What is a mammalian omnivore? Insights into terrestrial mammalian diet diversity, body mass, and evolution

Mammalian omnivores are a broad and diverse group of mammals that are often lumped together in ecological studies. As a result, there are open questions about what macroevolutionary and macroecological information can be gained when omnivorous dietary differences are investigated in ecological and phylogenetic comparative studies. In this study, we investigate the frequency at which vertebrate prey, invertebrate prey, fibrous plant material, and non-fibrous plant material co-occur in the diets of omnivorous species. We quantify the body size distributions and phylogenetic signal of terrestrial mammals that consume different omnivorous diets and using multistate reversible jump MCMC, we assess the transition rates between mammalian diet strategies on the mammalian phylogenetic tree. We find that omnivores that consume all four food types are rare and most omnivorous mammals consume only invertebrate prey and non-fibrous plants. We also find that omnivores that only consume invertebrate p..., Dataset and phylogenetic tree
Using previously published datasets, we compiled diet data and body masses for 1437 extant terrestrial mammals (about a quarter of all mammal species) (Supplemental data 1). Aquatic mammals, dependent on food webs with a dramatically different structure than their terrestrial counterparts, are expected to experience different ecological and evolutionary pressures than terrestrial mammals and have been excluded from this analysis. We chose to use a dataset compiled from primary literature sources generated previously by some of the authors (Price et al. 2012). This dataset did not use dietary inferences based on phylogeny or morphology, only using studies that reported stomach contents or cheek-pouch contents, the contents of food stores, direct behavioral observations, or fecal analysis. While this dataset contains fewer species, and uses a categorical schema, we use it because of the high diet resolution and because it allows us to directly compare our res...,