摘要In a number of species,males and females have different ecological roles and therefore might be required to solve different problems.Studies on humans have suggested that the 2 sexes often show different efficiencies in problem-solving tasks;similarly,evidence of sex differences has been found in 2 other mammalian species.Here,we assessed whether a teleost fish species,the guppy,Poecilia reticulata,displays sex differences in the ability to solve problems.In Experiment 1,guppies had to learn to dislodge a disc that occluded a feeder from which they had been previously accustomed to feed.In Experiment 2,guppies had to solve a version of the detour task that required them to learn to enter a transparent cylinder from the open sides to reach a food reward previously freely available.We found evidence of sex differences in both problem-solving tasks.In Experiment 1,females clearly outperformed males,and in Experiment 2,guppies showed a reversed but smaller sex difference.This study indicates that sex differences may play an important role in fish's problem-solving similar to what has previously been observed in some mammalian species.