Diving for food: Analysis of a possible case of social learning in wild rats (Rattus norvegicus).

Many members of some colonies of wild rats living along the banks of the Po River dive for and feed on molluscs living on the river bottom, No members of nearby colonies, having equal access to molluscs, exploit them as a food source. It has been suggested that these field observations indicate that social transmission processes are responsible for the spread of mollusc predation within predaceous colonies. The results of the present laboratory analysis of the development of diving behavior in wild and domesticated rats indicate that differential exposure of various colonies to shaping procedures occurring in nature and differences in resource distribution within colony home ranges are probably more important than social transmission processes in producing the intercolony variability in diving behavior observed in nature.