Cooperative breeding in marmots

Whenever individuals live in stable social groups and not ail individuals b reed, group members may breed cooperatively. While well-documented in a var iety of birds and mammals, there is some controversy over whether, and to w hat degree, sciurid rodents breed cooperatively. We identify cooperative br eeding when: individuals delay dispersal beyond reproductive maturity. repr oduction in mature individuals is suppressed, and when non-breeders provide alloparental care. In this paper we note that the 14 species of marmots (M armota spp.) large ground-dwelling sciurid rodents found throughout the Nor thern Hemisphere. provide an excellent taxon in which to study the evolutio n of cooperative breeding. Marmot species fit none, some, or all of the att ributes of cooperative breeding. Most interestingly, delayed dispersal and alloparental care may be de-coupled interspecifically, and possibly intrasp ecifically making marmots an excellent taxon For additional study. Environm ental harshness increases maturation time and is associated with dispersal delayed beyond reproductive maturity. The opportunity to gain direct fitnes s may be associated with gaining indirect fitness by alloparental behavior. In addition to its theoretical attraction, cooperative breeding has profou nd implications for conservation and management of species that breed coope ratively. To maximize marmot production, managers and breeders need to pay particular attention to social group structure to prevent the expression of reproductive suppression. If cooperative breeding results from an environm ental constraint, habitat modifications may increase the percent of females that breed.