Behavioral and genetic aspects of male social groups in raccoons

Gehrt, S. D., W. F. Gergits, and E. K. Fritzell

Many mammalian species exhibit intersexual differences in sociospatial behavior; however, sociality of adult
males in species with solitary females is relatively rare. Male raccoons (Procyon lotor) in southern Texas form
social groups that have many similarities to male coalitions in other species, including spatially distinct homerange boundaries that are maintained year-round. Within these groups, males rest and travel together with varying frequencies. However, the length of social bonds and genetic relationships among group males are unknown. We quantify characteristics of male social groups for raccoons in southern Texas, examine the genetic structure of the population, and finally test whether variation in relatedness within groups is related to the frequency or length of association between males. Mean proportions of locations within 50 or 100 m for each dyad ranged from 0.04 to 0.48 for the duration of group membership, although most dyads had means between 0.20 and 0.30. Duration of dyads ranged from 6 to 39 months, with a mean of 18.4 months. Mean band-sharing coefficient for males within groups was not different (1-tailed = 0.376) from males between groups. However, mean coefficient for males within groups was lower (P < 0.01) than that for litters, suggesting that male groups were not exclusively composed of close relatives. Genetic relatedness explained little of the variation of proportions of locations within 50 or 100 m within groups (1-tailed = 0.26); however, band-sharing coefficients were positively related (1-tailed P = 0.06) to duration of associations within groups. Kin selection does not appear to explain male sociality in raccoons, but relatedness may be related to the length of associations between males within groups.

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Gehrt, S. D., W. F. Gergits, and E. K. Fritzell. 2008. Behavioral and genetic aspects of male social groups in raccoons. Journal of Mammalogy 89:1473-1480.