Meeting Abstract

75.5  Wednesday, Jan. 6  Dynamic stability during quadrupedal arboreal locomotion in the Siberian chipmunk (Tamias sibiricus) LAMMERS, A.R.*; ZURCHER, U.; Cleveland State Univ., Ohio; Cleveland State Univ., Ohio a.Lammers13@csuohio.edu

Locomotion on narrow tree branches, twigs, and foliage presents many challenges to maintaining stability during locomotion. We hypothesize that the movement of an arboreal animal plays an important role in maintaining its stability. Because the substrate reaction force applies a non-zero torque, the angular momentum of the animal is not conserved (constant). Specifically, we expect that angular momentum is regulated during each gait cycle of the animal. Three Siberian chipmunks (Tamias sibiricus) were trained to run across a 2 cm diameter cylindrical trackway about 1.8 m long. The animals were filmed at 120 Hz from two angles, and we used a motion analysis program to digitize body segments from each viewpoint. Digitized coordinates were converted into a 3-D coordinate set. Using body mass distribution obtained from a dead specimen, we calculated both the angular and linear momentum of each segment and the whole-body values. We found partial cancellation of segmental contributions resulting in distinct patterns for the whole-body angular momentum. Our results suggest that dynamic stability plays an important role in quadrupedal arboreal locomotion.