Dryosaurus Characteristics

Dryosaurus had a long neck, long slender legs and a long stiff tail. Its arms, however, with 5 fingers on each hand, were short. Dryosaurus was about 8 to 14 feet (2.5 to 4.5 metres) long, 5 feet (1.5 metres) tall at the hips and weighed 80 - 90 kilograms (170 to 200 pounds). Dryosaurus eyes were quite large, leading many to believe that it possessed excellent eyesight. Dryosaurus had a horny beak and self-sharpening cheek teeth. Its upper front jaw was toothless. Some scientists suggest that it stored food in its cheeks. Dryosaurus from the Morrison Formation subsisted primarily on low growing vegetation in the ancient floodplain. Dryosaurus was a herbivore and probably a herd animal, which laid eggs and raised and protected its young after hatching.

A quick and agile, bipedal runner with strong legs, Dryosaurus used its tail as a counter-balance. It probably relied on its speed as a main defense against carnivorous dinosaurs such as the Allosaurus. Its intelligence, as measured by its Encephalization Quotient (brain-to-body ratio), was midway when compared to other dinosaurs.

Fossils have been found in the western United States and Tanzania and were first discovered in the late 19th century. The Tanzanian site proved to be an especially fertile hunting ground for Dryosaurus fossils, this specimen was previously called Dysalotosaurus (meaning 'lost wood reptile'). An expedition led by German paleontologist Werner Janensch found a great many fossils that represented Dryosaurus at many stages of development.

Dryosaurus was named by Othniel Marsh in 1878.