Amphibians are frogs, salamanders, and caecilian. Amphibians vary greatly but have a few common traits. Amphibians have moist skin, the skin is smooth, thin, and has no scales. They usually live in moist environments. They also breath through their skin, though most also have lungs. Amphibians also have a three chambered heart and almost all go through a metamorphosis . Frogs and Toads have short broad bodies with four legs but don’t have a neck or a tail. Salamanders have long slender bodies and short legs. Caecilian look similar to snakes or worms.
Amphibians usually live in moist, wet environments. They need bodies of water to reproduce, and it must be fresh water. Such as lakes, ponds, etc. They live all over the world, almost where ever bodies of fresh water is found.
Amphibians fertilize their eggs through external fertilization. This means that after the female releases the eggs the male fertilizes them. They usually are laid in water, or somewhere where they will fall into water. The eggs do not have a shell, so they must be are then coated in a jellylike substance to keep them moist. After hatching, the young amphibians are tadpoles. These are similar to fish, and have a tail, gills and a two chambered heart. They then go through metamorphosis, which is a transformation. After metamorphosis they are the same as their adult versions. Some rainforest frogs do not go through metamorphosis, but hatch the same shape as the adults.
Before metamorphosis, amphibians eat cyanobacteria, plants, insect larva, or even small fish. After metamorphosis, they rely mainly on insects. Frogs hunt these with tongues that fold out and hold the insects with sticky saliva. Amphibians also sometimes eat small mammals, such as mice, other amphibians, and some even eat berries. They cannot chew, so they must eat things they can swallow whole.