Caecilians, pronounced seh-SILL-yens, may look like worms or snakes, but these long, lithe creatures belong to a group of legless amphibians. There are nearly 200 species of caecilians known to science, ranging from the 3.5-inch-long Idiocranium russell in Cameroon to the nearly 5-foot-long giant known as Caecilia thompsoni in Colombia.

Caecilians tend to have very small eyes, which are thought only to be able to detect differences between light and dark. In some species, the eyes are completely covered by skin—an adaptation suited to a life spent almost entirely underground. A pair of tiny, chemically-sensitive tentacles on the caecilians’ faces can detect food and possibly help the animals navigate.

While the amphibians possess no arms or legs, they are powerful