The annual fat bear week competition is back, and 16 brown bears are stepping into the spotlight for a contest where size tells only part of the story.

Among this year's competitors is last year's champion, Chunk, officially known as Bear 32, who is returning with hopes of defending his crown. Chunk reportedly tipped the scales at about 544 kilograms when he won the 2025 competition.

Now in its 12th year, Fat Bear Week gives people around the world the chance to vote for the bear they believe has done the best job packing on weight before hibernation.

But behind the playful competition is a serious lesson in survival.

Fat Bear Week Puts Survival on Display

Mike Fitz, a resident naturalist at Explore.org, told The Associated Press that the contest highlights one of the most important challenges facing brown bears: building enough body reserves to survive the winter.

Bears prepare for hibernation by consuming enormous amounts of food during the months when it is available. Once hibernation begins, they do not eat, and they must rely on the energy stored in their bodies to carry them through the season.

That makes every salmon, every fishing opportunity and every extra kilogram potentially important.

Yet picking the winner is not simply a matter of placing the bears on a giant biological weighing scale.

More Than Just the Biggest Bear

Fitz said this year's competition could be particularly difficult to predict because the largest bear does not automatically have the strongest story.

A massive adult male, for example, may be building his body while competing for access to prime fishing territory at Brooks Falls. Other bears may have different challenges, victories and struggles that help explain how they reached their winter-ready condition.

The contest therefore asks voters to look beyond sheer body mass and consider each bear's journey.

Katmai National Park and Preserve in Alaska is home to approximately 2,200 brown bears, making it a remarkable stage for the annual event.

Fat Bear Week began in 2014 as a way to increase public awareness of the bears and showcase their extraordinary preparations for the harsh months ahead.

How Much Can a Brown Bear Weigh?

Adult male brown bears generally weigh between 270 and 410 kilograms, although exceptionally large males can surpass 450 kilograms after spending the summer feeding heavily on salmon.

Females are typically about one-third smaller than males.

When hibernation arrives, the bears stop eating and drinking. During that period, they can lose roughly one-third of their body weight.

That dramatic transformation helps explain why the seemingly simple act of gaining weight becomes a matter of survival.

Salmon Are the Fuel Behind the Bears

Fitz also emphasized that healthy salmon populations are essential to the bears' ability to build those critical reserves.

He pointed to the abundant sockeye salmon runs in Alaska's Bristol Bay region as an example of what healthy river ecosystems can provide.

For Fitz, the region also offers a broader environmental lesson. Protecting and restoring salmon populations across North America is increasingly important, particularly in places where salmon numbers are falling.

The bears' annual race to bulk up is therefore tied to something much larger than the animals themselves: the health of the ecosystems supplying their food.

Fat Bear Week Reveals the Bears Behind the Numbers

While enormous bears attract the biggest headlines, Fat Bear Week also gives viewers a window into the animals' everyday lives.

Fitz said cameras allow people to watch bears succeed at fishing, play together and interact peacefully. But viewers can also witness the darker side of life in the wild, including mothers struggling to feed cubs and the devastating loss of young bears.

The result is a portrait of wildlife that is far more complicated than a simple popularity contest.

There are moments of abundance, when a bear's belly is full of fish and the river seems to offer everything it needs. There are also moments of hardship, when mothers fight to provide for their cubs or cope with losing them.

Those contrasting stories are part of what makes the competition compelling.

Final Round Set for Tuesday

The final round of this year's competition is scheduled for Tuesday, Sept. 29, when the public will decide which bear earns the Fat Bear Week title.

For fans who want to join the fun beyond casting a vote, Google has added an interactive surprise.

Searching for "Fat Bear Week" brings up a small bear on the screen that users can feed salmon. As the virtual bear eats, it gains the weight it needs to survive winter hibernation.

For the real bears of Katmai, however, there is no virtual shortcut. Their winter survival depends on the food they can find now — and the body reserves they manage to build before the long season begins.