Dog communication refers to the methods dogs use to transfer information to other dogs, animals, and humans. Dogs may exchange information vocally, visually, or through smell. Visual communication includes mouth shape and head position, licking and sniffing, ear and tail positioning, eye contact, facial expression, and body posture. Auditory communication can include barks, growls, howls, whines and whimpers, screams, pants and sighs. Dogs also communicate via gustatory communication, utilizing scent and pheromones.
Humans can communicate with dogs through a wide variety of methods. Broadly, this includes vocalization, hand signals, body posture and touch. The two species also communicate visually. Through domestication, dogs have become particularly adept at "reading" human facial expressions. Dogs recognise and infer emotional information from humans. When communicating with a human, their level of comprehension is generally comparable to a toddler. Dog–human communication
Dogs tend to be highly responsive to human cues, especially the direction of a gaze and the direction in which a human points. Dogs rely on the gestures of humans more than verbal cues, most importantly eye contact. Eye contact is considered an ostensive cue. A human-dog gaze helps dogs establish stronger relationships by being able to communicate better with humans, as well as other dogs. Dogs will start to act and react much like their owners do. Dogs will pick up on how their owners respond to strangers and non-friendly dogs.
Both humans and dogs are characterized by complex social lives with complex communication systems, but it is also possible that dogs, perhaps because of their reliance on humans for food, have evolved specialized skills for recognizing and interpreting human social-communicative signals. Four basic hypotheses have been put forward to account for the findings. Dogs, by way of their interactions with humans, learn to be responsive to human social cues through basic conditioning processes. By undergoing domestication, dogs not only reduced their fear of humans but also applied all-purpose problem-solving skills to their interactions with people. This largely innate gift for reading human social gestures was inadvertently selected via domestication. Dogs' co-evolution with humans equipped them with the cognitive machinery to not only respond to human social cues but to understand human mental states; a so-called theory of mind. Dogs are adaptively predisposed to learn about human communicative gestures. They come with a built-in "head start" to learn the significance of people's gestures, in much the same way that white-crowned sparrows acquire their species-typical song and ducklings imprint on their own kind.
The pointing gesture is a human-specific signal and is referential. Human infants acquire it weeks before the first spoken word. In 2009, a study compared the responses to a range of pointing gestures by dogs and human infants. The study showed little difference in the performance of 2-year-old children and dogs, while 3-year-old children's performances were higher. The results also showed that all subjects were able to generalize from their previous experience to respond to relatively novel pointing gestures. This can be explained as a joint outcome of their evolutionary history as well as their socialization in a human environment.
Most people can tell from a bark whether a dog/canine was alone or being approached by a stranger, playing or being aggressive, and able to tell from a growl how big the dog is. This is thought to be evidence of human-dog coevolution. research available here
Visual
Dogs communicating emotions through body positioning were illustrated in Charles Darwin's The Expression of the Emotions in Man and Animals published in 1872.
In her book On Talking Terms with Dogs, Turid Rugaas identifies around 30 signals that she calls calming signals. The notion of dominance and submission is much debated. In her book, she does not use these terms to differentiate behaviour. She describes calming signals as a way for dogs to calm themselves or other humans/dogs around them. These are some of the signals she identifies: By moving different parts of their bodies, whether facial expressions or postures, dogs can express a wide range of emotions and signals.
Mouth shape Mouth relaxed and slightly open; tongue perhaps slightly visible or draped over the lower teeth – this is the sign of a content and relaxed dog. Mouth closed, no teeth or tongue visible. Usually associated with the dog looking in one direction, and the ears and head may lean slightly forward – shows attention, interest, or appraisal of a situation. Curling or pulling the lips to expose the teeth and perhaps the gums – a warning signal. The other party has time to back down, leave, or show a pacifying gesture. Mouth elongated as if pulled back, stretching out the mouth opening and showing the rear teeth – a submissive dog yielding to the dominant dog's threat. "Smiling:" a calming signal.
Head position A dominant or threatening dog that looks directly at another individual – a threat. It is pointing its weapons (muzzle/teeth). A dominant dog turning its head away from a submissive dog – a calming action, indicating that it is not going to attack. A less dominant dog approaching a dominant dog with its head down, and only on occasion quickly pointing its muzzle towards the higher-status dog – shows no fight is intended. In an alternative interpretation that does not involve dominance and submission, turning the head away is recognized as a calming signal.
Yawn Similarly to humans, dogs yawn in an attempt to awaken. Dogs will also yawn when under stress, or as a pacifying signal when being menaced by aggression signals from another dog. Yawning, accompanied by a head turned away from the aggressor, can defuse a potentially threatening situation. It is also recognized as a calming signal.
Licking and sniffing Licking behavior has multiple causes and meanings and should not be simply interpreted as affection. Dogs that are familiar with each other may lick each other's faces in greeting, then sniff any moist membranes where odors are strongest (i.e. mouth, nose, anal region, or urogenital region.) Mating behaviors are characterized by licking in a more vigorous manner than used during greetings. Licking can communicate information about dominance, intentions, and state of mind, and, like the yawn, is mainly a pacifying behavior. All pacifying behaviors contain elements of puppy behavior, including licking. Puppies lick themselves and their littermates as part of the cleaning process, and it appears to build bonds. Later in life, licking ceases to be a cleaning function and forms a ritualized gesture indicating friendliness. When stressed, a dog might lick the air, its own lips, or drop down and lick its paws or body. Lip-licking and sniffing are also recognized as calming signals.
Ears Dogs' ability to move their ears is different among each breed. In addition, some ears move very little if they are artificially altered or cropped by humans.
Ears erect or slightly forward – signals attention or alertness. Ears pulled back flat against the head, teeth bared – signals an anxious dog that will defend itself. Ears pulled back flat against the head, teeth not bared – signals submission. Ears pulled slightly back and slightly splayed – signals indecision, or uneasy suspicion that may become aggression. Ears flickering, slightly forward, then slightly back or downward – signals indecision with a submissive or fearful component. Ears pulled close to the head to give a "round face" – a calming signal. Ears pulled back in varying angles – expresses arousal. Ears flattened or pressed down – indicates fear, anger, or frustration. Ears pressed tightly to the head – expresses extreme fear. Ears held sideways – indicates conflicting emotions due to an unsettling situation.
Eyes When dogs want to threaten a perceived adversary, they will stare. In contrast, dogs will avoid eye contact if trying to decrease tension. They can communicate emotional states by having "soft" eyes or "hard" eyes. Soft eyes are used when a dog feels relaxed and not threatened. Hard eyes are used when feeling tension and unease about a potentially threatening situation. The eyes are slightly closed, the brow area is wrinkled, and their teeth may be showing. A dog should not be approached when they are communicating this way and should be removed from the high tension situation, if possible.
Direct eye-to-eye stare – a threat, expression of dominance, or warning that an attack is about to begin. Eyes turned away to avoid direct eye contact – breaking off eye contact signals submission; it is also recognized as a calming signal. Blinking – a calming signal.
Tail
Tail held high – communicates confidence, arousal, and willingness to be approached by other dogs or humans Tail horizontal, pointing away from the dog but not stiff – signals attentiveness. Tail horizontally straight out, stiff, and pointing away from the dog – displays an initial challenge that could lead to aggression if feeling threatened or anxious. Tail up, between the horizontal and vertical position – conveys dominance . Tail up and slightly curved over back – signals confidence; seen in a dominant dog that feels in control. Tail held lower than horizontally but still some distance off from the legs, perhaps with an occasional swishing back and forth – an unconcerned, relaxed dog. Tail down, near hind legs, legs straight, tail swings back and forth slowly – dog feeling unwell, slightly depressed or in moderate pain. Tail down, near hind legs, hind legs bent inwards to lower the body – expresses timidity, apprehension, or insecurity. Tail tucked between legs – expresses fear, anxiety, or nervousness; can also be a ritualized pacifying signal to fend off aggression from another dog. The expression tail between one's legs is used in English about people too. Tail fast wagging – excitement. Slight tail wag, each swing of only a small size – greeting. Broad tail wag – friendly. Broad tail wag, with wide swings that pull the hips from side to side – happy greeting. Slow tail wag with tail at half-mast – unsure of what to do next, insecure. Tail wagging is also recognized as a calming signal. Tail wagging to the left side of the body – the dog senses a negative situation, such as unfamiliar dogs or people. Tail wagging to the right side of the body – the dog feels comfortable and safe.
Dogs are said to exhibit a left-right asymmetry of the tail when interacting with strangers, and will show the opposite right-left motion with people and dogs they know."Asymmetric tail-wagging responses by dogs to different emotive stimuli", Current Biology, 17(6), 20 March 2007, pp R199-R201
Dogs' ability to move their tails can be different among different breeds due to the fact that humans can dock their tails or remove them completely. In addition, some breeds, such as the Australian Stumpy Tail Cattle Dog, are born with extremely short tails, or other breeds, such as the Pembroke Welsh Corgi, may be born without a tail altogether.
Body
Dogs' bodies alone can communicate a lot. By increasing the size and tension of their bodies and making themselves look larger, they can communicate confidence, alertness, or even threat. Actions meant to reduce the size of the body, such as lowering to the floor with tail tucked and lowered ears, can communicate stress, fear, nerves, or a desire to avoid conflicts.
Stiff-legged, upright posture or slow, stiff-legged movement forward – dominant dog. Body slightly sloped forward, feet braced – challenge to a dominant dog, conflict may follow. Hair bristles on back of shoulders – possible aggression, may also indicate fear and uncertainty. Lowering the body or cringing while looking up – submission.