Data from: Geckos significantly alter foot orientation to facilitate adhesion during downhill locomotion

Geckos employ their adhesive system when moving up an incline, but the directionality of the system may limit function on downhill surfaces. Here, we use a generalist gecko to test whether limb modulation occurs on downhill slopes to allow geckos to take advantage of their adhesive system. We examined three-dimensional limb kinematics for geckos moving up and down a 45° slope. Remarkably, the hind limbs were rotated posteriorly on declines, resulting in digit III of the pes facing a more posterior direction (opposite to the direction of travel). No significant changes in limb orientation were found in any other condition. This pes rotation leads to a dramatic shift in foot function that facilitates the use of the adhesive system as a brake/stabilizer during downhill locomotion and, although this rotation is not unique to geckos, it is significant for the deployment of adhesion. Adhesion is not just advantageous for uphill locomotion but can be employed to help deal with the effects of gravity during downhill locomotion, highlighting the incredible multi-functionality of this key innovation.壁虎在攀爬倾斜面时会启用其粘附系统（adhesive system），但该系统的方向性可能限制其在下坡表面上的功能发挥。本研究以广食性壁虎为实验对象，探究其是否会通过肢体调节来适应下坡斜面，从而得以利用自身的粘附系统。我们对在45°上坡和下坡斜面运动的壁虎开展了三维肢体运动学（limb kinematics）分析。值得注意的是，当壁虎处于下坡状态时其后肢会向后旋转，导致后足（pes）的第三趾朝向更靠后的方向（与行进方向相反）。其余所有实验条件下均未观测到肢体朝向的显著变化。这种后足旋转会使足部功能发生显著改变，使其在下坡运动中可作为制动/稳定装置发挥粘附系统的作用；尽管这种旋转并非壁虎所独有，但对于粘附功能的启用具有重要意义。粘附系统不仅对上坡运动有益，还可用于抵消下坡运动中重力的影响，这凸显了这一关键创新所具备的卓越多功能性。