THE EFFECTS OF ADULT REMOVAL ON DISPERSAL OF YEARLING YELLOW-BELLIED MARMOTS

The relative importance of adult-yearling interaction and individual behavioral phenotypes on dispersal of yearling yellow-bellied marmots was investigated. Two marmot colonies near Gothic, Colorado, were studied; one was treated as an experimental colony from which all adults were removed, while the second was left undisturbed. Analysis of dispersal patterns and behavioral observations indicated that agonistic behavior between adults and yearlings is not necessary for dispersal to occur. Dispersal or male yearlings appears to be independent of adult-yearling interactions, although dispersal of female yearlings probably is mediated by social interactions. Individual behavioral phenotypes could not be used to predict which animals dispersed nor the relative timing of their departure. Dispersal can be viewed as an important mating strategy; for yearling males it is likely to be the only option available for reproductive success.