Grizzly bears are large, fierce predators, but during the summer, their main food source isn’t large animals—it’s tiny army cutworm moths. Every summer, billions of army cutworm moths migrate to the Northern Rockies, seeking refuge from the heat of the plains. With their bodies composed of up to 75% fat, they’re a perfect energy source for grizzlies. Grizzlies climb up to 13,000 feet to dig through rocky slopes and feast on them, eating up to 40,000 moths a day. 📸: Tanner Saul | National Wildli