Classifying Animals

Fish have existed on Earth for more than 500 million years. The first fish were eel-shaped, with slimy skin. Find out more in Fish, one of the titles in the Classifying Animals series.

All reptiles are cold-blooded and have dry, scaly skin. Ancient reptiles first appeared more than 300 million years ago. Find out more in Reptiles, one of the titles in the Classifying Animals series.

The word amphibian comes from a Greek word meaning "to live a double life." These animals are known for spending part of their lives in water and part on land. Find out more in Amphibians, one of the titles in the Classifying Animals series.

Mammals can be found living in habitats all over Earth. Many mammals have hair or fur on their bodies. Find out more in Mammals, one of the titles in the Classifying Animals series

There are more than 10,000 known species of bird on Earth. These animals have feathers and many species are able to fly. Find out more in Birds, one of the titles in the Classifying Animals series

All insects have three main body segments. These are the head, thorax, and abdomen. Find out more in Insects, one of the titles in the Classifying Animals series.