Fossils can tell us a great deal about the past. Studying fossils, researchers have found the oldest known fossil animal. It is called an archeopteryx. The researchers believe it is the "missing link" between dinosaurs and birds. It contains features of each.

On the one hand, the fossil shows clear impressions of feathers. The animal "frozen" in time has an expanded braincase. It also has large eye sockets and a pronounced beak, just like those of modern birds. In addition, the animal's hind legs have three claws at the ends. Also, it has well-developed wings. The structure and arrangement of its feathers indicate it could fly.

On the other hand, it appears to have well developed teeth, like a theropod (meat-eating dinosaur). It also has a long, well-formed tail. These are traits that are similar to those of small dinosaurs. Scientists can only guess about its status until more such creatures are found to support their theory.