Maternal Response to Conspecific Visits at Natal Dens in Raccoons (Procyon lotor)

The response of postparturient females to conspecifics at the natal den can provide insights into intraspecific dynamics, particularly the risk of infanticide. In solitary species, the risk of infanticide may be high and mothers are expected to secure dependent young in dens and tolerate little, if any visitation by males. We monitored 10 male raccoons (Procyon lotor) and 11 females from pregnancy through lactation that were equipped with proximity detecting collars during the neonate rearing period (Apr.-Jul.). Natal den trees were identified and proximity detectors were also attached to these trees to document the mother's movements and visitation by conspecifics. A total of 21 den trees (1-8 dens/mother) were used, yielding 337 den-nights of data. Besides those of the mother, 284 visits (0-2.9 visits/night) were recorded and dens were visited by three to 10 individuals. Time spent away from the den by the mother increased with litter age (F = 45.36, P < 0.001, R-2 = 0.19). Females who moved their litters from the primary natal den tended to receive more (t = -1.99, P = 0.08, df = 8) male visits/night before their move, than females that stayed in the primary natal den. Males also visited natal den trees more often (t = 2.26, P = 0.05, df = 7) when a natal family was occupying the den tree than once the family had stopped using the den tree. We were unable to examine den trees that were abandoned by their mothers, but our data suggested that female raccoons are intolerant of adult males at natal dens while raising their litters. This may be a response to the risk of male-driven infanticide.