Pallade Veneta - US voters weighing candidates for Fat Bear Week winner

The final day of voting saw contestants "128 Grazer" and "32 Chunk" battling it out for the crown of biggest bruin in Alaska's Katmai National Park.

The contest asks members of the public to compare before-and-after pictures of brown bears as they stuff themselves full of salmon in preparation for the lean months of hibernation.

The champion is the bear who makes it through the series of head-to-head match-ups.

"Your vote decides who is the fattest of the fat," organizers said.

"128 Grazer's powerful presence is as thunderous as her thick tree trunk thighs," they added.

"32 Chunk's gargantuan gut has cast a shadow on his competition and has launched this Leviathan to the last round. Can his pudginess propel him to the prize?"

The online contest began in 2014 with just a few thousand people voting, but has now turned into an eagerly awaited exercise in tongue-in-cheek democracy, with hundreds of thousands of ballots cast every year.

The aim is to raise awareness of brown bears and their habitat in Alaska, and the risks they face from human activity.

The 2,000 bears of the Katmai National Park pile on the pounds in late summer and early autumn in readiness for five months of hibernation in which they can lose up to a third of their body weight.

This means gorging themselves on the plentiful salmon runs of the Brooks River.

"Fat bears are successful bears," organizers said.

The contest, which had appeared imperiled by the near-shutdown of the US government after a Washington stand-off, was rocked last year by a ballot stuffing scandal.

Spam votes had tipped the scales in favor of scrappy challenger Bear 435, with only a careful recount crowning Bear 747 the rightful champion.

Voting in this year's poll -- at explore.org/fat-bear-week -- closes at 5:00 pm Tuesday in Alaska (0100 GMT Wednesday).

R.Zaccone--PV