This article has been retracted at the request of the authors.
Amgen requested the retraction as an outcome of an internal review where it was determined that one of the Amgen authors had manipulated specific experimental data presented in Figures 1 and 3. Because of data manipulation, this author is no longer employed by Amgen. The authors at Washington State University and University of Idaho are confident that the physiological data generated for this manuscript are accurate and representative of the true metabolic responses of these grizzly bears and are currently repeating the mechanistic portions of the study. Amgen deeply regrets this circumstance and extends their sincere apologies to the scientific community.