Dog communication comes in a variety of forms. Dogs use certain movements of their bodies and body parts and different vocalizations to send signals to other dogs, animals and humans. There are a number of basic ways a dog can communicate. These are movements of the ears, eyes and "eyebrows", mouth, head, tail, and entire body, as well as barks, growls, whines and whimpers, and howls.
One of the most common communications between dogs, and from dogs to their human companions, is the display of either dominance or submission. Most dogs and wild canines live in groups, or packs, with an established hierarchy. Dogs will, usually, submit to any dog that is more dominant than they are. There are innumerable ways a dog can show their dominance or submission, depending on situation, the amount of difference in social rank, and each dogs' own personality. Dominant dogs are more confident, while submissive dogs are more insecure. Both of these traits show in almost every communication signal a dog gives.
How high or low the tail is held, in relation to how the dog's breed naturally carries their tail, and how it is moved can signify the dog's mood and/or rank. The higher the tail is carried, the more dominant/confident the dog is; the lower, the more submissive/insecure. A tail held straight up, or even slightly curved over the back, shows that the dog is very dominant. If the fur on the tail is also bristled, the dog is saying they are willing and able to defend their position.
Small, slow wags of the tail says the dog is questioning things around them. Either they aren't sure if the target dog or person is friendly, or they aren't sure what is going on or what is expected of them.
Large, fast wags of the tail is a sign of a happy dog. If the wags are large enough to pull the dog's hips with them, the message includes a bit of submission to someone they view as pack leader.
Dogs with docked tails, like Dobermanns, tend to have some problems communicating with other dogs, since their tail movements are extremely difficult to detect.
Ear position relates the dog's level of attention, and reaction, to a situation or animal. Erect ears facing forward means the dog is very attentive, while ears laid back suggests a negative, usually fearful, reaction. Dogs with drop ears, like Beagles, can't use these signals very well, as the signals first developed in wolves, whose ears are pricked.
Mouth expressions can provide information about the dog's mood. When a dog wants to be left alone, he might yawn (although yawning also might indicate sleepiness, confusion, or stress) or start licking his mouth without the presence of any food. When a dog is happy or wants to play, he might pant with lips relaxed, covering the teeth and with what sometimes appears to be a happy expression (it might appear as a smile to some observers) or with the mouth open. Mouth expressions that indicate aggression include the snarl, with lips retracting to expose the teeth, although some dogs also use this during play.
It's important to look at the dog's whole body and not just the mouth or tail before deciding what the dog is trying to communicate. What appears initially as aggression might be an invitation to play.
While dogs don't have actual eyebrows, they do have a distictive ridge above their eyes, and some breeds, like the Rottweiler and the German Shepherd, have markings there. A dog's eyebrow movements usually express a similar emotion to that of a human's eyebrow movements. Raised eyebrows suggest interest, lowered brows suggest confusion or mild anger, and one eyebrow up suggests bewilderment. Slitted eyes translate the same as human's also: suspicion or anger.
Dogs bark for many reasons, such as when perceived intruders (humans, dogs, or other animals) approach its territory, for identification, when hearing an unfamiliar or unidentified noise, when seeing something that the dog doesn't expect to be there, or when playing. Barking also expresses different emotions for a dog, such as loneliness, fear, suspicion, stress, and pleasure. Play or excited barks are often short and sharp, such as when a dog is attempting to get a person or another dog to play.
Dogs generally try to avoid conflict; their vocalizations are part of what communicates to other dogs whether they mean harm or are in a playful mood.
The bark of a distressed or stressed dog is high pitched, atonal, and repetitive (and tends to get higher in pitch as the dog becomes more upset). For example, a dog left home alone and who has separation anxiety might bark in such a way.
Some research has suggested that dogs have separate barks for different animals, including dog, fox, deer, human and cat.
Growls can be used to threaten, to invite play, and to show dominance. Growling should be watched with special attention because it can indicate dominance or aggression. A soft, low-pitched growl often indicates aggression; the dog may feel threatened and may be provoked to attack. An intense growl, without showing any teeth, may often indicate a playful attitude. Always consider the context of a growl, and approach with caution.
Dogs whine and whimper to show that they are in pain or are afraid, but also when excited, such as when greeting another dog. Some dogs may use whining as a means of getting attention.
Howling provides long-range communication with other dogs or owners. Howling can be used to locate another pack member, to keep strangers away, or to call the pack for hunting. Sometimes dogs howl in response to high-pitched or loud noises such as alarms, sirens, music, or singing. In Russia, a howling dog represents a bad sign, for it is believed that howling dogs sense somebody's death somewhere in the vicinity.
Never stand between a dog and the hydrant.
Paper and canvas prints of "Growing Up Chinese Shar-Pei" by Barbara Keith are available online.