Amphibians include frogs, toads, newts, salamanders, and caecilians. They are vertebrate animals which spend part of their life in water and a different part of their life cycle on land. Some of the early amphibians, known only from fossils, had scales but the survivors of the class, all falling in the subclass Lissamphibia, lack scales and are smooth.

Usually starting out their lives in water, and then moving onto land as they mature. Amphibians are cold-blooded or poikilothermic vertebrate animals. They differ from reptiles in that they lack scales and generally return to water to breed. They are one of three types of Amphibians. Anura, also called Salientia, (frogs and toads), caudate (salamanders and newts) and caecilians (worm-like amphibians).

Frogs breath and drink through their skin, so pollution, pesticides, and acid rain have really devastating effects on them. This is particularly true in their developmental stages. In addition, chemicals can interfere with a frog's natural ability to fight off diseases and infection. Just imagine what chemicals spilled out of factories must do to the poor critters!

Amphibians together with reptiles make up a larger group called Herps. The study of reptiles and amphibians is called Herpetology. A herptile is an individual herp. A person who keeps and breeds herps is called a herpetoculturist and the hobby is called herpetoculture.