What Is the Outer Covering of a Frog?

Unlike toads, frogs have a smooth outer skin that can come in an almost countless array of colors. Frog skin is water permeable, meaning that water can easily pass in and out of it. The result of this is that frogs often absorb liquid through their skin rather than their mouths. Much of this water is absorbed through a "seat pouch," found on the bottom of the frog. The various colors of frogs have important biological functions, including warning potential predators that a frog might be poisonous.

  1. Coloring

    • There are roughly 3,000 species of frogs and toads, and each has a slightly different color combination. One of the main functions of colors in frogs is to warn predators whether or not a frog is poisonous. Colored frogs tend to be poisonous while soft-colored frogs are not. Some frogs are only brightly colored in some areas. The White's tree frog can even change colors depending on where it is sitting.

    Breathing

    • Breathing is a gas exchange, taking in oxygen from the air and giving off carbon dioxide. Unlike reptiles, frogs begin their life underwater as tadpoles, where they begin breathing through internal gills and their skin. Most frogs lose their gills when they change from tadpoles, so they breathe through a combination of their skin and air cavities connected to their lungs. It is possible to see the breathing rhythm when watching a frog at rest.

    Shedding Skin

    • All frogs shed their skin, and most eat the shed skin for nutrients. Some frogs keep their shed skin to use as cocoons for storing water in dry environments. The rate at which frogs shed their skin varies. Some frogs shed their skin weekly, and some shed every day. When the frog is shedding, it typically twists and turns until it has loosened its old skin, then pulls the old coat over its head. It then eats the old coat of skin.

    Slime

    • Frogs are known in popular culture to be slimy. The slime found on most frogs is caused by a mucus secretion that is meant to keep the frog moist. Without this secretion, frogs would not be able to live outside of the water. Even with this mucus, most frogs are frequently near the water because of the extra oxygen they receive through their skin.