This is the fattest of the extremely fat bears

Welcome to Fat Bear Week 2021! Katmai National Park and Preserve’s brown bears spent the summer gorging on 4,500-calorie salmon, and they've transformed into rotund giants, some over 1,000 pounds. The Alaskan park is holding its annual playoff-like competition for the fattest of the fat bears (you can vote online between Sept. 29 through Oct. 5). Mashable will be following all the ursine activity.

We are witnessing greatness.

In an Alaskan realm where the natural world is flourishing, nearly all of Katmai's bears are fat and healthy. Yet for the past half-decade or so, one bear has consistently been the largest, putting on eye-opening fat stores for the long winter hibernation.

He is bear 747. He is an MVP in his prime in a hyper-competitive league. He is last year's champ.

His greatest rivals, like bear 480, are certainly dominant and impressive. "Yet, for those of us who recognize greatness and celebrate success when we see it, there is one clear choice for Fat Bear Week 2021 — the mighty 747," Mike Fitz, a former Katmai park ranger and currently a resident naturalist for the wildlife streamers explore.org, wrote on his blog.

In the bear world, where animals must subsist on their fat to outlast the winter, a fat bear is a successful bear. "747 cultivates mass at an exceptional rate," noted Fitz, who has watched bear 747 consume some 67,000 calories over the course of a few hours.

The explore.org camera footage, which livestreams the Katmai bears along the park's Brooks River, doesn't lie:

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747 is the case of a naturally large bear that grows much larger each summer. The biggest bears are typically the most dominant and use their power to earn a position in the most productive fishing spots. In 2021, 747 overtook the aggressive large male bear 856 as the most dominant, imposing bear of the Brooks River by intimidating and displacing him from a prime location. Add in 747's fishing savvy, and he's able to capitalize on thriving salmon runs at will.

During the annual (and very subjective) Fat Bear Week competition, however, 747 is at somewhat of a "disadvantage" in the light-hearted contest. 747 hibernates with so much fat that he returns back to the river each summer in relatively good shape, compared to skinnier and more gaunt-looking bears. His summertime transformation, then, might not look as impressive as that of other bears.

Months ago, while other bears were just starting to fatten up, 747 was already huge.

"747 looked like he was ready to hibernate in July," Naomi Boak, the media ranger at Katmai National Park and Preserve who spent the summer observing the bears, told Mashable earlier this week.

747's transformation over the summer of 2021. Credit: n. boak / l. law / nps

It's true, however, that all of Katmai's successful fat bears are winners. And regardless of whether 747 wins this year, perhaps we can recognize his consistent greatness.

By mid-August, he had already fattened up so much that he had trouble ascending the riverbank.

"He's the fattest and largest bear I've ever seen," Fitz told Mashable last year. "I feel a special bit of privilege to witness a bear as big as he." (This year Fitz noted that 747 is just as big, at some 1,400 pounds.)

In past years 747 may not have often won, but rangers on the ground hinted at who was king. As a ranger noted in 2018, when 747 had stepped into his bear prime: "He seems to be more hippopotamus than bear at times."

Related video: Fat Bear Season: Everything you need to know about the best time of the year