Filmmaker Finds 47 Grizzlies Gorging On Moths High Up Absaroka Mountains

Seeing grizzly bears far above timberline, overturning rocks to gorge on army cutworm moths, came as no surprise to wildlife filmmaker Casey Anderson. What shocked him was seeing 47 grizzlies before noon in one day high in the Absaroka Mountains in the Greater Yellowstone Ecosystem. It was more than twice the number of grizzlies he has ever seen in one day in the Yellowstone area. “That even broke my all-time record, which included one day in Alaska at one of the hottest salmon streams when I saw 46 bears in one day,” said Anderson, who lives in Emigrant, Montana.

He featured his Absaroka mass grizzly sighting, which happened last August, in the latest episode on his Endless Venture YouTube channel. Seeing so many grizzlies could mean that army cutworm moths are becoming a more popular item on the bears’ menu. Anderson understands why; he has eaten the moths himself. “It sounds disgusting, but they’re actually really good,” he said. “They taste like honey-roasted peanuts.” In late summer, the moths migrate from prairies to the east, flying up over the mountains and stopping to take shelter under rocks far above timberline at elevations of 11,000 feet or higher. Grizzlies travel many miles from the low country and climb to the mountain peaks, flipping rocks and eating as many moths as they can find. It is a high-calorie, high-protein feast at a time when bears are trying to pack on pounds for winter hibernation.

Anderson has been trekking grizzly country in Montana and Wyoming for decades. He has seen a steadily increasing number of bears gathering at high altitudes for moth feasts. “I remember it being, ‘Wow, I saw nine grizzlies up above timberline in one day.’ Then the number started to be in the teens, and then the 20s,” he said. State Sen. Larry Hicks once recounted seeing 26 grizzlies on the slopes of Francs Peak in the Wyoming section of the Absarokas. The common assumption is that such mass sightings mean the greater Yellowstone grizzly population is ballooning, perhaps well beyond official estimates of 1,000 or so bears. Anderson is not sure it is that simple. While the population has risen, it could also be a matter of bears congregating in certain areas because of food sources. Grizzlies used to rely heavily on whitebark pine nuts, but that has changed. “Some areas where I used to see congregations of bears eating whitebark pine nuts, I’m not seeing as many bears,” he said. It could be that some of those bears switched to climbing above timberline for moths.

Recent grizzly attacks in Yellowstone and Glacier national parks have rekindled calls to delist grizzlies and allow hunting. Anderson is not necessarily opposed to delisting but wants decisions to hinge on “objective science” and not “emotion and politics.” He also questions whether allowing hunting would cause bears to avoid humans more. In places where grizzly hunting is allowed, he did not see that it changed bear behavior. “They’re afraid of people and they think we’re a threat, so they’re going to go over and try to eliminate that threat,” he said, emphasizing the importance of giving bears plenty of space. With more bears and more people—including more inexperienced people—in the backcountry, he expects attacks to increase. “These aren’t the last attacks of the year, I can promise you that,” he said. He noted seeing hikers without bear spray or with spray attached to the back of their backpack where they cannot immediately access it. “I’ve even had people stop me and ask, ‘Hey, how do you operate this thing?'” about a can of bear spray, he said.