The biggest members of the wild dog family are timber wolves, which grow to a length of 1.4 (4 ft) and weigh about 68kg (150lb).
Timber wolves generally live in packs, or groups, and patrol a territory. Within the pack there is a very definite social structure, with dominant and submissive members. Wolves communicate with each other by a complicated system of facial expressions and body patterns; they are also extremely vocal on occasions, and their plaintive howls can be heard over long distances.
The main food of wolves is caribou, deer and horses, but they will also eat smaller prey such as squirrels, insects, worms and even berries.