Step 1 : Introduction to the question "What do ptarmigans, Siberian hamsters, collared lemmings and peary caribou have in common?"
...What all these animals have in common is their ability to exchange their fur or plumage to white in the winter. These animals, unlike polar bears or snowy owls, shift their colors as the seasons change. This alteration in color gives the animal the benefit of camouflage in the snow-covered winter environment. Although protection is probably the most obvious reason for this evolutionary trait, scientists believe there are probably other benefits, such as better insulating properties. Source: Britannica.com