The Caecilians are an order (Gymnophiona) of amphibians which resemble worms or snakes. They mostly live hidden in the ground which makes them the least explored order of amphibians.
Caecilians' feet and tails have degenerated, making the smaller species resemble worms, while the larger species with lengths up to 1.5 m resemble snakes. Their skin is smooth and usually dark-matt, and bears some calcite scales which suggests that they are related with the fossil Stegocephalia. Due to their underground life the eyes are degenerated and covered by skin.
They are found in the tropic areas of South-East Asia, Africa and South America, where they live in the upper parts of the soil feeding on small invertebrates like earthworms or slugs. Some species are aquatic and live in brooks.
Taxonomically the caecilians are divided into 5 families: