Dryosaurus (name meaning "Oak Lizard") is a genus of an ornithopoddinosaur that lived in the Late Jurassic period. It was an iguanodont (formerly classified as a hypsilophodont). Fossils have been found in the western United States, and were first discovered in the late 19th century. Known specimens were about 8 to 14 feet (2.4 to 4.3 m) long and weighed 170 to 200 pounds (77 to 91 kg). However, the adult size is unknown, as no known adult specimens of the genus have been found. Dryosaurus had a horny beak and cheek teeth and, like other ornithopods, was a herbivore. Some scientists suggest that it had cheek-like structures to prevent the loss of food while the animal processed it in the mouth. A quick and agile runner with strong legs, Dryosaurus used its stiff tail as a counterbalance. It probably relied on its speed as a main defense against carnivorous dinosaurs.
It is the main dinosaur in the Late Jurassic segment. 3 Dryosaurus look for water but fail to find any. Suddenly, a Ceratosaurus comes out of ambush and attack the Dryosaurus. The Ceratosaurus catches the slowest youngster. The 2 remaining Dryosaurushide under a Camarasaurus. Later, while some more Camarasaurusfeed upon the trees, the Dryosauruspick their scraps of tree leaves. Lastly, the Dryosaurus run from the Ceratosaurus again but are saved by an Allosaurusthat kills the Ceratosaurus.