by Pat Murphy Cornelius
Barks - can serve as alerting calls, alarm barking, greetings, indications of annoyance and excitement, or warnings.
Growls - can range from a dominant aggressive threat/warning to a sound signifying fear. Generally the lower the pitch, the more aggressive, the higher the pitch the more frightened or insecure the dog.
Howls/Baying - can be territorial and/or predatory sounds.
Whines/whimpers/cries - can be used to express a range of emotion including excitement, want, pleasure, fear, shock, surprise, and pain/panic. Panting is a form of this vocalization and can indicate stress, excitement or anticipation. Panicked screaming, because it may sound so close to the sound of prey in extremis, can evoke attacks (packing-in) by other dogs. Which is why it is not recommended that you scream loudly when trying to break up a dog fight; the results may not be what you desire or intend!
Dogs use their entire bodies as a form of "sign" language. Thus the ears, the eyes, the lips, the face, the tail, and the attitude of the entire body, either singly or in combination may speak volumes about the dog´s state of arousal, desires and intentions.
EARS - erect and forward is a sign of interest/attention and, depending upon other body language signals, aggression and confidence. Ears pulled back and flattened is a submissive signal but when coupled with baring of teeth and changes in eyes, lips and body can signal an incipient attack. Ears back with relaxed open mouth can be a friendly or even playful gesture depending upon what the rest of the body is doing. Ears flattened off to the side is normally a sign that the dog is uncertain and tense; within a short time of that sign, that dog may shift either to flight or fight although if confronted with a strange dog and the discomfiture has to do with whether that dog is friend or foe, a friendly gesture by the other dog may cause the discomfited dog to shift into play mode and play body language.
EYES - either a direct or indirect look. Direct usually signifies arousal and aggression; indirect signals uncertainty or submission. Blinking of eyes and/or lowering of the head may be a sign of active submission or a further sign of uncertainty that might shift to either flight or fight if the efforts to appease the other are not successful. Pupil size can also be significant - the larger the pupil, the more aroused the dog. If it appears that the dog is squinting or even closing the eyes, that is a sign of efforts to appease and pacify the other.
LIPS/MOUTH - Relaxed and slightly open (perhaps even with tongue showing) signifies contentment and relaxation. Closing the mouth coupled with leaning forward and/or looking in a certain direction signifies attention/interest. Lips curled to expose some teeth but mouth still mostly closed is a sign of annoyance, menace and may be accompanied by a growl (but also may not be...). Lips curled up to show major teeth, with wrinkling of nose and mouth in a "c" shape is an active aggressive response and if the stimulus causing this response is not removed, there will most likely be a further threat display which may or may not include an actual attack. Lips curled to show major teeth accompanied by head dipping and lips drawn back so that mouth is in more of a "frown" position indicates a submissive response to a threat but does not necessarily mean the dog is submitting; rather the dog may be getting ready to attack as it perceives no other option. Yawns do not signify indifference or boredom; rather they are a sign of tension and stress, and may be an effort to diffuse the threat. Licking the other is a pacification gesture.
TAIL - Tails are eloquent in their expressiveness, even in docked breeds. Thus, the attitude of the tail (i.e. held vertical versus horizontal) can tell you a lot about the dog´s state of mind and particularly his confidence level. Horizontal tail can signify relaxation and that all is well. Even a little lower than horizontal can be interpreted in that fashion. If held stiffly at the horizontal when greeting another, it can be a sign of a cautious greeting - feeling out the other to determine their state of mind. Tail down reflects various states of submission and can also reflect physical or mental distress. Strongly tucked tail is a sign of total submission - but must be read in conjunction with other signs as well to determine what the dog´s next act will be. Wags of the tail can range from a slow, metronomic like wag with the tail held up (which indicates strong arousal and interest, possibly aggression) to a faster wag but with the tail down which can be a submissive signal, to a broad wag that might even involve the hips and which indicates friendliness and even playfulness. And all sorts of combinations of the above. Generally the higher the tail, the more confident and/or aggressive the dog; the lower the tail the more submissive. The rate of tail movement indicates the extent to which the dog is aroused; thus rapidly wagging tail at horizontal to slightly lower with parted lips, tongue slightly out, ears forward, eyes normal is normally a forerunner to an invitation to play.
BODY - Stiff legged upright posture is an active aggressive and dominant signal; when coupled with leaning over the front end so body appears to be sloping forward and feet appear to be braced, it is a signal that active aggression is imminent. Hackling on shoulders and down back can be a sign of rising aggressive feelings who is preparing to attack or can be a sign of a dog that is attempting to buck up its own confidence by making itself appear to be a bigger threat (other signals and actions must be looked to in order to determine which). Lowering of the body or other gestures designed to make the dog appear smaller (including lowering the head and looking up at the other, rolling onto the side, or turning its side to the other) are active submissive gestures intended to pacify the more dominant dog. Muzzle nudges are attention getters but are also submissive signals. Sitting when approached by another is a neutral gesture by a dog whose social rank may be only slightly lower than the other; it is neither dominant or submissive but more designed to indicate no challenge is being made. Standing over another dog, or putting head over the neck of another dog, or paws over or on another dog are all assertions of social dominance, as is a shoulder bump. Sniffing the ground, digging at something, staring at the horizon, scratching, and other gestures reminiscent of Tom Sawyer scuffing his feet and saying "aw shucks" are exactly that - pacifying signals designed to distract and to displace whatever stress the dog feels into some other activity. Raising a paw or sitting with one paw slightly raised may be a sign of mild anxiety. And the classic posture of forelegs flat on the ground and rump high in the air is an invitation to play. Generally anything that makes the dog bigger is a sign of dominance; anything smaller is a sign of submission. Directly pointing eyes, head or body at another is dominance; turning eyes, head or body away is submission.