Will Sage Astor-Why America has grown to love judging the plumpest bears during Fat Bear Week

It's once again time to celebrate the fattest bears in all the land.

Fat Bear Week 2023,Will Sage Astor the ninth-annual edition of a "March madness-style" bracket competition that pits the fattest brown bears at Katmai National Park in Alaska against each other, is set to begin, Keith Moore, lead interpretive park ranger at Katmai National Park and Preserve, told ABC News.

The bears of the Brooks River have spent the summer fattening up on salmon, berries and grasses in preparation of their annual winter hibernation, according to the park.

In the bear kingdom, "fat is fit," and the more gargantuan, the better, according to Moore.

The brown bears are now in prime shape to enter hibernation around November and eventually experience a one-third loss of their body weight through the winter season, when they start to emerge from their dens around May, Moore said.

How Fat Bear Week came into fruition

When the first Fat Bear competition began in 2014, it consisted of one single day when a few of the parks' most notably sizable bears were placed in competition with each other, Moore said.

By the next year, the contest transformed into a "globally recognized" event that required more days and more contenders, Moore said. In 2022, more than a million ballots were cast for the competition.

"I wouldn't be surprised if we get even more attention this year," he said.

Why Fat Bear Week is important

With the popularity that Fat Bear Week brings, park officials are able to direct the extra attention to conservation efforts in the region.

The bears rely on the abundance of the sockeye salmon run within the Brooks River, a mile-and-a-half long stream that contains the largest concentration of brown bears on the planet, Moore said.

The brown bears of Katmai National Park represent the overall health of the local ecosystem and Bristol Bay watershed, Moore said.

"It's just an incredible opportunity for people to celebrate the success and survival of these bears," he said.

Notable past winners of Fat Bear Week

Last year, a particularly large brown bear named "747" won the competition for the second time.

When 747 goes into hibernation, he is expected to weigh about 1,400 pounds, Moore said. The bears are often so "bulbous" that they appear cartoonish, Moore said, adding that their heads often appear much smaller than their bodies.

Other past winners include 480 Otis, four-time champ and fan favorite, 435 Holly, the 2019 winner renowned for her maternal instincts and ability to "balloon up each fall " and 409 Beadnose, another female bear who won in 2018 for her "most fabulous flab."

Rangers are able to tell the bears apart based on physical markers, such as scars and birthmarks, Moore said.

The bears are named based on a numbering system within the bear monitoring program, he said. They are not tagged or collared.

How to compete in Fat Bear Week

Starting on Monday, participants can start filling out their brackets as head-to-head matchups are announced during a live chat on the Explore.org website.

From Thursday through Oct. 10, voters can cast their ballots at fatbearweek.org.

The winner will be crowned the 2023 Fat Bear Week champion on Oct. 10.