Data and R code for "Long-term cooperative relationships among vampire bats are not strongly predicted by their initial interactions as strangers"

In many group-living animals, survival and reproductive success depend on the formation of long-term social bonds. Yet it remains largely unclear why particular pairs of groupmates form social bonds and not others. Can social bond formation be reliably predicted from both individuals’ traits and behaviors at first encounter? Or do changes in the social environment over time make social bonding unpredictable? To begin to address these questions, we asked how well long-term cooperative relationships among vampire bats were predicted by how they interacted during their first encounter as introduced strangers. In Study 1, we found that the first 6 hours of observed interactions among unfamiliar bats co-housed in small cages did not clearly predict formation of allogrooming or food-sharing relationships over the next 10 months. In Study 2, we found that biologger-tracked first contacts during the first 4—24 hours together in a flight cage did not strongly predict allogrooming rates over the next 4 months. These results corroborate past evidence that social bonding is not reducible to the individual traits or behaviors observed at first encounter, because “first impressions” can be overshadowed by future interactions.