Liopleurodon was a true giant of a marine reptile carnivore. Adults could reach 25 metres and could possibly even attain a length 30 metres long. Liopleurodon were gigantic weighing in at a staggering 150 tonnes and. The largest teeth were 30 cm long with jaws that were 3 metres long and the head's total length was 5 metres. The flippers which could reach 4 meters in length helped it to catch even the fastes marine animals like Optalmosaurus. They would have lived as solitary carnivores, most liekly behaving in the same way as some apex predator sharks do in their habitats - swimming at depth, and looking for silhouettes at the surface to then attack with extreme velocity and fatal energy. No individual solitary carnivore has ever been this large or this deadly. It was was the largest carnivore ever and is second to only the Blue Whale in size and possibly the huge fish Leedsichthys but no other animal not even the truly immense sauropods like Seismosaurus which weighed 50 tonnes less than Liopleurodon even comes close (although Seismosaurus was much longer than any Liopleurodon at 45 metres it still only weighed 100 tonnes larger than any other dinosaur prehaps but much lighter than LIopleurodon).
Liopleurodon featured in the third episode of Walking with Dinosaurs - Cruel Sea. At the beginning, one Liopleurodon snatched a Eustreptospondylus off a shore, and took it underwater. Later apparently the same animal, an old male of immense size even for his species, attacked and killed a female Ophthalmosaurus that was unfortunate enough to be attacked whilst having difficulties giving birth. She was bitten in two. Then he fought a much younger female for territory, and won, injuring one of her flippers. But in the end, he was beached by a fearsome Jurassic tropical storm, and became a living banquet for Eustreptospondylus. However, it was made clear that whilst the giant was still alive, his great jaws were lethal, and instead of eat him alive - because the Dinosaurs themselves could be eaten alive - the scavengers bided their time and waited for the old Liopleurodon to pass away. The marine adapted lungs of the Liopleurodon were being crushed under the giant's own 150 tonne body. Death by exhaustion and suffocation essentially, was inevitable. When the Eustreptospondylus were compared to the Liopleurodon, it just showed how enormous it was.