What is an Amphibian?
The word Amphibian is derived from two Greek words, amphi (double) and bios (life). This "double life" refers to the two phases in the life cycle of most amphibians, an aquatic larval stage and a terrestrial adult stage. One of eight vertebrate classes, Class Amphibia is composed of three orders: Gymnophiona (caecilians), Caudata (salamanders), and Anura (frogs and toads). Amphibians are ectothermic, which means they need an "outside" source of heat to generate adequate body heat. They must regulate their body temperature by moving into areas that provide the right temperature for their survival, such as by hiding under rotten logs for insulation to keep themselves from freezing. Most adult salamanders have tails, have moist, glandular skins, lack claws on their toes and their front and back legs are almost equal in size. Frogs and toads do not have tails, and their back legs are larger than their front legs.
There are about 4,550 living species of amphibians worldwide, with additional new species of tropical rain forest frogs being discovered each year. Currently 245 species of amphibians are known to live in North America north of Mexico.
Salamanders belong to the Order Caudata. The ordinal name Caudata is from the Latin for tail, cauda, referring to the long tails of these amphibians. Members of this order are found only in North America, Eurasia, the northern coast of Africa, and northern South America. There are nine families of salamanders, eight of which are present in North America and seven in Georgia. Of the approximately 360 species of salamanders found worldwide, North America has the highest number of species, 150. The southeastern United States has more salamander species than any other region of the world and Georgia has 51 species of salamanders, more than any other state. Return to top
All frogs and toads belong to the Order Anura, and are thus called anurans. The name of the order comes from the Greek an, without, and ura, a tail, referring to their tailless condition. Frogs and toads have four legs, the back legs being longer than the front legs. They lay eggs in water or in moist terrestrial sites. The eggs hatch into larvae (tadpoles) that live in the water until they metamorphose into adults. Male anurans can vocalize, calling or chorusing to attract females during the breeding season or to establish territories. Adult anurans are carnivorous, feeding on insects and other invertebrates. The largest individuals will eat almost anything they can fit in their mouths, including birds, mice, snakes, and other amphibians. Return to top
Georgia Wildlife Web
USGS Checklist of Amphibian Species
and Identification Guide
Animal Diversity Web