Communicating visually is probably as important to wolves as communicating with sounds and scents, but it can be much harder to master. Wolves use their face, posture, hair, and tail to communicate, and often use multiple cues at the same time, according to Fred Harrington and Cheryl Asa in "Wolves: Behavior, Ecology, and Conservation." A dominant wolf ready to attack, for instance, will bare its teeth, have its hackles raised and legs stiff, and move slowly and deliberately. A submissive wolf, on the other hand, will hide its teeth, carry its body low, keep its fur sleek, and lower its ears and tail.
The tail is the wolf's most dynamic visual aid, according to one researcher. A raised tail makes a wolf look bigger. A wagging tail conveys friendliness. A stiff tail moving slowly may signal an attack. That researcher illustrated eleven tail positions that convey a variety of moods including assertion, intimidation, threat, submission, uncertainty, and depression.
To survive in a pack, a young wolf must learn to read a countless combination of visual signals. Knowing the signals to read or send reduces conflict with family members. Harrington and Asa give two examples: