Tracks Reveal Dinosaurs Swam

Sets of scratch marks from the theropod swiming trackway. A-D are left-side claw prints; E-H are right-side claw prints. Note the delicate nature of the scratches and the marked asymmetry in response to a water current evidenced by flow ripple-marks; the dinosaur was probably strugling to maintain a straight path. Scale bar is 10 centimeters. Credit: GSA/Geology/R. Ezquerra et al.