DIVING-FOR-FOOD - A NEW MODEL TO ASSESS SOCIAL ROLES IN A GROUP OF LABORATORY RATS

In an experimental situation called ''diving for food'', groups of lab oratory rats are tested in an aquarium where they have to dive and swi m under water to reach the single source of food located at the other end. A behavioural differentiation appears: some rats - the carriers - dive to get food and others - non-carriers - stay in the cage and fee d by stealing. We examine whether carrier and noncarrier profiles can be considered as social roles, defined as supraindividual features dep endent on the social context. Carrier/non-carrier differentiation resu lted in all groups tested. Individually tested, almost all rats can ge t food by diving and swimming. Differentiation also occurred in groups that had been previously trained alone in the device, and in groups w hose members had all been carriers or non-carriers exclusively in a pr eliminary stage. As the access-to-food behaviour of a rat having to co pe with the diving-for-food situation is settled by its social environ ment, we consider that the present experimental model is promising for the study of interactions between the individual and the social struc ture.