Hypsilophodon foxii

Hypsilophodon foxii's slender skeleton provided maximum support but added minimal weight to the body. This small, two-legged plant-eater grew up to 2.3 metres long. H. foxii's bones were thin-walled and hollow, like those of a gazelle. Its thigh bones were short so they could be pulled quickly back and forth, allowing the dinosaur to sprint. Its long and slender feet ended in thin toes and small hooves, sustaining long periods of running. Hypsilophodon had no means of defence, and could only escape predators by using speed and manoeuvrability. Hypsilophodon is known only from 125-million-year-old rocks on the Isle of Wight.