This fat bear won't win Fat Bear Week. But the bears know he's king.

In the fat bear world, size matters. But so does attitude.

A Katmai National Park and Preserve legend, bear 856, isn't in the Fat Bear Week contest this year (rangers couldn't get quality images of him for the online competition). But no matter. This aging Alaskan bear sits atop the hierarchy of Katmai's famous salmon-clogged Brooks River, where the livestreamed bears are beamed to the world on the explore.org webcams.

Over the last decade, bear 856 has either been the most dominant or one of the most dominant bears of Brooks River, affording him the best fishing spots. In recent years, the giant bear 747 asserted dominance over 856 by pushing him out of prized areas, denying 856 of plentiful or easily-caught calories. This is a big deal in the bear world, where fat stores are essential for outlasting the harsh winter hibernation.

Yet in 2023, bear 856, though old for a brown bear, returned to top form.

"He's older than 20. He's not a young bear. But he still maintains his dominance and size," Mike Fitz, a former Katmai park ranger and currently a resident naturalist for the bear cam livestreamers explore.org, told Mashable.

While a large boar, he's never quite the biggest nor fattest. But he establishes dominance with aggression, though he rarely needs to fight.

His presence alone regularly intimidates other bears. When 856 shows up at the river, he often displaces bears, meaning they move off to another fishing spot, or leave the river altogether. If other bears fish near 856, it's because he tolerates their presence. Sometimes bear 856 will chase other dominant bears from the river, as seen in 2018 bear cam footage.

In the clip below, from July, bear 856 asserts his will over an extremely large male, bear 32, "Chunk." 856 assertively moves into Chunk's fishing spot. After posturing for 30 seconds, Chunk turns away, ceding bountiful fishing territory to the more dominant bear.

This Tweet is currently unavailable. It might be loading or has been removed.

For bears like 856, avoiding fighting while achieving dominance is the premier victory. Fighting other big bears exposes 856 to potential injury. Bears are awfully resilient, but a wounded leg or injured jaw could jeopardize 856's status, and ability to fatten up.

Other bears, like Chunk, may simply remember that 856, while older, is likely still a formidable foe. Choosing to test the hierarchical waters, especially when 856 appears full of vitality, may be too dangerous a gamble.

"Other bears know his reputation. They know his size. They know his fighting skills," Fitz said.

"Bears have really great memories for locations of food and where food can be found," the naturalist added. "But I think they have great memories for interacting with individuals. They see each other, smell each other, and recognize each other."

Want more science and tech news delivered straight to your inbox? Sign up for Mashable's Light Speed newsletter today.

After asserting his dominance in July, 856 returned to the Brooks River, looking quite big, in September. The dominant bear wasn't seen much, but bear cam viewers did spot the huge bear Chunk avoid 856. As far as we know, no bear challenged 856 this year.

His continued dominance is particularly impressive because the competition is intense. Beyond Chunk, there's bear 747, the largest known bear of this Katmai population and last year's Fat Bear Week winner. And there's the emergence of bear 503, a younger, strong-looking animal. In the coming years, the fat bear hierarchy could see change, challenge, and chaos.

But this year, as in many years past, the king stayed atop his throne.

"He's still great at what he does," Fitz said.