What makes an amphibian an amphibian?
Skeleton:
Amphibians have an endoskeleton (meaning an internal skeletal system).
Skin:
Amphibian skin does not have scales and allows fluids to pass through (permeable). Typically, amphibians have moist, slippery skin. Some amphibians, like toads, have drier, bumpy skin.
Feet:
Amphibians typically have webbed toes and skin covered feet. (Amphibians do not have claws.)
Breathing:
Most adult amphibians breathe through lungs and/or through their skin. Breathing through the skin is called cutaneous respiration. To breathe through their skin, the skin must stay moist/wet.
Early in life, amphibians have gills for breathing. Most will lose their gills as they become adults, however some will keep their gills throughout their life spans.
Body Temperature:
Amphibians are ectotherms. This means that their body temperature varies with the temperature of their surroundings.
Eggs and Young:
Amphibians lay eggs. Amphibian eggs must be laid in or near water to stay moist.