Jim O'Reilly, Dale Ritter, Nate Kley and I are interested in the ways in which limbless amphibians and reptiles burrow.
There are only a few ways in which limbless animals move around. The principal modes of locomotion are:
'Swimming undulation' a rythmic thrashing back and forth employed by most fishes. An undulatory wave moves down the animals body aat a higher speed than the speed at which the animal progresses forwards.
'Lateral undulation' in which the animal pushes off against tiny (even microscopic) surface irregularities, is used by many snakes, lizards, and caecilians. The undulatory wave passes down the animal's body at the same speed as forward progress.
'Concertina' locomotion is also known as 'inch-worm' locomotion and is used by amphibians and reptiles. In this form of locomotion the animal holds part of its body still while the rest pushes forward. A special case of concertina, called 'internal concertina' is employed during burrowing by some snakes and caecilians. Jim O'Reilly and I compared these locomotor strategies in two species of caecilians