Laterality of hand use pays off in foraging success for wild chimpanzees

The aim of this study was to see if behavioral lateralization in hand use b enefits a lateralized organism in nature. We recorded wild chimpanzees (Pan troglodytes schweinfurthii) at Gombe, Tanzania, fishing for termites (Macr otermes spp.), an extractive foraging task using elementary technology. We compared individual apes who were completely lateralized, using only one ha nd or the other for the task, versus those who were incompletely lateralize d, using either hand. Exclusively lateralized individuals were more efficie nt, that is, gathered more prey per unit effort, but were no different in s uccess or error rate from incompletely lateralized apes. This is the first demonstration of a payoff to laterality of behavioral function in primates in conditions of ecological validity.