The ability to climb with adhesive pads conveys significant advantages, and is hence widespread in the animalkingdom. The physics of adhesion predict that attachment is more challenging for large animals, whereas detach-ment is harder for small animals, due to the difference in surface-to-volume ratios. Here, we use stick insects toshow that this problem is solved at both ends of the scale by linking adhesion to the applied shear force. Adhesiveforces of individual insect pads, measured with perpendicular pull-offs, increased approximately in proportion toa linear pad dimension across instars. In sharp contrast, whole-body force measurements suggested area-scalingof adhesion. This discrepancy is explained by the presence of shear forces during whole-body measurements, asconfirmed in experiments with pads sheared prior to detachment. When we applied shear forces proportional toeither pad area or body weight, pad adhesion also scaled approximately with area or mass, respectively, provid-ing a mechanism that can compensate for the size-related loss of adhesive performance predicted by isometry.We demonstrate that the adhesion-enhancing effect of shear forces is linked to pad sliding, which increased themaximum adhesive force per area sustainable by the pads. As shear forces in natural conditions are expectedto scale with mass, sliding is more frequent and extensive in large animals, thus ensuring that large animals canattach safely, while small animals can still detach their pads effortlessly. Our results therefore help to explain hownature’s climbers maintain a dynamic attachment performance across seven orders of magnitude in body weight.