The salmon? Eaten. The days? Shorter. The bears? Fatter.  After spending the summer eating the fatty pink salmon swimming through Katmai National Park and Preserve in Alaska, it’s time to celebrate the park’s iconic brown bears (Ursus arctos). Fat Bear Week begins on Tuesday, September 22, a nd here is everything you need to know.  What is Fat Bear Week? Think March Madness, just without the basketball and significantly more bears. Fat Bear Week is a single-elimination tournament, where bear enthusiasts from around the world can vote online for their favorite chunky bear. After each round, the bear with the most votes advances until the winner is announced on September 29. According to the Katmai Conservancy, the event began as a one-day event in 2014 with 1,700 votes cast. Only 10 years later, 1.2 million votes were cast from over 100 countries. The brown bears return to Brooks Falls for the salmon migration every year in late June, where viewers can watch them on explore.org’s livestream. There, they will feast to fatten up for the long winter ahead. By late summer, the nutritious fish will spawn and then begin to die. The bears will then move to the lower Brooks River in September and October to eat the dead and dying salmon near the river’s mouth. Eating all of this salmon is important because the heftier the bear, the better chance they will survive their long winter hibernation. Despite being the poster species for winter hibernation, bears are not “deep hibernators,” they way that squirrels, bats, and bees are. Bears enter a state called torpor, which is an involuntary state primarily triggered by lack of food. During this time, the bears rely on stored fat reserves for energy. A torpid bear’s eating, drinking, and waste functions will cease, as its body metabolizes these stores it put on over the summer.  When is Fat Bear Week 2026? This year, Fat Bear Week begins on Tuesday, September 22, and a winner will be crowned on Tuesday, September 29.  How can I vote? Votes may be cast from noon to 9 p.m. EDT (9 a.m. to 6 p.m. PDT and 8 a.m. to 5 p.m. ADT) from September 22 and 29 at fatbearweek.org. Photographs comparing the bears from earlier in the summer and later in the summer will be shown, so voters can get an idea of just how much weight the bears put on during their salmon fest. An adult male bear can go from roughly 700 pounds in the early summer to over 1,200 pounds by fall.  Voters are also encouraged to get familiar with each bear’s life history and the unique challenges they face to survive. Which bears are competing this year? The 2026 Fat Bear Week Bracket will be released on Friday, September 18.  In 2025, Bear #32 (Chunk) took the crown, despite beginning the salmon run with a freshly broken jaw. He was likely injured while fighting with another bear for a mate, but he still managed to catch plenty of fish. Chunk is known for his dominance and size, but also narrow-set eyes, dark fur, a prominent brow ridge, and a distinctive scar across his muzzle.  Fat Bear Week 2025 champion Chunk. Image: NPS/ T. Carmack How can I support Katmai’s bears? Donations can be made to Katmai Conservancy’s Otis Fund. The Otis Fund is named after Bear #480 (Otis), who won four Fat Bear Week titles before his death around 2024.  All donations made between September 22 and October 3 will be matched by explore.org.  What happened with the bears this summer? This year’s livestream featured an example of how wild (and upsetting to humans) nature can be. On Tuesday, July 28, the live-cams captured a young brown bear cub being killed and eaten by an unrelated mother bear (Bear #806). The deceased cub was born this spring and the child of Bear #909, a 10-year-old brown bear. Bear #909 started the season with two cubs, but now lost both.  On Sunday, August 2, one of Bear #335’s (Jolly) cubs died, after following three unrelated cubs up a tree. The mother of the cubs already in the tree attacked Bear #335’s cub, who did not survive the encounter. The identity of the mother bear who killed the spring cub was not confirmed.  Following the first cub’s death, naturalist Mike Fitz and park rangers Christine Loberg and Sarah Bruce said this likely the first documented case occurring at Brooks River. While there is no one answer as to why mother bears are killing cubs, some experts suspect bear adoption, food scarcity, and fights for dominance all play a role.  Additionally, this year also saw the cub with silver-hued fur, a cub who hopefully learned important lesson about porcupine quill safety, the unique fishing stylings of Bear #164 (Bucky Dent), and Bear #284’s (Electra) family who can “walk on water.” The post Fat Bear Week kicks off September 22 appeared first on Popular Science. ...read more read less