Hypsilophodon was a small, fast-running ornithopod dinosaur that lived during the Early Cretaceous period, around 125 to 120 million years ago. Measuring about 2 meters (6.6 feet) in length and weighing up to 20 kilograms (44 pounds), it had a lightweight, bipedal build with strong hind legs adapted for swift movement. Hypsilophodon had a beak-like mouth and cheek teeth designed for processing plant material, indicating it was herbivorous. Its fossils have been primarily found in Europe, particularly in the Isle of Wight, UK, providing valuable insights into the diversity of small herbivorous dinosaurs.