Role of sex, body size, and sexual state in determining aggression in Tamias striatus (Eastern Chipmunk).

Abstract

We studied dominance structure in a human-acclimated population of Tamias striatus on University of Michigan Biological Station (UMBS) property in the northern Lower Peninsula of Michigan. We predicted that larger, sexually mature individuals who were closer to their burrows would be dominant over smaller, immature animals that were farther from their burrows, and that males would be more aggressive than females. We captured and marked chipmunks and observed them over several weeks. We found that sex and sexual state did not have an effect on aggression but that chipmunks further from their burrows won more fights than chipmunks closer to their burrows. We attribute these unexpected results to the presence of juveniles on the peripheries of the community with a high drive for food who were less willing to back down from confrontations.