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.

壁虎在攀爬倾斜坡面时会启用其粘附系统（adhesive system），但该系统的方向性特征可能会限制其在下坡坡面的功能发挥。本研究选用广适性壁虎，旨在测试其在下坡坡面是否会通过肢体调节来充分利用自身的粘附系统。我们对在45°上坡和下坡坡面运动的壁虎进行了三维肢体运动学分析。值得注意的是，壁虎在下坡时其后肢会向后旋转，导致其足部（pes）的第三趾朝向更靠后的方向（与行进方向相反）。其余肢体状态均未出现显著的方位变化。这种足部旋转会使足部功能发生显著改变，使得粘附系统可在下坡运动中充当制动/稳定装置；尽管这种旋转并非壁虎所独有，但它对于粘附系统的有效启用具有重要意义。粘附系统不仅适用于上坡运动，还可在下坡运动中辅助抵消重力作用，充分展现了这一关键创新的惊人多功能性。