Temporal range: Late Jurassic
|A restoration of Stegosaurus armatus|
| Stegosaurus armatus|
Stegosaurus meaning "roofed reptile", for the plates on its back (Greek stego = plate/roof + sauros = lizard), was a genus of large herbivorous dinosaurs from the Upper Jurassic of Europe and South Africa. It is among the most easily identifiable dinosaurs, due to the distinctive udouble row of kite-shaped plates along the animal's back (the basis for its scientific name) and the four long spikes on its tail (referred to as the thagomizer).
FeaturesStegosaurus was the largest stegosaur, reaching up to 11 meters (35 feet) in length and weighing up to 5,000 kg (5.5 short tons). However, most specimens never exceed 9 meters (23 feet) and 2,000 kg (2 short tons).They lived some 155 to 145 million years ago, in an environment and time dominated by the giant sauropods Diplodocus, Camarasaurus, and Apatosaurus.Stegosaurus was the largest of all the stegosaurians (bigger than genera such as Kentrosaurus and Huayangosaurus) and, although roughly bus-sized, it nonetheless shared many anatomical features (including the tail spines and plates) with the other stegosaurian genera. Although a large-bodied animal, it was dwarfed by its contemporaries, the giant sauropods. Some form of armour appears to have been necessary, as it coexisted with large predatory theropod dinosaurs, such as the fearsome Allosaurus and Ceratosaurus.
The plates of Stegosaurus were highly modified osteoderms, or bony-cored scales, similar to those seen in crocodiles and many lizards today. The largest plates were found over the animal's hips and measured 60 centimeters (2 feet) wide and 60 centimeters tall. The arrangement of the plates has long been a subject of debate, but most paleontologists now agree that they formed a pair of alternating rows down the animal's back. The purpose of the plates is also debated. Their large size suggests that they may have been used to increase the apparent height of the animal in order to intimidate enemies or to impress other members of the species. However, the plates were fragile and ill-placed for defensive purposes, and both male and female Stegosaurus had them. A more recent theory proposes that they may have helped to control the temperature of the animal, much as elephants and jackrabbits do with their ears. The plates had blood vessels running through grooves and wind flowing around the plates would have cooled the blood. The temperature-control theory has recently been discounted, since the closest relative to the common plate-wielding species, Stegosaurus stenops, had low surface area spikes instead of plates, implying that cooling was not important enough to require specialized structural formations such as plates. A study published in 2005 points to a simpler purpose: identification. Researchers also believe this may be the purpose behind other unique formations found in various dinosaur species.  The tail appears to have acted as a weapon. Its tail included four spikes, each about 2 to 3 feet long, an arrangement known as a thagomizer.
The skull of Stegosaurus was long and narrow, and its head was carried close to the ground, probably no higher than 1 meter (3 feet). Stegosaurus had a small brain, often said to be the size of a walnut. This is actually a misconception, for the brain is actually twice that size. Another well known misconception is that Stegosaurus had two brains, although that is untrue.
How It Lived
Stegosaurus lived during the Late Jurassic Period about 150 million years ago. It lived in Western North America.Tracks discovered by Matthew Mossbrucker of the Morrison Natural History Museum from Colorado suggest that Stegosaurus lived in multi-age herds. One group of tracks is interpreted as showing four or five baby stegosaurs moving in the same direction, while another has a juvenile stegosaur track with an adult track overprinting it.
In the media
Stegosaurus is among the most recognizable of dinosaurs.It has been depicted on film, in cartoons, comics, as children's toys, as sculpture, and even was declared the State Dinosaur of Colorado in 1982.
- Stegosaurus appears in the Jurassic Park novel and in The Lost World: Jurassic Park (both the novel and the movie). It has also been in several Jurassic Park videogames.
- A sketch of a Stegosaurus (based on a drawing by Ray Lydekker) forms an important plot point in the opening chapters of The Lost World by Arthur Conan Doyle.
- Evelyn Sibley Lampman's The Shy Stegosaurus of Cricket Creek is a children's book about twins who find a talking Stegosaurus on their ranch in Oregon. She also wrote a sequel, The Shy Stegosaurus of Indian Springs.
- The main hero and protagonist of Steve Cole's Astrosaurs series is an anthropomorphic Stegosaurus named Captain Teggs.
- In the classic monster film, King Kong (1933), the first creature that the band of rescuers meet, as they chase the abducted Fay Wray deep into Skull Island, is a roaring Stegosaurus, which charges. In the 2005 Peter Jackson remake Stegosaurus is nowhere to be seen, although in the extended edition the Triceratops-like fictional "Ferructus" takes its place.
- In the Hasbro toy series, Transformers, the Autobot Snarl transformed into a mechanical Stegosaurus. Snarl is affiliated with Autobots. He is the sub-group member of the Dinobots.
- Over the years, Stegosaurus has often been pitted in battle against large carnivorous dinosaurs, on both the big and small screen. It came up against Ceratosaurus in Journey to the Beginning of Time (1954), in The Animal World (1956), the documentary When Dinosaurs Roamed America (2001),and Jurassic Fight Club where it also faces Allosaurus (2008). It faced Allosaurus in episode two of "Walking with Dinosaurs" (1999), as well as in the special The Ballad of Big Al (2000), and in Dinosaur Valley Girls (1996). It has even been pitted against the Tyrannosaurus, in Planet of Dinosaurs (1978), Walt Disney's Fantasia (1940) which was the first time the defense of the spike tail was seen, in the cartoon series Dino Riders (1988), in the remake of the series Land of the Lost (1991–92), and in the anime TV series Dinosaur King (2007-2008).
- An ailing Stegosaurus is encountered by the characters in the novel Jurassic Park,but was replaced by a Triceratops in the film version. Although it makes no actual appearance in the film, the name is used; it is on one of the embryo vials stolen (misspelled as 'Stegasaurus'). A Stegosaurus also appeared in The Lost World: Jurassic Park, as one of the first dinosaurs to be seen. They also were seen briefly in Jurassic Park III.
- Stegosaurus is one of the three dinosaur types whose physical characteristics were combined by the designers at Toho, to create the Japanese monster Godzilla; the other two dinosaurs were Tyrannosaurus and Iguanodon. In the American version of King Kong vs. Godzilla this is remarked upon by a reporter, claiming Godzilla was half-Stegosaur, half-Tyrannosaur.
- Stegosaurus has also featured in several television series. For example, several Stegosaurus were featured in the 1989 animated TV Series, Dink The Little Dinosaur. A Stegosaurus has also appeared in one episode of Doctor Who. More recently, in 2010, a Stegosaurus appeared in the first Series 4 Prequel Webisode of the ITV series Primeval. It was incorrectly shown as having a horn on its head. This is due to the fact that, instead of creating another model, for the Stegosaurus, entirely, the special effects team decided to use the same Embolotherium model, which they had previously used, earlier on, in the making of Episode 3.9 of Primeval.
- Stegosaurus has also often been featured in children's cartoons. The Transformers toyline and related television series features four characters which can transform into stegosaurids: Snarl, Slugfest, Saberback and Striker. In The Land Before Time and its sequels, the character Spike is a young Stegosaurus. In the 1980s cartoon Dinosaucers, the character Stego is an anthropomorphic Stegosaurus who while still only a trainee soldier accomplishes difficult tasks despite his inexperience. Also, Stegz was an anthropomorphic stegosaur featured in the series "Extreme Dinosaurs". Ironically, despite the tiny brain size of Stegosaurus, he was the most intelligent of the characters in the show. One of the Dino Knights and Drago Clones in Dinozaurs were Dino Stego and his evil counterpart Drago Stegus.
- Gary Larson's The Far Side comic strip often used stegosaurs when he showed dinosaurs. The term "Thagomizer" originated as a joke from a Far Side comic strip, in which a group of cavemen in a lecture hall are taught by their caveman professor that the spikes were named in honor of "the late Thag Simmons". (The implication is that the Thagomizer was responsible for Thag's death.) The term has been popularly adopted by many palaeontological authorities, including the Smithsonian Institution.
- In September 2002, a hoax poster was presented at the Society of Vertebrate Paleontology entitled "The case for Stegosaurus as an agile, cursorial biped", ostensibly by T. R. Karbek (an anagram of R. T. Bakker) from the non-existent "Steveville Academy of Palaeontological Studies". This was reported in New Scientist magazine, where it was remarked that Stegosaurus was generally believed to be "about as cursorial as a fridge-freezer".
- Stegosaurus made several appearances in the famous documentaries Walking with Dinosaurs and Jurassic fight Club.
- Sculptor Jim Gary created several, almost-life-sized versions of Stegosaurus. One always was displayed among his traveling exhibition, Jim Gary's Twentieth Century Dinosaurs, and they are frequently used as an illustration of his work in books and articles about the artist because of their distinctive characteristics. One of these was displayed for months before the electrical engineering research facility at the University of North Carolina at Charlotte during a 2005 campus-wide display of the exhibition, which was hosted by Belk College, and became a mascot of sorts to students studying in nearby buildings.
- Howard the Duck walked under a Jim Gary Stegosaurus when a museum display of Gary's work was used as a set for the 1986 film.
- A battle between a Stegosaurus and a Tyrannosaurus similar to the Rite of Spring scene animated for Fantasia was created using new Audio-Animatronics for Disney's Magic Skyway attraction at the 1964 World's Fair. When the Fair ended, the attraction was dismantled. However, in 1966 the Dinosaurs were moved next to the Grand Canyon Diorama along the Disneyland Railroad to make the Primeval World. Tokyo Disneyland's Western River Railroad has the same diorama. A similar scene is depicted in Epcot's Universe of Energy pavilion.
Stegosaurus has long been featured in popular informational books about dinosaurs. This is ostensibly due to its status as being one of the most famous dinosaurs, in popular culture. Several older nonfiction books incorrectly stated that Stegosaurus had two brains, due to a mistake made by Marsh during the 1800's, in which a bundle of nerves located in the hips was thought to be a "second brain". However, newer informational works have corrected this, and most nonfiction dinosaur books published nowadays cite the correct fact that Stegosaurus had only one (albeit tiny!) brain, located in its skull, as all other known vertebrates do.
Walking with Dinosaurs
Mammals vs. Dinos
When Dinosaurs Roamed America
Jurassic Fight Club
Ultimate Book of Dinosaurs; by Paul Dowswell, John Malam, Paul Mason, Steve Parker
Dino Wars; by Jinny Johnson, consulted by Michael J. Bento
Vertebrate Paleontology; by Michael J. Benton
How do We Know Dinosaurs Existed; by Mike Benton
The Audubon Society Pocket Guides Familiar Dinosaurs; by Alfred A. Kn
The Dinosaur Heresies; by Robert T. Bakker
Rise and Fall of the Dinosaur; Joseph Wallace