Collection: Amphibians

Amphibians belong to a class of egg-laying vertebrates adapted to life both on land and in water. They are the most primitive of the quadrupedal vertebrates (tetrapods) and the first vertebrates to come ashore. Adaptations developed by adult amphibians for life on land include lungs for breathing, a tough outer skin to control water evaporation from the body and, in some species, legs. They return to the water to lay their eggs. The Mazon Creek area of Illinois, and areas of west-central Indiana which were once part of a Middle Pennsylvanian river delta and swampland, would have been well-suited for the success of these animals.