Dryosaurus (Dryosaurus altus) belongs to the family Dryosauridae and inhabited what is now North America during the Late Jurassic, approximately 155 to 145 million years ago. Its name translates to "oak lizard," indicating its presumed diet and habitat. The first fossils of Dryosaurus were discovered in 1876 in Colorado, USA, and subsequent finds have provided valuable insights into the biology and lifestyle of this intriguing dinosaur.

Dryosaurus was a small to medium-sized dinosaur, measuring around 2 to 4 meters in length and weighing approximately 100 to 200 kilograms. It possessed a lightweight build with long, slender legs, indicating its exceptional agility and speed. Its neck was elongated, and its head boasted a beak-like snout and leaf-shaped teeth, well-suited for browsing on vegetation. Additionally, Dryosaurus possessed long hind limbs and a long tail, providing balance and agility during locomotion.

Dryosaurus inhabited lush forested environments during the Jurassic period. Its lightweight and agile build suggests that it was primarily a bipedal dinosaur, capable of swift movements to evade predators. As an herbivore, Dryosaurus likely fed on low-lying vegetation such as ferns, horsetails, and cycads.