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Language: en
T-Rex is definitely weird even compared
to all the other giant tyrannosaurs that
are very closely related to it because
it is by far ludicrously by far the
largest carnivore in its ecosystem.
>> So it doesn't really have competition
actually.
>> I mean so so this is a velociraptor
skull. There are some carnivores that
are a bit bigger than this but not
enormously so. Um which we're knocking
around as T-Rex. the the skulls the same
time tooth crown, right? But but like
you think about that
>> and that's like going
that's like going to Africa and going,
"Okay, there are lions. What's the next
biggest predator?" And it's like, "Well,
there's a weasel about this big."
>> Yeah.
>> Like it it's that kind of size
difference. And you don't get that
normally in ecosystems.
>> It would eat those the juvenile of the
herbivore.
>> Yeah. It's going to be eating
Triceratops, Edmontosaurus, and
Parasauralus. There's even a couple of
giant sorapods knocking around in some
places. It's It's going to be hoovering
them up. But like, how often is it going
to eat? Again, Velociraptor isn't there,
but how often is it going to eat
something the size of an adult
velociraptor? I mean, they're a fraction
of our size, and we're probably too
small. This is like lions hunting mice.
Like, you're just not going to unless
one like virtually runs into your mouth,
you're not going to go and try and eat
it.
The following is a conversation with
Dave Hone, a paleontologist, expert on
dinosaurs, co-host of the Terrible
Lizards podcast, and author of many
scientific papers and books on the
behavior and ecology of dinosaurs. This
was truly a fun and fascinating
conversation. This is the Lex Freeman
podcast. To support it, please check out
our sponsors in the description and
consider subscribing to this channel.
And now, dear friends, here's Dave Hone.
Let's start with the T-Rex dinosaur,
possibly the most iconic predator in the
history of Earth. You have deeply
studied and written about their
evolution, biology, ecology, and
behavior. So, let's uh first maybe put
ourselves in the time of the dinosaurs
and imagine we're standing in front of a
T-Rex. What does it look like? What are
the key features of the dinosaur in
front of us?
>> It's gigantic. It's almost trite now
because everyone knows T-Rex is massive.
But yes, if you actually stand in front
of one, you would be seriously impressed
just how absolutely vast they are. Um,
so I've got a copy of a T-Rex skull
downstairs from my office. And yeah, I I
could fit comfortably through its mouth.
So it would be just about capable of
swallowing me whole. And I'm a pretty
big guy.
>> Your body you can fit in.
>> I can fit through I can fit through it.
>> Wow. Oh,
>> and it's not even a particularly big
one. It's a copy of the one that's in
the Smithsonian. And they get bigger
than that.
>> You have a two scale copy.
>> Yeah. Yeah.
>> Of
>> Yeah. It's a It's a car. So, it's just a
giant mold made and then
>> pulled out like the dentist do your
teeth, but very very big. So, yeah, they
are
12ish meters long. So, what's that? 14
yards.
Four and a half maybe five to the top of
the head standing up. So, another six
yards high. And then
7ish metric tons. What's that about 8
and a half short tons? So a colleague of
mine, Tom Holtz, described them as an
orca on land. That that's it. It is a
killer whales sized animal but on legs
on land. And those are massive
predators. So you're looking at
something absolutely colossal. And I
think that is what will stun you. I
think people don't realize how big a lot
of animals are, which sounds weird. Um,
but I used to work in a few zoos and
something I think you notice is when you
go and see things like elephants or
giraffes or rhinos, everything's built
to the scale of the animal. The elephant
house is huge, the doors are huge, the
bars are huge, the food is huge, and so
you don't see them in the context of
something that you have a good frame of
reference for. And I learned this, yeah,
when I was at London Zoo and was going
into the basement of the old elephant
and rhino pavilion and a rhino stuck its
head out from like this gap in the wall
and the head was twice the size I
thought it was once you stood next to
it. And the same with an elephant. I
once stood next to an elephant closer
than you are to me now and you go, "Oh,
oh, they are so much bigger than I
thought." And I think it's similar in
museums. Like even when you get up
relatively close to a T-Rex skeleton,
there's a bit of space between you and
it and then some bars and then it's
usually raised up a little bit on a
mount on a little mount to hold the
platform and then you stand back from
that and you don't actually get to stand
like under them. And when you do that,
yeah, you realize that Yeah. the the
foot finishes at my knee.
>> So is a T-Rex bigger than an elephant?
Would that be fair to say?
>> Yeah. I mean, a a very large savannah
African elephant is five to six tons and
we're looking at seven plus
>> and a biped and a carnivore. So, yeah,
you know, a a big lion a big lion is 200
kilos, so 430 lb.
>> Yeah. Well, that's what that's why I
mean it's widely considered to be
probably the most epic uh predator in
the history of Earth.
>> Yeah. I mean, and I think more than
that, it's I think it's one of the most
iconic animals, period. I mean, if you
if you're listing things that the
average person has heard of, lion,
elephant, giraffe, tiger, hippo, rhino,
there's a few more, but T-Rex is coming
somewhere up in that list. That that's
how prominent it is as an animal. So,
yeah, it's it's almost inescapable as a
paleontologist. And then doubly so for
me who works on dinosaurs and doubly so
again because I do work on tyrannosaurs
that yeah it just dominates
conversations.
>> Well some of the other features maybe we
can go through. So big skull, big head,
small hands,
>> massive head, very kind of boxy. It's
very robust. Um big forward- facing
eyes. Massive eyes. Massive m I mean
tennis ball sized eyes. These things had
amazing eyesight. Um, yeah, giant teeth.
There's a cast of a
>> what?
>> Tyrannosaurus Rex tooth. Yeah, I know.
So, it it it looks a bit bigger than it
is. So, this is all root. So, this would
be stuck in the jaw. This
>> tip part is the tooth.
>> The the tip as you call it and Yeah. Um,
you know, so that would comfortably go
through pretty much any bone
>> and then you realize just how thick it
is. So, this is a cast of a thing called
Cararodonttosaurus from um Africa. You
get it down in Nishair and a few other
places like that
and they're very very big. Not as big as
T-Rex but not a million miles away. And
then if you look at the teeth in
profile, they're a surprisingly similar
shape and not far off in size as well.
And then you look at them that way on
and you realize it's a third of the
width. So this isn't just massive, it's
thick. And of course being thick, it
makes it strong. And with that giant
head, with all that extra bone and then
all the extra musculature attached to
that giant head, they've got this uber
powerful bite and the ability to just
chomp through basically
it it wants to. Um, so yeah, they they
are truly unusual in that regard. Even
actually compared to a lot of the other
very big tyrannosaurs, they're often a
kind of step above in their proportions.
>> So incredible crushing power in the jaw.
>> Yeah. And then as you say like this
really short bull neck because you've
got this massive weight of this head up
front so you need to hold it up and not
tip forwards. Um really quite a massive
body. Again there's two or three other
big carnivorous dinosaurs which people
argue oh maybe they're a little bigger
than T-Rex. Maybe they're a little
smaller but it's always in terms of
length which is one way of looking at
things. You know pythons are very long
but they're nothing like as massive as
yeah lion or a tiger. Same thing. T-Rex
is massive. it is built. So really big
kind of barrel-shaped chest making the
body very very big as well. And so
that's why yeah there's things like
Gigonosaurus and Maposaurus from South
America maybe they get a bit longer
another meter or so in length but in
mass we're talking about maybe only 2/3
3/4. So T-Rex is just massively bigger
than basically any other big carnivore
we know of. Um and then yeah little arms
as you say. So, this is a not great, but
it's a cast of a T-Rex arm. It's not the
biggest animal. They do get a bit bigger
than this. Um, but as I love showing it,
it's not a million miles off the size of
my own. And I could do with a diet, but
I don't weigh seven tons. So, yeah, it
really is really pretty small.
>> Two claws, two fingers.
>> Yeah. So, two fingers. Some You'll see
sometimes that they say there's a third.
This is a slight misnomer. So you do see
this extra little bone here. This
doesn't turn up in all of them and it's
an extra hand bone. So it's these the
metacarpals, but it's not supporting an
extra digit.
>> So mostly functionalitywise it wasn't
very functional.
>> They're not doing very much at all. Um
you know you've this is what's called
the delto pectoral crest. It's really
important for basically big arm
movements because it's deltoids and
pectorals. Um the radius and ulna are
really quite thin, thinner than ours.
The fingers are pretty stocky. The claws
look big and curved and they are, but
other tyrannosaurs and indeed other
carnivores generally much more curved
claws. And then they have um these
little things. Where can I say it? There
you can see there's a little mark.
That's a ligamentous pit. And so what
you can imagine is if you're trying to
hold on to something and something's
wriggling, you want grip.
>> Mhm.
>> And there's a risk that you just like
dislocate your fingers. So we have
ligaments that hold bone to bone and if
you just put it flat to flat surface
area there's only so much you can
attach. Whereas if you turn that into a
little hemispherical dip you get a lot
more surface area for your area if that
makes sense.
>> So if you have a really big ligamentous
pit it means there's a really big
ligament which means your fingers are
really strong and they're really
resistant to being wiggled around and
pulled as if you know you've grabbed
something that doesn't want you to kill
it. Well, T-Rex has probably the
smallest ligamentous pits of any
Tyrannosaur.
So, that kind of suggests it's not doing
very much. And again, when you look at
the claws proportionally, they're not
that big and they're not that curved.
So, even though it looks like quite a
wicked thing to us, remember, put this
on a 7 ton animal whose individual teeth
are the size of entire fingers.
Suddenly, that arm doesn't look like
it's doing very much. What about the
feet? So massive. Again, not
surprisingly, you're supporting a
colossal amount of weight. Um, but they
have this beautiful adaptation in the
foot. So, the equivalent bones in the
foot, the metatarsils, so for us, make
up the flat of the feet, but these
animals walk like birds. They got three
toes on the ground and then the
metatarsils stick nearly vertically.
That overall extends the length of the
leg. So, you can walk a little bit
faster. You get a slightly bigger stride
length. Um, don't worry, I've got the
right bone here.
Nice. But they also have Yeah, there's a
good one. That one's a great one. Um,
but they also have this really neat
adaptation in the middle bone. So, you
can see it on this one quite well. And
then this is actually not a tyrannosaur.
This is an ornithmosaur.
Um, so one of the really ostrich-like
ones, galaminus from the first Jurassic
Park. Um, it has the same thing. You can
see the normal bones would be really
quite long and square and then flat at
the top. and instead this thing shrinks
in the middle and turns into this kind
of flattened diamond shape. And what
that means is
the bones either side kind of lock it.
In fact, at the top end, it actually
tends to wiggle a bit. So, actually goes
left and then right. And of course, what
that really does is then help these
things lock together. And so, this is an
adaptation to basically lock the foot
and make it stable. And we see it in a
whole bunch of things independently
evolved. Early Tyrannosaurs don't have
this. early or minus don't have this.
The over at Tauros, the early ones don't
have this and the later ones acquire it.
And a couple of other groups as well.
And it's about making the foot stable.
And what that really does is make the
foot energy efficient. So you can
imagine as an animal, you know, we we
have some cartilage and we've got some
ligaments and tendons joining all the
bones together and holding joints
stable. When you push down, that's going
to compress them to a little degree. And
when you lift that weight off, they're
actually going to spring back. You're
going to get a tiny little energy
return. It's the idea of those aerosols
they put in all the trainers and stuff
in the in the '9s. It's that same
principle. And you will you'll get a
little bit of energy return. But of
course, big force, particularly for a
big heavy animal, it's going to take the
kind of path of least resistance. And so
if your bones are all kind of loose in
the foot, what they're going to do is
they're going to tend to spllay out and
you're actually going to lose that
energy. But if you lock the feet
together, the bones can't move. And
instead, that's going to further
compress those soft tissue bits and give
you a bit more spring. And this is all
about I mean, this is about the
mobility, about the dynamics of the
movement.
>> It makes you more efficient. It means
you're putting less energy in to walk
because you're just getting a little bit
of spring off every single step. Uh, I
should say that I deeply admire people
like uh Russ Dedric, like the Boston
Dynamics teams, like uh the Tesla
Optimus robot teams that look at Bipedal
and Quadropeds robot movement. Yeah.
>> And they tried to make
>> humanlike movement to, you know,
basically efficient movement. And so the
question here is how the hell is a T-Rex
its size bipeedal able to move as a
predator? It's a weird body shape, is it
not? I mean the big head makes it look
more odd. But you look at dinosaurs as a
whole and over a third probably 40 45%
is the group called theropods which were
all bipeds. So T-Rex, Allosaurus,
Velociraptor, Spinosaurus, many many
others that people may have heard of.
They're all bipeds built in this way.
There's a whole bunch of ancestral
groups which were doing something very
similar including various crocodiles or
relatives of crocodiles. And then the
birds are bipeds. Um, birds are actually
doing it in a much weirder way than
theropods are. The the therapods are
basically a lizard on its back legs.
I'm oversimplifying a lot. I can hear
paleontologist screaming as I've just
said, it's a lizard standing up. It's
not a lizard standing up. But they're
doing a lot of the same stuff in the
same way. And that is really
functionally about where you put
muscles. Because what you really want to
do to walk forwards is you want to
basically pull the leg back so that
you're pushing the body off.
>> And the way they do that is the
musculature on the tail. So we don't
have a tail. And indeed mammals that
even do have a tail, you know, elephants
and even lions, you know, it's a piddly
little thing. There's not a lot of
muscle there. But if you look at a
lizard, particular if you look at
something like a crocodile, you see this
massive, massive block of muscle sitting
on the first third to half of the tail.
And that's what dinosaurs are doing.
It's the same thing as lizards and
crocs. They have this giant set of
muscles on the first half of the tail
that's anchoring on the femur, so the
thigh bone on the back of that. And
muscles contract. That's the one thing
they do. But now you've got a giant
muscle. Yeah. and T-Rex. This this
muscle is like two and a half, three
meters long.
>> It's going to be like this wide in the
middle.
>> So when that contracts, the leg goes
back, the foot stationary on the ground,
so the animal goes forwards.
>> So the the tail is integral to movement.
>> So it's a huge part of the biomechanics
of the movement.
>> We do it with the butt. So, we're kind
of weirdly how we organize our muscles,
but there's a this is generally probably
a better way of doing it because you can
get a really long muscle. Of course, the
longer the muscle, the more contraction
you can have. The hyper version of this
is kangaroos. So, kangaroos supposedly
get more efficient the faster they move.
They get so much energy return that when
they're moving faster, they get more
compression from the landing, meaning
they get more spring. So, we should be
imagining this gigantic thick tail, big
body, big head.
>> Yep.
>> And uh biped. And how fast does it move?
>> So, this is one of those things that's
gone backwards and forwards and
backwards and forwards. There was a
paper arguing that we've probably been
overestimating various speeds primarily
based on footprints. Um there's been I
don't know how many papers trying to do
T-Rex speed. The most recent one that
was pretty detailed I think had it
clocked at so I think it I think it was
25 miles an hour. So 40 kph was the very
upper end of the estimate. So probably a
bit less than that.
>> Well that means it can move.
>> Yeah. So
that's the but that's the thing like big
things move quick. I've seen Rhino and
Hippo going at full tilt and Yeah.
They're a lot quicker than you'd think.
Um, and at least part of it is simply
stride length. When your legs are 3ish
meters long, it's hard not to cover a
lot of ground with a single step. Um,
and yeah, big big therapods T-Rex is
going to be a power walker. It's not
going to run in the conventional
biomechanical sense where both feet are
off the ground at one.
>> So, it's not running as power walking.
>> Yeah. But when you've got a four or five
meter long stride,
doesn't really matter whether you're
airborne or not.
>> Power walking. So you're never So
running there's moments in time when
both feet are off the ground. And you're
saying likely here one foot is always on
the ground.
>> Yeah, it pretty much has to be for
loading.
>> Oh, if just because of the mass of the
thing.
>> Yeah. Yeah. Yeah.
>> Okay. All right.
>> The you know that's the origin of
cinema. What's that is whether is where
this is uh Edward Mbridge. So the the
origin of cinema was a bet as to whether
or not whilst running a horse had all
four feet off the ground
>> and no one really knew this for sure.
And a guy called Edward Mybridge, he was
British but he was living in the states.
He was a king photographer and he
basically did what people have seen the
Wowskis do for the Matrix. He set up a
whole row of cameras and set up a whole
bunch of triggers and had a horse run
through them. So, it took loads of
photos and lo and behold, in one of
them, the feet are off the ground. The
guy won his bet. But he also realized
that we already had things like zoo
practiscopes. You know, the little thing
you spin with a with a slit.
>> Uh, so you see them, right? So, he did
that with horses and now you have a
moving photograph. And that's pretty
much the origin of cinema was a bet
about biomechanics. Yeah, it's always a
good question and a bet. And there you
go. You're off the off to the races.
>> Yeah.
>> All right. All right. So, we're standing
in front of this thing.
>> Yes.
>> Uh, how screwed are we, you and I? We're
back in the time of the dinosaurs.
What's the probability of our survival?
There's two big things to weigh up which
are going to be interesting, which is
would they even consider us a potential
meal? Because we know that animals that
have never animals have to learn stuff
and so animals that have never
encountered things before are often
that they don't have a response because
they don't know what their response
should be.
>> We should say during that time there was
not something that looked like primates.
>> No, absolutely nothing. We would look
very weird.
>> We would we would look weird. Yeah. Um,
so you know, there's lots of really cool
records of um, particularly you've got
down in um, Indonesia and stuff where
you've got these insane volcanic spires
and it leads to these tiny little
valleys and people go in there and they
go, "Yeah, the animals walk up to us.
They've never seen a human. They don't
know what it is." So it might look at us
and animals are fundamentally cautious.
It doesn't know if we're a threat. So
maybe it might just find us weird or in
some way, shape or form off-putting and
so we may not even be considered on the
menu. Um the other thing is we might be
too small. Um my suspicion is we're not.
So animals, carnivores typically take
stuff that is much much smaller than
them. despite basically every dinosaur
documentary and movie ever shows T-Rex
hunting an adult triceratops which is
like the same size as it uh and every
documentary you got to have lions taking
down a wilderbeast or even a buffalo
like these are weird and rare outcomes
these don't usually happen the vast
majority of active predation is on stuff
much much much smaller than you I toted
some of this up for a paper I did on
microaptor this really small gliding
dinosaur from China where we actually
have a bunch of specimens with various
stomach contents in them. And we were
coming up with numbers of about like 5
to 20% of the mass being typical, so
prey versus predator. And that's
actually very similar to what we see
with modern carnivores. And it's not far
off what we've seen even with things
like tyrannosaurs where you occasionally
find consumed bones from prey. So if we
put the lower end of that as 5% of the
mass of a T-Rex, we might actually be
okay. Um, if it doesn't consider us
worth the hassle,
then
assuming you're encountering a big adult
and not a half-sized one that maybe only
weighs a ton, then we might be all
right.
>> What would be the survival strategy? So,
the there's a thing that you criticized
not being true that I I guess in
Jurassic Park, uh, not moving.
>> Yeah, it's nonsense. They they can see
really well. Like I said, like T-Rex has
giant eyeballs. People don't realize
that because like whales and like
elephants, it looks small compared to
the size of the animal. But what you're
really important for vision is absolute
size, not proportional size. And
absolutely, their eyes are gigantic.
>> Probably the biggest on Earth at that
time.
>> Yeah. Uh guy called Kent Stevens did a
paper. He's got a really nice graphic of
it. If if you if you just put sdev ns
t-rex
there it's the one with the we go.
That's the one with the with the googly
eyes. That's a baseball or a tennis ball
sized eyeball. And when you think about
the incredible visual accurity of
something like an eagle, which has eyes
not much bigger than ours, think about
what that's going to do. And we we
absolutely know there's been loads of
studies on this in mammals and birds and
other things as well that
basically eyeball size correlates with
visual acuity. And that can fold in two
different ways. It can be like general
sharpness, like how well can you see a
long way away? So, eagles and vultures,
it's really important. Or it can be good
in low light.
>> And I now discovered that there's a
nature was metal.
>> Oh, yeah. Subreddit. Yeah. Yeah. For
gnarly paleo things.
>> Yeah.
>> Yeah. I come across it occasionally
>> for dinosaurs. Let's see what's the top
post of all time.
>> Oh, that's eclipted.
Argentinian farmer recently found a
20,000 years old fossilized crypto.
>> So these are these are giant armadillo
like animals with club tails.
>> Interesting. Wow.
>> Oh, that's black beauty. That's at the
Royal Terrell Museum. So giant eyeballs,
they can either see very well they can
see a very long way in daylight or they
can see very well at night. And my
suspicion is it's the latter. I think
they're probably primarily nocturnal
when when they get that size. Well, not
moving might be a good strategy because
it's cautious because it doesn't
understand what these primates are.
>> Yeah. Um, but I think if it if it starts
coming towards you, if you're truly in
the open, then you're in real trouble.
And I'm not sure what you do. I mean,
the one thing, the one advantage humans
have over almost
anything else on Earth, there's a
handful of exceptions, is we have range.
I can pick up a rock and hurl it with
reasonable accuracy.
Most things can't do that. And animals
probably don't like being hit in the
face or hit in the eyes with a rock at a
range because again, they're not going
to know how it's happened or how to
respond to this. All they know is
they're taking damage, and that's bad.
And that that might genuinely be enough
to do it. I wouldn't want to try, but
again, if I was dumped on a plane or a
prairie with nothing else but a T-Rex
that was interested in me, it's worth a
shot. Um, if you're in the forest, I
would try and get behind a tree. They're
they're quite good at turning. There's
been a couple of nice papers looking at
like the the mechanics of the foot and
the ankle and how quickly they could
like pivot. Um, but we're much better
cuz we're just so much smaller. So, it
it would be very kind of Looney Tunes,
but I think you could go round and round
a big tree, right? Yeah. But much faster
than it could.
>> Yeah. And so
>> it's going to get bored or lack interest
sooner or later.
>> So Luma, what did it eat? I mean, the
you could go for the classic joke of
whatever it wanted, but the reality is
um the relatively big herbivores that
are around at the time, it's probably
largely leaving them alone because
again, just the classic dynamics of
predators, even like quote super
predators like Tyrannosaurus, they're
still real animals. If you get injured
and you can't hunt, that's probably the
end of you. So, you don't want to tackle
an adult triceratops that weighs the
same as you and has meter meter and a
half long horns on its head and is
potentially pretty aggressive. Um, and
then even the big uh so the hydrosaurs,
the kind of classic duck build
dinosaurs, they're not they're not
present with any like obvious defenses.
They don't have armor. They don't have
horns or spikes or anything like this,
but they're simply massive. Again, you
know, yes, T-Rex has got the teeth and
the bite and even if they're a bit
rubbish, the claws on the hands, but
like just grappling another animal which
is the same size as it, there's a risk
you're going to get a foot trotten on
that it's going to get off some kind of
body slam or whatever. And then even if
you do bring it down, you're never going
to eat it. Like if you you bring down an
animal that weighs five tons, it's
nearly your own mass. You're not you're
not going to eat it before it goes
rotten. That's a huge amount of kind of
not like wasted energy, but you've
probably put a lot of effort into this
and you're not getting that much reward
out. And again, there are again there
are exceptions. You've got things like
lyns are the classic one. Lynx are not
very big cats and yet they'll hunt adult
deer, way bigger than them. Lions hunt
things like buffalo, but they're
operating in a group, so it's a bit of a
cheat. So, there are some things that do
this, but fundamentally, the vast
majority of carnivores tackle stuff
that's way, way smaller than them. And
that's what we see. Um, every record we
have of basically any large carnivorous
dinosaur where you have stomach contents
where it's like consumed something or
healed bite marks, we get quite we get a
not quite a few. There's a handful of
them where there's an obvious damage to
a bone in more than a couple of cases
with a tooth broken off in the bone and
then the bone has healed over it so you
know it got away. They're they're
juveniles. They're relatively young
animals and that's what they're
targeting. Um, it makes ecological
sense. It's what modern animals do for
very good reason. Juveniles are
relatively small and weak. They don't
have the horns or frills or armor or
shields and other stuff. They're naive.
They don't they have you often have to
learn what predators are or you have to
learn how to avoid them or to check the
wind or even physically see them before
you know see them kill something else
before you know that they're a threat.
And juveniles forage badly. Um they're
relatively inefficient. So actually they
need to eat more for their size than an
adult does. And then on top of that
they're not very experienced at foraging
in the right areas. And even if they can
find a good patch, the adults will often
beat them up and chase them off.
>> You're talking about juveniles across
various species.
>> Everything. This is just a universal
pattern of being a smaller animal versus
a larger or a younger animal versus a
larger animal.
>> So So hunting young things,
>> young things is easier cuz they're dumb,
>> right? They're dumb, but they're
inexperienced. But but they're often
they're often feeding in suboptimal
areas. So this is the place with all the
best food. The adults will kick you off,
so now you have to feed somewhere else.
Maybe the food isn't as good, in which
case you need to eat more of it, so it
takes longer. Or maybe it's the one next
to the edge of the forest where the
T-Rexes hide, but either way, you're
stuck there, and then you don't really
know what you're looking for, and you
haven't got the armor. So, guess who's
getting eaten. Like, this is again,
there's lots of exceptions. You can't
have nature without things like that.
But this is the absolute rule of thumb
for how foraging and growth and
predation operate across everything from
fish to star fish as predators,
starfish, praying mantis, all the way up
to things like big cats via stuff like
crocodiles. It it's how it works. So
it'd be very weird if it didn't also
operate for dinosaurs. And then as I
say, we've actually got the direct
evidence for this from bite marks and
stomach contents. They're taken small
stuff. Bet Marks give a lot of
information.
>> Yeah,
>> that's a powerful signal in
paleontology.
>> Yeah, absolutely. I've done really quite
a lot of work on it and they can tell
you an awful lot if you've got the right
understanding of the burial conditions
because you weird thing that I think a
lot of people don't appreciate is you
basically can't take fossils at face
value particularly when you're trying to
get into stuff like behavior and ecology
because
so between the animal dying and the
paleontologist digging it up potentially
quite a lot has happened and that's
where it's really easy to start
misinterpreting things because if you
just go I I had one like this not too
long ago where I was an editor on a
paper and the the authors have done a
pretty good job to be fair but it was
this discussion of whether or not
several animals were together at the
time of their death
>> said multiple um theropods together in
this quarry and it's like right but
there was loads of debris and you had
loads of things like fish scales and
other small bones and it's like okay but
this looks Like these animals died,
potentially died somewhere else and then
a flood or a river washed them into this
bay or a channel or it then the water
level dropped and they ended up
together, but that doesn't necessarily
mean they were together when they died.
And so just cuz you've got three animals
together, what is potentially the story
of how they got there?
>> So you have to consider multiple
explanations and then try to figure out
what is the most likely.
>> Yeah. or what can you test with various
bits of evidence? So, there was some uh
tyrannosaur inflicted bite marks on a
duck bill from Mongolia that I worked on
years ago. The specimen was from
Mongolia, but it was held in Japan in a
Japanese museum. I was working with the
Japanese on it. And I'm I'm not a
tonomist of the study of like decay and
the history of specimens. And I am in no
way, shape, or form a geologist. I did
zoology for my degree. Um, but the guys
I was working with, like they were
really hot on erosion and damage and
they were looking at some of the way the
bones had been damaged and they're like,
"Okay, we're pretty confident that the
bite marks are sitting on top of
erosion."
>> What does that mean?
>> So, it means that the animal had died
and it was found in a it was found in
sand covered but in what would have been
a river channel. So, this animal has
died, washed down stream, ended up on a
sandbank. The sand is whipping past cuz
I've been in a sandstorm in China and it
is not fun. And that's starting to etch
some of the bones and damage them.
>> And after that, there's a bite mark.
>> After that, you're getting bite marks
coming in.
>> So, that can only be scavenging. That
thing has been dead and sitting out for
days, possibly weeks before something
came along and chewed on it.
>> It pretty much can't have happened any
other way. and you have to take these
really subtle signals to to reconstruct
the story,
>> but then you can start piecing some
other stuff together. So, in this case,
the skeleton is pristine. It's one of
the best skeletons out there. It's
certainly the best from Mongolia I've
ever seen. Um, and all the bite marks on
one bone, the humorus, the upper arm
bone, every every mark. We we went over
the rest of the skeleton, nothing. And
then the humorous is chewed to bits.
There's bites all over it. But when you
look, there's two really distinctive
patterns. There's deep circular
punctures. And remember what the shape
of this thing looks like.
>> Yeah.
>> At the ends and then along the delta
pectoral crest. Okay. It's much much
bigger than a hydrosaur. But this bit,
remember that's where all the big
muscles attach. There's all of these
types of this is from a different bone
but different animal, but all these
types of close parallel scratches.
And so that looks like selective feeding
because it's using its giant crunchy
teeth at the ends to get the bone off.
And this is off a buried skeleton.
And then it's got these actually T-Rex
has really small teeth at the front of
its mouth right right in the front where
our incizers are. They're called
incizform teeth. They look like
incizers. They're a fraction of the size
of the big ones. Um and they got a
really weird flat back.
>> Mhm. And that's what these are. It's
hidden this with the front of the mouth
and pulling.
>> And that's mostly for eating.
>> Yeah. And that's why it's just on the
delta pectoral crest because that's
where all the muscles are.
>> So it's I always liken it to getting
something like an Oreo and you take the
top off and you scrape the cream out
with your teeth. I think most people
have done that.
>> Yeah.
>> Right. But but that's what it's doing.
So, it's got this little row of teeth
and everywhere you get lots of muscle,
you get little rows of teeth together.
>> So, there's different bite marks for
sort of fighting, killing, and then
there's different bite marks for eating.
>> Yeah. So, it kills and dismembers with
the big teeth up the side
>> and then it feeds with the little front
teeth.
>> And all of that has evidence.
>> Yeah.
>> In the bones.
>> Yep.
>> What hunting strategy does it use? Can
we figure that out?
>> So, that comes down to the um to that
foot stuff. um they're relatively
efficient compared to a lot of other
things and particularly compared to the
herbivores. So that means they're
probably looking at long distance rather
than speed. And that makes sense cuz
even though the kind of stuff we're
talking about, like I said, maybe
they're getting to 20 25 mph. That's
pretty quick, but some of the smaller
stuff is going to be a lot faster than
that. And remember, that's a real upper
estimate. They're probably not that
quick. But yeah,
>> they're just jogging after you,
>> right? But but they've got they've got
the distance. So yeah. So it's much more
uh hyena or wolflike strategy than like
a cheetah going for hypers speed or a
lion going for a relatively quick burst
and it either gets you or it doesn't.
And then you the people kind of go well
like but that's ridiculous. Like they're
not even that quick. And it's like yeah
but if you're hunting something big
that's not that quick either. And so
that's a misconception. Like when I'm
talking about juvenile dinosaurs, I
don't mean just out of the egg and weigh
a kilo. Like a juvenile triceratops can
still weigh a ton
>> and be the size of a rhino. They're not
that fast. And again, if you get a head
start on them, because as I said, I
suspect they're nocturnal.
So, cuz that's the other thing. It's
really hard to hide a T-Rex. Even lions
and tigers struggle to kind of hide in
long grass. when you're three and a
half, four meters tall, like you you
can't hide. Maybe in a forest, but even
then you're probably going to stick out
and it's going to be hard to maneuver
between the trees. And we've got big
tyrannosaurs living in what we know to
have been relatively open environments.
Maybe there's some stands of trees, but
it's not like a woodland or a forest or
anything like that. So, they're living
in the open and surviving in the open.
So, they've got to have a way of doing
this. And I think it's either or some
combination of being nocturnal. So it's
you relatively easy to sneak isn't quite
the wrong word, but approach things to
cut the the distance down for your
initial strike and then just run in them
down because yeah, maybe a one ton
triceratops or one hydrasaur is rather
faster than you. But if you've covered
the first couple of hundred meters to
get up to your top speed before they
start running,
then you're probably much closer to
them. And then will they exhaust faster
than you'll keep going? Well, probably
not 100% of the time. No predators that
effective, but I suspect that's what
they're doing. And it fits with what we
know of their size, their vision. They
got a very good sense of smell. Again,
that makes sense at night. It makes less
sense if you're dial and operating
primarily in the day. and you got to
hide this thing and then we know they're
pretty efficient versus relatively fast
but not that efficient prey.
>> Well, there's a bit of a debate of
scavenger versus hunter.
>> They're obviously both. A because we've
got things like the bite marks I just
described which is pretty much
definitive scavenging and then we've got
the healed bite marks with T-Rex teeth
buried in bones which is pretty much
definitive active predation.
So, we've got evidence of it doing both.
But can we possibly figure out what was
the primary strategy?
>> That gets much harder. My guess is
they're probably still primarily
uh actively carnivorous because if you
look at stuff that's reliant on being a
uh scavenger um I mean the true
scavengers like the vultures and condors
and stuff like this, you have to be
ultra long distance very energy
efficient travelers. You know, they're
they're thoring soaring in thermals.
They're barely using any energy to fly.
It It's It's really hard to to get very
far.
>> How far were they spread? Where do they
Where did they live?
>> So, the ones we found, you've got them
from Alberta down to probably New
Mexico. There's some I want to say
there's some Tyrannosaurine,
so very close to T-Rex teeth that may or
may not be T-Rex in New Mexico. There's
similar teeth in Mexico proper down in
Kohila. Um so about halfway down Mexico
>> Mongolia also or
>> so Mongolia you have a thing called
Tarbosaurus which is a very very close
relative of T-Rex. It's the nearest
species or nearest genus that we have.
Um but T-Rex is probably occupying
almost all of western North America.
>> So at times the east was kind of split
off and and separate
>> but the entire surface of Earth had
dinosaurs on it. Yeah, most of it.
>> Yeah, we we've got them in Antarctica.
We've got them in Antarctica, even close
to the mass extinction event.
>> Just an insane number of dinosaur
species all over the earth. Just the
same kind of variety we have in the
animal kingdom today. You just have in
the dinosaur.
>> I mean, this is this is like how many
dinosaur species were that? I mean, I
basically wrote an entire book chapter
about this because there's so many.
But this would make the number higher,
but this would make the number lower,
but this would make the number high, but
this would make the number lower.
Counter versus counter arguments that
you can guesstimate almost any number
and probably be very accurate or very
far out.
>> Yeah, but we should say that a large
number of dinosaur species are
constantly being discovered.
>> Yeah. So, we've named give or take in
the realm of 1500,600 valid species.
that is not everyone agrees on every
species but most people would be
satisfied with that number
but we also name in the realm of 40 to
50 a year and we've been doing that for
at least the last 10 12 years that
number is rocketing up shows no signs of
slowing down there's loads of air like
we still never really explored India
very much we're starting to find
entirely new beds in places like Ecuador
um Argentina we know has a ton of stuff
but we've never excavated there very
much Austral Australia, we know there's
a ton of stuff we haven't excavated
there very much. Um, so there's lots of
places
even now to still go through. This is a
a good moment to take a brief tangent
and look at paleontology. So, how how do
we how do we find these fossils? What's
the uh what's the magic? What's the
science, the art? the same way more or
less that people did in the 1750s or
whenever you first start getting them
that there's for dinosaurs in
particular, but this is true of the vast
majority of stuff. There's essentially
two ways of doing it. The simple one is
where you have quaries of particularly
things like lithographic limestone. So,
the printing limestones or stuff that's
very similar to that uh sometimes that's
often volcanic.
um you get these super super super fine
layers of sedimentation and that's where
you get these places of exceptional
preservation. Whenever you see like the
feathers or almost always whenever you
see feathered dinosaurs it's like oh we
got the skin we got the claws and like
the whole skeletons laid out archaoptric
being like the the first bird in this
absolute classic example it's from these
beds and there you find them by
basically splitting limestone. We don't
usually dig for them. It's because there
are quarry workers and people who are
already doing this because the stone is
useful. Because there might be one
decent fossil for every, you know, few
hundred tons of rock you shift. In which
case, you could get every paleontologist
in the world there for a couple of years
and you wouldn't find very much. You
rely on the fact that there's hundreds
of guys doing this constantly and then
sooner or later they'll find something
and then you've got it. That's the super
easy way. The only slightly more
complicated way is you go to somewhere
where geologically we know it's the
right age and it's the right kind of
rock and ideally fossils have been
reported from there before. And again,
you know, geologists map all the world's
geology years ago in quite a lot of
detail. There's there's gaps. There's
places where we don't have the details,
but in general, we know. And then you go
there and then you walk around and you
look and that's basically it. and you're
looking for something that's sticking
out of the rock.
>> Yeah. So, you always get the So, there's
this constant and I think, you know,
borderline myth of the idea that
dinosaurs and mammoths and lots of other
fossil things like entered lots of
indigenous cultures because it's
impossible that the guys were wandering
around, say, Dakota and the Native
Americans didn't come across some
dinosaur fossils. That I'd agree with.
It's pretty much impossible they didn't
come across some dinosaur fossils. Did
they come across a whole skeleton laid
out on the ground? No, because those
don't usually exist.
Because even if they're tougher or it
doesn't matter if they're tougher or
weaker than the surrounding rock,
dinosaur bones are, you know, in some
way, shape, or form, they're lithified.
They they've turned to rock and they
will absorb some of the minerals from
whatever they've been buried in. And so
even in places like Mongolia and
northern China where I've been to where
actually the the fossil bone is quite a
lot tougher than the sandstone that it's
embedded in, like you can find a bit of
bone and pull it out like almost like
rub it with your hands and the the sand
comes off and there's your bone. They
will decay pretty quickly. You know,
sandstorms, you know, sand just etches
stuff. Um the tiniest bit of moisture,
particularly in winter, gets into the
cracks. Bones are incredibly porous.
that freezes, that expands, that cracks,
bones just shatter. And yeah, you find
shattered bone on the surface
everywhere. What you rarely find is a
decent bone on the surface, let alone a
skeleton.
>> So, there has to be something that's
sticking out just a tiny bit.
>> So, that you can see it, but it's still
buried, right? And it and it happens.
the the the greatest one that I saw or
that that I didn't see it happened by
with a friend of mine when we were in um
northern China and he went yeah I can
see a bit of a claw sticking out of a
hill and it was it was like this this
much you could see you know less than a
centimeter coming out of a hillside
and it's like so you know that's the
dream right
>> dig a little bit and there's a little
bit more dig a little bit there's a
little bit more dig a little there's a
little bit more okay and then the system
we were running there is some guys were
searchers and some guys were diggers So
he and I were searchers. We're told,
"Okay, you guys have you guys, he found
it. You found something. Go and look for
something else. We'll dig it out." And
so we come back a couple of days later
and check in on the digging team. So
what is it in the end? Oh, it's a
complete skeleton. And it was it was a
thing very very close relative of um
Velociraptor. Ended up naming it
Linhurraptor. So the raptor from Linhur,
which was the nearest town. And it was
Yeah. The legs were a little messed up
because water had got to them and the
end of the tail was missing. And that
was about it. So like 90 plus% complete
skeleton and it had been found with,
you know, 5 mil, a couple of 16 of an
inch of bone sticking out of a hill. And
that's what you want because every so
often behind that is a whole skeleton.
If you're looking for skeletons on the
surface, they're going to be gone before
you get to them.
>> And when it's near complete skeleton,
you you did a show of uh terrible
lizards on uh Stan.
>> Oh, yeah. T-Rex fossil that sold for
$31.8 million.
>> Exciting money.
>> So that that's a nice sort of big adult
T-Rex. So looking at a fossil like this.
>> Yeah.
>> So for $31.8 million, what's the
excavation process for when you have a
claw sticking out like you were
mentioning and getting that whole thing
out without damaging the bones? What can
you say about that process?
>> So it depends where you are. It depends
how many people you've got. It depends
on your budget and it really depends on
the rock. So again, like going into
China and Mongolia where this little gu
is from, the bone tends to be relatively
strong compared to the sandstone that
it's in. That also that means that a
it's fairly tough and resistant. Um, but
it also means that uh it's really easy
to dig. Like again, I've dug stuff by
long like pulling it with my hands or
like getting my fingers in. Getting
something like a chisel or a hammer, you
can just cruise through this rot, but
like you have to be really careful not
to touch the bone, I guess.
>> So, it depends how how strong it is. So,
again, some some bone is incredibly
strong, some isn't because they've all
fossilized differently. Um, what we're
usually doing is applying glue to it,
though. There's this um wonderful stuff
called paraloid and it's a special glue
for fossils. And I said bone super
porous. So it's really good at sucking
up liquids.
>> Oh, so you're basically filling it with
glue. So it like makes it stronger.
>> Yeah. And paraloid is really great
because you can dissolve it with acetone
and it basically doesn't react with
anything. So you can fill your fossil
with glue, but then if you want to take
all that glue out, you can pretty much
just dissolve the glue back out again.
>> Very cool. Um so yeah what you would
normally do is for for something say in
China
um where the rock is relatively soft uh
and the bones relatively tough and um
where we don't have any like manpower
and shipping problems which is a real
issue in other places. You basically map
out where you think the skeleton's
going. So, um, in the same way that you
were doing it, like, you know, if you
can imagine like a cake or something and
someone said, "I put a toy dinosaur in
there and you you you've got to find it
without damaging it." So, like, well,
you stick your finger in the cake and
just kind of