Comportement social des marmottes alpines : saison, groupes et variation individuelle. Social behavior of alpine marmots: seasonal, group and individual variability.

Résumé

Composition and social interactions of three family groups of Marmota marmota were observed during a study in the Vanoise National Park (French Alps) from mid-June to late September. Interactions between members of the same group were mainly cohesive, which confirms the social nature of this species. Social interactions between marmots from different family groups were rare and agonistic. The rate of social interactions decreased as the season progressed, probably in relation to a shift in energy allocation to preparation for hibernation. Some cohesive interactions increased just before immergence when marmots restricted their activity to the main burrow system. Rates of social interactions differed between groups and between individuals. Fewer agonistic acts, more play-fighting and its persistence in late season among the immatures suggest the influence of an ontogenetic component. The most agonistic of the studied groups included an adult male that had recently immigrated. He focused most of his agonistic acts on three 2-year-old males, of which two dispersed during the season. Social events characteristic of each group, individual variability and level of familiarity between group members can influence the quality of social interactions and the dispersal of immatures. Social relationships between familiar individuals are amicable and can facilitate the retention of immatures in their natal group as well as their recruitment by emigrant adults.