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January 3 - Febuary 28, 2021

Meeting Abstract

73-7  Sat Jan 2  Turning in treacherous terrain: Slip and fall risk and locomotion priority in guinea fowl Whitacre, TD*; Goldsmith, HL; Hubicki, CM; Daley, MA; University of California Irvine; Royal Veterinary College; Florida State University; University of California Irvine

Locomotion in the real world is rife with trade-offs between task-level demands such as speed, economy, stability, and injury avoidance. Here, we investigate locomotor dynamics in helmeted guinea fowl (Numida meleagris, n=7) on four runways: straight and 90-degree turns, each with high- and low-friction surfaces. We expected turns to shift priority towards force regulation, and slippery terrain to shift priority towards intrinsically stable gaits while limiting the horizontal forces to avoid slips and falls. Strategies to achieve this include slower speed, shorter steps, and shallower turn angles. Counter to predictions, slippery substrates did not induce a large shift in turn strategy. Guinea fowl opted for a speed-mediated turning behavior on both substrates, slowing down on turns compared to straight runs, slowing only slightly more in slippery turns compared to control terrain. In slippery turns, speed centered around the walk-to-run transition speed, corresponding to grounded running. After accounting for speed effects, duty factor increased and peak force decreased significantly in turns vs straight runs, suggesting a shift in priority towards stability and force regulation. In slippery turns, birds maintained a more upright posture with increased body height and sagittal leg angle – indicating postural shifts as a strategy for turning in slippery terrain. Despite changes in strategy, guinea fowl slipped in 36% and fell in 17% of trials on slippery turns. Taken together, we posit that slip and fall avoidance may not always be a critical priority for guinea fowl. In ongoing work, we are developing cluster analysis based on ground reaction force features to identify steps with slips and falls, and a model in DeepLabCut to track limb kinematics.