Amphibians Blue Poison Dart Frog. Suriname, South America.

The amphibia class includes:

Frogs, Green tree frog. Costa Rica, Central America.

toads, American Toad. North America. Click to hear its call:

salamanders, Red-Backed Salamander. California.

and newts. Great-Crested newt. Europe.

The word amphibian means "double life," Leopard Frog. North America.

because most amphibians depend on both water and land. Green Frog: Europe.

There are over species of amphibians. Smooth Newt. Europe.

Amphibians have existed on Earth for 368 million years. Archegosaurus. A long extinct amphibian.

Amphibians are cold-blooded. Their temperature changes with their environment. Green Frog. Europe.

Amphibians have soft, usually moist, and permeable skin, which helps them to absorb oxygen and water. Giant Salamander. China.

Amphibian skin is without scales, hair, or feathers. Giant Salamander. Japan.

Amphibian eggs do not have shells and so must be laid in a damp environment. Spotted Salamander Eggs. North America.

Amphibians go through a two-stage life cycle.

When an amphibian egg hatches, the emerging animal is in a larval stage. Mandarin Newt Adult. China. Mandarin Newt Larvae

It uses gills to breathe. Blue-Spotted Salamander. Great Lakes Region, North America.

In frogs and toads, larva are called tadpoles. Common Bullfrog Tadpoles. North America.

In salamanders, they are simply known as larvae. Tiger Salamander Larvae. North America.

Amphibian larvae may transform into their adult form after a few weeks or months. Tiger Salamander. North America.

Red Salamander. North America.