Working with the US Fish and Wildlife Service, Alaska Department of Fish and Game, and Washington State University, USGS researchers paired stable isotope techniques with behavioral observations and energy balance estimates to examine the feeding behaviors of Arctic grizzles leading up to hibernation. By analyzing stable nitrogen and carbon isotopes, the team assessed levels of carnivory with respect to available dietary resources. They found that bears in the foothills were primarily herbivorous and bears on the coast were primarily carnivorous, diets that likely reflect differences in resource availability across different Arctic habitats. 

At the completion of the study, coastal bears had on average gained more body fat but were also more likely to lose body mass prior to hibernation due to the energetic costs associated with carnivory. Arctic grizzlies in both locations had an average of 34% less fat than bears living in areas like the salmon-rich Kenai Peninsula, suggesting an overall lack of calorically dense food sources in the study area. This study demonstrated that dietary plasticity is likely driven by resource availability in the Arctic, which may be more limited than in other parts of this species range.