In late spring throngs of new visitors start enjoying Rocky Mountain National Park. One of the most common questions is "Why do the elk look so scruffy?" The short answer is that they are losing their winter coats and putting on much shorter, cooler summer coats. This involves a complete molt - loss of all their hair and regrowth of new hair. During the process they can look profoundly unkempt. In the fall the process reverses, but the longer winter coat grows out over the summer coat so the process is not so obvious.
The cue for the elk to change coats is day length. Starting in March as days get longer, the old winter coat starts dropping off. Their summer coat is short, glossy, and generally much more uniform in color than the winter coat. All the hair of the summer coat is the same length. As the days get shorter in September, the longer, thicker winter coat starts growing out. The winter coat consists of two layers - a longer coat of guard hairs protects the short thick undercoat. By winter both male and female elk have thick, dark manes covering their necks, and long, light tan coats over the rest of their bodies.
The process of losing a winter coat is apparently not without annoyance to the elk. It is not uncommon to see elk scratching their front quarters and head with hind feet or licking any areas they can reach to remove the old hair. Some either are much more efficient at this process or shed earlier than others, because it is not uncommon to see shedding elk alongside those that have already completed the process. Finally, while it is not uncommon to see magpies (Pica pica) riding around on elk (elk jockeys) picking off ticks both summer and winter, it is a much easier process in the summer when the elk have substantially less hair to interfere.