Age, but not sex or genetic relatedness, shapes raccoon dominance patterns

Raccoons are generally regarded as solitary, yet several studies have found that raccoons frequently form social affiliations. One benefit to sociality in many mammal species is that relatives and close associates can form coalitions against third parties during agonistic encounters. We tested whether raccoon dominance patterns were influenced by age, sex, genetic relatedness, and association patterns at two anthropogenic feeding stations in an urban forest. We found that genetic relatedness had no significant effect on patterns of agonism at one of the feeding stations. At the second feeding station, raccoons were more likely to act aggressively toward close relatives, which is opposite of the predicted pattern. However, when we controlled for the number of times raccoons arrived at feeding stations in close proximity, the effect of relatedness on dominance patterns was not significant at either feeding station. These results suggest that relatedness plays little or no role in shaping dominance patterns of raccoons. Older raccoons were ranked significantly higher in the dominance hierarchies regardless of sex. This pattern leads us to conclude that age is the primary factor driving the outcome of aggressive interactions in raccoons at our study site. Despite frequent social interactions at the study site, the patterns of raccoon dominance more closely resemble patterns found in solitary animals. To confirm the generality of these results and to better understand the evolution of raccoon social behavior, similar studies need to be undertaken in other raccoon populations