The annual Fat Bear Week contest on the Alaska Peninsula is set to begin, showcasing the brown bears' resilience as they prepare for winter by gaining weight. The event includes a preliminary voting round for adolescent bears, leading to a tournament to determine the fattest bear. The contest highlights the bears' survival strategies and the impact of environmental changes on their food sources. Notable bears include defending champion Grazer and Chunk, who has returned with a broken jaw. The event emphasizes the importance of a healthy ecosystem for the bears' survival.