Poster Elk Herd Wading in The Big Thompson River

"Elk Herd Wading in The Big Thompson River, Estes Park, Colorado" by Catherine Sherman. A bull elk bugles as a herd of elk wade through the Big Thompson River surrounded by lush forest in Estes Park, Colorado. The trees display autumn foliage, adding vibrant color to the scene. A bull elk watches over his herd (harem) of females and calves as they drink in the Big Thompson River in Estes Park, Colorado, in early Autumn. Estes Park adjoins Rocky Mountain National Park. The elk or wapiti (Cervus canadensis) is one of the largest species within the deer family, Cervidae, in the world, and one of the largest terrestrial mammals in North America and Northeast Asia. This animal should not be confused with the still larger moose (Alces alces) to which the name "elk" applies in British English and in reference to populations in Eurasia. Elk range in forest and forest-edge habitat, feeding on grasses, plants, leaves, and bark. Male elk have large antlers which are shed each year. Males also engage in ritualized mating behaviors during the rut, including posturing, antler wrestling (sparring), and bugling, a loud series of vocalizations that establishes dominance over other males and attracts females.