Effect of the energy-budget over the risk-sensitivity in rats) (Rattus norvegicus

Abstract

A free-choice experimental task with rats (Rattus norvegicus), that simulates extreme foraging conditions in natural environments, was used to study risk-sensitive foraging (RSF). During the experimental session, two energy sources provide different rate of energy. Each one provide the same amount of resources (in this case, water), through the experimental session, being manipulated the delay of water gained on both sources. We compared the preference for one or the other alternative, constant delay versus variable delay, when rats 1) have sufficient energy resources to survive independiently of the water gained on the source choosen or, 2) their possibilities of survival depends on its choice. The results are similar as predicted by the Energy-Budget Rule (Stephens, 1981), emphasizing that the disponibility of energy resources is a relevant factor to explain risk-sensitive foraging not alone in smaller animals, but in bigger animals. at least fats, when the restriction in energy resources is severe.