(indistinct chatter on radio)
NARRATOR: Imagine if the government found the complete body of a dinosaur,
and then assembled the world's leading paleontologists
to carry out a secret autopsy.
With only access to fossils,
even the most brilliant minds
struggle to fully understand how these giants lived.
Now, for the first time,
eminent scientists can cut into the body...
(dog growls)
...of one of the greatest predators the earth has ever seen.
(dogs barking)
What secrets can they learn?
What myths can they dispel?
What can they reveal about one of the deadliest dinosaurs
to have ever lived,
Tyrannosaurus Rex.
(thrilling music)
Today this team of experts is about to make history.
They will dissect the world's most complete
and detailed T-Rex ever seen.
Luke Gamble is an all-action vet who's leading the autopsy.
I've got to find out how this beast died.
But I've also got a chance to figure out how it survived.
How it worked? What made it tick?
NARRATOR: Matthew Mossbrucker has discovered
groundbreaking dinosaur fossils.
We didn't learn things about this dinosaur.
We've only been able to speculate up until this point.
NARRATOR: Steve Brusatte is a leading expert
on the anatomy and biology of T-Rex.
STEVE: The biggest, fattest meat-eater that ever lived.
And I've been studying it's bones for a decade.
But I want to know how it lived.
That's the mystery that keeps paleontologists up at night.
NARRATOR: Paleobiologist, Tori Herridge,
brings with her experience of dissecting an Ice-age mammoth.
I'm interested in seeing if the theories
that scientists have put together, hold water when you actually do see
a Tyrannosaurus Rex in the flesh.
(suspenseful music)
NARRATOR: The team is about to get it's first glimpse
of this awesome dinosaur.
(grandiose music)
(exhales deeply)
-This thing's massive. -It's huge.
MATT: When I first saw the T-Rex, I was overwhelmed.
I just nearly wept. It was just so beautiful.
STEVE: My first thought, this thing's an alien.
It was so different from the skeletons that I'm used to
that it took me a few minutes to realize
this was the animal that I study.
NARRATOR: Forty-three feet long, thirteen feet tall,
this monster is one of the largest land carnivores of all time.
Oh, Jeez.
LUKE: Look at the size of these claws.
Wow.
NARRATOR: Weighing seven tons,
its name means, "King of the Tyrant lizards."
Its skin is just amazing, isn't it?
-Yeah. -Like armor plating.
MATT: So thick.
NARRATOR: Over 50 serrated teeth dominate its half-ton head.
LUKE: Look at that. Absolutely terrifying.
NARRATOR: It's one of the most familiar of all dinosaurs.
The T-Rex's body still holds surprises.
-What's on the arm? -Bristles.
It's the best description of them.
MATT: They go down to the tail tip.
NARRATOR: This forensic examination will explore how T-Rex evolved
to become the dominant species of its age.
MATT: All right, Luke.
You've dissected everything from barnyard animals
to elephants.
This is clearly not an elephant.
(laughter)
Where do we start?
To be honest, we're gonna approach this with the same logic
that we'd approach any autopsy.
So let's just review the external features.
I need to know if it's an adult or not.
If we can sex it, ideal.
Let's create a portal here.
Let's get right inside the belly of the beast.
And that's gonna have the key to the answers we need to know.
If we know how it died, we can learn how it lived.
-We're gonna get dirty. -LUKE: We're gonna get very dirty.
NARRATOR: Luke regularly performs animal autopsies.
His start point
is establishing if old age could be the cause of death.
So, how on Earth do we age this?
The secret is in the bones.
Maybe you've seen a tree that's been cut down?
You look at the tree stump, you see rings.
-Sure. -And you can count the number of rings.
That tells you how old the tree was when it was cut down.
Dinosaurs are the same.
-MATT: No way. -STEVE: One ring each year.
So this, right here, that's what we have to cut.
NARRATOR: To see the rings,
the team needs a cross-section of a bone of the leg.
Oh! Challenge one. How do we get the leg off this beast?
This is your area of expertise,
-I believe. -(sighs)
NARRATOR: T-Rex's lower leg is two-and-a-quarter feet wide
and packed with dense muscle and bone.
Matt, get some of the guys mark up exactly where I've gotta cut.
Try and raise this leg and support it so that it's steady.
I'll go and get some gear.
-STEVE: We're gonna need a bigger knife. -TORI: Yeah.
NARRATOR: Luke's dissected cows, horses and elephants.
But does he have a blade big enough
to slice through the massive hindlimb of the T-Rex?
Each of T-Rex's muscular legs weighs nearly two tons.
LUKE: Hey, guys.
(laughter)
-Trust me, I'm a surgeon. -(Tori laughs)
TORI: Then you'll be needing these.
LUKE: Where am I got to cut?
STEVE: Right in through here.
NARRATOR: Luke must cut through nine muscles
and a bone as thick as a branch of a tree.
(chainsaw whirring)
TORI: I was not expecting a chainsaw.
But it makes sense because this is a big animal
and you're gonna need something bigger than a, you know,
sensible, sedate, anatomical knife.
All right then. There's no going back from this.
Okay, job done.
Little trickier than the dogs and cats and horses you're used to, huh?
-Nothing to it, Bowie. -(laughs)
(blood trickling)
NARRATOR: Luke has amputated this limb just above the ankle.
-TORI: Nice, thank you. -STEVE: Thank you.
NARRATOR: Despite being a massive six-feet-long,
this isn't the entire leg.
It's just a foot.
Before they extract the all important bone sample,
Tori and Steve want to take a closer look at the foot's anatomy.
-TORI: Let's see what we got here. -STEVE: Right.
TORI: I want to have a look around this side
because that's where the sharp stuff seems to be.
So, am I looking here at the foot
going along up to the ankle bone here?
That's right. Absolutely so...
this is the part that would be equivalent
-to the arch of our foot. -Right.
And these are the toes.
We got three toes which are absolutely enormous,
rather frightening looking claws at the end.
-STEVE: Yeah, very scary. -And...
top from here is the fourth claw.
Well, it's kind of bird-like isn't it.
It's like the three claws of a bird and a back one which in your typical,
you know, sparrow or pigeon would be used to perch
and cross around a branch potentially.
You got it. I think if you look at this,
you look at the skin, it's scaly, it's green,
maybe, kind of, looks like a crocodile or a lizard.
But you look closer at the structure of the foot,
there's nothing croc-like about this.
This looks like an overgrown chicken.
TORI: Does it do anything in a T-Rex?
STEVE: It probably doesn't do very much.
This is what did all the work these three main toes.
And it was all the work.
Because this dinosaur, this T-Rex, only walked on its toes.
A seven-ton dinosaur on the tips of its toes.
NARRATOR: T-Rex isn't lighter at feet.
Its toes impacted with same force
as a car hitting a wall at 30 miles per hour.
That's why T-Rex had special shock-absorbing pads on its feet.
And these are also found in birds.
T-Rex walks like a big bird.
(roars)
(chain rattling)
Vet Luke thinks he's found evidence of an injury.
-LUKE: Look, can you see these ridges? -MATT: Uh-huh. Okay.
Yeah, that's different.
Feels like crepitus, so I suggest there's some sort of trauma
under the skin.
What we should do is just X-Ray.
NARRATOR: When bones break, air can bubble to the skin's surface
causing a spongy feeling known as crepitus.
LUKE: Don't drop it on me.
All right.
Okay, it's perfect.
NARRATOR: While Luke carries out the X-Ray,
Steve and Tori
are trying to age the dinosaur from the rings and the bone sample.
We can look at a super thin slice under the microscope
to count those growth rings.
I'm seeing some really, really, really clear lines.
It was really easy to count them at first, but then I hit this bit.
Maybe I just looked away from the screen for a second
because actually I'm struggling to count the lines.
So I'm gonna get in the realm of 20, but I mean it's really hard.
They seem to really pile up on each other towards the edge.
Now, what's going on there?
STEVE: That's really interesting. And this... this holds the key
to figuring out the age.
Because during its teenage years, from the time it was about ten-years-old
to the time it was about 20-years-old,
it grew at a supercharged rate.
It put on about two or three kilograms.
So about five or six pounds
-of weight every single day for ten years. -(chuckles)
So imagine that teenage growth spurt.
But then towards the end of that growth spurt,
growth slowed down
and you start to get very little growth and those lines pile up.
TORI: So it's still laying down a line of bone every year incrementally.
But it's not growing as fast.
There's less distance between each line.
Hence, that really densed up at the top.
Yeah, so this is an animal that
has basically stopped growing, but it still had some years to live.
So, I think somewhere in the realm are 20. Would that make sense?
-STEVE: Yeah. -So, this animal probably didn't die
-of old age. -Probably not.
NARRATOR: Scientists have only found T-Rex remains
in a narrow band from southern Canada to Texas.
They named the most complete skeleton "Sue."
And it's bone rings revealed it died when it was only 28-years old.
The oldest recorded age of any T-Rex.
T-Rex, it grew fast, it lived hard,
and it died young.
-Matt, Luke? -LUKE: Yeah.
TORI: Come over here.
So those are the rings, are they?
-TORI: Can you see them? -It's amazing.
TORI: Each dark line you can see, really visible.
That's absolutely brilliant.
Well, we've got a pretty good time.
So that hunch on soft tissue trauma proved right.
Matt and I just X-Rayed it. If you have a look at the image here.
-(chuckles) -Okay.
Yeah.
So, what we've got here is a lateral view of the femur.
All right, the knees here, hip would be up here.
And you can see
there's a slightly oblique transverse overriding fracture,
it's quite a clean break.
STEVE: The femur's the strongest bone in the body.
How do you break your femur like that?
Well, in race horses, for example,
there'll be a trauma as such, fell on a rock
or a clean impact. So, we see this a lot actually
in smaller animals that might
have a hit by motor bike or something like that.
-Big motorcycle though. -Yeah.
-(laughs) -Big motorcycle to hit this guy.
But you know what? What it tells us, this definitely
would've been a game changer.
NARRATOR: A massive injury like this will immobilize any animal
and leave them unable to eat.
Could this T-Rex have died from hunger?
Let's just get into it. Let's get inside,
just look at the stomach. Let's see what's in there,
work out if it's starved to death,
'cause that's gonna tell us
if this wound was the end game for this guy.
-MATT: Okay. -LUKE: Okay. I have a feeling we're...
NARRATOR: The answer is deep within the creature's body.
LUKE: Watch the block.
All right here's your saws, Dr. Luke.
TORI: Enough knives for you there?
-There's never enough knives, sorry. -(Tori laughs)
There's no point tickling this, is there?
So let's just get on with it.
Cut into that abdomen.
NARRATOR: Paleobiologist Tori is the only member of the team
to have previously autopsied a pre-historic creature.
A 40,000-year-old mammoth.
TORI: I've been here before.
The stench hit you, I mean, your eyes, your nose are streaming.
It absolutely reeked.
(chuckles)
LUKE: Let's get it done.
(Luke grunts)
STEVE: There you go.
(squishing)
LUKE: Okay, we're in.
Tori, could you bring me that really big, long, sharp one.
Yeah, on it.
Okay, cool. Let's swap him over.
Okay. (sighs)
Let's see how this goes. (grunts)
This is hard going. It makes elephant skin feel like velvet.
Okay. All right. (grunts)
Guys, come on in close.
Give me a hand with this, all right?
I'm gonna go across. Hold tight, all right?
Tori, come in close. Come in closer.
-STEVE: Oh, it's getting wet. -LUKE: All right, guys, all right.
Mind your thumb, mate. I don't want that off.
(Luke groans)
NARRATOR: The team isn't just cutting through skin.
-MATT: Yeah, we're good. We're good. -LUKE: We're good.
-(Steve retches) -(laughter)
LUKE: Soak it up, guys. Soak it up.
NARRATOR: There is a thick slab of insulating fat.
-(indistinct chatter) -LUKE: Come on, come on.
NARRATOR: And three layers of muscle full of blood vessels.
MATT: That smell is something else, isn't it?
-(blood squirts) -(all) Ooh!
What did this guy eat? (laughs)
-MATT: That got into my mouth. -LUKE: Oh, jeez.
(coughing)
STEVE: This is why I study bones. (laughs)
LUKE: Okay, let's go.
(Luke grunting)
That's a bit hard. Almost there, guys.
All right. Peel this back.
MATT: We're gonna open it like the trunk of a car.
NARRATOR: Luke is expecting to uncover rib cage.
What he finds is unlike any animal he has ever seen.
LUKE: My goodness me. What's going on here?
MATT: Wow!
(Luke grunts)
STEVE: Wow. Look at that.
LUKE: Hang on. This can't be ribs.
This just can't be ribs.
NARRATOR: The team carrying out the postmortem
on a T-Rex, ushered a problem.
They've uncovered a row of bones.
STEVE: Wow.
LUKE: Oh, look at those.
Oh, in fossils usually just see bits and pieces
you know, one or two bones, but they're all together.
Wow.
(chainsaw whirring)
NARRATOR: So far, the team has discovered their T-Rex has feet like a bird.
A bone sample has revealed it didn't die of old age.
But it had a broken femur
which could have caused it to starve to death.
(chains rattling)
What we're doing now is crane our portal
into the belly of the beast.
In here, we're gonna get the answers.
We're gonna find out, and only hopefully,
why it died. If that leg had anything to do with it.
We're all are taking our chance to understand how it lived.
How it survived.
Keep it going, guys.
Stop!
NARRATOR: The evidence lies in the dinosaur's internal organs.
But bones are blocking the team's path.
STEVE: The whole belly of this animal is covered in bone
in addition to all those muscles.
So this guy was a reinforced tank.
NARRATOR: Matt Mossbrucker is the curator of a National History museum,
deep in T-Rex country.
And he recognizes these bones.
This feature, that's a croc feature.
NARRATOR: They are gastralia.
When I dissect crocodilians
from the bottom of the sternum, all the way to the pelvis,
there's a short series of gastralia.
Like these. I've never seen them this big with muscle around them.
This is something else.
NARRATOR: In crocodiles, these bones provide abdominal protection.
Also called belly ribs, they don't attach to the rest of the skeleton.
Scientists think T-Rex had over 30 gastralia.
But they are yet to find a fossil of an entire rack.
LUKE: Well, guys, you know what, it's wonderful they're here
but we gotta get through 'em.
NARRATOR: Luke thinks the equipment he uses
for dehorning cattle might work.
This is just gonna be hard sawing.
So, what I'm gonna do is I'm gonna thread
this embryotomy wire, which is steel.
I'm gonna put it through and it works like a cheese wire.
And it's gonna go through these holes here
and hook it around the base of the rib.
STEVE: Okay.
LUKE: And then what we're gonna do
is pull it out and work it like a saw.
STEVE: You make it look easy.
LUKE: Well, this wire is razor sharp. There we go.
-STEVE: Wow. -LUKE: So that's one done.
NARRATOR: With eight more to cut,
Tori and Steve decide to investigate T-Rex's infamous jaws.
These hold the secrets to the way this giant dinosaur fed.
So, first thing I see when I look at his mouth is,
"Oh, my goodness it's full of really sharp teeth."
STEVE: About 50 of 'em. What T-Rex could do,
and it was very good at this, it could chop.
-Right. -STEVE: And it was
a record-setting chomper.
And it was mostly these teeth,
these big ones, right in the middle, that were doing the chomping.
So I think we should try
-to take a look at one of its teeth. -TORI: Oh, I'd love to do that.
So can we get a car jack or some kind of scissor jack or something.
STEVE: Come on in. (chuckles)
TORI: You kind of resist what you feed in,
is that helpful? Open a bit.
NARRATOR: The front eight teeth scrape.
The rest of its 50 teeths
are dedicated to crushing bone and ripping flesh.
TORI: I love it, doc. Thank you.
Okay. All right.
STEVE: These teeth at the side of the jaw, the bigger teeth,
these were the steak knives, these were doing the cutting.
-These were cutting up Triceratops steaks. -TORI: Mm-hm.
These were crushing.
And so, I think it would be really nice to look at one of these.
TORI: Oh yeah, definitely.
NARRATOR: To fully understand the size and function of these teeth,
the team need to extract one.
STEVE: This one seems
-a little bit like weak. -TORI: It does actually.
We need a sharp blade and a man who can wield it.
Luke. Hey, Luke.
LUKE: I'll leave you to it. (chuckles)
You mind taking a look at the tooth for a minute?
-I'd love to. -Matt can do the ribs.
I'm gonna assume it's just, like, for the moment,
a massive dog.
Because this looks like a canine. Canines generally have one root.
So, I suspect that.
What we're gonna have to do
is probably just breakdown these periodontal ligament.
-Yeah, ligament that holds the teeth in. -LUKE: It does.
Yeah, so we're just going to stretch that out.
NARRATOR: Ligaments are tough pieces of tissue that connect bones together.
TORI: Phew.
STEVE: Oh, look at that, it's coming out. It's coming out.
TORI: Wow.
LUKE: Okay. (grunts)
(Steve chuckles)
LUKE: It's a perfect extraction.
STEVE: Look at that.
NARRATOR: Measuring 12 inches long
this serrated tooth
is the perfect tool for ripping into flesh.
This is all about piercing, biting.
How powerful would a bite like this be?
Well, this thing had a lot of force.
-LUKE: Yeah. -TORI: It could puncture.
STEVE: It could puncture.
It's an armor piercing shell that's what it is.
So, biting through a car, totally doable.
I think T-Rex, it could've probably bitten through your Land Rover.
-I would say that. -LUKE: No, never.
-I think so. -(laughter)
Oh, I'd fall out of love
with this T-Rex if it bit through my Land Rover.
(growls)
NARRATOR: Crocodiles and alligators
have the strongest bite of any living animal.
(zebra shrieks)
Some species can snap their jaws shut
with a force of 3,700 pounds.
Enough to crush the skull of a zebra in a single bite.
(zebra shrieks)
But that is nothing compared to a T-Rex.
(roars)
Scientists digitally reconstructed the dinosaurs jaws,
and found it delivered a bite
three times more powerful than a crocodile.
Twenty -two massive muscles gave T-Rex the hardest bite
of any known land animal.
(growls)
LUKE: Weird thing is these teeth are so tough.
Was that one loose, is it?
Some infection of the root or something 'cause that'd be making it septicemic.
NARRATOR: Septicemia or blood poisoning can be a killer.
Who knows how to work this rig?
-Yeah, sure. -You do, right? The Vet.
NARRATOR: Is this a major clue to the T-Rex's death?
LUKE: Please thread it up there for us.
NARRATOR: To find out they insert an endoscope into the tooth cavity.
LUKE: Further more. Go up, bit more.
Hang on. There's a... No, no...
Look there. There, there, there. See that right there? Right there.
The white object, conical. See the line of serrations?
-MATT: Now I see it. -STEVE: I know it. I know.
-You know what this is. What is it? -STEVE: I know what this is.
MEN: This is a replacement tooth.
STEVE: These guys, they're not like mammals.
They don't have baby teeth and adult teeth, and that's it.
-MATT: Yeah. -They replace throughout their lives.
-Like sharks? -Like sharks.
Yep. And they do this every few weeks or so.
NARRATOR: The tooth wasn't loose because of an infection,
the one going behind it was pushing it out of the way.
Throughout their lives?
These guys had a never-ending supply of teeth.
It's a wonderful dental plan.
NARRATOR: But one kind of tooth is conspicuously absent from T-Rex' jaws.
There are no molars, or chewing teeth.
The Komodo dragon, the world's largest living lizard,
also lacks these teeth.
(snarls)
It feeds in a very specialized way.
Ripping massive chunks of flesh from a carcass.
Then with a flick of its neck muscles it swallows the meat whole.
T-Rex's 12 powerful neck muscles allows it to feed in a similar way.
Even with 500 pounds of meat in its mouth,
the dinosaur can throw back its half-ton-head with ease.
(growls)
T-Rex didn't chew, but swallowed chunks of meat whole.
(metal rustling)
LUKE: That's it.
-Great work. -MATT: Thank you. My first time.
(chuckles)
NARRATOR: But did it hunt or scavenge its food?
(Tori grunts)
The answer is inside the stomach.
MATT: I got it. We're getting somewhere now.
NARRATOR: To get to it, the team must rip out the ribs and gastralia.
LUKE: Guys, we're gonna go in five, four, three, two, one.
(all grunting)
-Okay, you're on it. Go. -Yep.
(all grunt)
We're the T-Rex wreckers.
-MATT: All right, good stuff. Great. -STEVE: That's it.
NARRATOR: But under the gastralia there is yet another barrier.
LUKE: So guys, this is peritoneum. Inside here are all the organs.
This lines the abdominal cavity.
But it also contains all the supply of blood vessels.
Here's the lymph nerve.
So we'ere gonna cut through this.
We can go delicate here.
-Almost proper surgery. -TORI: Right.
LUKE: Let's just slice this out.
NARRATOR: This thin membrane is vital to the animal's well-being.
STEVE: Look, look, look.
(squelching)
LUKE: Okay, let's hold it up. See what we've got.
TORI: I'll take this end.
-MATT: It's like a map. -LUKE: That's amazing.
TORI: Yeah.
LUKE: That is a support for all the abdominal organs inside.
So, not only have we got ribs, gastralia,
three layers of muscle but you've also got this.
Which is really nature's, kind of, band-aid.
So if the guts get lacerated, it'll have a bit of injury,
it wraps around them and it seals them up.
NARRATOR: The team finally reaches the organs of the digestive system.
Their contents will uncover if this T-Rex is a hunter
or a scavenger.
Or even if it starved to death.
Steve come on here, have a... have a good look.
So, all of this stuff here, it's gonna be the intestines.
-LUKE: Okay, right. -MATT: That's lovely.
LUKE: Okay, lets just get under it.
TORI: It's here.
Let's pull this out. So this is the small intestine, I'm guessing.
TORI: Small intestine? Right! (chuckles)
STEVE: Yeah, that's funny.
NARRATOR: The name small intestine is misleading.
LUKE: Smoke it down, guys.
(Steve chuckles)
(Matt grunts)
LUKE: Guys, can I get a little bit light in here? Would that be all right?
-(all grunting) -Oh, wow.
Nice, nice.
LUKE: It keeps coming.
-TORI: I got it. -LUKE: Oh, my gosh. Okay.
(spits)
Nothing like the taste of T-Rex first thing in the morning.
-Wow. -LUKE: Right.
That is small intestine.
-Unbelievably big as it is. -Yeah, unbelievably.
There's nothing small about it, my friend.
LUKE: This small intestine is where it absorbs
all the nutrients from the food it eats.
Typically, less than four percent fat
only traces of protein are gonna make it beyond the small intestine.
So, this is really the powerhouse. We should get a lot from this.
Trying to free up some of the stomach. (grunts)
NARRATOR: The team also start freeing the other parts of the digestive system.
The stomach.
(indistinct chatter)
-What secrets will they find inside? -(Luke groans)
And could its contents hold the key to this creature's death.
-One, two, three. -(both grunt)
(roars)
LUKE: We've to spin it around. It's heavy.
-(all grunting) -STEVE: It's heavy.
LUKE: Okay, that's perfect.
NARRATOR: Imagine if it was possible
to perform an autopsy on a 65-million-year old dinosaur.
Well, this team is doing just that.
And they're about to examine the inside of its stomach.
LUKE: Let's cut in to see what's inside.
NARRATOR: Already they know this animal didn't die of old age.
-(machine whirring) -But a fractured leg
could've prevented it from finding food.
If it did starve to death, the stomach will be empty.
It's just going till here. Could be bloated.
(Steve breathing heavily) Okay, I'm smelling something.
-Holy moly, that smells. -(Luke coughs)
LUKE: This is unpleasant.
(Luke retches)
-Are you ready? -Let's go.
MATT: Just slide it on.
(all grunting)
STEVE: Oh, I think I'm gonna add to this.
NARRATOR: The stomach is brimming with partially digested food.
TORI: Ugh.
It certainly didn't die starving.
-MATT: No. -LUKE: Come on, guys.
(coughs)
So, what we got here, this is absolutely brilliant.
That big, thick, muscular wall here.
This is just like the gizzard, basically on a bird.
And this bit is the proventriculus.
So it's just like the true stomach.
NARRATOR: A human stomach only has one chamber.
But like birds and crocodiles this T-Rex has two.
Because of the way it eats.
T-Rex can rip off and swallow massive chunks of flesh
without chewing.
(thrilling music)
Muscles propel this meat down the esophagus
and into the first part of the stomach,
the proventriculus,
where powerful acid starts to break up the food
before passing it into the gizzard.
LUKE: So this is the esophagus here, okay?
So this is where the food comes in here first,
proventriculus, into the gizzard,
and it will contract that big muscle
just to grind out with the acids in here.
-STEVE: It's a little biley in there. -LUKE: I wouldn't drink it.
-Were you considering it? -It's just mixed up.
(laughs)
LUKE: Into the gizzard...
NARRATOR: T-Rex doesn't chew its food with its teeth,
but its stomach.
Any damage to this vital organ
could spell trouble for the creature.
There's no fresh blood in the stomach, which is important.
There's no signs of ulceration I can see on this stomach lining.
Anatomically, guys, to me, this looks normal.
NARRATOR: Next, the gizzard passes the partially digested food
into the intestines.
where the dinosaur absorbs the nutrients.
-Let's put this guy over here. -TORI: Here you go.
LUKE: Tori, you and I, are going to check out the small intestine.
And I think, just taking a good section here,
it's gonna tell us all we need to know. (grunts)
NARRATOR: A disease or infection could cause death.
LUKE: I don't think anything would've survived going through this.
I wouldn't worry too much.
(Luke groans)
LUKE: It's quite a volume pumping through here.
TORI: Okay. So we just squeeze it out? Mmm.
Oh, lovely.
-LUKE: Look at these bits. -TORI: Mm-hmm.
LUKE: These are worms.
TORI: Amongst this is kind of, you know, goo, which is processed food,
you can see amongst this some...
worms. I need to catch this thing dripping off my finger.
NARRATOR: Intestinal worms are parasites that infect the gut.
and multiply by feeding off the contents of the host's intestines.
When you're inside the gut, this food is all being digested,
and that's producing all kinds of good stuff, nutrients, vitamins.
So it's a great place to live if you wanna be lazy.
And something like a parasite, takes advantage of that.
And if you have too many parasites,
that can cause a real problem.
'Cause it's taking away some of your own food.
And that can make you ill,
it can make you not as energetic, it can slow you down,
make you more susceptible to other diseases.
Question is, could it actually be causing harm to the animal
and therefore, contributing to its death?
NARRATOR: Luke and Tori, want to find out if the parasite infestation
could've been fatal.
Let's see what we have in this disgusting cesspool of a stomach.
NARRATOR: While Matt and Steve are left with the delightful job
of confirming whether this dinosaur is a hunter
or a scavenger.
If this thing is a hunter,
-we should see a lot of fresh meat, right? -Yeah. Fresh meat. Right.
And if it's a scavenger, we should probably see a lot rotten meat.
-MATT: Look here, I don't think... -STEVE: Wow.
...these have been in the gut for terribly long.
-Look at this. It's a piece of bone. -Wow. What's...
NARRATOR: While the guys forage in the stomach,
Tori and Luke want to establish
the cause of the parasites in the intestines.
How did that T-Rex get infested with worms?
The answer is that, obviously it didn't graze.
We've worked out now it's a carnivore through and through.
But it would have got these from eating the intermediate hosts
of these worms.
(ominous music stings)
(growling)
NARRATOR: Depending on which animal a carnivore consumes,
a different organism can infect it.
Tanzanian lions feasting on a wide range of creatures
had 19 different types of parasites in their guts.
Fossil evidence suggests T-Rex gorged itself
on a variety of dinosaurs, including other T-Rex.
One of its main snacks was a herbivore called Hadrosaur.
A tooth found lodged between the vertebrae of one,
belonged to a T-Rex.
(roars)
But was this T-Rex's parasite infestation large enough to cause its downfall.
It's from experience, on the animals I've autopsied
that died from mass parasitic infestation of the gut.
There aren't just a few bunch of worms.
There are literally thousands.
It's really common to get a few worms,
I mean, it's some staggering stat
like a quarter of the world's human population
have some evidence of worm burden.
So I think there's nothing here or in the bits we've seen
to explain why this beast would've died.
So it's not enough in this situation to being responsible
for the death or even the ill-health of the T-Rex.
LUKE: Absolutely. Let's call the guys over
and see what they've got with that stomach. Guys?
-STEVE: Yeah. -LUKE: What've you found?
Well, we've learned a lot from the stomach.
And we've got some goodies. So, stomach is full of meat,
but also full of a lot of broken pieces of bone,
and you can see some of these here.
Wow.
This is part of the foot bone of a raptor dinosaur.
NARRATOR: If T-Rex was like a crocodile,
it would secrete incredibly powerful acid in the stomach,
allowing it to breakdown everything including bone.
The T-Rex doesn't have this ability.
It simply passes it out of it's body.
A fossilized specimen of its feces known as a coprolite,
had pieces of bone embedded in it.
(growling)
But bones weren't the only thing to get through its system.
-There is teeth. -(Tori chuckles)
-LUKE: Wow. -This is a T-Rex tooth in its own stomach.
-MATT: From another T-Rex. -LUKE: From itself?
-Almost certainly from itself. -LUKE: Okay.
So, when they would crunch through bone like this,
they were biting in such a strong force,
that their teeth would sometimes break and they'd just swallow them.
NARRATOR: They've also found evidence that could dispel
one of the biggest myths about T-Rex.
MATT: We get questions all the time:
"What did T-Rex eat?"
"Was it a predator? Was it a scavenger?"
Well, the meat that we found in T-Rex's stomach,
gives us some insight into what it was actually feeding on.
We have pieces of fresh meat,
and are mingled with pieces of rotten meat.
Oh, look at that size, that's really gross.
They're together.
This animal, before it died,
had had a meal of something that was alive,
something that wasn't.
NARRATOR: This reflects the current thinking
that the T-Rex was both a hunter and a scavenger.
You're not gonna turn down free protein when you need
to fuel that sized body.
NARRATOR: Because the stomach was full, this has also cleared
the prime suspect in the death of the T-Rex.
We know it didn't die of starvation.
And that tells us instantly,
that broken leg was probably not the game changer
for this animal at this stage.
But the thing is we still don't know how this thing died.
So guess what, back inside.
-Let's go. -Bet you were gonna say that.
NARRATOR: Luke still believes, the cause of T-Rex's death
is to be found in its inner organs.
LUKE: Back in.
NARRATOR: What they're about to uncover,
will take them by surprise.
-MATT: Spin it around. -STEVE: Back into the belly of the beast.
NARRATOR: Veterinary surgeon, Luke, is about to make his way
deeper into the body of this T-Rex.
I'm just cocooned in solid bone and muscle.
I mean, it's so well protected, the abdomen of this beast.
Not to mention the rock-solid armor-plating of the skin.
The stomach and intestine were healthy,
providing no clues as to why this creature died.
Now, they are investigating the other organs.
LUKE: This here is liver. This is home from home.
This looks incredibly familiar to me.
Basically, it's the chemical laboratory...
Let's get the membrane off... of the body. What it does, it absorbs
all the nutrients in the small intestine.
It removes all the toxins from the blood.
Oh! Matt, you're gonna have to give me a hand.
-Can you grab that? -MATT: Yeah.
NARRATOR: The liver mops up poisonous substances in the body.
Could a diseaed or damaged liver be the cause of death?
LUKE: Careful with all that stomach acid down here.
(grunting)
We're gonna just check the surface for the marks.
These guys wouldn't have lived
long enough, probably, to have got cancer.
There's no trauma to the liver.
The surface's quite smooth. There's no cuts or anything like that.
It does look good, isn't it?
Not seeing a parasitic scar or anything like this.
To me, it looks like a healthy liver.
(grunting)
-TORI: Next up? -LUKE: Check out this thing here.
-We've got the lung. -STEVE: Ah.
LUKE: But do you know what this is?
STEVE: That is an air sac.
This lung is not like our lung at all.
Because birds have air sacs. We don't.
So, it is basically,
-like massive angry chicken. -STEVE: Yes.
NARRATOR: Just like birds,
T-Rex had baloon-like air sacs either end of its lungs.
When T-Rex breathes in,
air enters the lung and the rear air sac.
The lung strips out oxygen and pushes the spent air into the front air sac.
When T-Rex breathes out the rear sacs pumps its air into the lung
extracting more oxygen and forcing the spent gas
out of the front air sac and through the nostril.
Unlike humans, the lung extracts oxygen continuously
throughout the breathing cycle.
This is the most efficient way of breathing in the animal kingdom.
And allows it to perform seemingly impossible tasks.
On the summit of Mount Everest,
there is only a third of the amount of oxygen there is at sea level.
Humans struggle, yet birds can fly at these altitudes with ease.
Their air sacs allow them to extract enough oxygen
to power their wings and continue to fly.
For a seven-ton, forty-three foot long dinosaur,
this adaptation would power its massive muscles
allowing it to dominate its environment.
LUKE: I reckon,
-we should get this lung out. -All right.
LUKE: I'm gonna need some help here.
STEVE: We can make it.
-Watch your head. -(Steve groans)
Okay, let's get this all the way back from here, please.
(Steve grunts)
(grunting)
-Look at that. -Look at that.
(Steve grunts)
STEVE: I wish I could breathe in and out oxygen right now.
-Like a T-Rex. -(Tori laughs)
-MATT: You want this lung? -I want that lung.
NARRATOR: There is no evidence of disease here.
So with one of the two lungs now removed,
the team can get to the next vital organ.
LUKE: Look up there.
I'm seeing something that looks a little bit like a heart.
LUKE: Can we get some light here, please, guys.
Oh, look at that. The heart.
NARRATOR: The heart is the pump that pushes blood around the body.
The bigger the animal, the bigger the heart.
LUKE: Let's cut through some of these vessels.
And free it up.
NARRATOR: And the bigger the blood vessels leaving and entering the organ.
(Luke grunts) We're gonna have to go into the aorta,
the inferior and superior vena cava.
Oh, wow. It's really difficult.
Let's cut through this.
(Luke pants)
Okay, Matt, we're gonna need some muscles here, pal.
Okay. Oh, Jesus, this is massive.
LUKE: Oh, Christ!
(grunts)
(Luke exhales deeply)
Perfect surgery, I'd say.
NARRATOR: But something is puzzling Luke about the heart.
It's absolutely exhausting to be honest.
And it's crazily heavy 'cause it's dead weight.
But typically, in a mammal,
you'd expect body mass of the heart to be 1% of the body weight.
So, in an animal that weighed
about eight tons, that'd be about 80 kilos.
And I'm guessing. That doesn't look 80 kilos to me.
So, what that tells us is that this heart has to be
supremely efficient.
And it's gonna be fascinating to cut inside because,
fish have two chambers in their heart,
lizards will have three chambers,
but birds and mammals have four.
Help out, Steve. Let's have a look at the heart.
NARRATOR: Before they can investigate the inner structure of the heart,
the team need to remove a protective membrane.
-LUKE: Okay, everyone, get that. -(overlapping chatter)
(Luke groans) It's like...
LUKE: Here's a...
So what you see here is the pericardial sac.
It's basically like a support blanket of the heart.
So when the heart pumps it expands within this sac.
And inside, we've got all the rest of it.
And this is absolutely amazing.
Why don't we lift this over, cut it open.
-TORI: Right. -STEVE: All right.
Those guts.
Guts and acid and blood and bile.
Beautiful.
NARRATOR: If it has four chambers, it will be more like a bird than a lizard.
(pants)
LUKE: That's awesome, isn't it. Look at that.
A T-Rex heart.
Honestly, look at that thing.
It's massive.
How could this tiny little pump
get the blood around a beast that size.
NARRATOR: The small size of the heart is a mystery.
The answer might lie in its internal structure.
The ventricles go straight into that.
Here.
(grunts) Oh.
There's gonna be some blood here. Look at that.
MATT: This would be the blood, full of oxygen from the lungs
that'd be sent around the body.
LUKE: Exactly right.
Right. All right! Let's open it up.
NARRATOR: The team is about to uncover
the secret of T-Rex's most vital organ.
Wow.
That is amazing.
NARRATOR: Inside the heart of the most complete T-Rex ever seen,
our experts discovered a strange substance.
This is completely new to me.
Luke, so, talk me through what you're seeing here.
Well, all these stuff here, that we can see, are clots.
-STEVE: Wow. -MATT: Wow.
Moment the heart stops, blood clots. So we would expect clots in here.
This is absolutely fine and, in fact, looking at this right now,
it doesn't seem to be any abnormalities to it.
NARRATOR: But the structure of this organ can help to shed light
on one of the most debated issues:
was it cold or warm blooded.
A clue lies in how many chambers are in the heart.
LUKE: Well, this is a four-chambered heart.
This is incredibly evolved.
And it does tie in as in why this heart,
isn't absolutely massive.
Because being so efficient, allows it to be smaller.
Imagine the divided into four,
and down the middle we got a big muscular section separating them.
So blood comes in from the lungs.
It's oxygenated into the left atrium here.
And it passes through the atrio-ventricular systems here.
These are valves
that go down from the atrium into the ventricles.
Now, this ventricle, look at that wall.
Can you see how thick and muscular that is?
This is the left ventricle.
But compared with the right, it's much thinner.
And the reason is because this left ventricle
then has to compress like that power-house there,
pushing that blood out at massive, massive pressure
to the biggest artery of this guy's body all the way up to the aorta.
And then that... that blood, oxygenated, then goes into all the muscles,
fueling them, giving the energy they need to do their job.
(growls)
NARRATOR: Lizards have a three-chambered heart.
This could never generate the required pressure.
Only a four-chambered heart is powerful enough.
And this system
combined with an incredibly efficient respiratory system,
and we've got just the ultimate,
ultimate efficiency of fueling those guy's muscles in this body.
NARRATOR: Every cell and muscle in the body has a rich supply of oxygen,
allowing them to work at a high rate.
This primes the creature for action.
And also generates heat, warming the body from within.
This is the heart and circulatory system
of a warm-blooded creature like a bird.
Not a cold-blooded creature like a lizard.
Something like a croc or a lizard,
they've to go out to the sun to get warm.
And when it cools down at night they're gonna get cold.
They can't grow as fast, they can't move as fast,
they can't run as fast.
But, birds and mammals have four-chambered hearts.
They're very efficient. They're warm-blooded animals.
They have this internal furnace
where the body temperatures are pretty much constant.
And you need that consistency to grow faster.
So what we're seeing here, to me, with the four chambers we've seen,
it looks like just a super size heart of a bird.
So, T-Rex was probably a seven-ton killer-big bird.
(chuckles)
Well, it's actually funny that you mentioned the big bird thing.
'Cause this thing has been preying on my mind a little bit.
And the bristles that we noted right at the very, very beginning,
and of course, if you say bird,
that usually brings up the idea of feathers.
I'd love to have a better look at those.
-Should we go have a look? -Let's do it.
-We could do the bird. You guys... -Good plan.
-We'll do the killer bit. -Right.
NARRATOR: T-Rex ruled 65 million years ago.
New fossil evidence has revealed a link between dinosaurs and feathers.
Like the ones on our creature.
TORI: All right, Steve.
When we first encountered the beast here,
the looks of these nice little bristles are a little bit reminiscent
-of the slides that we're slowing now. -(chuckles)
TORI: And why don't we pluck one of these out, like that.
I mean, this is so simple.
Yeah. So, you're right. When you look at this,
I mean, it, kind of, has some give to it.
It is, kind of, like a porcupine quill.
Or like hair we have.
And that's not what we think of, when we think of bird feathers.
We think of quill pen type of thing
with a long shaft and all the fluffy bits.
And of course, in birds, they use feathers to fly.
That's not what we're seeing here.
This is a much simpler arrangement.
And this is what we call protofeathers.
These are the ancestral start of feathers.
A lot of dinosaurs, maybe even all dinosaurs, had feathers.
And we know that because of fossils.
We have thousands of dinosaurs.
from China, fossilized, covered in feathers.
And then, because we have so many fossils,
we can trace how feathers change.
Those feathers start forming wings and long arms
in a small animal with big muscles,
and that's how flight evolves.
NARRATOR: Bird feathers evolved so they interlocked
forming a flexible wing.
At seven tons, T-Rex was never going to fly.
(roars)
But birds don't just use feathers for flight.
They're important in display,
and attracting a mate.
Scientists now think
T-Rex used it's feathers in the same way.
These protofeathers on T-Rex give us more evidence
of the bird-dinosaur relationship.
NARRATOR: As the team search for a cause of death,
they're revealing much about T-Rex's life.
Matt and Luke are now investigating the next big question:
"How did this seven-ton carnivore kill it's prey?"
(roars)
If we can understand how it moved, we can understand how it hunted.
If we understand how it hunted, we know how it killed.
(growls)
Here's a deal.
These legs are, kind of, a funny chimera
because you have some bird-like characteristics and the feet.
But you also have some other things going on too.
NARRATOR: Imagine if it was possible to perform an autopsy
on the world's most infamous carnivore "T-Rex".
Our team of experts have so far discovered
the dinosaur didn't die of old age or starve to death.
It's full stomach and powerful heart
have hinted that it was a fierce and active predator.
Now, Matt and Luke want to understand
how it hunts for food.
So did it lie and wait or did it chase?
I mean, these muscles are huge and it's bit, like,
you know, sprinters versus long distance runners, okay.
So the sprinters, generally speaking pretty big guys,
you know, great big muscles, explosive power.
But long distance runners could just go forever.
So what do you reckon?
Did this beast just have this sudden surge of power
and just come out, just get its animal.
But potentially, you could outrun them.
NARRATOR: Predators use ambush and pursuit tactics.
Ambush predators try and catch their prey unawares.
They select a target...
and approach stealthily.
(growls)
Their attack is sudden and short-lived.
Pursuit predators have a very different strategy.
They chase after their prey trying to outpace their victims.
This is a sustained rather than a sudden attack.
So was T-Rex, a pursuit or ambush predator?
Or both?
(growls)
The answer lies in understanding how T-Rex moves.
When T-Rex wants to start moving, first thing that happens,
bam, these toes begins to flex.
They dig into the ground because the calf muscle itself
all the way up in the shank begins to flex and bend
and pulls the toes in. While that's happening,
the big thigh muscle begins to rock back and forth,
powered by these enormous muscles.
And then, the secret to dinosaur locomotion,
that turbo charger, kicks in.
See this group of muscles right here?
This is the caudofemoralis all they way down here.
When this giant muscle group contracts,
it gives the dinosaur a lot of leverage,
powerfully pulling the knee back towards the tail tip
pushing a T-Rex forward going after Triceratops
or getting away from the Triceratops.
But that's how T-Rex moved through the world.
NARRATOR: But were these giant muscles primed for speed?
Could this T-Rex outrun its prey?
Or would it have taken its victim by surprise.
One person who knows the answer is scientist John Hutchinson.
JOHN: Animals don't move using just their bones.
A dead chicken, it's skeleton won't get up and walk around on it's own.
It needs the muscles, the tendons, the nervous system ans so forth
that actually generates movement in real, live animals.
NARRATOR: Fossils rarely preserve soft materials like muscles.
But they do contain clues to where these tissues existed.
What we have here is the right thigh-bone or femur of a T-Rex.
It's been scaled down by a factor of five or so.
But that allows me to hold it
and move around and look at it quite easily.
What we can tell from it right away is, it's got a hip socket right here.
So its got thisbow and socket joint that allows the hip to move around a lot.
And it's got a knee joint down here, kind of, like ours.
But we've also got bumps and squiggles on the bones
that we call trochanters.
These are where tendons and muscles of the leg attached onto the bone.
NARRATOR: These trochanters revealed
that there are 33 different muscle groups in a T-Rex's leg.
Mapping these connections onto a computer simulation,
John has made his dinosaur walk.
What we're doing with T-Rex is, digitally resurrecting it.
We're bringing it back to life.
Some muscles pull bones in one direction,
and other muscles pull bones in, like, the opposite direction.
(growls)
NARRATOR: These muscles contract in a precise sequence
propelling T-Rex forward.
But how fast could this seven-ton dinosaur run?
JOHN: T-Rex would never been a thoroughbred racerkind of animal,
let alone a cheetah.
Once you try get the model going faster than say 25 miles an hour,
it's not possible.
It would've required ridiculously large leg muscles.
More than we could fit onto the skeleton of a T-Rex.
A T-Rex probably had leg muscles big enough to enable it
to do between about 15 to 25 miles per hour.
NARRATOR: Its huge stature meant that surprise attack was unlikely.
But 20 miles an hour was fast enough to chase and catch its prey.
Like many advanced apex predators
T-Rex would have used both ambush and pursuit methods.
So seven-ton beast of power coming towards you, 20 miles an hour.
Key question: Could you outrun it?
(exhales deeply)
Not on these boots. Could you?
I wouldn't need to outrun it. I just need to outrun you.
Oh, nice. Nice...
NARRATOR: Sixty-five million years ago, T-Rex was at the top of the food chain.
(roars)
Powerful enough to prey on anything.
This mega predator needed 50,000 calories a day
to fuel it's massive frame.
(growls)
Okay, so what we got here is an apex predator.
All apex predators have fantastic senses.
-Right. -Why don't we go to the shop
-and check 'em out. -Let's do it.
NARRATOR: Acute senses are vital for predator survival,
allowing them to identify and attack their prey.
But how capable were T-Rex's?
-LUKE: Hey, guys. -TORI: Hey.
We came here to look at the senses.
Matt, let's start with the eye.
We want to know three key things about these eyes.
First, we wanna know if he's got monocular or binocular vision.
So it sees out of one eye or both eyes at the same time.
We wanna know how good its sight was.
And the third thing,
is if we stood still, could we actually hide from it?
Well, true form. Let's cut it out.
I'll be back in a minute. I'm gonna get some gear.
One thing that I'm really interested in is whether this T-Rex could see in color.
And this has been a big mystery with dinosaurs for a long time.
But just over the past few years we've gotten some clues,
believe it or not, from real fossils.
'Cause if we have colors like we see here on their bodies,
that's a pretty good sign that they could see in color.
-Hey, guys. I'm back. -(chuckles)
You don't look like a bloody clown anymore.
Come on, I'm feeling fresh and beautiful.
-I might not look it. I can't but try it. -(laughs)
Okay, let's get this out.
First, go in-- oh, that is so tough.
Okay.
Have you ever removed the eye of something this big before?
I removed a frog's eye once.
Cow's eyes. Lot of dog's eyes, a few cat's eyes,
but never a T-Rex eye.
Just gently give it some tension.
You do it from this side.
All we wanna do is, we wanna remove the eye intact.
That's the crucial part of how we get to look at structures,
how it works, understand its function.
So I've placed two anchoring sutures here,
which tore him up.
I'm gonna put some gentle pressure on.
I'm then gonna cut nice and big around here
and we'll dissect underneath.
And as they pull it, we should be able to get that eye out.
Now behind the eye,
is gonna be an optic nerve and there's gonna be vessels.
So you might be getting a bit of blood around this.
Let's just see what we've got.
I'm gonna go with the free blade
just to give me a bit more flexibility.
Okay, so just mind your fingers.
Just pull that little bit there.
(Luke grunts)
The skin is actually coming away little bit easy around here.
Which is expected.
Okay, good. (grunts)
So far, this is really similar, this is home turf, removing this.
Only if I can get behind. You guys pull a little bit.
Just get a clamp ready.
-Just lift it up a bit here. -TORI: Do you wanna take that...
We just gotta get this eye out in one piece.
I don't want to burst this eye. It's gonna ruin everything.
Right around. (grunts)
Look at this.
You know this is here.
Optic nerve, okay.
So this massive cable magic like a huge great data cable.
It's taking all the information here,
from the eye,
surging it up this cable which is going to the brain.
I'm just gonna cut this here.
Just going to clamp it there.
NARRATOR: The autopsy team are extracting one of T-Rex's eyes
to see how well it could sense its prey.
MATT: An optic nerve this big, I mean,
this thing must have had great eyesight.
LUKE: And wait, look, there's a bit of blood here as well.
We expect that.
That's fine.
Okay, great. One eye removed.
-STEVE: All right. -TORI: Nicely done.
LUKE: Okay, let's get it over.
NARRATOR: The large optic nerves suggest T-Rex could see well.
(indistinct chatter)
TORI: Okay, this thing, yep?
NARRATOR: Dissecting the eye will reveal its inner workings.
LUKE: Let's see what we've got.
So have a good look at this eye.
We can all relate to this, so let's slice this off.
Let's see what we got.
Get them out of the way.
And then let's just dissect this bit off here.
So how like a human eye is this?
Well, I mean, it's beautiful. It's absolutely beautiful, this eye.
And, like us, there's a big cornea here.
And then you see all that fluid under there,
that's the anterior chamber.
And then beneath that, we can see the pupil lens.
Obviously, we all know, we have a bubble of air
-underneath the cornea here. -TORI: Oh, yeah.
You can see the hume is coming out a little bit.
But, you know what, it just feels a bit...
Tori, have a squeeze at that.
Now, that is something we definitely don't have.
Yeah. It's pretty rigid. Wow. Okay, that's hard.
-Like bone almost. -LUKE: Really hard.
Ring of bone in there, I think.
That's not it. That there is a Sclerotic ring.
So, mammals don't have Sclerotic rings.
But actually these things are much more advanced than our eyes.
NARRATOR: The Sclerotic ring is formed of interlocking bony plates
that hold the shape of the eye in place.
It anchors powerful muscles
that alter the shape of the lens very quickly.
Allowing the eye to change focus in an instant.
LUKE: Guys, look at the little flesh here.
-TORI: Oh, wow, okay. -And there...
It's like an onion ring.
Here's your Sclerotic ring.
So, the muscles will attach here,
and as they contract, it's gonna help it focus its vision
much sharper than we'll be able to do that.
NARRATOR: These thin bones don't fossilize well.
Few complete Sclerotic rings have ever been found.
They're very, very rare. I mean, I must say,
of all the dinosaurs I've dug up and all the ones I've studied in museums
I mean, I can probably count the number
of good Sclerotic rings that I've seen on one hand.
These Sclerotic rings in a T-Rex is yet to be found.
But in T-Rex's cousin Tarbosaurus from Asia,
we do have some specimens that show the same bony eye ring.
LUKE: Here, we gonna have the lens and this bit here, the iris.
The iris controls the light levels getting into the eye.
And then, if we go through... Look here.
Can you see... Oh, that's just magic. Look at that.
That's what they do. That's exactly right.
This is the lens.
Just feel how lovely and smooth that is.
It's just great. So the image is focused through that lens
onto the back of the eye and to the retina.
And then through that it travels down this thing here,
the optic nerve, the massive data cable that powers it to the brain.
Right in to what's called the optic lobes.
These parts of the front of the brain
where all of that information from the eye is processed.
And in Tyrannosaurus, those are really big.
So that's another sign they had a good sense of sight.
NARRATOR: T-Rex didn't just hunt with its eyes.
It may have been extinct for 65 million years
but the latest technology is uncovering new information
about its other senses.
And they're just as remarkable.
(growls)
One of the amazing things is that we can use CAT scanners
to study senses in dinosaurs.
-Very high powered X-ray? -Yes.
We can do that with dinosaurs skulls.
So we actually have very good evidence
from CAT scanners of what a T-Rex brain would've been like.
The brain of the T-Rex was pretty big
in relation to its body size. That's what's important.
If you're really big, you're gonna a big brain,
but it's not a relationship to your size.
So there's a measurement a statistic that we can use to put a number on that.
And it's called an "Encephalization quotient"
or EQ for short. (chuckles)
And it's just a measure of brain size to body size.
The number in a Tyrannosaurus is about 1.2.
It was a pretty smart animal.
NARRATOR: T-Rex is more than twice as intelligent as a crocodile.
The CAT scans also reveal its other senses prime T-Rex to detect prey.
Massive nasal cavities gave it an acute sense of smell.
An amazingly large inner ear
allows it to hear sounds over huge distances.
T-Rex have the senses of a perfect predator.
So they were pretty smart beasts.
'Cause they had to process all this information
from really complex eyes with great senses.
And let's pretend I'm smelling absolutely lovely,
a lot easy to imagine.
And I'm quiet as a mouse.
And I see the T-Rex coming around that corner
and I decide to stand still. What are my chances?
I think you've maybe seen this in the movies.
This idea, that if T-Rex is chasing you,
stop, stand still and I can't see you.
But, that's just movie magic.
Like us it had binocular vision, it had depth perception.
NARRATOR: Impala have eyes on the side of their head,
allowing them to see in nearly every direction.
Perfect for spotting approaching predators.
Ambush predators like crocodiles,
often have a similar field of vision.
Their eyesight overlaps only slightly over its snout.
Here, it sees with binocular vision.
In this narrow arc, perception of depth and 3D shapes is increased.
T-Rex had a far wider field of binocular vision,
giving it a superior ability to detect and attack its prey.
Even if its target was standing still.
(roars)
And so, if this T-Rex was chasing you,
he would see you and he would eat you.
Okay, Steve.
That was all very, very convincing except for one slight thing,
-Yeah. -You keep saying "he".
Okay, T-Rex,
-King of the dinosaurs. -King of the dinosaurs.
Except, we don't know about this creature, was it male or female.
-That's right. -He-rex or She-rex,
that's something we need to find out.
That means it's a waste of time changing my scrubs, wasn't it?
-(Steve laughs) -LUKE: Let's have a look, find out.
NARRATOR: It's time for the team to sex the rex.
If they discover it's sexually active,
they will know it's generally healthy.
And if so, what can they rule out as its cause of death.
(roars)
(chain rattling)
TORI: That's good. Now that's out of the way.
Down here, it's where you might expect, were it a male,
to find a penis.
At least if you were a mammal, you would.
This, of course, isn't a mammal.
It's something that's related, we think, to a bird.
And birds, some males have penises and some don't.
So the absence of the penis here doesn't tell us anything
about whether this is a male or a female whatsoever.
-(Tori grunts) -Look at this.
NARRATOR: The T-Rex autopsy team is exploring this creature's anatomy
to find the cause of death.
Now, they want to sex it.
This could uncover how the seven-ton dinosaur mated
and possibly how it died.
TORI: Here, we have an opening.
And this opening, if I get inside
I'm gonna figure out. See what's going on.
Now, this is what is known as the cloaca.
It's a single opening
where everything comes out. So, the waste products, the wee, poo,
things like that. But also sperm, and if it was a female,
that's where it would pop out an egg.
So, having a feel in here might give us some clues
as to what we're dealing with, male or female.
One thing though, that really interests me, as I'm...
in here, having a bit of a feel, it's really tight actually.
I can't get my arm up.
As of here, it's probably actually what I don't know about is
if there's any fossil evidence at all
for T-Rex gender.
With dinosaur fossils, lot of bones,
sometimes if we're lucky, feathers, muscles, skin.
But as far as I know, dinosaur genitals, never.
So I think this is one of the biggest mysteries.
When we find a dinosaur, is it a male, is it a female,
we just can't tell.
Yeah, and of course in birds,
the difference is that the ones who don't have penises
when they're having sex,
they have to push their cloacals up against each other.
It's called the cloacal kiss.
NARRATOR: In some birds, mating is a balancing act.
The male mounts the female.
But if he doesn't have a penis,
he has to transfer the sperm by contact.
This is the cloacal kiss.
Imagine trying to do that with a seven-ton beast.
-STEVE: Seven times two. -TORI: Yeah, quite.
Elephants, like a big male African elephants weighs seven tons.
And you can't imagine that happening.
I mean, there really is nothing I can feel in here.
It just feels like a tight passage
where I've got no identifying features whatsoever.
So I'm really sorry, Luke.
It's back over to you.
There's only one way we can ask this question.
Nothing is going in at the other end from the inside.
Okay, back in the office.
-Steve, grab a light. -STEVE: All right.
-LUKE: Join me in. -STEVE: I'll follow you to hell and back.
(chuckles)
NARRATOR: Luke and Steve are entering the abdominal cavity
to search for reproductive organs.
STEVE: Back into the belly of the beast.
I don't know what I'm looking at. So you gotta explain.
Let's cut through this. (grunts)
This looks very familiar.
All we gotta do is we gotta find whether it has testes,
internal testes like elephants, for example, have internal testes
or ovaries.
And the only way to do that, is have a look
at few more of these internal organs that we haven't yet checked out.
So I'm just cutting through
here, to look inside
and see what this is in exactly the right place.
And oh, my goodness me.
STEVE: What do we got?
LUKE: Well, what this is, is an ovary.
-STEVE: All right, female. -So he is definitely a she.
-So she would've hunted you down. -She. Yes. Yes.
Thanks for that, Steve.
Birds generally only have left ovaries. They're born with two but one
is pretty much just visual, it doesn't really do much.
We think that happened in an evolutionary sense.
Because as birds started to fly they needed to lighten their skeleton.
And they lost one of the ovaries. That's what we think.
Brilliant. So did... did dinosaurs have two ovaries or one ovary?
(clicks tongue) Well, we don't know directly because
we don't find fossil ovaries. But what we do have
are the eggs. And because eggs of dinosaurs,
including very close relatives of T-Rex are laid in pairs,
that's a pretty good sign they had left and right ovaries
both laying eggs at about the same time.
LUKE: So look how it works here, right?
All of these are basically eggs to be.
-She would ovulate, right? -Okay.
And the ova, would travel down the oviduct
and it moves down. Look at the thickness of this.
NARRATOR: In birds, when a follicle is mature
it bursts and releases an ovam from the ovary into the oviduct.
If it encounters a male sperm they fuse to form an embryo.
As this travels down the oviduct,
cell adds layers of supporting protein. The white.
This protects the embryo and provides it with water.
It then enters the uterus
whose walls spin the embryo downwards.
Finally, specialized cells
secrete calcium carbonate onto its surface forming the eggshell.
So guys, could you just have another really good feel.
and just see if there's anything up there at all
because was definitely ovulating here.
TORI: No problem. I didn't quite get my arm up quite far enough.
Okay.
This time we're really gonna put our backs into it.
MATT: All right.
What are you feeling in there?
The walls look like they're really, kind of,
gripping onto my arm.
Are they soft, the walls of the cloaca?
Strongest support fucking you could ever imagine.
-Wow. -And oh, okay, yeah.
-Something hard? -Yeah.
But I can only touch it with my finger tips.
Yeah. I just need some forceps
or something, so I can extend the length of my arm.
All right, let me go find something.
Awesome, thank you.
(grunts)
The very tips of my finger tips, I can feel something solid.
But because I couldn't really get my fingers around the edges of it
or get any kind of traction,
I couldn't really get the sense of its shape.
Forceps hopefully, I'll able to get around it,
give it a tug and draw it out.
-Luke? -LUKE: Yeah.
Could you come out?
I'm going to go with the forceps
so I could do with a little bit
of veterinary instructions at the same time.
LUKE: You found something?
Coming for her.
Okay, put them in close, just slip 'em up a little bit
and then part them as far as you can.
-All right. -LUKE: And then tease them around it.
Once you're right around it should be quite stable.
Did you get around it?
(suspenseful music)
-Think you got it? -TORI: I think so.
LUKE: Ease it out.
-TORI: Right. -LUKE: Slip it down.
TORI: Something coming.
You've seen that?
I could see something.
I could see the head!
It's coming.
-LUKE: Take it out. -TORI: All right.
Slowly, slowly, you had it in position.
LUKE: Just in case.
-LUKE: Got it? -TORI: I think so.
NARRATOR: Tori is trying to ease an object from the cloaca of the T-Rex.
The team has discovered this is as a she-rex.
And she's fertile.
TORI: God, look at that.
-Oh, it's beautiful. -LUKE: Brilliant job.
NARRATOR: It's Tori's job to deliver the baby.
TORI: I could do the last bit with my hands.
LUKE: Yeah, yeah, do it.
Beautifully done.
Great.
TORI: So it's still coming as well.
Okay. That's much more elongated than I expected.
-LUKE: It is like a torpedo. -TORI: It is, isn't it?
-Oh, look at that. -LUKE: Check it out.
STEVE: That's beautiful.
TORI: Beautiful as it is.
Think we really ought to crack it open to look inside.
Okay, I'm gonna hold right here. I just...
We haven't got a cause of death.
Everything so far just checks out great.
And... and we're missing the tricks
so I'm just gonna have another look around.
You guys get into that.
(fiber saw whirring)
NARRATOR: The team decides the quickest way into the egg
is using a fiber saw.
At the T-Rex, Luke thinks that he's found some new evidence.
Something that could explain how the dinosaur died.
LUKE: It's brilliant news about the egg,
but not laying that egg didn't kill her, you know.
And I still don't know why she died.
Definitely missing the trick.
And we cannot leave without knowing what resulted in this.
We know she was eating. She didn't starve to death.
We know all her internal organs checked out fine.
There's no massive disease process going on
that would've slowly given her chronic illness
and brought her down. There's something else going on.
And I just remembered when we found that leg,
the only clue I had was just that bit of give,
that bit of crepitus under the skin.
And I come back here, I'm getting the same thing.
You see, here, that it's quite tight.
It's just rock solid.
Whereas just here, have a look, you see a sweep of the muscle,
and there's a slight bulge here, just slightly goes up.
And that's odd 'cause she's flat lying down.
And if you push, can you see that?
That just gives a bit more, doesn't it. Just there.
And it's exactly the same sort of feeling as I got
when I checked out that leg.
So what we've gotta do is check this out.
Because if there's neck trauma,
then that potentially is life-ending situation.
And that could mean sudden death.
NARRATOR: Luke calls in the radiographer to scan the beast.
KAT: X-rays.
(fiber saw whirring)
Thank you.
-Okay. -Wow. Well, this is the moment of truth.
This is...
Oh, wow.
Now, I don't wanna crack this yolk while it's going over.
That's all the white coming out.
Must be a couple of liters.
-(chuckles) -Wow.
Clearly this isn't a very well-developed embryo.
So its only gonna be a few days old at most.
What you can see, is the white around the outside
that you'd expect in a chicken egg.
And then, of course, it's broken yolk in the middle.
But within that yolk, this is the red spot just here.
This is the exciting bit of business
because this shows that the eggs been fertilized.
'Cause this is the germinal disc.
-Germinal disc? -And tiny
and unprepossessing as it is,
from tiny things great things born.
We're gonna go from this, all the way to that.
(chuckles)
MATT: Hey, Luke. Come here. You gotta see this.
-What have we got? -TORI: Come over have a look at this.
-Scootching over to. -(laughter)
-You're gonna like this one. -Oh, brilliant.
Absolutely brilliant.
So she definitely was pregnant then.
-TORI: Look at that. -LUKE: Awesome.
Very, very good. I wonder how long.
The incubated eggs form in a chicken.
Incubated eggs are about 24 days and in ostriches it's 40, so...
It's not the size of an ostrich egg, right?
-Not too far off. -TORI: Yeah. good shape.
NARRATOR: If the T-Rex embryo developed in the same way as an ostrich.
First the nervous system, heart and spine would form.
Then its limbs.
And finally the skin and claws.
See, chickens lay an egg every day.
Every 24 hours they pop an egg out.
Did they sit on their eggs? Do you know? I...
Something like that "sitting on its eggs". Maybe.
(chuckles) If you could imagine.
Other dinosaurs though, we know, did.
Small dinosaurs. The very bird-like dinosaurs with feathers.
And not only did they sit on their nests
but they used their feathers to protect their eggs,
to guard their eggs just like birds.
So maybe T-Rex did that too.
We haven't actually found a T-Rex nest or anything
really that size. But if it did lay big nests,
and I'm sure it obviously did,
it must have had to excavate a large crater in order to lay its eggs.
Could it sit on that though?
That's a lot of mass to put on the little thing.
-So I don't... -STEVE: I'd like to see that.
Hey, you know what. I found something too.
-Come and have a look at this. -STEVE: All right.
NARRATOR: With the discovery of a healthy reproductive system,
the team is still no closer to finding the cause of death.
But has Luke found something significant near the neck?
Guys, I found a small swelling on the neck,
so I asked Kat here to run a few more X-rays for us.
Imagine if it was possible to perform an autopsy
on one of the world's largest carnivores,
Tyrannosaurus Rex.
(chainsaw whirring)
A team of experts has dissected the creature
in a quest to find the cause of death.
All right. (grunts)
NARRATOR: Its full stomach revealed it didn't die of starvation.
(Luke grunts)
But its contents showed T-Rex was both a hunter and scavenger.
LUKE: This is not pleasant.
These are worms.
Look at their size. That's... that's really gross.
This animal, before it died,
had had a meal of something that was alive and something that wasn't.
NARRATOR: A loose tooth showed no signs of infection.
But revealed it had the teeth of a reptile.
I think T-Rex could've easily...
It probably could've bitten through your Land Rover.
NARRATOR: When they cut into the belly, they encountered a second set of ribs.
This feature, that's a croc feature.
NARRATOR: They cut into its heart to find signs of disease.
And found it had the heart of the bird.
STEVE: Wow.
...proventriculus.
NARRATOR: A stomach that chews food.
LUKE: ...which will contract that big muscle
just to grind out all the acids in there.
NARRATOR: Specialized bird-like lungs that power its giant muscles.
-Look at that. -(grunts)
NARRATOR: They discovered a leg fracture.
And the king of the dinosaurs ran on its tip toes.
STEVE: There's nothing croc-like about this.
This looks like an overgrown chicken.
NARRATOR: And something else.
These are the ancestral start of feathers.
NARRATOR: T-Rex's closest living relatives aren't crocodiles but birds.
Veterinary surgeon, Luke,
thinks he might have a new lead as to why this dinosaur died.
-LUKE: Kat, how did it go? -Got some nice pictures.
Did four or five through the mac and I've just pasted them together.
I'm just on the way over.
We can see here, guys. Look at this.
This clean break through the neural spine here.
But the fracture line going through the vertebral body
and that with several spinal cords just broken clean.
She would've stopped breathing instantly,
and that would've been death. No coming back from that.
And it ties in, sadly, but it does explain that
huge trauma in the back leg, the clean break there.
And then there was quite a bit of blood inside
wasn't there, we were around and that would explain a big trauma on a fall.
And I guess she landed on her neck, broke it. Game over.
(dramatic music stings)
Really sad but, you know what, this isn't actually a story of death.
The real treasure in this is the story of life.
And how was anything but primitive.
Natural fact, she was one of the greatest and most evolved predators
in the history of planet Earth.
NARRATOR: For our experts, after years of studying bones,
the opportunity to dig into the flesh of a T-Rex
was the dream of a lifetime.
TORI: Just getting the chance sort of, you know,
get to grips and see in three dimensions
is just supremely helpful in terms of understanding what's going on.
MATT: I'm used to working with dry dead bones.
I've never gotten this filthy, dirty, disgusting in my entire life.
Climbing in to a Tyrannosaurus Rex cadaver,
that sort of close proximity, it's... it's indescribable.
You just have to see it to believe it.
This is so much different from digging up bones out in the desert
which is what I usually do.
I think the heart, maybe more than any other organ,
really told us about how this dinosaur lived.
This wasn't a little lizard. This was a big bird.
You come in to contact with people in different spheres of life.
You know, I'd never, sort of,
had the pleasure of bumping into these guys
or working with them normally.
You know, we work in completely different worlds.
And coming together and getting a lot of bounce
and having a good crack with it.
It's just great.
I now can tell my kids stuff about T-Rex.
Thanks to Matt, Steve, and Tori, you know, for getting loads.
NARRATOR: This ground breaking creature took six months,
and over 10,000 man-hours to build.
It was modeled on the most complete T-Rex skeleton ever found
with scientific input from the world's leading experts,
pulling together all their latest theories
into a practical anatomically correct creature
has allowed our team to see T-Rex
in a whole new light.