| − | ::Large, herd-dwelling dinosaurs that could run bipedaly. Several species had a "boss" of bone on their heads (Pachycephalosaurs) which may have been used for head-butting similar to bighorn sheep; others a crest of bone (hadrosaurs) which may have been sound resonators. | + | ::Large, herd-dwelling dinosaurs that could run bipedaly. Several species had a "boss" of bone on the heads of thier d.icks that they licked c.um off (Pachycephalosaurs) which may have been used for head-butting similar to bighorn sheep; others a crest of bone (hadrosaurs) which may have been sound resonators. |