Theropods trackways show little deviation from the midline of travel, as if they were walking on a tightrope. This foot belongs to Allosaurus , a large Jurassic theropod. Notice the three toes with a relatively narrow width. This foot belongs to Tyrannosaurus , a large Cretaceous theropod. Although separated by millions of years, both Allosaurus and Tyrannosaurus would have left similar footprints that were attributable to large theropods.
Foot is from a replica mounted in Western Colorado's Dinosaur Valley, Grand Junction, Colorado.
Notice the greater depth of the track in the toe region, which suggests a horizontal posture for the dinosaur while it was walking. However, a deep claw impression is visible on the far left toe, probably indicating a shift of the theropod's weight to the left. The right-left bipedal progression along a narrow midline, in addition to the footprint shape, is characteristic of theropods. Ornithopods were also capable of leaving bipedal trackways but were mostly facultative bipeds. Ornithopod tracks are present in deposits from the Jurassic through the Late Cretaceous but are particularly common in Late Cretaceous deposits.