Dinosaurs a visual encyclopedia Smithsonian

We are surrounded by fascinating animals. Gigantic whales and sharks swim in the oceans. Spectacular large animals—such as big cats, elephants and giraffes— live on the land. Wild places everywhere are filled with insects, birds, and thousands of other living things. But Earth’s fossil record shows us that these creatures are just the tips of an amazing hidden tree of life that stretches back hundreds of millions of years into the distant past. This rich fossil record tells us an incredible and complicated story of evolution and extinction. While modern animals may well be fascinating, those of the past were often bigger, stronger, or much, much weirder.