Gecko locomotion study. Researcher with a gecko (family Gekkonidae) climbing a non-stick vertical track (blue). A high speed camera is used to monitor the animal's locomotion. The surface of gecko toes are lined with microscopic hairs (setae and spatulae) that create weak intermolecular forces known as van der Waals forces. These forces are strong enough to allow the gecko to stick to any surface. To take a step, the toes open out from a curled position on contact with a surface, then unpeels to take the next step. This uncurling and peeling action can be produced up to 15 times per second, enabling the gecko to move rapidly. Photographed in 2005 at the PolyPEDAL Lab, University of California, Berkeley, USA.