Crab locomotion research. Ghost crab (Ocypode quadrata) being released from plastic cup onto a miniature treadmill. The adjustments the crab makes to sudden changes in the speed of the treadmill are being studied here. This is being done to aid the development of robots that mimic animal forms of locomotion for traversing difficult and varied terrain. Photographed in 2005 at the PolyPEDAL Lab, University of California at Berkeley, USA.