Snakes use zigzag anchor points and friction to maneuver through tight spaces. Snakes move quickly across a variety of difficult terrain, from scorching sand to rocky crevices, and have developed highly specialized methods of locomotion—all apparently without any additional assistance. Scientists are particularly interested in the technique by which snakes move through narrow channels, called “concertina” locomotion, as it could have life-saving applications in robotics. The word “concertina” refers to a small musical instrument similar to an accordion. This demonstrates a similar locomotion to that used by snakes.

To get through a narrow channel, the snake will continuously compress and expand, like the movement of a concertina playing. First, the snake will extend its head along the channel, then bring a point on one side of its body, just behind its head, to one wall; then it will fold its body up so that another point, on the other side, can press slightly further back, to the opposite wall, and so on. When the snake has three to five such anchors, it will move its head forward again. The front points break away from the wall, but the points further back hold the snake in place until a new “hold” can be created for moving forward. Research has shown that friction is key to the functionality of this movement. If you were to run your fingers from the snake’s head to its tail, you would feel a perfectly smooth surface. The lack of friction in this direction allows it to move forward quickly. The overlapping scales, however, create a jagged surface in the other direction. During concertina movement, snakes actually dig their scales slightly into the walls around them, which creates high resistance to backward movement and allows the snakes to propel themselves forward.

Potential

This simple combination of texture and movement has great potential in the field of research robots. One possible setting is in search and rescue missions, where the passageways through the rubble created by a collapsed building are narrow, irregular, and unpredictable. There are more applications in the fields of bioengineering and medicine. Perhaps one day, when we visit the doctor, we will be able to go through the colonoscopy procedure very well, because the little snake robots will get where they need to go. This would also reduce pain and damage to surrounding tissues.

At first glance, it might seem strange to associate snakes with medicine and healing. One such symbol was the ancient Greek “Rod of Asclepius,” which depicted a snake wound around a rod, and echoes the one Moses used to heal the Israelites in the book of Numbers. It continues to appear in the logo of the World Health Organization and many other health groups around the world.

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Summarized by AskNature.org