Sandfish lizard "swims" through sand

A team at Georgia Tech has been studying the biomechanics that allow the "sandfish lizard" to propel itself so quickly through sand.

"Goldman described the sandfish as a little lizard that lives in the desert in North Africa. When startled, it can burrow 10 cm beneath the surface in less than half a second. Its wedge-shaped head, which biologists believe gives the critter its lightning-quick burrowing ability, was the project's inspiration..."

A cylinder pulled through sand generated lift, but the lizard's head generated "negative lift," keeping it submerged.

"On an earlier research project, Goldman's CRAB Lab used high-speed x-ray imaging to observe the lizard's movement when submerged. They found that it doesn't use its legs when swimming through sand, instead tucking them by its side and slithering like a snake."

 
Additional information at Physics Buzz.