Welcome back to the Deep Dive. Today we're opening
a cold case file that's been sitting in the archives
of paleontology for, what, almost 150 years now.
Just about. We're talking about a creature that
you know. I guarantee you know it. It's on gas
station logos, it's the star of arguably the
most heartbreaking kids movie ever made, and
it's the centerpiece of every natural history
museum. And yet, if you really look at the history
of this animal, it's... Basically a rap sheet
of mistaken identity, academic, well, vandalism,
and just a profound biological misunderstanding.
Exactly. We're talking about the Apatosaurus.
And if you are sitting there screaming, don't
you mean Brontosaurus, at your device, hold that
thought. Because that name is just the tip of
the iceberg. Today we're going to find out why
this animal spent 50 years wearing the wrong
head. We're going to explore why it was called
a swamp monster when it was really a land tank.
And we're going to get into some high level data
that suggests everything we thought we knew about
how a 20 ton animal breathes might be, well,
completely wrong. It's a messy story. It involves
the infamous Bone Wars, some very fragile egos,
and some really cutting -edge computer modeling
that has just turned the family tree completely
upside down. So let's get into it. We are pulling
from a massive stack of sources today, everything
from the original 1877 Field Notes by Othniel
Charles Marsh, all the way to a huge... 2015
phylogenetic analysis. Right, the one by T -Shop
and his colleagues, plus some fascinating biomechanics
papers from as recent as 2020. We're covering
the whole timeline of discovery. Let's start
with that name, Apatosaurus. It's Greek for deceptive
lizard. Now, usually dinosaur names are the marketing
gold. Tyrannosaurus is the tyrant lizard, Velociraptor.
So why on earth did Marsh call this magnificent
giant deceptive? Was it... Like hiding something?
It's funny people often think that. That the
name implies it was sneaky or camouflaged or
that it was tricking the scientists. But the
deception was purely anatomical. You have to
remember this is 1877. Marsh is looking at a
partial skeleton. He's examining the chevron
bones. These are the small bones on the underside
of the tail that, you know, protect the blood
vessels. Right. I'm with you. And in Apatosaurus,
these chevrons, they didn't look like the dinosaur
bones Marsh was used to. They looked, well, deceptively
like the chevrons of a mosasaur. A mosasaur.
You mean the marine reptiles, the sea monsters
of the Cretaceous. Exactly those. So Marsh saw
these tail bones and thought, this is weird.
It looks like a marine reptile's tail structure
grafted onto a... land animal, hence Apatosaurus,
the deceptive lizard. It tricked him. So that's
1877. Marsh publishes the name. But then only
two years later, 1879, his team sends him another
shipment of bones. And this is where the trouble
really starts. Oh, yeah. This new skeleton was
spectacular. It was huge. It was relatively complete.
And Marsh was absolutely floored by it. Now,
you have to understand the context here. This
is the height of the bone wars. It's the height
of the bone wars. Marsh is in this bitter, frantic
race against his rival, Edward Drinker Cope.
They're just trying to name as many new species
as they can to outdo each other. Quantity over
quality, they say. Often, yes. So Marsh sees
this massive skeleton, assumes it's a new species,
and gives it arguably the best name in the history
of science. Brontosaurus excelsis. Noble thunder
lizard. It's a great name. It's so evocative.
It sounds like a creature that shakes the earth
when it walks. And because that skeleton was
so complete, it became the first sauropod ever
mounted in a major museum. The public didn't
see a patasaurus. They saw a brontosaurus. They
fell in love with the thunder lizard. But scientifically,
the clock was ticking on that name from the start.
It was. In 1903, a paleontologist, Elmer Riggs,
at the Field Museum in Chicago. He takes a hard
clinical look at the two specimens. He compares
the 1877 Apatosaurus and the 1879 Brontosaurus.
And he figures it out. He figures it out. He
realizes they're the same animal. The differences
Marsh had seen were mostly due to ontogeny, which
is just a fancy word for growth stages. So the
Apatosaurus was just a teenager. Essentially,
yes. The Apatosaurus specimen was a juvenile
and the Brontosaurus was an adult. They were
the same genus. And in the strict rules of taxonomy,
there is only one law that matters. Priority.
First name wins. Apatosaurus was published in
1877, so it has priority. Brontosaurus 1879 becomes
a junior synonym. It's technically invalid. In
1903, the thunder lizard ceased to exist. But
and this is the part that always confuses me.
I grew up in the 90s. I ate Bronto burgers. I
watched the land before time. If Riggs killed
the name in 1903, why did it survive for another
century? You can thank Henry Fairfield Osborne
for that. He was the head of the American Museum
of Natural History, a titan. the field and frankly
a bit of a chaotic figure with a massive ego.
And he just liked the name better. He liked Brontosaurus
better. He had a label to print for his museum
and he essentially just ignored Riggs publication.
He just ignored a peer reviewed correction. He
did. And when you run the most famous museum
in the world, your label becomes the truth for
millions of people. So you had this split reality
where scientists quietly said Apatosaurus in
their papers and the entire rest of the world
said Brontosaurus. That's unbelievable. It's
like branding just completely won out over fact.
For about 100 years, yeah. But hold on, the outline
mentions a plot twist in 2015. So just when we
finally got everyone to stop saying brontosaurus,
I feel like I spent years correcting my friends.
The science flipped again. This is why paleontology
is so exciting, right? It's never truly settled.
In 2015, Emmanuel Chopp and his team published
this massive study. And I mean massive. They
didn't just look at Apatosaurus. They looked
at the whole family of Diplodocidae. How many
data points are we talking? They analyzed 477
different morphological characters across 81
individual specimens. Wow. So they're measuring
every single bump on every bump. Precisely. They
fed all this data into a computer algorithm to
sort out the family tree. And the algorithm...
It spit out a surprise. It clustered the original
brontosaurus skeleton that 1879 won apart from
the apatosaurus cluster. Distinct enough to be
its own genus again. According to their data,
yes, they identified key differences. For instance,
in the neck structure, apatosaurus has a much
wider, more robust neck and also in the shoulder
blade. They concluded that, yeah, the differences
were significant enough to separate them. So
brontosaurus was resurrected. This is a brontosaurus
is back. For real this time? It's considered
valid by many paleontologists now. Not all of
them, mind you. Taxonomy is a consensus game.
But for now, yes, you can say brontosaurus without
a scientist correcting you. It's recognized as
a separate, slightly more slender cousin of the
tank -like apatosaurus. That is a rollercoaster.
But the name isn't the only identity crisis this
poor animal suffered. We have to talk about the
head. Ah, yes. the Frankenstein portion of the
story. Because for a long time, the Apatosaurus
literally had the wrong head screwed onto its
body. And it all stems from a simple problem
in taphonomy, the study of how organisms decay.
Sauropod skulls are pretty small compared to
their bodies, and the connection to the neck
is fragile. So when the animal dies, the head
often detaches. and just rolls away so you find
the massive body but the head is gone exactly
marsh's skeletons were headless but museums need
to display complete animals right you can't put
a headless giant in the main hall so a guy named
adam herman at the american museum needed a head
for his mount and the only sauropod skull they
really knew well at the time belonged to camerasaurus
okay paint a picture for us what does a camerasaurus
head look like Think of a bulldog. It's boxy,
high -arching nose, a blunt snout, and these
big spoon -shaped teeth for chomping tough vegetation.
It's a really heavy, robust skull. And Apatosaurus
is a heavy, robust animal, so they just assumed.
They made an assumption. Big body, big blocky
head. They sculpted a Camasaurus -like skull
out of plaster and stuck it on the Apatosaurus'
neck. And that became the image of the dinosaur
for decades. Every toy, every movie, it was this
boxy, flat -faced creature. But there were clues
that this was wrong. There were. In 1909, a paleontologist
named Earl Douglas, working for the Carnegie
Museum, he found this beautiful, nearly complete
apatosaurus skeleton. And right next to the neck,
there was a skull. But it didn't look like a
bulldog. What did it look like? It looked like
a horse. long, slender, with a square snout and
these pencil -like teeth just at the front. It
looked almost identical to the skull of Diplodocus,
just a bit heavier. So we have a Diplodocus -like
head found right next to an Apatosaurus body.
That seems pretty conclusive. It should have
been. The director of the Carnegie Museum, William
Holland, he was convinced. He wanted to mount
the Diplodocus -style head. But, and here comes
the politics again. Henry Fairfield Osborn, that
powerful rival. The guy who kept Brontosaurus
alive. The same guy. He insisted the boxy head
was correct. He essentially bullied Holland into
doubt. So what did Holland do? He did something
incredibly petty and principled. He mounted the
skeleton in the museum hall, but he left it headless.
He just left the neck ending in a stump. For
years. He basically said, if I can't put the
right head on it, I won't put any head on it.
That is a level of academic stubbornness I have
to respect. Unfortunately, after Holland died...
The museum caved. They put the wrong boxy skull
on it anyway. Unbelievable. So when did we finally
fix it? Not until the 1970s. Two researchers,
John McIntosh and David Berman, they went back
and did this incredible forensic work. They traced
the original field notes, the maps, everything.
And they proved conclusively that the skull Douglas
found was the real Apatosaurus skull. So if you
saw a drawing of a Brontosaurus before 1980,
it was essentially a Chiamera. A mythological
beast. Body of one dinosaur, head of another.
A complete lie. Okay, so now that we've got the
name back, sort of, and the head fixed, let's
look at the actual animal. Biologically, what
are we dealing with? Apatosaurus was built differently
than its cousins, right? It was a tank. I mean,
if Diplonicus was a suspension bridge long and
Slender Apatosaurus was a fortress wall, it averaged
about 21 to 23 meters long, but it was massive.
We're talking 16 to 22 tons, with some individuals
maybe pushing 30. And the neck is where it gets
really interesting structurally. The notes mention
deeply bifurcated vertebrae. Can you break that
down? Bifurcated just means split. If you look
at the neck vertebrae, the spines on top aren't
a single blade. They're split into a V shape.
This creates this wide... deep trough running
all the way down the neck. And what goes in the
trough? A massive ligament, the neutral ligament.
Think of it like a giant rubber band that runs
from the shoulders to the head, helping hold
the neck up passively. It saves a ton of energy.
But the really mind blowing thing about these
bones is what was inside them. They were full
of holes. Holes. Pseumaticity. They were honeycombed
with air pockets, all connected to the respiratory
system. Which connects to the bird comparison.
Precisely. And this is a key take. away. You
cannot build an animal this big using mammalian
biology. It just doesn't work. Why not? Why couldn't
a mammal get to 30 tons with a 30 -foot neck?
It's the breathing. Mammals have tidal respiration.
We breathe in, air goes into a dead end, our
lungs, then we breathe out. That means there's
always dead space, stale air left in the trachea.
If your neck is 10 meters long, you'd just be
rebreathing your own CO2. You'd suffocate. So
how did apatosaurs do it? Almost certainly with
a flow through system like modern birds, air
flows in one direction through the lungs and
into these air sac that permeate the skeleton.
It allows for continuous oxygen extraction. It's
highly efficient. It helps dump heat and it makes
the skeleton incredibly light for its size. So
this massive lumbering giant actually had a respiratory
system more like a falcon than an elephant. Exactly.
An air cooled, high performance biological machine.
Which brings us to growth. I was stunned by the
numbers here. These things. They started from
eggs, so they started tiny, right? Tiny. The
size of a small dog, maybe. And they grew to
20 tons in how long? About 10 to 15 years to
reach near adult size. That seems impossible.
It does if you think of them as cold -blooded
reptiles. But the bone histology, where we cut
the bone and count the growth rings like a tree,
it shows they were growing at an explosive rate.
In their peak teenage years, they were putting
on up to 5 ,000 kilograms a year. That's... Over
13 kilos a day. Imagine gaining the weight of
a toddler every single day for a year. You would
just be an eating machine. That's all you'd do.
That was their life. Fermentation vats on legs,
processing massive amounts of low -quality vegetation
just to fuel that metabolic furnace. Let's move
to the other end of the animal, the tail. It's
incredibly long, tapered like a whip. And I remember
hearing about the supersonic theory in the 90s.
Yes, this was a huge deal. In 1997, a computer
model suggested the tip of the tail was thin
and light enough that the animal could flick
it fast enough to break the sound barrier. Creating
a sonic boom. Over 200 decibels, like a cannon
shot. The theory was they use it for defense
or signaling. But I saw a 2020 study in our stack
that challenges this. And this is a great example
of physics versus biology. The model said the
physics could work, but the 2020 study looked
at the biology of it. They argued that if you
actually snapped a tail made of flesh, bone,
and skin at supersonic speeds, the stress would
just shatter the vertebrae. Because they could
do it once. Exactly. And then they'd have a broken
necrotic tail. It's a biological structure, not
a leather bullwhip. So if they weren't cracking
them like whips, what were they doing with them?
That study proposes something else, something
gentler. A tactile organ. This is fascinating.
The suggestion is they use their tails for touch.
Like an antenna. Think about it. You're a 70
-foot -long animal. Your head is way up front.
How do you know where the rest of your herd is,
especially if you're migrating in the dust or
at dusk? You can't see behind you. Right. But
if you have this long, sensitive tail that you
can gently sweep back and forth, you can maintain
physical contact with the animal behind you.
Like holding hands in a line. Or like elephants
using their trunks to touch each other. It turns
the tail from a weapon of war into a tool for
social cohesion. It implies they were tight -knit
groups communicating through touch. I love that
image. It completely reframes the animal from
a solitary swamp monster to a social creature
that needs to stay in touch with its family.
It makes them real. And speaking of swamp bound,
we used to think they lived in swamps because
they were just too heavy for land. That's the
old sluggish reptile bias. But we know from the
geology of the Morrison Formation that it wasn't
a swamp. It was semi -arid. Think of a Serengeti,
but with ferns instead of grass. Wet seasons
and dry seasons. Man, it was a crowded ecosystem.
Very. They lived alongside Stegosaurus, Camarasaurus,
and the apex predator Allosaurus. And Allosaurus
was actively hunting them. We have evidence for
it. There's an Apatosaurus hip bone with bite
marks that perfectly matched the teeth of an
Allosaurus. So yes, they were on the menu. But
they weren't defenseless. See, on just size.
They had one specific tool. A single, massive
claw on their thumb. The other toes were blunt,
but that thumb had this wicked, recurved claw.
Could have been for grasping trees, but it'd
also be a nasty surprise for a predator. There's
one last debate. The posture. I always picture
their heads held high, reaching for the treetops
like a giraffe. But the sources are conflicted.
This is the ostrich versus vacuum cleaner debate.
Go on. One camp looks at living animals and says,
look, almost all of them hold their necks up
in an alert posture. They argue the joints allowed
for a high vertical reach, the classic swan neck
look. But the other side? The other side, using
computer models, argued that the neck was actually
quite stiff vertically. They claimed a patasaurus
couldn't lift its head much higher than its shoulders.
So it was just a low browser. Exactly. They suggest
it stood in one spot and swept its neck side
to side in a huge U -shape, mowing down ferns
on the ground without moving its heavy body.
A biological lawnmower. So what's the consensus
now? It's leaning back toward a mix. The models
probably missed the effect of cartilage, which
would have made the neck more flexible. So they
likely could lift their heads high when needed,
but probably spent a lot of time feeding at mid
to low levels. It really feels like every time
we apply a new technology, the animal changes.
That's the beauty of it. Apatosaurus is the perfect
example. It started as a deceptive lizard because
we didn't understand it. It lost its name. It
lost its head. It was put in a swamp. And now?
Now we see it as this terrestrial masterpiece.
genus from Brontosaurus with a bird -like respiratory
system growing at speeds that defy logic, living
in complex social herds. It's a redemption arc
150 years in the making. It really is. So I want
to leave the listener with a little assignment.
Next time you're in a museum looking up at that
giant sauropod mount, do some detective work.
Check the label, of course, but check the skull.
Look at the face. Is it the boxy bulldog face
or is it the slender horse -like face? Because
even today, some museums haven't updated their
mounts. And if you see that boxy head, you'll
know you're looking at a piece of history. Just
not natural history. You're looking at a mistake
preserved in plaster. And maybe, just maybe,
picture that tail not cracking like a gunshot,
but gently brushing the flank of another dinosaur
in the dark. Thanks for diving in with us. We'll
see you on the next one.