Social security: Does social position influence flight initiation distance?

Abstract

Specific social relationships that individuals have with others may modulate perceptions of risk and explain variation in antipredator behavior. We asked whether and how yellow-bellied marmots' (Marmota flaviventer) connectivity and position in their social network explained variation in flight initiation distance (FID). We examined the relationship of both direct and indirect measures of sociality and separated models by age and sex classes to isolate the relationships for different life-history stages. Following the "social security"hypothesis, we predicted that more socially connected individuals would have a lower FID because they are less fearful. When examining all age-sex cohorts, there was a weak effect of social interaction frequency on FID: individuals in stronger relationships tolerated closer human approaches. When examining each cohort independently, we found adult male's FID was not associated with any social network measure, but female adults fled at greater distances as their number of social partners increased. Male yearlings more closely connected to their social group fled at shorter distances (only when perceived risk was high), but female yearlings experienced the opposite effect in which closer connection to others in their group led to greater FID at higher perceived risks. These results are partly consistent with the social security hypothesis in that they show that social relationships are associated with escape only at certain levels of perceived risk and for certain age and sex cohorts. Together, the results illustrate the importance of social attributes on antipredator behaviors and show how it depends on the life stage and the sex.