Arctic hares change color twice a year. They change from grayish-brown in the summer to white in the winter, and then back again when winter is over. The exact mechanism that triggers this change is uncertain. Some scientists think that it is caused by the sun’s cycle, meaning that as the days get shorter the hares turn white, and then as the days get longer they turn dark again. Other scientists suggest that it is the actual temperatures that trigger the change, so cold weather brings on the white coats while warmer weather prompt hares to turn back to grayish-brown. Whatever the exact mechanism that triggers change, arctic hares molt as winter approaches, meaning that they lose their old, dark hair as new white hair grows in to replace it. The same thing happens again as summer approaches, this time with the hares losing their white coats to have them replaced by new, darker fur for the warmer weather. In the northernmost parts of their territory, arctic hares remain white all year, providing better camouflage in areas where snow and ice are present most of the time.