Body language pays an important role in lupine communications. Wolves have a very complex series of expressions and they use to communicate to each other. The most obvious somatic communication involve the face and the tail. The posture of the ears, eyes, mouth, and tail communicate a lot about a Wolf's mood and intentions.
Happy: Ears in a neutral or slightly laid back posture, forehead smooth with brows slightly raised, eyes relaxed or wide, muzzle relaxed, jaw dropped, may be panting, pelt relaxed or slightly bristled, and tail in a neutral low swayed-back position or somewhat lifted and wagging.
Neutral: Ears raised or foreword, forehead and brows relaxed, eyes relaxed, muzzle relaxed, mouth closed or slightly agape, may be panting in warm weather, pelt relaxed, tail carried low, and may be straight out or raised in a dominant Wolf.
Depressed/Upset: Ears are down or back, forehead may be furrowed, eyes are downcast, muzzle is neutral, lips seem to hang down, pelt is neutral, tail hangs straight down or might slightly curve along the outside of a hip.
Anxious: Ears lay flat but outward, forehead is furrowed, eyes are somewhat slit-like and peering, muzzle twitches and lips are pulled back, but not so much that fangs are bared, pelt may be slightly bristled, and tail can take several postures, depending an the nature of anxiety: Up, notched to the side, and somewhat flicking is an imposing attitude; lowered and somewhat notched to the side is often observed while eating; straight down and notched when between uncertain.
Uncertain: Ears lay flat, outward and forward, forehead shows definite furrowing with raised brows, eyes are angry and slit-like, muzzle is furrowed and nose is pulled back and puckered, fangs are bared with tongue stuck out between incisors, pelt is bristled, hackles raised, tail is lowered, sometimes tucked. This posture is one of both defense and submissiveness... the Wolf has not decided on fight or flight and is confused.
Threatened/Angry: Ears raised and forward, forehead furrowed, eyes wide, wild, and angry, muzzle furrowed with lips lifted high and nose puckered, fangs and even teeth are barred, tongue is tucked back and mostly out of sight, pelt is bristled, hackles are raised, stance is somewhat crouched and ready to leap, tail is straight out or raised, notched or hooked in appearance, with the tip often twitching to one side.