Abstract

<jats:p> Body mass has been proposed as a factor that contributes to the onset of puberty in some species of mammals. In this study we examined the relationship between body mass and primiparity in the eastern chipmunk (Tamias striatus) by comparing females that reproduced and those that did not during any given breeding opportunity. We also investigated whether season of birth influenced the season of first reproduction. No differences in season of first reproduction were observed between spring-born and fall-born females. Females that produced a litter had significantly greater body mass than did females that did not. Significant differences in body mass were also observed, based on season of birth. Food availability and timing of hibernation may be important contributors to the observed pattern. </jats:p>