Theropod Locomotion

Theropod (carnivorous) dinosaurs spanned a range from chicken-sizedto elephant-sized animals. The primary mode of locomotion inthese dinosaurs was fairly conservative: Theropods were erect,digitigrade, striding bipeds. Even so, during theropod evolutionthere were changes in the hip, tail, and hindlimb that undoubtedlyaffected the way these dinosaurs walked and ran, a trend thatreached its extreme in the evolution of birds. Some derivednon-avian theropods developed hindlimb proportions that suggesta greater degree of cursoriality than in more primitive groups.Despite this, fossilized trackways provide no evidence for changesin stride lengths of early as opposed to later non-avian theropods.However, these dinosaurs did take relatively longer strides—atleast compared with footprint length—than bipedal ornithischiandinosaurs or ground birds. Judging from trackway evidence, non-aviantheropods usually walked, and seldom used faster gaits. Thelargest theropods were probably not as fleet as their smallerrelatives.