Dryosaurus altus
Name	Dryosaurus altus
Class	Iguanodontidae
Name Translation	High Oak lizard
Period	Late Jurassic
Location	Western U.S., Tanzania
Diet	Plants
Length	Around 10 feet (3 meters)

Dryosaurus altus meaning "high oak lizard", due to the vague oak shape of its cheek teeth was a species of an ornithopod dinosaur that lived in the Late Jurassic Period. It was a small variety of iguanodont (formerly classified as a hypsilophodont). 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" (Lost wood reptile). An expedition led by German paleontologist Werner Janensch found a great many fossils that represented Dryosaurus at all stages of development.

Dryosaurus had a long neck, long, slender legs and a long, stiff tail. Its 'arms', however, with five 'fingers' on each "hand", were short. It was about five feet (1.5 m) tall (at the hips) and weighed about 170 to 200 pounds (80 to 90 kilogram|kg). Its eyes were quite large, leading many to believe that it possessed excellent eyesight.

Dryosaurus had a horny beak and cheek teeth and, like other ornithopods, was a herbivore. Some scientists suggest that it stored food in its cheeks. It was probably a herd animal, which raised and protected its young after hatching.

A quick and agile 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.

Its intelligence, as measured by its EQ, (Encephalization Quotient) (brain-to-body ratio), was midway when compared with other dinosaurs.