Sex specific seasonal variation in the diet of brown bears in human dominated landscapes

Understanding the foraging ecology of brown bears (Ursus arctos) in human-dominated landscapes is essential for effective wildlife management and conflict mitigation. In this study, we investigated the seasonal diet composition of brown bears in the Western Carpathians, Slovakia, using a combination of molecular genetic and microhistological scat analyses. We analysed 198 brown bear scats (101 males, 97 females) collected throughout the year in central Slovakia, to assess seasonal variation in diet, identify sex-specific foraging patterns, and evaluate the use of anthropogenic food resources. Vegetation constituted the primary dietary component year-round, with hard mast frequency dominating in spring (FO = 45%), autumn (FO = 67%), and winter (FO = 82%), while soft mast (FO = 48%) and anthropogenic food (FO = 30%) prevailed in summer. Dietary energy intake from anthropogenic food was considerable in spring (EDEC = 15%) but peaked in summer (EDEC = 34%) and was consistently higher in males across all seasons. In spring, males consumed a considerable amount of anthropogenic food (EDEC = 32%), while it was negligible for females (EDEC = 3%). In summer, male consumption of anthropogenic food increased further (EDEC = 40%), and although females still consumed less than males, their intake rose by 23% compared to spring (EDEC = 26%). Males also consumed more vertebrates and hard mast, whereas females relied more heavily on soft mast and natural food sources, likely reflecting sex-specific trade-offs between energetic needs and risk avoidance. Seasonal dietary diversity was highest in summer and lowest in winter, with the greatest trophic divergence between sexes occurring during spring and summer. These findings highlight the dietary plasticity of brown bears in response to seasonal and anthropogenic resource availability, and emphasize the importance of regulating anthropogenic food access, particularly supplemental feeding and agricultural crops, to reduce human-bear conflict.