Scincus scincus is a type of skink native to the North African deserts. It carries the colloquial name “sandfish” because it is able to move through the sand as if it was swimming. Biomechanists have recently gained new insight into the skink’s locomotion considering approaches from mathematics, physics, and engineering.
Describing the movement through granular material is a demanding task since it can behave as a liquid and as a solid. The transition from liquid to solid can, for example, be described by the so called resistive force theory (RFT). RFT accounts for the fact that, when an object is submerged into the granular material, frictional drag – as opposed to viscosity – is often the dominant force.
Further insights can be gained by building a biomimetic sand-swimming robot. Biomechanist R. D. Maladen and co-workers, for example, used a robot consisting of 15 segments to examine their theoretical predictions of the lizard’s locomotion.
Read more:
S. B. Croft, A. B. Summers, “Swimming in the Sahara”, Nature, Volume: 472, Pages: 177–178
— Leonie Mueck