Frogs make up 85 percent of living species in the class Amphibia. They are widespread and successful on all continents except Antarctica. Large permanent bodies of water, such as ponds, are important for breeding, but most frogs only spend a small portion of their lives in the water. Many frogs do spend their lives in a moist environment, such as marshes, swamps, along a river, or in a forest. These moist environments are important because of frogs permeable skin and because they need water to breed in.
Frogs skin is important because they breathe and drink through their skin.
Frogs shed the outermost portion of their skin, sometimes weekly, and many eat it as they pull their skin off, recycling valuable nutrients. When the temperature rises, the hibernation ends. Newts, fishes, aquatic insects like dragonfly nymphs, and aquatic birds enjoy eating frog embryos and tadpoles. Once frogs mature, they have more predators on the land, such as snakes, bullfrogs, birds, fishes, turtles, crocodiles, and small mammals. Perhaps the worst problem frogs face is pollution, because frogs skin absorb everything that they come in contact with.