Brown bear 128, known as “Grazer,” was voted Fat Bear Week champion in 2023.

Fat Bear Week is back!

The famed March Madness-style bracket competition that pits some of Katmai National Park and Preserve's bulkiest and most beloved brown bears against each other in the arena of public opinion is returning for its 11th year later this month.

“Fat Bear Week is always a celebration of the success of the bears,” Naomi Boak, a media ranger at Katmai, previously told USA TODAY. “Not just the big boys, but the sows with cubs, the young teenage bears, the subadults.”

However, only one can be crowned Fat Bear Week champion.

Here’s what to know about the competition and when it will be taking place.

When is Fat Bear Week?

Fat Bear Week is scheduled to take place from Sept. 23 to 30, NPS announced on Sept. 4.

Fat Bear Week will be preceded by the "chubby cubby appetizer," Fat Bear Junior, which will take place Sept. 18-19.

What is Fat Bear Week?

Fat Bear Week is an annual park competition that "celebrates the healthy appetites of brown bears" and "the nourishing ecosystem in which the bears thrive," according to NPS. The competition not only highlights "the physical transformations of these iconic animals but also serves as a platform to educate the public on the importance of preserving their habitat, Katmai National Park and Bristol Bay, Alaska. The habitat is a wild region that is home to more brown bears than people and the largest, healthiest runs of sockeye salmon left on the planet," competition organizers say.

The annual event, which began as Fat Bear Tuesday in 2014 and expanded into Fat Bear Week in 2015, is held at the Katmai National Park and Preserve in Alaska. Wildlife and bear enthusiasts from across the world are invited to participate in the event via live cams on explore.org, through which they can observe the bears in their natural habitats as they "feast on a banquet of Alaska wild salmon in one of the greatest salmon runs left on earth," NPS says.

The single-elimination tournament is held as hibernating bears reach peak fat after a summer-long effort. For each match-up, contestants vote for the bear they believe "best exemplifies fatness and success in brown bears," officials wrote on the contest website.

"Choose the bear that you think has what it takes to survive the winter," NPS says.

Fat Bear Week 2025 participants

NPS has not yet announced bracket reveals and bear bios for this year's edition.

What happened during Fat Bear Week 2024?

In 2024, the competition was delayed a week after one of the contestants was fatally mauled by a rival bear with the attack seen on the live webcams.

Video footage from the incident shows bear number 469, an adult male bear named Patches, attack bear number 402, an older adult female while the two were in water. The killing was livestreamed prompting a short delay in the bracket reveal.

Last year's winner of the Fat Bear competition was a female brown bear named 128 Grazer.

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Grazer, whose cub was killed by her opponent in July 2024, beat 32 Chunk, a male bear weighing more than 1,200 pounds, to become champion. Out of more than a million votes, the mama bear received more than 70,000 votes, while Chunk, estimated to be 30 years old, netted nearly 30,000 votes, according to the competition's website.

It marked the second win for the mama spotted for years on the Brooks River at Katmai National Park and Preserve in Alaska. She has even earned a reputation among fellow bears as "a particularly defensive mother bear who has successfully raised two litters of cubs,” according to Fat Bear Week’s website.

“She often preemptively confronts and attacks much larger bears – even large and dominant adult males – in order to ensure her cubs are safe," the website says.

You can see all the previous winners in explore.org’s Fat Bear Week Hall of Champions.

Fat Bear Week is a partnership between Katmai National Park and Preserve, explore.org, and Katmai Conservancy.

Contributing: Eve Chen, Natalie Neysa Alund / USA TODAY

Saman Shafiq is a trending news reporter for USA TODAY. Reach her at sshafiq@gannett.com and follow her on X and Instagram @saman_shafiq7.

This article originally appeared on USA TODAY: Fat Bear Week 2025 dates have been announced: Here's what to know

Reporting by Saman Shafiq, USA TODAY / USA TODAY

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