We use generalized joint attribute modeling (GJAM) to estimate how the proclivity to consume different Piper species varies among three syntopic Carollia species my depend on bat traits (e.g., body size and age) or Piper fruit traits. How these ecologically and morphologically similar bats coexist is unclear. Compared to the Piper-specialist Carollia castanea, generalist C. perspicillata had a higher proclivity for several Piper species that were the lowest ranked for the specialist, indicating some degree of niche partitioning. Piper proclivity estimates were associated with bat forearm length and age after controlling for bat species, reproductive condition and sex. However, neither fruit nor seed shape influence dietary differences among bats. Understanding the mechanisms of coexistence for closely related species with a high degree of morphological and behavioral similarity is complex, but simultaneously controlling for multiple sources of variation among different data types allowed us to discover key differences in resource consumption and traits contributing to niche partitioning among frugivores.