Amphibians are ectothermic, anamniotic, four-limbed vertebrate animals that constitute the class Amphibia. There are only about 6,200 known living species of amphibians. They are placed in three orders: frogs, salamanders, and caecilians.     The frog order includes toads as well as frogs. Unlike other amphibians, frogs and toads lack a tail by adulthood.     Their back legs are also longer because they are specialized for jumping. Frogs can jump as far as 20 times their body length. That's like you jumping more than the length of a basketball court!     The salamander order includes both... Show more

Amphibians are ectothermic, anamniotic, four-limbed vertebrate animals that constitute the class Amphibia.

There are only about 6,200 known living species of amphibians. They are placed in three orders: frogs, salamanders, and caecilians.    
The frog order includes toads as well as frogs. Unlike other amphibians, frogs and toads lack a tail by adulthood.    
Their back legs are also longer because they are specialized for jumping. Frogs can jump as far as 20 times their body length. That's like you jumping more than the length of a basketball court!    
The salamander order includes both salamanders and newts. Salamanders and newts keep their tails as adults. They have a long body with short legs. They are adapted for walking and swimming rather than jumping. Unlike other vertebrates, salamanders can regrow legs or other body parts if they are bitten off by a predator.    
The caecilian order is the amphibian order with the fewest species. Caecilians are closely related to salamanders.    
They have a long, worm-like body. They are the only amphibians without legs. Caecilians evolved from a fourlegged ancestor but lost their legs later in their evolution. As adults, they often burrow into the soil. That's one reason why Caecilians tend to be less well known than other amphibians.    

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