Figure 5.

Shear forces may be used to control the normal stress distribution in the contact zone of adhesive pads. When legs are pulled towards the body, normal stresses may be relatively uniform, resulting in strong attachment. If pads are pushed away from the body, the chain-like tarsus may buckle, causing strong stress concentrations at the proximal edge of the pad, facilitating easy detachment. A more detailed discussion of the effect of pushing and pulling on the stress distribution is given in §7b. Note that the figure is not drawn to scale, and stress distributions are shown only schematically.