The body length of ichthyosaurs is mostly between 2 and 4 meters, some species are smaller, and some species can exceed 4 meters in length.

When you see these marine reptiles, your first impression is that they resemble dolphins. But dolphins are mammals, and these are reptiles, which are completely different animals. However, we know that marine reptiles, like dolphins, also have to breathe air and give birth to bouncing babies. The evidence comes from some amazing fossils discovered in Germany - an ichthyosaur baby with half its body still in its mother's birth canal. Bigeye Ichthyosaurus has two other characteristics that pinpoint its habits. First of all, their eyes are very large, which means they are used to hunting in low-light areas, so the Bigeye Ichthyosaur in the film hunts at night. Secondly, the smooth and streamlined body of Bigeye Ichthyosaurus and its powerful tail show that they can swim quite fast. The difference between Bigeye Ichthyosaurus and dolphins is that the tail hook of Bigeye Ichthyosaur is vertical like a tuna instead of horizontal. This means that the big-eyed ichthyosaurs may not be able to jump to the water like dolphins, although they still have to swim to the sea surface to breathe from time to time. So will they jump on the sea surface? Judging from the speed at which they swim, they should also be able to jump. Dolphins jump to shake off parasites, and ichthyosaurs must have had the same parasite problem.