Geckos’ foot hair structure and their ability to hang from rough surfaces and move quickly

Geckos generate the necessary adhesion force through their foot hair. The direction of the geckoʹs foot hair is not perpendicular to its finger surface, giving compliance to the hair. The effect of this compliance on the adhesion force is analysed and expressed theoretically in terms of contact mechanics. We conclude that the compliance of the foot hair is sufficient to generate the large adhesion force necessary for adhesion to rough surfaces, and that the structure of the seta with the spatulae allow the normal adhesion force to be controlled, allowing the gecko to make quick steps.