Quadrupedal tracks are different from biped tracks in that they have front and back prints which differ from each other in size and shape (rear prints being larger than front prints). Also, each foot can have up to five digits. The imprints are rounded and the digits are very blunt. Due to the walking motion, the front prints are often overlapped or entirely covered by the rear footprint. Quadruped tracks are rare compared to biped tracks. Of those which have been discovered, most come from the sauropod.