Abstract

Rainforest primates need to apply distinct foraging rules for efficiently using the spatial knowledge of the distribution of resources showing different temporal patterns of renewal. A win-stay rule is very important for exploiting abundant, long-lasting resources. Here, the author tests the use of this rule in wild groups of emperor tamarins (Saguinus imperator imperator), saddle-back tamarins (Saguinus fuscicollis weddelli), and titi monkeys (Callicebus cupreus cupreus) during a series of foraging tasks. Four feeding stations composed of 8 visually similar feeding platforms (2 containing a food reward and 6 containing a sham reward) were constructed. The location of food rewards was reliable during some experiments and unreliable during others. All 3 species consistently adopted a win-stay rule for returning to reward platforms when their location was predictable over time but stopped using it when their spatial distribution changed randomly across experimental trials.