Ichthyosaurus, the "Fish Lizard," was described by Jules Verne as "the most terrible of the ancient monsters of the deep." However, the real Ichthyosaurus was very different from the hundred-foot-long monster depicted in "Journey to the Center of the Earth." These small, two-meter-long, torpedo-shaped reptiles were rather dolphin-like. They moved their tails side-to-side like fish, but still breathed air, controlled their boyancy, and gave birth to live young. Ichthyosaurus lived from the late Triassic to the early Jurassic Periods across what is now Europe and Asia. It was a common sight in both coastal and open ocean habitats, giving it an extremely wide range to roam. It was a successful carnivore, feeding on smaller aquatic reptiles and fish with its pointed jaws and sharp, conical teeth. Fossils of other ichthyosaurs show effects of decompression sickness, a condition that arises when a creatures goes from a high pressure environment to a low pressure one too quickly. It is likely that Ichthyosaurus, like its relatives, dove to great depths to hunt and would suffer from the same illness if it returned to the surface too quickly. Its large eyes allowed it to hunt fish by sight, even in the low light of great depths.