar challenge today. An

elephant can collect and chew about 130 kilos, that's 300

pounds, of vegetation in a day. But our titanosaur could

have eaten five times that amount. It's been estimated that

a large titanosaur would eat enough plant material to fill a

skip in a single day. So how did they digest it all?

Elephants solved the problem by giving their food long,

preparatory chews. But titanosaurs didn't bother. They

simply gathered leaves by nipping them off and then

swallowing them whole. But that, in turn, would mean that

they needed a bigger and longer gut to digest all that

untued food. And it might well have taken 10

days for food to pass through their system.

A bigger gut needs a bigger body. So titanosaurs grew bigger

and bigger until they approached the limits of what their

bones could support.

The 3D data used to make the skeleton has also been used

to create a computer model. It means I can get a preview of

what the final skeleton will look like. The first thing

is to look at these very, very lovely legs if you turn it

around. They're very, very column-like. Now this is like

elephants, but interestingly, this titanosaur had slightly

splayed legs. At an angle, about five degrees, and this

slight change would have really increased the ability to

take all that extra weight. Can you see the splay because

of the joint or because of the shape of the bone? A bit of

both. You can tell from the shape of the bone and from where

certain parts of the bones form and how they sit, and then

how the bones fit with one another. You can really tell how

it would have sat in real life. Another thing you can see is

a very, very long neck, and we've just found out that ours

had 15 bones in its neck. Interestingly, some of them were

five or six times longer than they were wide. These

incredibly long vertebrae, and there's lots of them. Why

does it have such a long tail? Well, a couple of reasons.

If you've got an animal this big with a neck this long, the

last thing you want to be is top-heavy. And again, research

has just shown that the center of gravity in this animal was

somewhere right in the middle of the chest cavity. So the

heavy tail counterbalances the exceedingly long neck. But

judging from the size of the muscle attachments, the tail

was also immensely strong. You would have had huge muscles

from around here, right down to about a third of the way

down the tail, somewhere around here. So that would be solid

flesh? Yep. Muscle, tissue, other tissue, ligaments,

tendons. Do you think they might have fought with it?

Possibly. Flashing it about? It could have been used as

a defense mechanism. So you're walking up to that as a

predator. The last thing you want to be is on

the receiving end of... Don't put me into it. No.

The long and painstaking examination of the backbone has

now borne fruit, and Ben has got some important news.

Now, this is a vertebrae here, from right high up in the

back, right near the shoulder blades. And the most important

thing is this little ridge. It ends in this big lump, and

this is only found in this particular dinosaur. So from

that, and a few other physical differences, we think we've

got a brand new exciting species. So our titanosaur is not

only a giant, it's also a very large animal.

A giant, but it's a new species of dinosaur.

One that had to face many dangers, as it wasn't the only giant here.

This was a dangerous world, where meat eaters were giants too.

Fresh evidence of large carnivores has been found close to our dinosaur bones.

So these are some of the over 80 teeth we found at the dick

side. And you can feel how sharp they are. Oh yes, it's

serrated, just like a sharp tooth, in fact. Absolutely,

they actually belong to a family known as the shark tooth

dinosaurs. We can identify the teeth at the family level. We

know of one species that belongs to that family. It's called

Tyrannotitan chubutensis. Tyrannotitan? Yeah, Tyrannotitan.

That means a ferocious giant, ferocious beast. Exactly. Good

name. Chubutensis is because of the area it comes

from. Yeah, this is a Chubut province. Great.

Tyrannotitan must have been a ferocious looking beast. With

large eyes, sharp flesh-eating teeth, and strong legs, it

was a fast, alert, meat-eating dinosaur.

And it was as big as T. rex. Really? Yeah. Not as famous?

Yeah, not as famous. Tell that to Hollywood. And I have some

sauropod bones over there I would like to show you. So

this is one of the tail vertebrae we found at the dig site.

There's something really interesting here. You can see this

groove. Well, this groove is probably a bite mark made by

one of the carnivores. One of these teeth. Right. So it was,

what do you mean, like that? Exactly. Taking the flesh out

of the tail. Really? Yeah. The tender bits. There would be

too, yeah? Yeah, absolutely. Can you tell me whether it was

a scavenger or it was a hunter? We don't know if they were

dead. I mean, they were scavenging on the carcasses, or if

they were actually hunting and killing them. Well,

didn't make much difference to the old dinosaur.

In the detective story, to close the case, you really want

to know how the victim met its end. If our titanosaur didn't

perish in the jaws of a tyrannotitan, how did it die?

Clues can be found by the detailed three-dimensional mapping

of the location of every fossil bone, small and large.

That shows that the dig site contains the remains of not

just one, but seven different individuals. All of the new

species. And the first thing to notice is that they are on three different levels.

That's to say, the animals must have come here on at least three different occasions.

But why should they have done that?

There are several theories as to why seven bodies should

have all ended up at this one particular place. The first is

that this was a seasonal climate, and that as the dry season

proceeded, this was one of the last remaining pools of

water. And when this went, the sauropods that happened to be here died here.

The second is that these bodies were swept down by great

rivers during the rainy season, and then where the land

levelled out, so those bodies were dumped. Analysis of the

sediments around the bones shows that there were rivers

gently flowing across this site at the time of their death.

There was no shortage of water to drink. What's more,

the rivers were not moving fast enough to shift such huge

bodies. So the corpses weren't washed here by floodwaters either.

Could there be another reason why they all

died in one place on three different occasions?

We know from layers of ash around the bones that there were

volcanoes erupting in the neighbourhood, so doubtless there

were areas where the ground was warmed by volcanic fumes,

just as they are here today. We also know that dinosaurs

regularly laid their eggs in such places, doubtless taking

advantage of the volcanic warmth to help incubate their

eggs. So maybe that was the reason why they kept returning to the same place.

Certainly the excavation of the dinosaur egg site seems to

support this. Nests like these have been found at four quite

widely separated layers in the rocks, showing that dinosaurs

came back to this particular site again and again and again

over a long period of time.

Ash from a volcanic eruption can sometimes fall in such

quantities that the whole vegetation is blanketed by it and

killed. So life in the aftermath of a big

eruption can be very difficult for a plant eater.

Whatever the explanation, individuals over several

generations came to this one place and died here. The dig is

coming to an end and the team have assembled a record

-breaking number of bones, but they're still hoping to find

one last piece of the puzzle, the skull. So what number is

this, 203 or...? Well, actually it's 223 or so. 23? Yeah.

Between the seven individuals? Yeah, between all the seven

individuals we found here in this site. If these are neck

vertebrae, could they be leading towards the skull? Well,

yeah, that's what we're hoping for. We just found another

neck vertebra over there, so... That would be a great

triumph if we found a skull, wouldn't it? Oh, yeah, yeah,

there are only three titanus or skulls known so far. Really?

Yeah, so they're very rare. And that's because they're very

fragile, isn't it? Yeah, they're very delicate bones and

they have very light sutures between each of the bones. OK,

well, let's hope we find number four. Yeah. It could be

under there. It could be. We're going for that. Wonderful.

Alas, it was not to be.

So, I gather you haven't yet found the skull? Sadly not.

The only thing we have found out of skull is this tooth.

So, to complete the skeleton, the team have to reconstruct

one. We take that piece out of there. Basing it on the three

skulls of other titanus or species to produce one

which most suits the single tooth that we have.

The scientific team has discovered, collected, cleaned,

scanned and copied 220 bones of our giant. Soon it will be

possible to put those copies together to get some idea of

what the living animal actually looked like. But the fossil

bones themselves still have many secrets that are

waiting to be discovered. Something to be revealed.

All the theory can now be put to the test.

We can finally get the most accurate estimate

of our dinosaur's weight and true size.

It takes two weeks working day and night to fit all the bones together.

Wow!

Absolutely amazing!

Good gracious!

Well, Diego, you're pleased then? Yes, we are very pleased.

It has been a lot of work, it has taken 40,000 man hours to

get here. But we are really, really happy with it. And does

it take a lot of work to get here? Can you answer some of

your questions about the animal? Oh, yeah, absolutely. It

answers a lot of questions. But the good thing is it raises

more questions. So we had a lot of research to continue on

this animal. It's clear that this thing still wasn't fully

grown. It's massive, but it still had room to go. You mean

the structure of the bones looked as though they were still

growing? Yeah. So that raises the really big question. Is

it the biggest so far discovered? Well, according to our

estimates, this animal weights 70 metric tonnes. That's 77

short tonnes. What would that compare with? Well, that is

like 15 African elephants. 15 African elephants? Yeah.

We are now sure that this animal was 10% larger than

Argentinosaurus. The previous record? The previous record.

So, yes, we think we have the largest dinosaur ever known.

Fantastic. I can quite believe it. Congratulations to you.

Thank you. Congratulations to he, she or it. Wonderful.

Marvellous, marvellous dinosaur.

Piecing this complex jigsaw puzzle together has been a fascinating adventure.

It all started with the discovery of one enormous thigh

bone. And then a team of 40 worked for over two years to

excavate and put together the near-complete skeleton of the

largest land animal yet discovered. And so added one further

marvel to the astonishing history of life on Earth.

What a thrill it must have been to see it when it was alive.

What a thrill.

What a thrill.