GLACIER NATIONAL PARK, Montana – High alpine terrain may appear brutal and inhospitable, like the desolate wasteland of Mordor, but the rocky landscape houses plenty of wildlife. I’m personally a big fan of both the mountain goats and the marmots, but if you spend some time above 10,000 feet, you might see some pretty incredible wildlife, including… grizzly bears?
Grizzlies could be in the alpine for a few reasons, but the most surprising is their hunt for moths. According to Glacier National Park Conservancy, the army cutworm moth (~¾ inch long) acts as a major food source for grizzly bears in the area. These small insects spend their summers in the broken rock talus slopes of Glacier National Park, spending their days under the rocks while feasting on the nectar of alpine plants at night.
So how are they of any value to the bears? Well, while these cutworm moths show up with around 15% body fat, they wind up building one of the largest lipid reserves of all animals, reaching a point where 70% of their body weight is in lipids (fat). So they’re packed with calories, more so than elk, goats, or pretty much every other animal in the park.
These moths are small, sure, but they take a lot less energy to hunt and kill, meaning less calories burned and more weight gained. And with bears, everything is about total weight gained. Plus, with less human activity in the alpine, these moths are an ideal target for the grizzly bears.
