Spontaneous use of matching visual cues during foraging by long-tailed macaques (Macaca fascicularis).

A social group of 38 captive-born Macaca fascicularis was confined to a holding cage while food was placed in an outdoor enclosure next to a structure (e.g., stone, tree) that varied across trials. After the group was released and obtained the food, animals inspected other structures similar to the baited structure more quickly and more often than they inspected equally conspicuous nonmatching structures. Animals also varied their search according to the quality of food, remembered the exact location of food on the previous trial, and discriminated sharply between locations where other macaques found or did not find food. Use of visual cues by experimentally naive macaques seems far more efficient than would be expected from many prior laboratory studies but is consistent with wild macaque foraging behavior.