A meta-analysis of ungulate predation and prey selection by the brown bear Ursus arctos in Eurasia

Abstract

At the biogeographic scale, spatial variation in diets may reflect not only the ecological flexibility of carnivore feeding habits, but also evolutionary adaptations of different populations within a species. We described the large-scale pattern in brown bear Ursus arctos predation on ungulates, its selectivity for ungulate species, and its relative role in ungulate mortality. We collated data from 63 studies in Europe and Asia and analyzed them in relation to annual temperature. Ungulate meat makes up, on average, 8.7% of brown bear diets, with European bears feeding on ungulates more (mean 10.5%) than Asiatic bears (6.8%). In Europe (but not in Asia), the percentage share of ungulates in bear diet was negatively related to the mean annual temperature. Northern populations of Asian bears consumed less ungulate meat than the respective populations in Europe, because of the widespread occurrence of Siberian pine Pinus sibirica and dwarf Siberian pine Pinus pumila, which produce relatively large, protein-rich seeds. In both continents, ungulates peak in the diet of bears in spring. Brown bears’ preference for 10 species of ungulates increased with body mass of prey. The bear significantly preferred preying upon moose Alces alces throughout its range. Bears were the most important predator of moose and caused, on average, 23% of total natural mortality in moose populations. Brown bear preference for moose and its dominant role in moose mortality suggest an evolutionary predator–prey relationship between these two species. Brown bears illustrate that even an apparently omnivorous predator can prefer one prey species.