Geographic distribution of mammal diets

Abstract

The study of trophic interactions might be key to understanding the distribution of species on Earth. Particularly, the biogeography of heterotrophic species – such as mammals – could be strongly driven by trophic interactions (diet). Here, we map and discuss the division of dietary strategies (herbivory, frugivory, carnivory, etc.) of terrestrial mammals on a global scale. We analyzed the diet of 4854 extant terrestrial mammal species (with known range and diet data, representing 86.67 % of extant mammal species). We compiled species diets (EltonTraits database), species ranges (International Union for Conservation of Nature, IUCN, database) and climate data (WorldClim database) to illustrate how mammal dietary strategies are distributed across the globe. First, we performed a principal coordinate analysis (PCoA) with diet data. Second, we mapped the distribution of the main dietary strategies (PCoA axes) of terrestrial mammals globally. Third, we analyzed how climate relates to dietary strategies. We found that herbivory in mammals is more common in northern and desert areas, which corresponds to areas with lower minimum temperatures and lower precipitation. Mammals feeding on fruits and invertebrates (frugivory and invertivory) are more common in the tropics, which corresponds to areas with higher precipitation and higher minimum temperatures. Mammals feeding on seeds (granivory) are predominant in North America, Europe, Central Asia and Oceania, corresponding to areas with temperate environments. Carnivorous mammals are more common in the Northern Hemisphere and towards the poles, which corresponds to areas with lower minimum temperatures and less extreme dry periods. Terrestrial mammal diets show clear geographical patterns that can be partially explained by climate across the globe.