Sociality and asociality in white-nosed coatis (Nasua narica): Foraging costs and benefits

Abstract

White-nosed coatis maintain a social structure of female-bonded group (called bands) and solitary males. I examined the foraging success of social and solitary individuals and the possible importance of interspecific foraging competition in maintaining the social system, particularly in the associated context of sexual dimorphism. The study population was almost entirely frugivorous-insectivorous. Invertebrate foraging success did not filter between solitary band members, although solitary adult females more successful than those in bands. Fruit foraging success of solitary adult male was generally greater than that of band member, although this result varied with patch size and dependent on the age less of examined band members. Small food patches showed the greatest differential between the foraging success of solitary male and band members. Agonistic interactions between males and bands often occurred at fruiting trees, and foraging group size was important in determining the outcome of the event. Larger males were able to displace solitary females and small foraging groups from fruit patches. In turn, larger of smaller females displaced solitary males. Male-male agonism at fruit patches was also common, with larger, older males usually winning agonistic interactions. These findings suggest that coati social structure directly influence foraging, and I therefore hypothized that the coati social system is monitored (in part) by body size sexual dimorphism interacting with reliance on patchy defendable foods. Female group living allows increased access to patchy resources that are otherwise unavailable due to small body size relative to competing male. In contrast, larger male are able to access food patches without living in groups that might increase foraging competition.