AbstractFruiting plants and frugivorous birds are known to interact. In endozoochory, frugivorous birds consume fruits and subsequently disperse seeds. It follows that fruit characteristics would have evolved to allow birds to consume fruits easily. However, one's benefit does not always mean the other's. There are several conflicts between fruiting plants and frugivorous birds in terms of nutrient content, retention time and number of seeds in a fecal pellet. Retention time of seeds in guts is particularly interesting. Longer retention time benefits plants directly by increasing seed dispersal distance but may involve indirect costs through birds' preference by reducing their consumption. To understand the exact role of seed dispersers in the reproductive success of fruiting plants, we should pay more attention to the possible conflicts between fruiting plants and frugivorous birds.