Geckos, nature’s supreme climbers, can race up a polished glass wall at a meter per second and support their entire body weight from a wall with only a single toe. But the gecko’s remarkable climbing ability has remained a mystery since Artistotle first observed it in the fourth century B.C.

Working at Lewis & Clark College, the University of California at Berkeley, the University of California at Santa Barbara, and Stanford University, the interdisciplinary team:

• confirmed speculation that the gecko’s amazing climbing ability depends on weak molecular attractive forces called van der Waals forces,

• rejected a competing model based on the adhesion chemistry of water molecules, and

• discovered that the gecko’s adhesive depends on geometry, not surface chemistry. In other words, the size and shape of the tips of gecko foot hairs—not what they are made of—determine the gecko’s stickiness.