Liopleurodon was the mightiest aquatic predator of all time. Its 25 metre long body would have cruised silently through the shallow seas of the late Jurassic, propelled by its flapping flippers.
Liopleurodon was a hunter. Its long jaws and rows of needle-sharp teeth would have made marine crocodiles, the giant fish Leedsichthys, ichthyosaurs and even other pliosaurs vulnerable to attack.
Liopleurodon's nose allowed it to smell underwater. This allowed Liopleurodon to smell its prey from some distance away. Despite needing to breath air, Liopleurodon spent its entire life at sea and was unable to leave the water. Consequently, it would have given birth to its young alive and may have visited shallower water to breed.
Until recently the longest confirmed adult specimen was 18 metres. But in 2003 a fossil pliosaur (possibly a Liopleurodon) was discovered in Mexico which was 18 metres long and still a juvenile - suggesting that they grew considerably larger than this.