An Alaska national park's yearly celebration of the beefy, brown and bristly is getting underway as some of the chunkiest bears on the planet fatten up for their long winter slumber.

Fat Bear Week doesn't officially start at Katmai National Park and Preserve until Oct. 2, when fans can begin voting online for their favorite ursine behemoths in tournament-style brackets.

But on Tuesday organizers revealed the four cub contestants in this week's Fat Bear Jr. contest — with the “chubby champ charging on to face the corpulent competition” in the adult bracket, as Naomi Boak of the nonprofit Katmai Conservancy put it during the livestreamed announcement.

The annual contest, which drew more than 1.3 million votes last year, is way to celebrate the resiliency of the 2,200 brown bears that live in the preserve on the Alaska Peninsula, which extends from the state’s southwest corner toward the Aleutian Islands. The most dedicated fans watch the bears on live cameras at explore.org all summer long as they feast on sockeye salmon returning to the Brooks River.

This year's contestants for Fat Bear Jr. include some familiar muzzles: Both the 2022 and 2023 junior champs are up for a repeat; they remain eligible because they still meet the criteria for being considered a cub, including remaining with a sow. Most cubs stay with their mother for about 2 1/2 years, but the 2022 Fat Bear Jr. winner, known as 909 Jr., who has remained with an aunt, is almost 4 years old.

There's also an emotional favorite: a spring cub of Grazer, last year's Fat Bear champ. The cub's sibling died this summer after it slipped over a small waterfall on the Brooks River and was killed by a dominant adult male known as Chunk, or Bear 32 — an attack captured on the bear cams. Grazer fought Chunk in an effort to save the cub, but it later died.

Adult male brown bears typically weigh 600 to 900 pounds (about 270 to 410 kilograms) in mid-summer. By the time they are ready to hibernate after feasting on migrating and spawning salmon — each eats as many as 30 fish per day — large males can weigh well over 1,000 pounds (454 kilograms). Females are about one-third smaller.

The adult contestants for the Fat Bear Week tournament will be announced Sept. 30, with voting taking place Oct. 2-8.