Meeting Abstract
Animals propel themselves through physically challenging environments for a variety of tasks including dispersal, feeding, and predator evasion. Animal morphology is critical to meeting the physical demands of locomotion – each task and ecological context correspond with unique requirements. We studied the mechanics of turning in the Desert Kangaroo Rat Dipodomys deserti, a bipedal hopping rodent, after observing steady-state turns and rapid turns responding to simulated capture attempts in the field. We coerced and encouraged ten Kangaroo Rats to hop through a 90° turn connecting two straight 1.5m long x 0.2m wide wooden runways lined with thermoplastic rubber to improve grip. Three cameras recording at 200 hz coupled with two force plates recording at 600 hz allowed us reconstruct 3D kinematics and ground reaction forces. We observe that animals use both bipedal and quadrupedal strategies during turns. Preliminary observations suggest quadrupedal turns maybe faster than bipedal turns upon turn entry, but bipedal gaits maybe faster than quadrupedal gaits upon turn exit. This suggests bipedal turns are steadier than quadrupedal turns. Trajectory changes up to 46° are achieved during each bipedal stance while orientation is altered in both stance and swing phases. We discuss the tradeoffs and ecological implications associated with different turning strategies.
