Learning to outwit a competitor in mangabeys (Cercocebus torquatus torquatus).

To investigate whether monkeys would be able to acquire the location of hidden food from the experimenter and later from an informed conspecific, a group of 7 mangabeys (Cercocebus torquatus torquatus) was tested in an experimental design comparable to Menzel's (1974) with chimpanzees. Food was hidden in the presence of particular animals. An informed young male repeatedly lost his food to a dominant male. Accordingly, the young male developed a pattern, when he alone was informed, of moving in an indirect route to the goal, which generally functioned to mislead the dominant male to the young male's advantage. When the dominant male was also informed, the young male observed the dominant male taking the food or headed straight to the remaining hidden goal. His taking an indirect route, when he alone was informed, cannot therefore be considered his expected response to a competitive situation but rather is a case of tactical deception.