rectilinear locomotion

Rectilinear locomotion is a method of movement used by some limbless animals, most notably snakes, where the body moves in a straight line. This is achieved through a series of muscle contractions along the sides of the body, which lift and anchor individual ventral scales to push the body forward. This "caterpillar-like" motion is typically used by heavier snakes, such as boas and some vipers, allowing them to glide forward smoothly. Unlike serpentine locomotion, which relies on S-shaped curves, rectilinear movement keeps the body relatively straight. This method is distinct from other snake locomotion styles like concertina and sidewinding.12