How do serpentine locomotion and sidewinding differ in snakes?

Serpentine locomotion and sidewinding are distinct methods of movement used by snakes, primarily differing in how they interact with the environment and utilize surface resistance.

• Serpentine locomotion: This is the most common form of movement, where the snake forms a series of S-shaped horizontal loops. Propulsion is achieved by pushing these loops against environmental irregularities, such as rocks or twigs. Because it relies on lateral thrust against solid projections, this method is ineffective on smooth surfaces that lack resistance.12
• Sidewinding: This specialized adaptation is used primarily on loose, friable surfaces like desert sand where traditional pushing is impossible. Unlike serpentine movement, the snake moves laterally rather than forward. Only two parts of the body touch the ground at any given time, while the remainder is held aloft in an elevated loop. This rolling, spring-like motion minimizes contact with hot sand and allows the snake to progress without needing a rigid frictional base.31