Amphibians include frogs, toads, salamanders, newts and caecilians. They are four-legged vertebrates and they are cold blooded. Amphibians lay their eggs in water, which then hatch into tadpoles. Tadpoles live in the water and have gills instead of lungs. Tadpoles grow into adults in a process called metamorphosis. When they are fully grown, amphibians grow lungs and legs an are able to leave the water. Adult amphibians also use their skin to take in oxygen, and some species of salamanders do not have lungs at all!