Caecilians are harmless to humans, but in their ecosystems they are ferocious predators. Unusual for an amphibian, the caecilian possesses a mouthful of needle-like, often backward-curving teeth meant for seizing prey. They also have a powerful bite; most animals have one set of muscles for closing the jaw. Caecilians have two. When prey, usually a worm, enters the caecilian’s tunnel, the amphibian latches on and then spins in a rapid, corkscrewing motion. This action pulls the entire body of the prey into the tunnel, and may have the advantage of disorienting the hapless animal. Most caecilians feed on worms and insects, but larger species may eat small snakes, frogs, and lizards.