Speaker 1: Welcome to brain Stuff, a production of I Heart Radio,
Speaker 1: Hey brain Stuff, Lauren Bogobaum. Here words can become fossils
Speaker 1: in their own right. Triceratops means three horned face, and
Speaker 1: philociraptor translates to speedy plunderer. Abok genus names fit the
Speaker 1: dinosaurs they belong to. We know Triceratops had a trio
Speaker 1: of horns on its skull, while Velociraptor was a lightly
Speaker 1: built carnivore. The case of Stegosaurus isn't so straightforward. Rooted
Speaker 1: in Greek, this Jurassic plant gobbler's name means roofed lizard,
Speaker 1: which made a lot more sense when the animal was
Speaker 1: first discovered over a hundred and forty years ago. But
Speaker 1: let's back up a little. A Stegosaurus belonged to a
Speaker 1: suborder of dinosaurs called what else the stegosaurs found in
Speaker 1: North America, Europe, Asia, and mainland Africa. The stegosaurs walked
Speaker 1: on four legs and had long, beak tipped skulls, but
Speaker 1: it's the ornaments that really grab your attention. The spikes
Speaker 1: were a stegosaur mainstay, adorning the tails of every known species.
Speaker 1: Many of these creatures like Africa's Kentrosaurus also rocked big
Speaker 1: old spikes on the shoulders and lower back, and where
Speaker 1: the back spikes came to an end, a much weirder
Speaker 1: feature took over. A Stegosaurus and its kin are characterized
Speaker 1: by the vertical plates above their spines. The paleontologist Othniol
Speaker 1: Charles Marsh named Stegosaurus in eighteen seventy seven. He chose
Speaker 1: this name, which again means roofed lizard, because he figured
Speaker 1: the plates were sheets of armor that laid flat against
Speaker 1: the animal's backside. Instead, later discoveries proved the objects stood upright,
Speaker 1: leaving the flanks on these dinosaurs exposed. We may never
Speaker 1: know how these things functioned. Because the plates contained blood vessels,
Speaker 1: experts used to think that they helped Stegosaurus chill out.
Speaker 1: The heat would supposedly dissipate from blood as it entered
Speaker 1: the tall fan like structures. When the chilled blood circulated elsewhere,
Speaker 1: it would stay cool for a little while lowering the
Speaker 1: overall body temperature. This hypothesis is no longer popular. According
Speaker 1: to a study published in two thousand five in the
Speaker 1: journal Paleobiology, The blood carrying networks and Stegosaurus. As plates
Speaker 1: were there to promote healthy bone growth, but they played
Speaker 1: no role in dissipating body heat. Or maybe Stegosaurus and
Speaker 1: its kin were just showing off a made of bone
Speaker 1: and encased in horny sheats. The plates could have made
Speaker 1: these dinos look bigger than more intimidating. Capable of hitting
Speaker 1: over twenty nine feet that's nine meters in length and
Speaker 1: weighing about five tons or four and a half metric tons,
Speaker 1: a stegosaurus would loom large over today's land mammals. Even
Speaker 1: by stegosaur standards, it was a biggie, and most of
Speaker 1: the dinosaurs in that group were only thirteen to twenty
Speaker 1: three feet long that's about four to seven ms. Yet
Speaker 1: in the late Jurassic, when these species lived, the Stegosaurus
Speaker 1: was in the shadows of behemoths. Sauropods, or long necked
Speaker 1: dinosaurs like the sixty foot or eighteen meter Kmarasaurus and
Speaker 1: the eighty foot or twenty four meter Diplodocus were some
Speaker 1: of the creatures neighbors, but the Tyrannosaurus rex wasn't, and
Speaker 1: despite movies like Fantasia and The Camp Classic Planet of
Speaker 1: Dinosaurs showing Stegosaurus duking it out with the t Rex.
Speaker 1: Those two dinos never crossed paths in real life. Tyrannosaurus
Speaker 1: had a fairly short rain that lasted from sixty eight
Speaker 1: to sixty five and a half million years ago. The
Speaker 1: Stegosaurus came and went much much earlier. The oldest specimens
Speaker 1: on record are around a hundred and fifty five million
Speaker 1: years of age, while the youngest were fossilized hundred and
Speaker 1: fifty billion years before the present, So the mighty t
Speaker 1: Rex actually lived closer to the dawn of mankind than
Speaker 1: it did to the Stegosaurus is heyday. The Jurassic Period,
Speaker 1: which lasted from a hundred and ninety nine point six
Speaker 1: million to a hundred and forty five point five million
Speaker 1: years ago, was drawing to a close when Stegosaurus roamed
Speaker 1: the earth. Although its range included modern day Portugal, the
Speaker 1: beast is mainly known from fossil sites in western North America,
Speaker 1: and while Stegosaurus didn't have to worry about t Rex,
Speaker 1: a rogues gallery of Jurassic predators stalked its ecosystem. Allosaurus
Speaker 1: was especially common, measuring up to twenty eight feet that's
Speaker 1: eight and a half meters long. This carnivore had serrated
Speaker 1: teeth and jaws that could open wide at a terrifying
Speaker 1: seventy nine degree angle. Good things. Diegosaurus had four tail
Speaker 1: spikes at its disposal. We know they saw action once
Speaker 1: in a while too. A study published in two thousand
Speaker 1: one in the Armored Dinosaurs by the Indiana University Press
Speaker 1: found clear evidence of trauma on ten percent of the
Speaker 1: fifty one tail spikes that they studied, and apparently the
Speaker 1: roofed lizard hit below the belt. One Allosaurus pubic bone
Speaker 1: shows a deep wound thought to have been made by
Speaker 1: a Stegosaurus tailspike. The stegosaurus had another line of defense.
Speaker 1: The underside of its throat was covered in tiny pebble
Speaker 1: shaped chunks of bone called Ghouler armor. It helped protect
Speaker 1: the dinosaur when Allosaurus and other carnivores went for the
Speaker 1: jugular Paleontologists think Stegosaurus browsed on low lying vegetation. A
Speaker 1: computer simulation found that the animals bite force would have
Speaker 1: rivaled that of a sheep or cow, but however, it
Speaker 1: processed its food. This dinosaur didn't need much gray matter.
Speaker 1: A Stegosaurus had a brain cavity that was long narrow
Speaker 1: and tiny, tipping the scales at twenty ounces, that's eighty
Speaker 1: grams or so. The actual brain only made up about
Speaker 1: zero point zero zero one percent of the creature's total
Speaker 1: body weight. And note that we said brain, not brains.
Speaker 1: As absurd as it might sound, there was a rumor
Speaker 1: that Stegosaurus had a second brain located where the sun
Speaker 1: don't shine. Writing in one Marsh drew attention to the
Speaker 1: enlarged cavity that we find in the backbones above this
Speaker 1: dinosaurs hip region. Then he went and called it a
Speaker 1: posterior brain case. No one knows for sure what this
Speaker 1: opening was for, though some researchers think it stored glycogen,
Speaker 1: sugar that provides cells with energy. Regardless, there is no
Speaker 1: reason to think that Steatosaurus or any dinosaur had multiple brains.
Speaker 1: The Stegosaurus did have some pretty cool bragging rights though.
Speaker 1: Not only is the Jurassic her Before Colorado's official state fossil,
Speaker 1: but it was also the inspiration for Godzilla's dorsal plates,
Speaker 1: as we have discussed on the show before. Today's episode
Speaker 1: is based on the article Stegosaurus body like a bus,
Speaker 1: tiny little brain on how Stuff Works dot com, written
Speaker 1: by Mark Mancini Breen Stuff is production of by heart
Speaker 1: Radio in partnership with how stuff works dot Com and
Speaker 1: is produced by Tyler Klang. Four more podcasts from my
Speaker 1: heart Radio. Visit the iHeart Radio app, Apple Podcasts, or
Speaker 1: wherever you listen to your favorite shows.