Definition: Amphibians are remarkable animals that include
modern-day frogs, toads, caecilians, newts, and salamanders.
These animals are the descendents of the first vertebrates to
make the move from life in water to life on land. Despite their
early colonization of terrestrial habitats, most lineages of
amphibians have never fully severed their ties with aquatic
habitats. A majority of amphibian species return to the water to
breed and some species remain entirely aquatic throughout their
entire life cycle. Most amphibians go through a complex
metamorphosis process as they grow to adulthood.