Cutaneous respiration
The skin of amphibians is a major site of respiration in all species for which measurements are available. Cutaneous respiration is the sole respiratory mode of lungless salamanders (family Plethodontidae) which lack lungs entirely yet constitute the largest family of salamanders. Cutaneous respiration in frogs and other amphibians may be the primary respiratory mode during colder temperatures.
Cranwell's horned frog
At extreme temperatures, Cranwell's frogs enter a period of estivation, developing a thick layer of protective skin to trap moisture and aid in respiration. When estivation is complete, the frog uses its front and hind legs to help shed the protective layer. In many cases, the frog uses its jaws to help pull the skin over its back, often eating the skin in the process.