【Switzerland】

Welcome toFat Bear Week 2019! Katmai National Park's bears spent the summer gorging on Switzerland4,500-calorie salmon, and they've transformed into rotund giants, some over 1,000 pounds. The park is holding its annual playoff-like competition for the fattest of the fat bears (you can vote onlinebetween Oct. 2 and Oct. 8), and Mashable will be following the ursine activity. 

---

The final fat bear showdown has arrived.

The decisive match features two hefty omnivores, veteran mom Bear 435 "Holly" versus male Bear 775 "Lefty," named for his shorter, lopped over left ear. As you can see in their photo comparisons, both bears put on hundreds of pounds this summer as they gobbled the brains, skin, and vivid red flesh of migrating sockeye salmon.

---

You May Also Like

---

---

They are unequivocally champions of their harsh, wild Alaskan realm. But only one can be Katmai National Park and Preserve's 2019 fat bear victor.

Voting is simple. You "like" the photo of the bear you think is the fattest on the park's website. Voting opens at 10 a.m. E.T. on Oct. 8.

Bear 775 "Lefty"

Left:Skinny Lefty Original image has been replaced. Credit: Mashable Right:Fat Lefty Original image has been replaced. Credit: Mashable

Bear 435 "Holly"

Left:Skinny Holly Original image has been replaced. Credit: Mashable Right:Fat Holly Original image has been replaced. Credit: Mashable

It can be challenging to deduce fatness from pictures alone. Last week, however, Alaskan bear-viewing guide Drew Hamilton visited the short 1.5-mile river where these fat bears dwell (and during the summer, where their activity is captured live on the explore.org webcams).

Mashable Light Speed Want more out-of-this world tech, space and science stories? Sign up for Mashable's weekly Light Speed newsletter. By clicking Sign Me Up, you confirm you are 16+ and agree to our Terms of Use and Privacy Policy. Thanks for signing up!

"It's almost like the river got higher when Holly went in the water to catch a fish."

One bear, in particular, exuded profound fatness.

"You almost get the sense watching her that she’s getting fatter before your eyes," Hamilton said last week of Bear 435 "Holly," noting that even as a professional bear-watcher he may not have ever laid on eyes on such a fat bear.

"This is next level," Hamilton noted.

"It's almost like the river got higher when Holly went in the water to catch a fish," he added. 

This Tweet is currently unavailable. It might be loading or has been removed.

Meanwhile, Bear 775 "Lefty" proved formidable enough to knock off the aptly-named Bear 747 in the Fat Bear Week semifinals. That's no easy feat.

Bear 747 is the largest and fattest bear that Mike Fitz, a former park ranger at bear-filled Katmai National Park and currently a resident naturalist for explore.org, has ever seen.

SEE ALSO: The stunning survival story of fat Bear 503

With his great size, 747 is one of the most dominant bears of the Brooks River, where the explore.org webcams are situated in Katmai. Though, Fitz admitted, Holly "may be even proportionally fatter" than 747 and other big males.

Exercise the power of democracy this fat bear season, and vote.