In the age of dinosaurs there were not only loads of giant reptiles walking on the earth but there was also mammal like the ichthyosaurus in the lakes and oceans. The ichthyosaurus was a fully functional prehistoric mammal that was very common with the dolphin. Not only did it have the same shape, but the same size too. This was the most fish-like as opposed to other marine dinosaurs. From all that have found it was hard to tell what their skin was like, but many ichthyosaurus' were found with their fins preserved. ichthyosaurus' were found all over the world, unlike other dinosaurs which were only found in certain regions. Another interesting proven fact is that the ichthyosaurus did not come ashore to lay eggs. They gave birth to live babies. Fossils were found where babies were actually emerging from their mother's body. They did have to swim to the surface for oxygen but they are estimated to have a speed of 35m/p/h so it's no wonder that we know they must've been able to dive very deep in the ocean for long periods of time.

This species has gone through much evolving through the Triassic to the Cretaceous era. It's quiet amazing actually. In the beginning of the age of dinosaurs there were very large like a whale but as millions of years past they evolved smaller to 5 to 7 feet in length. Not only that, but they developed a dorsal fin. This type of evolution is very rare to track. Often there are traces of birds getting a lighter feather color for example, but developing a whole new body part is just very rare. Even with humans are has only been evidence of a slight average height difference.