Neighbor Recognition in Two "Solitary" Carnivores: The Raccoon (Procyon lotor) and the Red Fox (Vulpes fulva).

Male raccoons and red foxes were trapped alive and exposed to each other in captivity. Animals of each species trapped close to one another demonstrated a higher frequency of initial dominance-subordinance relationships and lower frequencies of more intense aggressive interactions than did animals trapped at greater distances from each other. This suggests the existence of neighbor recognition and thus a rudimentary social structure within these free-living "solitary" species.