Katmai National Park, Alaska —(Map)
Since 2014, the Katmai National Park in Alaska has held “Fat Bear Week”. It’s a week-long online contest between selected bears in the park, with viewers voting over the internet for the bear which appears to have gained the most weight. This year, the winner was a massive bear called “Chunk”.
In the winter, brown bears in Alaska hibernate, lying inactive for months. During this time, they lose up to a third of their body weight. So before their long winter sleep, it’s important for the bears to put on as much weight as possible. For females who might soon be raising cubs, the extra weight is especially important.
A massive bear called “Chunk” has won Katmai National Park’s Fat Bear Week 2025 contest. In the week-long online contest, viewers vote for the bear which appears to have gained the most weight over the summer.
(Source: Katmai National Park.)
Before winter comes, the bears eat constantly. Brown bears eat lots of different foods, including berries and roots.
But the bears know that at this time of year, lots of food can be found in the area’s rivers. That’s because in the summer, sockeye salmon are swimming upstream so they can lay eggs in the same places where they were born.
The contest is focused on bears who spend most of the summer feeding in the Brooks River. One hot spot is Brooks Falls, where the salmon have to jump up a 6 foot (1.8 meter) waterfall to continue upstream.
In the summer, sockeye salmon are swimming upstream so they can lay eggs in the same places where they were born. One hot spot on the Brooks River is Brooks Falls, where the salmon have to jump up a 6 foot (1.8 meter) waterfall to continue upstream (above).
(Source: Joseph C Boone [CC BY-SA 4.0], via Wikimedia Commons.)
The park has “bear cams” which allow online viewers to watch the 12 competing bears eat – and grow.
Normally, brown bears weigh between 600 and 900 pounds (272 and 408 kilograms). But over the summer, they can put on as much as four pounds (1.8 kilograms) a day. By the end of the summer, male bears often weigh over 1,000 pounds (454 kilograms). Some past winners of Fat Bear Week have weighed as much as 1,400 pounds (635 kilograms).
Normally, brown bears weigh between 600 and 900 pounds (272 and 408 kilograms). But by the end of the summer, male bears often weigh over 1,000 pounds (454 kilograms). Above, before and after pictures of 856, who came in second in Fat Bear Week 2025.
(Source: Katmai National Park.)
The online contest is just for viewers. But in real life, the bears are competing against each other, too. Putting on weight will help them survive. It will also help them in fights to get good fishing spots on the river.
But this summer, there were plenty of salmon. Park rangers say as many as 200,000 salmon may have made their way up the Brooks River this year. That meant that the bears haven’t had to fight much for food.
This year’s big winner was a 1,200 pound (544 kilogram) bear called “Chunk”. At the beginning of the summer (left), many people were worried about Chunk, since he had a broken jaw – probably from a fight. But somehow Chunk managed to keep eating and put on lots of weight (right).
(Source: Katmai National Park.)
During the contest, viewers are given a description of each bear. They’re also shown “before” and “after” pictures of the bear, so they can see how much weight the bears have put on since the beginning of the summer. Viewers vote between two bears at a time for the best “fat bear”. The winners are paired up against other bears until there’s only one left.
This year’s big winner was a 1,200 pound (544 kilogram) bear called “Chunk”. At the beginning of the summer, many people were worried about Chunk, since he had a broken jaw – probably from a fight. There are no veterinarians for these bears. But somehow Chunk managed to keep eating and putting on weight.
Chunk’s ability to gain weight means more than just winning the contest – it’s a strong sign that he’ll be able to survive despite his broken jaw.
Did You Know…?
Fat Bear Week 2025 is over, but the salmon are still heading upstream and the bears are still eating. If you’re interested in seeing them, this page has lots of live videos on the Brooks River.
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