Article from Encarta Encyclopedia provides a basic introduction to these creatures. Includes a look at their physical characteristics, range and habitat, behavior, and life cycle. Amphibian animal, animal with moist, hairless skin through which water can pass in and out. Nearly all amphibians live the first part of their lives in water and the second part on land—a double life reflected in the name amphibian, which comes from the Greek words amphi, meaning “both,” and bios, meaning “life.” Amphibians were the first animals with backbones to adapt to life on land. They are the ancestors of reptiles, which in turn gave rise to mammals and birds. Scientists recognize more than 5,000 species of amphibians, all of which are members of one of three main groups: frogs and toads, salamanders, or caecilians. Frogs and toads are the most abundant of all amphibians, numbering more than 4,000 species. Frogs have smooth skin and long limbs. Toads, in contrast, have warty skin and short limbs.

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