An amphibian, along with mammals, birds, fish and reptiles, is a vertebrate animal. This means it has an internal skeleton made of bone or cartilage and a backbone which is also called a vertebral column.
Amphibians include frogs, toads and newts. They are cold-blooded creatures (or ectothermic) and their body temperature is determined by the air, soil and water temperature around them. Adult amphibians have lungs, but they are also able to breathe through their skin which is smooth and needs to stay moist.
The word amphibian derives from the Greek words ‘amphi’ (meaning 'both') and ‘bio’ (meaning 'life'). In other words 'amphibian' means 'living a double life'. An amphibian begins its life in freshwater as a tadpole and breathes through its gills. Later it develops lungs and lives on land. The study of amphibians (or reptiles) is called ‘herpetology’.