These discontinuous shifts in leg coordination are hypothesized to minimize energy consumption by changing the number and relative timing of legs in motion 2, 3. Since the pioneering photographic studies of Muybridge 1, it has been widely appreciated that animals use distinct gaits at different locomotor speeds. We propose that the requirement to climb vertical terrain may drive the prevalence of the tripod gait over faster alternative gaits with minimal ground contact. Intriguingly, when adhesive leg structures in real Drosophila are covered, animals exhibit atypical bipod-like leg coordination. By contrast, novel two-legged bipod gaits are fastest on flat terrain without adhesion in the model and in a hexapod robot. Indeed, the tripod gait emerges to the exclusion of many other possible gaits when optimizing fast upward climbing with leg adhesion. To test this, we computationally discovered fast locomotor gaits for a model based on Drosophila melanogaster. One prevailing hypothesis for this difference in fast locomotor strategies is that tripod locomotion allows insects to rapidly navigate three-dimensional terrain. By contrast, most insects use a tripod gait that maintains at least three legs on the ground at any given time. To escape danger or catch prey, running vertebrates rely on dynamic gaits with minimal ground contact.

Webots hinge joint model