THIS WEEK IN SCIENCE

摘要

Although composed of solid particles, sand can behave like a fluid. If you had to swim through sand, how would you do it? Would you use your arms and legs for propulsion or would you make your body as compact as rnpossible and try to wiggle and slither your way through? Maladen et al. (p. 314) used x-ray imaging to study the motion of sandfish lizards as they burrowed into sand. The sandfish lizard does not use its limbs, but instead flattens them against its body and uses large-amplitude traveling wave oscillation of its body to propel itself. Modeling can explain the motion the lizard uses to propel itself through a medium that is neither liquid nor solid.