Fat Bear Week returns to Katmai National Park; public voting set for Sept. 23–30

The National Park Service said its annual Fat Bear Week will take place Sept. 23–30 in Katmai National Park and Preserve, inviting the public to vote on which Brooks River brown bear has achieved the greatest pre-hibernation mass. The season will begin earlier with Fat Bear Junior, a youth-focused showcase, on Sept. 18–19.

Park officials described the event as a lighthearted, bracket-style competition that highlights the bears natural cycle of hyperphagia, when animals consume large amounts of food to build fat reserves for winter. "Big, bold, and bear-y round: a fat bear champ will soon be crowned!" the park service said in its announcement, adding that bear biographies for the 2025 field will be released in the coming days.

Fat Bear Week began as a public-engagement effort in 2014 and returns this year for its 11th iteration. The contest encourages viewers to follow the Brooks River livestreams and vote weekly for the bears they deem the "fattest" as animals bulk up on salmon and other food sources before denning. The event has been used by park staff and partner organizations to draw attention to bear ecology and the seasonal dynamics at Katmai.

Recent winners illustrate the competitions popularity. Bear 128, known as Grazer, won the 2024 title with more than 71,000 votes, reportedly earning roughly twice the votes of her nearest rival, a male bear nicknamed Chunk. Grazer also won the contest in 2023. Other past champions include Bear 747, which won in 2020 and again in 2022, and Bear 480, Otis, who won in 2021. Bears 409 (Beadnose) and 435 (Holly) were champions in 2018 and 2019, respectively.

Organizers emphasize that the contest is not a scientific measurement of weight but a public celebration of natural behavior and the parks wildlife. Voting is conducted online, and the bracket format pits bears against one another over the course of the week.

Last years season included a widely viewed and fatal altercation between two adult bears captured on the Brooks River livestream. The incident, during which an adult male identified as Bear 469 attacked and killed an adult female identified as Bear 402, prompted commentary from naturalists and park staff monitoring the feed. Mike Fitz, a resident naturalist for explore.org, said viewing an attack can be difficult and that commentators had little information about what precipitated the fight. "Watching bears attack other bears is often difficult to see, especially if a bear kills another bear, so this is a difficult situation to witness," he said. Katmai Park Ranger Sarah Bruce characterized the encounter as aggressive and cautioned against viewing it as play: "He's a predator toward this female bear... We don't know why they're fighting... [These are] two bears very clearly not playing around."

Park staff and partners have continued to provide context during Fat Bear Week coverage, noting that intraspecies aggression can be driven by multiple factors, including competition for resources or social dominance. Officials said last years fatal fight was not related to the contest itself but occurred among animals that are also contenders in the public vote.

The event routinely draws national and international attention and has become a recurring point of public engagement for Katmai National Park, which manages visitor access and livestreaming platforms that make the bears accessible to a wide audience. Organizers said the public can expect the park to publish bear profiles and viewing links ahead of the junior and main competitions.

Fat Bear Week organizers and park officials encourage viewers to use the event as an opportunity to learn about brown bear life cycles, salmon runs that sustain them, and the conservation issues affecting their habitat in Alaska. Voting rules and a schedule of matchups will be posted by the park service prior to the Sept. 18 start of Fat Bear Junior and the Sept. 23 start of the main bracket competition.