Frogs

The highly permeable skin of frogs might lead us to expect that they must always have access to water. This is generally true, but not always. It is true that if a common aquatic species, such as a leopard frog (Rana pipiens), were to escape from its cage and roam on the floor for a night, it would be little more than a dried-up mummy by the next morning. However, during the millions of years of frog evolution, many species have found ways of adapting to varying water availability in natural habitats. Although many frogs are aquatic, and some never leave the water, there are also desert frogs, tree-frogs, and others that can withstand the drying power of tropical heat for a day or more.