Seed mass plays an important role in seed dispersal of many plant species during the hoarding process by rodents. Seeds of a particular plant species are usually dispersed by several sympatric rodent species. However, little is known about seed mass selection by different sympatric rodents that may show different hoarding behavior. In order to understand the role of different rodent species on the evolution of seed mass, we investigated the hoarding behavior and seed mass selection by three sympatric rodents (red spiny rat Maxomys surifer, Chinese white-bellied rat Niviventer confucianus, and yellow-bellied rat Rattus flavipectus) in semi-natural enclosures in southwest China. The hoarding behavior differed significantly among species: M. surifer showed predominantly scatter-hoarding behavior, N. confucianus showed both scatter- and larder-hoarding behavior, and R. flavipectus showed predominantly larder-hoarding behavior. All three rodent species preferred to remove and larder-hoard heavy seeds, but M. surifer and R. flavipectus were more selective on seed mass than N. confucianus during seed removal, while R. flavipectus were more selective than M. surifer and N. confucianus during larder-hoarding. The rodents showed contrasting preferences for seed mass during scatter-hoarding process. M. surifer and N. confucianus preferred to scatter-hoard heavy seeds, whereas R. flavipectus preferred to scatter-hoard light seeds. Our results show that different rodents may exert different selective pressures on seed mass during different dispersal processes. Changes in the composition of rodent communities, including those caused by human disturbance such as forest fragmentation, may influence the fates of seeds with different mass and the evolution of seed mass.Significance statementSeed mass plays an important role in seed dispersal of many plants by scatter-hoarding rodents. Previous studies usually focus on seed-mass selection by the whole rodent community while ignore the interspecific variation; and they often obtain inconsistent results. By using the semi-natural enclosure, we detected differences in hoarding behaviors among sympatric rodent species, and their different preferences on seed mass. These different preferences may exert different selective pressures on seed mass. Changes in the composition of rodent communities may influence the fates of seeds with different mass and the evolution of seed mass. We suggest that differences in hoarding behavior among sympatric rodent species should be considered in future field studies, as this will help us to better understand the role of the whole rodent community in the evolution of seed mass of forest trees that depend on dispersal by rodents.