Amphibians form the class Amphibia, which contains approximately 4,000 species and has a large variety of animals. Most amphibians can breathe through their thin skin, as their lungs are inefficient at inhaling air.


Nearly all amphibians are exclusively carnivorous as adults, though most prey on invertebrates far smaller than themselves, such as insects, annelids and gastropods. Among the exceptions are a few large species, most of which exceed 20cm, such as the bullfrog and goliath frog, which can prey on other vertebratess, such as fish and many mammals among their general size.