NEW YORK (WPIX) – Who is the chunkiest brown bear of them all? That’s what the National Park Service is trying to determine during its annual Fat Bear Week competition.

Fans can cast their votes for their favorite fat bear in a March Madness-style bracket from Oct. 2 to 8, according to the National Park Service.

“For each match-up, vote for the bear you believe best exemplifies fatness and success in brown bears,” the voting website reads.

Brown bears fatten up throughout the summer to survive the winter hibernation. They can lose about one-third of their body weight while dormant, according to the National Park Service.

All of the brown bears featured in the matchups live in Katmai National Park in Alaska. The bears in the park feast on salmon from the Brooks River between late June and early October, officials said.

Past contestants include 32 Chunk, 128 Grazer, 151 Walker and 164 Bucky Dent. To find out more about them, click here.

The Fat Bear Week bracket will be revealed on Sept. 30, ahead of voting. There is also a Fat Bear Junior competition, with voting starting on Sept. 26. The winner of the Junior competition will face off against 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 a 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 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. Females are about one-third smaller.

The Associated Press contributed to this report.