Locomotion
The snake uses five distinct forms of locomotion: Lateral Undulation, Side-winding, Concertina, Rectilinear, and Slide-pushing.
Lateral Undulation- This is the most common serpentine locomotion of snakes. In this form of locomotion waves of lateral bending are propagated along the body of the snake from head to tail. This allows the snake to propel its self forward by exerting force on the object it is in contact with. In lateral undulation the large dorsal muscles of the snake are activated unilaterally from the convex part of the bend to the concave part of the bend.
Side-Winding- This is used by many snakes crawling on smooth or slippery surfaces, but is best known in the sidewinder rattlesnake (Crotalus cerastes). Side-winding is similar to lateral undulation in the pattern of bending, but differs in three ways: First, each point along the body is sequentially placed in static (rather than sliding) friction with the substrate. Second, segments of the body are lifted off the ground between the regions in static contact with the ground. Thus, the body sort of rolls along the ground from neck to tail, forming a characteristic track in sand. Third, because of the static contact and lifting of the body, the snake travels roughly diagonally relative to the tracks it forms on the ground. Muscle activity during side-winding is similar to that in lateral undulation except that some muscles are also active bilaterally in the regions of lifting.
Concertina- This form of locomotion involves alternately pulling up the body into bends and then straightening out the body forward from the bends. The front part of the body then comes to rest on the surface and the back part of the body is pulled up into bends again, and so on and so forth. The bends may push laterally against the sides of a tunnel or vertically against the ground to keep the body from slipping. . Concertina locomotion is used in crawling through tunnels or narrow passages and in climbing. In concertina locomotion, blocks of muscles are activated simultaneously, and unilaterally, in regions of bending and of static contact with the sides of a tunnel.
Rectilinear- This is movement in a straight line. It is used mainly by large snakes such as large vipers, boas, and pythons. In rectilinear locomotion, the belly scales are alternately lifted slightly from the ground and pulled forward, and then pulled downward and backward. But because the scales "stick" against the ground, the body is actually pulled forward over them. Once the body has moved far enough forward to stretch the scales, the cycle repeats. Unlike lateral undulation and side-winding, which involve unilateral muscle activity that alternates from one side of the body to the other, rectilinear locomotion involves bilateral activity of the muscles that connect the skin to the skeleton. One set of these muscles lifts the belly scales up and pulls them forward and another set of muscles pulls the them downward and backward.
Slide-pushing- This involves vigorous undulations of the body that slide widely over the surface. Slide-pushing is used when a snake on a smooth surface is startled and tries to escape quickly, but slips over the surface. In slide-pushing, irregular bends of the body and tail press vertically on the surface at different points; although the body slips on the surface, it pushes down with enough force to move the center of mass in a quasi-regular, often step-like, pattern. Thus the snake progresses irregularly by slipping along the ground. The patterns of muscle activity during slide-pushing are unknown.
Sources:
Moon, Brad. "Snake Locomotion." Snake Locomotion. N.p., n.d. Web. 18 Mar. 2014.
"How Snakes Move & 'run' - Serpent - BBC Animals." YouTube. YouTube, 16 Jan. 2009. Web. 18 Apr. 2014.
Moon, Brad. "Snake Locomotion." Snake Locomotion. N.p., n.d. Web. 18 Mar. 2014.
"How Snakes Move & 'run' - Serpent - BBC Animals." YouTube. YouTube, 16 Jan. 2009. Web. 18 Apr. 2014.