Adult brown bear (Ursus arctos) scratching its back on tree, Brooks River, Katmai National Park near Bristol Bay, Alaska, United States of America

brown bear ursus arctos brooks river salmon spawning bristol bay alaska wildlife nature animal behavior scratching summer trees ecosystem outdoors observation habitat carnivore fur back natural fish migration north america large mammals wilderness predator conservation geography riverbanks feeding grounds alaskan flora fauna habits activities scenery activity sightings ecosystems refuge