Fat Bear Week: Alaskan brown bears are fighting to gain weight before hibernating

King Salmon, Alaska –

For brown bears in a national park of Alaska, bigger, it's better.

During the fourth edition of Fat Bear Week, all eyes turn to the bears that live along the Brooks River in Katmai National Park and Reserve as they struggle to gain tremendous weight before their winter winter hibernation. Rangers are tracking bears often seen on the site explores. Bear Cam as they head for hibernation, and they pit them against each other in hooks of March's madness. .

Brown bears in Alaska started gaining weight in July. According to the National Parks Service, bears enter a medical condition known as binge eating in which they eat non-stop and can earn up to four pounds in a single day. Some bears can eat dozens of sockeye salmon each day, each containing about 4,000 calories.

Fattening up with the approach of the winter is a matter of life and death for the bears: by consuming energy, they can lose up to one-third of their fat mass in hibernation. Their possible hibernation can last between five and eight months, and most of them come out of their dens in May.

Everyday, until October 9, home viewers can see big bears on Katmai's Facebook page. Readers vote with their likes to help creatures with generous curves to move to the next round, and the winner will be crowned Tuesday by Fat Bear.

Rangers in the park said they received money on a few selected bears: 747, whose fleshy belly almost touches the ground; 435, who is in charge of feeding not only herself but also her cubs; and 480, defending champion last year.

Home viewers can also watch the 24 hour Cam's Bear Cam to see the bears feeding on salmon in real time.