There is only one bone in the frogs middle ear. Some of the physicalfeatures of amphibans, like the scales of gymnophions, suggest their fish ancestry. Amphibans are unlike fishes in that most types have limbs instead of through gills. Unlike reptiles, amphibians lack a scaly or armored covering and take in water and oxygen through their skin. Amphibians have developed in many different ways in order to survive in areas with widely varying climates, dangers, and food sources.
Most amphibians are small animals.
Except for the salamander of Japan, the gaint among them became extinct long ago. The skulls are usually flat and wide, and the teeth, which grow in the jawbones and roof of the mouth, lack roots and are replaced intermittently. Amphibians do not chew with these teeth. They use their long, flexible tongues to capture their prey, which they then swallow whole. The moist, supple skin of most amphibians provides protection and absorbs water an doxygen.