Data from: The relationship between diet and body mass in terrestrial mammals

Diet and body mass are highly important factors in mammalian ecology, and
they have also proven to be powerful paleoecological indicators. Our
previous research has proposed a new classification scheme for mammals
with more dietary divisions that emphasizes the primary resource in a
given diet. We analyzed a database summarizing the dietary preferences of
139 species of marsupial and placental terrestrial mammals (including 14
orders) and their average body masses in order to explore whether this new
classification better highlights ecomorphological differences between
species. Additionally, the dietary diversity of every species in the data
set was quantified by applying the inverse Simpson index to stomach
content percentages. We observed a decrease in maximum dietary diversity
with increasing body mass. Having lower requirements for energy and
nutrients per unit of body weight or ecological advantages such as larger
home ranges allows larger mammals to feed on less nutritive feeding
resources (i.e., structural plant material). Our results also suggest that
body-size ranges are different across dietary specializations. Smaller
mammals (<1 kg) are mainly insectivores, granivores, or mixed
feeders, while bigger animals (>30 kg) are usually either
carnivores or herbivores that feed specifically on grasses and leaves. The
medium-size range (1–30 kg) is mostly composed of frugivorous species that
inhabit tropical and subtropical rain forests. Thus, the near absence of
medium-sized mammals in open environments such as savannas can be linked
to the decreasing density of fruit trees needed to support a pure
frugivorous diet year-round. In other words, seasonality of precipitation
prevents species from specializing on a totally frugivorous diet. Our
results suggest that this new classification scheme correlates well with
body mass, one of the most studied morphological variables in paleoecology
and ecomorphology. Therefore, the classification should serve as a useful
basis for future paleoclimatological studies.