Fig. 4. (A) Adhesion (-F ) vs shear force (F_||) at three scales: isolated setae (circles), isolated setal arrays (squares) and live gecko toes (triangles). For all scales, F=-F_||tan^*, where ^*30°. (B) Release angle (^*) vs adhesion (-F ) at three scales: isolated setae (circles), isolated setal arrays (squares) and live gecko toes (triangles). For all scales, ^* was near 30°. Values of ^* differed minimally but significantly among seta, array and toe levels (Kruskal-Wallis, H=90.133; d.f.=2; P<0.001). Letters A and B denote significant Dunn's pairwise contrasts. Array and toe values of ^* were not significantly different from each other (_rank=4.475; Q=0.273; P>0.05), and were significantly lower than ^* in setae, suggesting that the value of ^*=30° in single setae sets the upper limit for detachment angles at array and toe scales.