ABSTRACT
North American ground squirrels are medium-sized rodents found in habitats ranging from desert, to prairie, to mountain meadows, to arctic tundra. Repetitive capture of the same animals provides a data set that can be analyzed in two ways: date-based analysis which pools data collected on the same date without regard to the identity of the individuals composing the sample or event-based analysis which pools data collected from individuals of the same reproductive status without regard to the date of collection. Date-based analyses of body mass are weaker than event-based analyses when reproductive status has a significant effect on body mass and when individuals in the sample are not at identical stages of reproduction. Event-based analysis revealed that yearling female Richardson's ground squirrels immediately and steadily increased in mass postemergence and yielded the following conclusions with regard to growth patterns of female squirrels.
