Understanding the factors that explain animals' diet diversity is important to comprehend niche partitioning, co-existence, biotic interactions, and the vulnerability of species populations to habitat transformation. Species body mass and their geographical range are positively related to the diversity of food items they consume and consequently with their potential ecological niche occupied. However, the relative weight of these factors to explain diet diversity in mammals is poorly known. Using Artibeina frugivorous bats as a biological model, we evaluate the importance of body mass and ecoregions occupied to explain the diet diversity of these bats. We analyzed our data using phylogenetic correlations and Bayesian statistics techniques. Our results show a stronger phylogenetic correlation between bats' diet diversity with the number of ecoregions they occupied than with their body mass. These results suggest Neotropical frugivorous bats that occupy different habitats had a major possibility to have a higher diet diversity. In addition, these results are related with the ‘bottom-up’ diet diversity hypothesis that postulates that diet diversity in frugivorous bats is related to ecosystem plant diversity.