This change from larval to adult form is called metamorphosis . Amphibians include salamanders and newts, frogs and toads, and a group called caecilians. Caecilians live in the tropics, are shaped like worms and due to their burrowing habits are not often seen. Salamanders are the amphibians most often confused with reptiles because they have the same general body shape as lizards. However, it is easy to tell them apart, for lizards have scaly skin and claws, while salamanders are smooth-skinned and have no claws.
Salamanders differ in their dependence on water.
Some live their whole life in water, while others live on moist land and return to water only to mate and lay eggs. Newts, a water dwelling group without gills, have a land stage called an eft which occurs between the larva and the adult. The common tiger salamander, which live most of its life on land, has an alternate larval form called the axolotl which is able to reproduce without losing its gills and leaving the water. There are also several pale-colored, eyeless cave dwelling salamanders which live their entire lives in darkness. North and Central America together have a generous assortment of the world's salamanders.