A cow Elk weighs between 500 and 600 pounds and stands almost 5 feet tall yet it can almost completely disappear in a field of Bluebunch Wheatgrass. We spotted this cow munching on grass stalks while laying in a vast field of Bluebunch Wheatgrass along Old Yellowstone Road just outside the north entrance to Yellowstone National Park. She looked at us briefly with some interest, then returned to her task at hand. When she put her head down, she completely disappeared.