Meet a heavily-armored, 7-ton male Stegosaurus, an interesting enigma. He too is a herbivore, but very dangerous.
— Allen, about Stegosaurus
in Time of the Titans

Stegosaurus (name meaning "Roof Lizard") is a genus of armored stegosaurid dinosaur that originated during the Late Jurassic period in what is now North America. One of the world's most easily recognizable dinosaurs due to the large plates on its back and the lethal spikes, known as the thagomizer, on its tail, Stegosaurus is the largest of the Stegosaur family of dinosaurs, measuring 11 meters long, standing around 5 meters tall, and weighing 7 tons. However, it was also one of the least intelligent dinosaurs, having a brain the size of five walnuts.

In the Series 2 episode "Time of Giants", a small group of Stegosaurus were brought back to the park from Late Jurassic North America 150 million years ago. They them also brought some of their eggs back to the park so they can incubate them and hatched them.


Era & DiscoveryEdit

Stegosaurus lived during the Late Jurassic period from 156 – 145 million years ago. It shared the environment with the massive sauropods and little bipedal dinosaurs as well as the apex predator of the time, Allosaurus.

Stegosaurus was first discovered in Colorado by Othniel Charles Marsh in 1877. Since its very first discovery, Stegosaurus has become one of the most famous and easily identifiable dinosaurs in the world.

Physical AttributesEdit

ImagesBA BrachiosaurusWithStegosaurus

Stegosaurus was a giant, heavily-armored herbivorous dinosaur that stood 14 feet (4 m) tall at the hips (17 feet (5 m) at tip of the tallest plate), measured about 36 feet (11 m) in length, and weighed 7 tons (15,000 lbs.), making it the largest member of its family. Stegosaurus was primarily green and yellow with dark green splodges. The spots were outlined with white. The plates were translucent and the rim of the plates was blueish-green.

Stegosaurus is famous for its distinctive row of 17 large spinal bony plates arranged in a double row along is arch-shaped back, primarily there for display rather than defense, which would be an odd place for armor. The plates along were embedded in the skin of the animal, not attached to its skeleton, which is why in most fossil finds the plates are separated from the body. The function of the plates has been much debated. Initially thought of as some form of armor, researchers have also proposed that they may have helped to control body temperature. Wind tunnel tests have suggested that the plates are well shaped to gather and dissipate heat.

Thagomizer Edit

Stegosaurus is equipped with four, lethal spikes on the end of its tail, known as the thagomizer, each measured a meter long and that made it such a lethal dinosaur. Its tail spikes were known for being, without question, one of the most dangerous weapons ever evolved by a herbivore, let alone, a dinosaur. Such a weapon appears as necessary, considering Stegosaurus coexisted with large predatory theropod dinosaurs, such as the fearsome Allosaurus.

Additionally, though there are normally four spikes, some rare specimens of Stegosaurus have been discovered to possess eight. It is currently unknown what caused these particular specimens to possess four more spikes. Stegosaurus could weal those spikes with devastating effect, despite having a very small and remarkably tiny brain, at only 80 grams, for their body size, which is what they were also known for, despite their hefty size, and was apparently sufficient for their needs.

Behavior & TraitsEdit

Stegosaurus generally lived in pairs, but they have been known to have traveled in big and little herds as well. They also were often solitary creatures, as they sometimes ate, drank, and even traveled by themselves. Stegosaurus was not the brightest of beings. Due to its low intelligence, it was unable to probably determine what was dangerous and what was harmless. Stegosaurus would often mistake small dinosaurs, even harmless ones like Dryosaurus, as a threat and those unfortunate animals would often be slaughtered.

Although Stegosaurus was a plant-eating dinosaur, it was nevertheless a noticeably dangerous creature. Whenever threatened by predators, Stegosaurus could flush blood into their plates and that created a colorful but terrifying display, which was capable of confusing and intimidating even a fully grown Allosaurus. This was intended as a warning, but when directly attacked, Stegosaurus wielded the spikes on its tale with devastating effect. Stegosaurus was a species of dinosaur that stood and fought with lethal spines.

Journal EntryEdit

With their distinctive dorsal plates, Stegosaurus (“Roofed Lizard”) is one of the most universally recognized dinosaurs in the world. A species of heavily-armored dinosaur that is unlike any animal living today, Stegosaurus is said to be something of an icon of the dinosaur age, having been different in appearance from anything known, past or present. In other words, there is no animal that looks like Stegosaurus.

Standing 14 ft. tall at the hips, measuring 36 ft. long, and weighing more than 6300 kilograms, Stegosaurus had a double row of 17, bony plates on its back. Rather than for defense, these plates were for display during courtships but also to lose body heat and cool down as well as to warm up when too cold, much like the earlier and smaller Edaphosaurus. Additionally, when confronted by a predator, Stegosaurus could also force blood into their plates, which could create a terrifying display of color that could confuse and even intimidate predatory dinosaurs.

They are highly social animals, but can become quite aggressive when threatened. In addition to the bony plates on its back, Stegosaurus was also armed with four, large and formidable spikes at the end of its tail, known as Thagomizer, to warn off potential predators. As long as baseball bats and said to be the greatest dinosaur weapons ever discovered, these weapons were perfect for impaling attackers and, given the chance, killing them.

— Allen, in his journal, about Stegosaurus



  • Stegosaurus is the largest, as well as one of the only two members of its family to be brought to the park the other being Kentrosaurus.
  • The sound effects of Stegosaurus are that of bull, camel, elephant, tiger, and walrus sound effects. They also make the sound effects used in the Discovery Channel documentary "When Dinosaurs Roamed America".
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