Geckos are the envy of rock climbers. Without glue, suction, or claws, these lizards scamper up walls and hang from ceilings.
Scientists finally have pinned down the molecular basis of this seeming magic. Gecko feet are covered by billions of tiny hair tips, or spatulae, that hug surfaces. Temporary shifting of the electrons in the molecules of the spatulae and of opposing rocks, walls, or ceilings creates adhesive van der Waals forces, according to a study in the Aug. 27 Proceedings of the National Academy of Sciences. The collective action of these subtle intermolecular interactions contributes to countless properties, including a liquid's boiling point and a polymer's strength.