Hypsilophodon foxii HIP-sih-LOH-foh-don
"High-crested tooth"
You 1.8 m (5.9 ft) tall
Hypsilophodon 2 m (6.6 ft) long
as long as 2 people standing fingertip to fingertip
- Length
- 2 m (6.6 ft) — About 2 m long, ~20 kg — a fast bipedal herbivore the size of a small deer.
- Period
- Early Cretaceous (130–125 Mya)
- Place
- Europe · England · Isle of Wight
- Food
- Herbivore — Low-growing ferns and other soft plants, chewed quickly to escape predators.
- Clade
- Hypsilophodontidae Dinosauria Ornithischia Cerapoda Ornithopoda Small fast bipedal plant-eaters.
A small, agile runner of Early Cretaceous England with a parrot-like beak.
Hypsilophodon was a small fast-running herbivore — built to flee. Long legs, light bones, big eyes for spotting trouble. For a long time scientists thought it lived in trees, but the foot anatomy turned out to be wrong for climbing. It was a ground runner, sprinting through the Early Cretaceous forests of southern England.
More about Hypsilophodon
Discovery
The first remains were found in 1849, and the type species was named in 1869. Later, abundant discoveries on the Isle of Wight gave a good impression of the build of the species.
The name means "high-crested tooth".
Was Hypsilophodon really an ornithopod?
The text describes it as a neornithischian that has traditionally been considered an early member of the ornithopodA beaked, plant-eating dinosaur group that includes the duck-bills. group. It also notes that recent research has put this classification into question, so its exact place in the family tree is debated rather than settled.
How do we know it had cheeks and chewed its food?
The teeth are set far back into the jaw, which the text says strongly suggests it had cheeks, an advanced feature that would have helped it chew. Its 23 to 27 upper and lower teeth had vertical ridges and appear to have been self-sharpening as the jaws closed, so a simple chewing mechanism is inferred from the dentition rather than directly observed.
What we know
- Small and lightly built — about deer-sized, all running anatomy.
- Big eyes facing slightly forward, useful for spotting predators.
- Once thought to be tree-climbing — that idea was abandoned in the 1970s.
- Many skeletons known from the Isle of Wight in southern England.
What we guess
- Whether it traveled in groups for protection — likely, based on multi-individual finds.
- Top speed — bone strength models suggest 30–40 km/h.
- Whether young Iguanodon and Hypsilophodon competed for the same plant food.