Theropod locomotion

Theropod (carnivorous) dinosaurs spanned a range from chicken-sized to elep hant-sized animals. The primary mode of locomotion in these dinosaurs was f airly conservative: Theropods were erect, digitigrade, striding bipeds, Eve n so, during theropod evolution there were changes in the hip, tail, and hi ndlinb that undoubtedly affected the way these dinosaurs walked and ran, a trend that reached its extreme in the evolution of birds. Some derived non- avian theropods developed hindlimb proportions that suggest a greater degre e of cursoriality than in more primitive groups. Despite this, fossilized t rackways provide no evidence for changes in stride lengths of early as oppo sed to later non-avian theropods. However, these dinosaurs did take relativ ely longer strides-at least compared with footprint length-than bipedal orn ithischian dinosaurs or ground birds. Judging from trackway evidence, non-a vian theropods usually walked, and seldom used faster gaits, The largest th eropods were probably not as fleet as their smaller relatives.