DIFFERENTIAL INFLUENCE OF ADULT AND JUVENILE CONSPECIFICS ON FEEDING BY WEANLING RATS (RATTUS-NORVEGICUS) - A SIZE-RELATED EXPLANATION

Weanling Sprague Dawley rat pups (Rattus norvegicus) selected between 2 safe palatable diets in concordance with the preferences of either a n adult or a juvenile conspecific model (Experiment 1). Nevertheless, weanlings chase to feed more in the vicinity of an adult than in the v icinity of a juvenile, thus fulfilling the prediction of an adaptive f eeding strategy (Experiment 2). The weanlings' bias for feeding in the vicinity of an adult was eliminated by increasing the magnitude of pu p stimulus to 3 pups (Experiment 3). Thus, weanlings do not possess a specialization rendering them more sensitive to adults than to pups as models for diet selection. By responding to stimulus magnitude, weanl ings are more likely to feed with adult conspecifics, choose foods use d by them, and derive the benefits correlated with the adults' success ful feeding habits.