The word "amphibian" means double life. This is due to the fact that members in
this group spend part of their lives in the water as well as on the land. Amphibians
are thought to be the ancestors of all reptiles, birds and mammals. They are
found throughout the world. Most species of amphibians are characterized in
having long bodies, four small limbs and a large tail. They differ from the reptiles
by having soft moist skins that usually lack scales. Moreover, their eggs have no
hard shells. They do not have hairs or feathers. Most species of these cold blooded
vertebrates are brightly coloured. The respiration takes place through gills, lungs
and skin. They mostly rely on vision for food. Some are voiceless. Majority male
amphibians call out to attract females during mating. Most species breed for only
a limited period in a year.
Amphibians have been classified into three orders: Apoda or Gymnophiona (caecilians); Caudata or Urodela (salamanders and sirens); and Anura (frogs and toad).