"Camouflage is a necessity for nearly all of the animals that live in the Arctic. Since much of the landscape is frozen, it makes it diffcult for trees and other plants to grow, and hence for animals to find shelter or hiding places. For animals like the lemming, ermine, Arctic hare, and that bird you just saw, the ptarmigan, camouflage is a handy way to avoid predators. On the other hand, the snowy owl, Arctic fox, and polar bear use camouflage to sneak up on their prey without being seen. During the warmer parts of the year, most animals adapt by replacing their old white coat with a brown one."