Responses to a novel food acquisition task in three species of lemurs.

In order to study learning and social processes in lemurs, a food acquisition task was presented to three groups: Lemur macaco, L. fulvus and L. catta. The lid of a box had to be pivoted horizontally in order to expose figs contained therein. Individuals in all three groups learned the task, but they showed only limited comprehension. In L. macaco, two adult females learned, with one female showing increasing aggressive monopolization of the new food-source. In L. fulvus, two adult males learned, and one of them increasingly prevented the other from approaching. In L. catta, the adult female frequently threatened away the most efficient opener - a young adult male. The simultaneous presentation of two boxes led to a more equal distribution of the figs. Social processes revealed in the test situation included female dominance in L. macaco and L. catta, and an intermale dominance relationship in L. fulvus. The experimental situation also highlighted the privileged position of the offspring of the dominant female in L. macaco, reduced competitiveness of females with very young infants in L. fulvus, and a general tolerance towards others in L. fulvus.