Heading out the door? Read this article on the new Outside+ app available now on iOS devices for members! Download the app. This time of year, the brown bears in Katmai National Park are insatiably hyperphagic. They're storing up the fat that they'll need for hibernation, during which they'll lose up to a third of their body weight. So, we celebrate their rotund physiques during Fat Bear Week and vote on who is best primed to survive comfortably this winter.