Temporal range: Late Jurassic
An artist's illustration of Dryosaurus altus
Scientific classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Subphylum: Vertebra
Class: Sauropsida
Superorder: Dinosauria
Order: Ornithischia
Suborder: Ornithopoda
Genus: Dryosaurus
Marsh, 1894
Species: D. altus
Binomial name
Dryosaurus altus
Marsh, 1878

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 lettowvorbecki skeleton

Dryosaurus altus Skeleton.

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 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.

In the Media[]

  • Dryosaurus makes an appearance in the Walking with Dinosaurs Episode 2 Time of The Titans & the documentary special: The Ballad of Big Al, as a target of prey for predators such as Allosaurus.
  • Dryosaurus are mentioned in the chapter The Park of the first novel of Jurassic Park: "In the harsh quartz lights, the hypsilophodont's green head hung down out of the sling, the tongue dangling, the eyes dull. ... The hypsy was a small dryosaur, seven feet long, weighing about five hundred pounds. The dryosaur coughed, and then moved slowly across the field, away from the lights." The Dryosaurus is mentioned to be dark green with mottled brown spots.
  • Dryosaurus appeared in the video game Jurassic World: Evolution.
  • Dryosaurus is a playable dinosaur in the isle.
  • Dryosaurus altus appears in Prehistoric Kingdom.