Why Katmai National Park’s Bears Are Eating So Much Right Now

Katmai National Park’s brown bears are doing a lot of eating right now, so much so that the park has dubbed it “Fat Bear Week.” September and early October are some of the best times to see bears along Brooks River, and food is a big reason why.

The bears are getting ready for winter. During this time of year, they go through hyperphagia, when they spend much of their time eating and putting on weight before heading into their dens.

They have a lot of work to do. Katmai National Park says its bears need to eat about a year’s worth of food in roughly six months.

Once they go into hibernation, they won’t eat or drink for months. They can also lose up to one-third of their body weight before coming back out in the spring.

They Can Eat A Lot Of Salmon

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At Brooks River, that food is mostly salmon. A large male bear can sometimes catch and eat more than 30 salmon in one day. A sockeye salmon fresh from the ocean has about 4,500 calories.

September looks a little different than July at Brooks River. Earlier in the summer, bears gather around Brooks Falls to catch salmon as they make their way upstream.

By fall, many of those salmon have already spawned and are dying. Most of the bears move to the slower water farther down the river, where dead and dying salmon collect.

Those fish don’t have as many calories left. NPS says a spawned-out salmon in September may have about half the calories it had when it first came in from the ocean.

September Is A Good Time To Watch The Bears

If you watch Katmai’s bear cams, there is a good chance you’ll see plenty of activity right now.

NPS says early September through mid-October is one of the times when bear numbers are highest along Brooks River. Some bears use the river in both July and fall, while others only show up during one of those periods.

You might also see them fishing a little differently. Snorkeling, where a bear looks for fish underwater, is especially common in fall. Some bears will even completely dive underwater for salmon near the mouth of Brooks River.

Some Bears Can Top 1,000 Pounds

All of that eating can add up pretty quickly. Katmai says most adult males weigh around 600 to 900 pounds in the middle of summer. By October and November, large males can weigh well over 1,000 pounds.

Most of the bears head into their dens in October and November. Pregnant females and mothers with cubs generally go in earlier, while adult males tend to stay out the longest. Some males can still be active into December.