Labels:text | screenshot OCR: x SWIMMING AND MOVEMENT Elas mosaurus swam by means of its flippers. People once supposed that plesiosaur flippers had worked like oars, rowing these reptiles along. Yet each flipper seems to have been shaped not like an oar, but like the wing of a bird or an aircraft. Scientists now think that plesiosaurs used flippers as hydrofoils: flapping them up and down to "fly" through the water rather as penguins swim with their flipper-shaped wings. Instead of all four flippers working together, the pairs probably alternated: when the front pair flapped down the hind pair rose, and vice versa.
