Elk have adapted to blend into an array of landscapes, from the cold Canadian prairies to the deserts of the American southwest. There can be a broad range of coloration even within a single herd. But according to North American Elk, California’s tule elk—living with the highest average temperatures in sparsely vegetated, sunbaked shrubland—tend to be lightest in color. Meanwhile, the coats of Roosevelt’s elk that skulk the shadowy rainforests of the Pacific Northwest can be almost chocolate. Rocky Mountain Elk fall somewhere in between.
Elk coloration also changes radically from season to season. In mid-summer they are a handsome reddish-almond and by the time bulls start bugling they are a striking tri-color with long black manes, honey-colored bodies and buff rumps. Come the depths of winter, they can be dirty blonde, beige, even a lemony white. Darker coats would absorb more solar energy, but would also stand out like beacons in wintry conditions.
Colors vary by gender and age as well. Bulls can often be distinguished from cows even after their antlers drop because they are significantly lighter. And the older they get, the paler they get. This could be a process similar to that of other aging animals like dogs, horses and bears whose hair color can change as a result of bleaching from the sun and a change in gene expression over time.