Whales and dolphins are both mammals that live in the sea. You may think that dinosaurs were the biggest thing that ever lived but actually the blue whale is twice the size of the biggest dinosaur. The bottlenose dolphin, the genus Tursiops, have found a way to catch fish that no other animal has discovered how to do it them selves, they whip their tail up and down on the sand making a circle of whipped up sand around the fish, then the fish need to jump free right into the dolphins mouth.