Multimedia Gallery
All images in this series
Snake redistributing its weight as seen using force visualizations
The ability of a snake to redistribute its weight can be seen using force visualizations with photoelastic gelatin. When polarized light is shone through this material and viewed through cross-polarizing film, forces applied by the snake become visible. Specifically, bright regions indicate high force. While the snake undoubtedly sticks to the gelatin as it tries to move across it, it is clear that it tends to lift the peaks and troughs of its body, as observed by researchers during normal slithering.
Snake locomotion may seem simple compared to walking or galloping. But in reality, it's no easy task to move without legs. Previous research had assumed that snakes move by pushing off of rocks and debris around them. But a National Science Foundation-supported study (grant PHY 0848894) by David Hu, a mechanical engineer at Georgia Tech, and his team found that it's all in their design--specifically, their scales.
Overlapping belly scales provide friction with the ground that gives snakes a preferred direction of motion, like the motion of wheels or ice skates. And like wheels and ice skates, sliding forward for snakes takes less work than sliding sideways.
In addition, snakes aren't lying completely flat against the ground as they slither. They redistribute their weight as they move, concentrating it in areas where their bodies can get the most friction with the ground and therefore maximize thrust. In this way, snake slithering is not unlike human walking--we, too, shift our weight from left to right to enable us to move.
To learn more about this research, see the LiveScience article Study shows how snakes slither. (Date of Image: 2009)
Credit: ©Grace Pryor, Mike Shelley and David Hu, Applied Mathematics Laboratory, New York University, and Department of Mechanical Engineering, Georgia Institute of Technology
Images and other media in the National Science Foundation Multimedia Gallery are available for use in print and electronic material by NSF employees, members of the media, university staff, teachers and the general public. All media in the gallery are intended for personal, educational and nonprofit/non-commercial use only.
Images credited to the National Science Foundation, a federal agency, are in the public domain. The images were created by employees of the United States Government as part of their official duties or prepared by contractors as "works for hire" for NSF. You may freely use NSF-credited images and, at your discretion, credit NSF with a "Courtesy: National Science Foundation" notation.
Additional information about general usage can be found in Conditions.
Also Available:
Download the high-resolution TIF version of the image. (11.3 MB)
Use your mouse to right-click (Mac users may need to Ctrl-click) the link above and choose the option that will save the file or target to your computer.