Snakes most commonly move by lateral undulation. Bending their bodies from side to side in waves of motion that pass from head to tail, they push off objects and surface irregularities to propel themselves forward. Snakes can also swim using lateral undulation.
In narrow passages, snakes use a concertina motion, anchoring the rear end and extending and straightening the forward end. The forward end is then anchored to pull the rear end forward. On loose surfaces with limited irregularities, snakes can use sidewinding, in which the relatively static portions of the body pointing in the direction of travel remain on the ground while it lifts the rest of its body up. This mode of travel minimizes slippage. Snakes can also move straight forward by lifting and pulling forward with their belly scales.