If you visit the Natural History Museum
in South Kensington, and you enter via Exhibition
Road, you’ll start off in Earth Hall, where
you are greeted by a very unusual character.
This is Sophie, the world’s most complete
Stegosaurus, with 85% of her bones intact.
I should be clear, it’s nicknamed “Sophie”,
but we don’t know for sure if it’s a male
or female. It’s hard to convey in photos
just how big Sophie is- already 6m long, and
not a grown-up yet! The biggest ones would
have been up to 9m! She is an American immigrant,
found in the dinosaur-rich soil of Wyoming.
Stegosaurus means “roof lizard”, because
when palaeontologists first found them, they
thought the plates lay flat like a turtle
shell.
Stegosauruses are herbivores that lived
155-150 million years ago in the western US,
Portugal, and, we found out this year, Scotland!
Sophie would have known other dinosaurs like
Diplodocus, Brachiosaurus, Allosaurus, and
Ceratosaurus. Parts of about 80 Stegosauruses
have been found worldwide.
And what Sophie’s famous for is those
big spiky bones on the back. Well, strictly
speaking, they’re not quite bones. They
are hard enough to fossilise, but they’re
more like the ridges you see on crocodiles.
They grow out of the skin, not out of the
skeleton. Weirdly enough, we still don’t
know what quite they were for. The obvious
answer seems to be defence, but scientists
these days tend to think that they’re too
fragile for that, and anyway they’re not
much good if someone comes at you from the
side. Instead, they might have had a few uses.
They might have been good for display, like
a peacock’s tail. They might even have been
fun colours originally. Maybe other Stegosauruses
just thought this looked really sexy? Some
people have suggested that female and male
Stegosauruses have different shaped plates,
so maybe that helped them tell the difference.
Also, we know that the plates had blood vessels
running through them, so the blood would get
cooler as it went through the plates, where
it’s closer to the skin. Maybe they’re
a good way of cooling down if you can’t
sweat because, y’know, you’re a lizard.
Or maybe they’re like nature’s platform
shoes, making you look taller than you really
are.
What is good for defence, though, are those
BRUTAL spikes on the tail. You can swing that
round and actually aim it at whatever’s
attacking you. Until 1982, there was no word
for this kind of spiky tail. Everyone just
called them “tail spikes” or whatever.
Finally, it was given a name, not by a paleologist,
not by a researcher, but by a cartoonist called
Gary Larson. He wrote a quick funny comic
where some cavemen are giving a presentation
on dinosaurs, and one points to the tail and
says, “Now this end is called the thagomizer,
after the late Thag Simmons”. And amazingly,
the word actually caught on among real scientists,
and is now used in books and by museums!
Despite its size, Sophie’s brain was about
the size of a dog’s. To be fair, animals
only have to be smarter than the food they
eat, and in this case, Sophie ate ferns. Still,
scientists were so shocked by the size of
its brain that some used to think it must
have a second brain in its hips, where there’s
a big gap in the bones. This is called the
brain-in-the-butt theory, and as weird as
it sounds, was taken seriously in some quarters
for a while. But birds have this gap too,
and they don’t have brains in their butts.
It has no front teeth though, so how did
Sophie bite things? Well, we think it might
have had a beak, a bit like a turtle! Turtle
beaks are hard and will definitely take your
fingers off if you get too close, but they
don’t fossilise, so we wouldn’t find them.
What with the thagomizer and the plates
and the beak and the size, Sophie looks pretty
scary, but its back legs are way longer than
its front legs, meaning if it tried to run
fast, its back legs would OVERTAKE its front
legs and it would get all tangled up. So Stegosaurus’
top speed, like, as fast as Sophie could run,
was probably 3-4mph- about the same as your
normal walking speed.
And because its back legs are so long, it
probably ate low-lying vegetation like ferns,
bushes and herbs. We don’t know if it could
rear up on its back legs to reach tree leaves
or not. It also ate rocks, on purpose! They
went into its stomach and helped mash up all
the plants in there.
Some dinosaurs were pretty solitary, but
Stegosaurus lived in herds. How would you
possibly know that from fossils? Well, we’ve
found footprints of whole herds of them intact,
which is apparently, if you know what you’re
looking for, what these photos show!
So we think they were pretty social, living
in herds rather than on their own.
Nobody knows how they mate. It is a mystery
to science.
The Stegosaurus was first discovered during
this amazing period of history called the
BONE WARS.
It was an explosive rivalry between two
palaeontologists- Edward Drinker Cope and
Othniel Charles Marsh. Each tried to outdo
the other, and ended up resorting to bribery,
theft, smears in the press, and the destruction
of specimens!
This took place in Colorado, Nebraska and
Wyoming (particularly rich fossil country)
in 1877-1892. The rivalry was so great that they both
ended up broke and disgraced in the pursuit
of "paleontological supremacy”, but they
made hugely important contributions to their
fields.
They met in Berlin in 1864, and started
off as friends. They even named new species
after each other! But after a while, they
started to have arguments. Their work styles
didn’t mesh well.
Cope was from a wealthy Quaker family, while
Marsh grew up poor (although it just so happened
that his uncle was the very wealthy banker
George Peabody, so don’t feel too sorry
for him).
One day, they went on a dig together at
a mine in New Jersey, and afterwards, Marsh
secretly bribed the pit operators to bring
any future finds to him instead of Cope.
They started attacking one another in the
papers- Marsh claimed that Cope had put the
head on the wrong end of Elasmosaurus (he
was wrong about that, but it was pretty humiliating
for Cope, who tried to buy up every single
copy of the journal).
By 1873, they were at war. They were finding
new species at a tremendous rate (partly because
the area they were digging was very rich,
and partly because not many dinosaurs had
been discovered yet). Cope would name new
species when actually Marsh had found them
first; Marsh would claim that all Cope’s
new-named dinosaurs were incorrect.
Between them, they discovered 136 new species
of dinosaur, including Stegosaurus, by Marsh,
Triceratops, Allosaurus, and Diplodocus! (I’d
be happy just with one!), and massively increased
public interest in dinosaurs.
However, in their haste to be the first
to convincingly reconstruct the skeletons
they’d found, they’d slap the bones together
very quickly, making mistakes that would lead
to confusion decades later.
They also destroyed hundreds of fossils
so “the other team” couldn’t get them.
At one point, Cope hired “dinosaur rustlers”
to sneak onto Marsh’s dig site and steal
fossils! Marsh’s men destroyed bones to
keep them out of Cope’s hands. At one point,
the rival teams THREW ROCKS AT EACH OTHER.
And the rivalry didn’t end until Cope
died in 1891. He kept it up to his dying breath:
in his will, he donated his skull to science,
and challenged Marsh to do the same, so he
could prove who had a bigger brain. Marsh
never took him up on the offer.
So as far as we know, Stegosaurus weren’t
native to London- at least, no-one’s ever
found one here, and we’ve done a lot of
digging here over the years. So Sophie got
here thanks to a donation from the hedge fund
manager Jeremy Herrmann, and their specimen
is nicknamed “Sophie” after his daughter.
(There were 69 other donors, but he was the
main one. And if you’re wondering just how
much a Stegosaurus skeleton costs these days,
the actual price has not been disclosed.)
And today, Sophie greets five million visitors
to the Natural History Museum every year.
