Combinations of footprints of different species provide clues about the interactions of those species. Even a set of footprints of a single animal gives important clues, as to whether it was bipedal or quadrupedal. In this way, it has been suggested that some pterosaurs, when on the ground, used their forelimbs in an unexpected quardupedal action. A creature named Cheirotherium was, for a long time and still may be, only known from its fossilised trail. Its footprints were first found in 1834, in Thuringia, Germany, dating from the Late Triassic Period.