It is virtually impossible to describe the typical appearance of the wolf Canis lupus. Wolves of many large arctic islands and Greenland usually appear snow-white from a distance, but closer up often reveal grey, black, or reddish shades. Wolves of northern North America and Eurasia vary in colour. A single pack may contain animals that are black, shades of grey-brown, and white. Wolves in the heavily forested areas of eastern North America are more uniform in colour. They are often a grizzled grey-brown, similar to some German shepherd dogs.
This colour variation is a good example of natural selection, a process that enables those animals best suited to a particular environment to survive. On the arctic islands, where much of the ground is snow-covered for at least nine months of the year, being white is a distinct advantage, so wolves in the Arctic may be nearly white. In the mottled grey, green, and brown world of the eastern forests the normal coat of the wolf is an effective camouflage. As a wolf moves stealthily, or rests, it blends into the background and is hardly seen.
Wolves in the Arctic have extremely dense underfur, which insulates them against rigorous winters. Another adaptation to environment is their habit of hunting in packs, or groups, which enables them to kill large animals, such as deer, elk, moose, caribou, bison, and muskox.
Signs and sounds
The howling of a wolf pack is one of the most awe-inspiring wilderness sounds. It is a form of communication among wolf packs.
Wolves often howl spontaneously at a rendezvous site, or place where the pack meets. This howling may be a form of "song-fest," for the wolves apparently enjoy it. In one instance, a pack of arctic wolves separated from some pups by a fast-flowing river howled frequently for several hours. As they did so, the pups moved anxiously along the river bank. This howling seemed to be a form of calling or coaxing. Howling by a pack may also be a way of warning other packs to keep away from occupied territory and may serve to separate packs.
