Some dinosaurs appear to have been able to run, perhaps relatively quickly. In particular, small ornithopods (such as hypsilophodontids) and long-limbed theropods (such as ornithomimosaurs and troodontids) may have been fast animals. Most herbivorous dinosaurs were not built in this manner, however, but rather resembled elephants or rhinos in their limb design. Large herbivores— ceratopsians, thyreophorans, sauropods, and hadrosaurs—do not appear to have been especially fast animals. And their contemporary large predators were often similarly constructed.
One problem in estimating speed in dinosaurs derives from the varied ways in which bone structure is related to function. "Cursorial", or running, animals such as ungulates and cheetahs tend to have long limbs, especially the segments near the toes. Most of their limb muscles are close to the hip and shoulder. But whereas some cursorial animals are indeed fast runners, others use these limb adaptations for long-distance travel. It is difficult to distinguish between these two strategies from bones alone, and therefore "cursorial" dinosaurs may have been adapted for either mode of locomotion.