Meeting Abstract
Many studies of terrestrial locomotion have expertly characterized maximum speed and metabolic cost of transport (relative to speed) for a variety of animals. Although these metrics can inform evolutionary hypotheses for a subset of animals that sustain high speeds for survival, biomechanical inquiry could be more broadly applicable by considering how the natural diversity of locomotion has evolved. For example, a predator with only one striking opportunity and limited feedback during the strike exerts a specific selective pressure on their prey. Measuring this prey’s cost of transport may misleadingly report low fitness. In this case, locomotor unpredictability is more informative to evolutionary, ecological, and neuroethological hypotheses. To characterize the movement patterns of prey of single-strike predators, we developed methods to quantify the unpredictability of locomotion, and then determine the components of locomotion that generate unpredictability. We applied this method to sympatric desert rodent species and identified distinct predator evasion strategies. The bipedal ricochetal rodent varies speed and 3D direction of locomotion in short bursts to increase unpredictability. The quadrupedal rodent returns to safety using predictable 2D locomotion over a short distance when in danger. These results, when coupled with known differences in foraging behavior, suggest that this divergence in locomotor strategy may decrease interspecific competition for limited food resources. We demonstrate the broad benefits of developing new methods to analyze a variety of locomotor strategies: from engineering applications of pursuit and evasion tactics, to informing hypotheses regarding behavior, evolution, and ecology.
