Amphibian Types

Amphibians are classified as cold-blooded vertebrates that breathe through their skin and go through a metamorphosis. As cold-blooded animals, they rely on the heat of the sun to warm their bodies, but will burrow or hide when the temperatures get too hot. Amphibians don't resemble their parents when born. For example, frogs hatch from eggs as tadpoles and as they grow, change into adult frogs.

Caecilians are amphibians that have a snake or earthworm appearance. Caecilians usually hide underground, which means that they are rarely seen. Known as the legless amphibian, there are over 120 species of caecilians, but scientists know very little about them. The longest species observed by man is more than 5 feet long. Some species have been known to live up to 13 years in captivity and may give birth to eggs or live animals, depending on the species.

Salamanders are quite common in the United States. There are 400 species of salamanders, newts and mudpuppies. Some salamander breeds live on land, while others live in the water. The mudpuppy is a breed of salamander that lives on the bottoms of lakes, rivers and other water sources. They are also the largest in this group, growing up to 16 inches in length. Newts prefer moist environments, residing in forests, gardens and even parks. Salamanders and newts are sometimes kept as pets and have a lifespan up to six years.

With roughly 4,000 known species of frogs and toads, this is a group of amphibians that have been well-studied. When determining whether an amphibian is a frog or toad, look at the characteristics. A toad is much fatter than a frog, while a frog has long legs for jumping and smooth skin. Depending on the species, frogs and toads can lay up to 50,000 eggs at once and may live up to 30 years. The largest frog is the goliath, weighing more than 6 pounds.