The influence of lifting behavior on energy efficiency in rectilinear locomotion

In rectilinear locomotion, snakes propel themselves by extending or contracting parts of the body. It is interesting that some large snakes will lift the activated part of the body during rectilinear motion. We hypothesize that snakes use this unique strategy named “lifting behavior" to improve the performance of rectilinear motion on a rough horizontal surface. The purpose of this paper is to examine our hypothesis by examining whether rectilinear motion benefits from lifting behavior. In this study, we derive equations to estimate the energy consumption of rectilinear motion on a simplified 4-link snake robot model. We consider not only mechanical energy dissipation but also heat energy loss during motion. A criterion of minimum energy loss is used as a candidate for the strategy to show how much lifting behavior improves energy efficiency. Our analysis provides a framework for theoretical analysis of the energy cost of rectilinear locomotion for snakes, which can help biologists to further understand the behaviors of snakes. This study also provides some new insights into rectilinear locomotion.