The bottom of a gecko's foot bears about half a million microscopic hairs called setae, each one tipped with hundreds of teeny pads, or "spatulae." These spatulae, say Kellar Autumn of Lewis and Clark College, Robert J. Full of the University of California at Berkeley and their colleagues, hug the surface so closely that they interact with its molecular structure.
But simply placing its foot on or removing it from the substrate perpendicularly is not enough to engage or disengage the gecko's spatulae. Rather, these creatures have a unique behavior of toe uncurling and peeling that enables them to rapidly attach and detach their feet--15 times a second when running-while achieving 600 times more adhesive force than friction alone could account for.
Image: Kellar Autumn
Another fascinating feature of the gecko foot hairs is that they appear to be self-cleaning. Microspheres embedded by researchers into the hairs disappeared as if by magic after the gecko had taken only a few steps. Considering the extraordinary efficacy of this lizard's setae and spatulae system, it should come as no surprise that members of the team are investigating commercial applications: a dry adhesive modeled after gecko feet may not be far off.