Robbins CT. 2005. Nutritional ecology of North American bears. In Graffam W, Hellinga D, Maslanka M, Ward A, Eds. Proceedings of the Sixth Conference on Zoo and Wildlife Nutrition, AZA Nutrition Advisory Group, Omaha, NE.
North American brown (Ursus arctos) and black bears (U. americanus) are well known for undergoing major seasonal physiological and nutritional cycles. These cycles can include switching from herbivory to carnivory, from ingesting diets with minimal protein (e.g., fruit) to diets that are primarily protein (e.g., meat), from fasting during the 5 or 6 months of hibernation to daily food intakes as high as 40% of body weight, and therefore from losing as much as one-third of their body weight during hibernation to gaining more than 5 kg/day during fall hyperphagia. Understanding this physiological flexibility has broad implications for captive and wild bear management.RobbinsBearsFINAL14Aug.05.pdf     89 KB