Normal Adhesive Force-Displacement Curves of Living Geckos

In this paper, we report experimental measurements of normal adhesive force versus body displacement for living Tokay geckos (Gekko gecko) adhered to Poly(methyl meth acrylate) (PMMA) or glass surfaces. We have measured the normal adhesive force needed for reaching the gecko detachment. Atomic force and scanning electron microscopies are used to characterize the surfaces and feet topologies. The measured safety factors (maximum adhesive force divided by the body weight) are 10.23 on PMMA surfaces or 9.13 on glass surfaces. We have observed minor and reversible damage of the gecko feet caused by our tests, as well as the self-renewal of the gecko adhesive abilities after the moult.