While dinosaurs walked Earth, many reptiles lived in the ancient sea! These prehistoric reptiles had large jaws, filled with sharp teeth used to hunt and devour unsuspecting prey. But this group of marine reptiles doesn't just have one deadly hunter in it. From one of the biggest marine reptiles ever discovered, the ichthyosaur, to the deadly mosasaurs, these ocean reptiles were the best hunters around! Through this classification exploration, readers discover more about these amazing ocean reptiles.