The Dryosaurus (aka tree lizard) was a small but speedy Ornithopoda that lived primarily in North America. These tiny bipedal dinosaurs may look like scary theropods, but their flat teeth allowed them only to eat plants. These dinos liked to travel in groups and used quick footwork to escape hungry predators.
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Some Quick Facts about the Dryosaurus
| Name | Dryosaurus (meaning “Oak lizard” or “tree lizard”) |
| Type of dinosaur | Ornithopoda |
| Territory | Forests, marshes, Tanzania, Western United States (Colorado, Utah, and Wyoming) |
| Size | 10 feet long, 5.6 feet tall |
| Color | Green/brown |
| Interesting Characteristics | No teeth on the upper jaw, incredibly fast |
| Diet | Plants |
| Major Threats | Larger meat-eating dinosaurs, like the Ceratosaurus |
The Dryosaurus was a small yet speedy dinosaur that lived in the upper Jurassic to the early Cretaceous period (around the same time as the Torvosaurus). As a herbivore, it lived in the forested areas of North America and dined on plants, seeds, and berries.
What was a Dryosaurus’ Nickname?
We know that the nickname for Dryosaurus means tree lizard or oak lizard, but we don’t know why. There are a few theories on why Marsh gave this nickname to this Mesozoic dino.
One theory is that it earned its name based on the shape of its teeth. The few cheek teeth it had on its lower jaw resembled the leaves of an oak tree.
However, some scientists don’t believe that’s where it got its name. In a separate camp, others believe that the nickname “tree lizard” comes from where the Dryosaurus lived. These late Jurassic period dinosaurs liked to live in forested areas with plenty of trees to eat, hence the name Tree Lizard.
What Did the Dryosaurus Look Like?
While the Dryosaurus has many similar characteristics to early sauropods like the Stegosaurus, this ornithischian dinosaur was different. It was surprisingly short and weighed just under 200 pounds. It was around 10 feet long and walked around on its strong hind legs. It was one of the smallest dinos found at the Carnegie Quarry.
While many herbivore dinosaurs were slow, the Dryosaurus was surprisingly fast. It used its very strong back legs and tail to propel it forward to escape from predators. Even though it was fast enough to catch a meaty snack, its teeth were not built for eating meat.
The most exciting feature of the Dryosaurus was its unique jaw structure that was perfect for chomping down on leafy green in forested areas.
How Many Teeth Did a Dryosaurus Have?
While we don’t know how many teeth the Dryosaurus had, we know its teeth were unusual.
It had a long beak-like snout and was missing teeth on its upper jaw. The lack of teeth on the Dryosaurus made it difficult to eat meat, so paleontologists concluded that it was an herbivore. It only had a series of leaf-shaped teeth on its back cheeks, which some believe allowed it to store food in its mouth.
How Fast Did the Dryosaurus Run?
The Dryosaurus was one very fast dinosaur. Its powerful back legs and stiff, tail propelled it at speeds that peaked at around 50 miles per hour. To put that into perspective, the fastest man alive (Usain Bolt) can run about 27 miles per hour. If you were to run a race with the Dryosaurus, you would lose!
Palenologosits believe that the Dryosaurus developed its speed to allow it to escape from predators quickly. As a small herbivore, it could only use its quick and agile speed to avoid being lunch to a hungry T. rex or Allosaurus.
How Was the Dryosaurus Discovered?
In 1876, Samuel Wendell Williston uncovered the first Dryosaurus fossils in Wyoming, USA. Later in 1894, Othniel Charles Marsh classified the unearthed fossils as the Dryosaurus. Many believe that Marsh named it Dryosaurus from the Greek word ‘drys,’ meaning ‘tree oak,’ based upon where this dino lived.
This initial fossil specimen of the Dryosaurus was just another dino found in the Morrison Formation and was dated to live in the Tithonian area around 150 million years ago.
But the story of the Dryosaurus discovery doesn’t end there. A family passing by a recently bulldozed site noticed what looked like a dino fossil. This site, found near Uravan, Colorado, unearthed some pretty unique finds.
There, paleontologists found unfossilized bones of the Dryosaurus and shells of eggs in fantastic condition. Nearly 2,500 Dryosaurus fragments were removed from this site, and we learned so much about this dino!