Overview
Hypsilophodon foxii was a small, bipedal ornithopod dinosaur
living in what is now Europe during the Early Cretaceous.
Its name, meaning “high-ridged tooth,” references the distinct shape of its teeth.
Typically weighing around 60–70 lbs and measuring about
6 ft in length, Hypsilophodon was known for its speed and
agility—factors that likely helped it avoid predators in forested habitats.
Fossil discoveries indicate it had long hind limbs suited for
running, and its stiffened tail provided balance while navigating dense vegetation.
Though once considered tree-climbing, most modern research suggests it was a
ground-dweller relying on swift sprints rather than arboreal tactics.
Quick Facts
Diet
Herbivore (plants, seeds, possibly fruit)
Speed
Estimated up to ~25 mph
Weight
~60–70 lbs (~27–32 kg)
Bite Force
~200 psi (estimated)
Discovery & Significance
Hypsilophodon was first described in the mid-19th century from fossils found on
the Isle of Wight in southern England. Early theories labeled it as an arboreal
dinosaur, but subsequent research refuted that notion. Nonetheless, the genus
remains key to understanding basal ornithopod evolution—its
slender body and bipedal stance showcasing how smaller herbivores adapted for
speed and agility in lush Cretaceous environments.
The structure of Hypsilophodon’s hind limbs and its specialized teeth indicate
a dinosaur well-suited to a low-browse diet, feeding on
ferns, cycads, or seeds near ground level. Despite its modest size,
Hypsilophodon thrived in various European locales, forming part of the
broader ornithopod radiation that became abundant before larger hadrosaurs
appeared later in the Cretaceous.
More Details
Among the smaller dinosaurs of the Early Cretaceous, Hypsilophodon stands out as a swift, lightweight herbivore discovered primarily on England’s Isle of Wight. While its remains were initially mistaken for those of a juvenile Iguanodon, detailed studies by pioneers such as Thomas Henry Huxley and John Whitaker Hulke revealed it to be a unique genus, distinguished especially by certain vertebral and dental features. Most authentic fossils come from a single, meter-thick layer of marl known as the “Hypsilophodon Bed,” giving us a wealth of skeletal data for analysis.
Typically reaching around 1.5 meters in length and weighing roughly 20 kilograms, Hypsilophodon possessed a pointed head with an edentulous (toothless) premaxilla and triangular, chisel-like cheek teeth. These traits suggest a high-quality vegetarian diet of young leaves and roots, although some researchers have proposed occasional omnivory. The dinosaur’s jaws were proportioned so that the lower set of teeth fit neatly inside the upper, and the premaxilla itself formed a sharp beak likely used for clipping tender plant shoots.
Hypsilophodon lived on two legs and was built for running. Strong hind limbs, stiffened tail vertebrae, and a rigid trunk allowed it to maintain agility while evading predators. Historically, some paleontologists believed it to be an armored, tree-dwelling species, but later research has discredited these ideas: ossified tendons once interpreted as armor were in fact part of its specialized rib cage, and any notion of arboreal habits has been conclusively debunked by functional anatomy studies.
Though at one point known from other European locations, all current evidence indicates the only legitimate Hypsilophodon fossils come from the Isle of Wight’s Wessex Formation. Its evolutionary relationships are still somewhat debated; previously assigned to Hypsilophodontidae or basal Ornithopoda, more recent studies place it in a basal position among neornithischian dinosaurs. Whatever its precise classification, Hypsilophodon remains an excellent window into the life and adaptations of small, bipedal herbivorous dinosaurs in Early Cretaceous ecosystems.