Caecilians (New Latin, blind ones) are a group of limbless, serpentine amphibians. They mostly live hidden in the ground, making them the least familiar order of amphibians. All modern caecilians and their closest fossil relatives are grouped as a clade, Apoda, within the larger group Gymnophiona, which also includes more primitive extinct caecilian-like amphibians. Caecilians are mostly distributed in the tropics of South and Central America, Africa, and southern Asia. The diets of caecilians are not well known.