Dogs are, by nature, social and cooperative animals and most adult dogs have very well-developed aggression-inhibiting mechanisms we call “ritualized pacifying signals” which they start to learn as puppies just a few weeks old.
Dogs mainly use body language to communicate (“postural communication”) and learning “dog language” helps enormously in socialization and training. Generally groups of signals make up the message the dog is sending and we can look at them as distance reducing or distance increasing behaviors, which gives us insight into how the individual dog is feeling.
Distance reducing signals (which indicate the dog is approachable) include the avoidance of direct eye contact, blinking or having the eyes half closed, the lowering of ears and then the head and then the neck.
Generally the signals escalate as the dog sends a stronger message and may include tongue flicking and retraction of the lips (tongue flicking is the movement of the tongue in and out of the mouth and across the muzzle). Sometimes a front paw is raised and the tail held low. The dog may lie down and show its belly.
Distance-increasing behaviors (which mean the dog would like some space) are often used in response to a threat or a perceived threat. They begin with the most subtle signals such as direct eye contact with eyelids wide open to produce a “stare”. This alone will often minimize the need to escalate the confrontation and minimize the risk of injuries. If not, the dog may pull his lips back at the corners and may escalate to a snarl with head held high, ears up. If the threat intensifies, the dog lowers its head to protect its throat. The dog may also make itself appear bigger by shifting its weight, raising the hair along its back, holding the tail high or vertically.
By professional trainer Jane Bowers