Interpreting Body Language
It is important to note that while many gestures and actions may have common, stereotypical meanings, researchers regularly find that animal communication is often more complex and subtle than previously believed, and that the same gesture may have multiple distinct meanings depending on context and other behaviors. So, generalizations such as "X means Y" are often, but not always accurate.
For example, even a simple tail wag may (depending on context) convey many meanings including:
• Excitement • Anticipation • Playfulness • Contentment/enjoyment • Happiness, self-confidence
But could also mean:
• Anxiety • Uncertainty/apprehension
Combined with other body language, in a specific context, many gestures such as yawns and direction of vision all convey the dog's emotions or feeling states. Thus statements that a particular action "means" something, or that the dog is using its body language with the intent to report information to others, should be avoided.
How high or low the tail is held, in relation to how the dog's breed naturally carries its tail, and how it is moved can signify the dog's mood. When the tail is held high, it shows that the dog is alert; tail between the legs means that the dog is afraid. If the fur on the tail is also bristled, the dog is saying it is willing to defend. Small, slow wags of the tail say the dog is questioning things around it. Either it is not sure whether the target dog or person is friendly, or it is not sure what is going on or what is expected of it. Large, fast wags of the tail may be a sign of a happy or excited dog, but can also signal aggression. A large percentage of the victims of dog bites are bitten while the dog is wagging its tail. 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.
When a dog's lips curl back this shows that the dog has a strong urge to bite. This is an unconscious reflex, designed to get the soft flesh of the lips away from the teeth before the dog bites, and is often misinterpreted as a way of communicating aggressive intent. For example, many dogs will curl their lips back into a "snarl" when they take a cookie or bone.
Mouth expressions can provide information about the dog's mood. When a dog wants to be left alone, it might yawn (although yawning also might indicate sleepiness, confusion, or stress) or start licking its mouth without the presence of any food. When a dog is happy or wants to play, it 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. However, some dogs will pull back their "top lips" in what looks like an aggressive way, when they are excited or happy. For example a dog prone to "smiling" may do so in greeting to a much loved owner and this should not be punished lest the dog become less affectionate and more withdrawn. It's important to look at the dog's whole body and not just the mouth or tail before deciding what the dog is feeling. What appears initially as aggression might be an invitation to play, or vice-versa.
A very common form of communication is for a dog to lick another dog, or a person. Dogs lick other dogs' faces and mouths when they greet each other to indicate friendliness. Dogs like to lick human skin not only for the salt from the sweat, but also as a form of greeting, such as by briefly licking a person's hand after sniffing it. Licking is also used as a social bonding analogous to primate social grooming and stroking. This can indicate intimacy. Such licking is longer and slower, as compared to the brief licking of faces during a greeting.
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 or a timid reaction. They also lay their ears back for the sounds surrounding them. Dogs with drop ears, like Beagles, can't use these signals very well, as the signals first developed in wolves, whose ears are pricked. Wolf-like dogs (such as the Samoyed or Husky) will, when content and happy, often hold their ears in a horizontal position but still forward. This has been referred to as the "wolf smile".
Eyes and Eyebrows:
While dogs don't have actual eyebrows, they do have a distinctive ridge above their eyes, and some breeds, like the Labrador Retriever, Rottweiler, 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 uncertainty or mild anger, and one eyebrow up suggests bewilderment. Eyes narrowed to slits indicate affection for the person or animal the dog is looking at.
Although a dog's feet lack the dexterity of human hands, a dog can use them as an avenue of communication. A dog might stamp its feet, alternating its left and right front legs, while its back legs are still. This occurs when the dog is excited, wants something, or wants its owner's attention. Pointers tend to tuck one front leg up when they sense game nearby. This behavior is not communicative so much as the dog exhibiting a fixed-action pattern called "the eye stalk." It is also common for dogs to paw or scratch for objects they desire. Many dogs are trained to mimic a human handshake, offering a paw to a human stooping down and offering their own hand in exchange.
The leaning of a dog's head to the right or to the left often indicates curiosity and/or a sound it has not heard before. This, however, may also be a sign of recognition to a familiar word. If the dog's head is held high with its neck craning forward, it is showing interest, although, it could also mean an aggressive mood if other body language is present. Some adult dogs that were not properly raised have been known to challenge their owners for alpha position. One of the signs, though this is rarely seen in dogs, involves the dog slightly lowering its head while standing tall with its eyes fixed upward at the owner or any human beings they are about to challenge (start a fight with). This behavior is extremely rare and usually occurs with dogs that have been severely neglected or in some cases, abused. This can also be dangerous and sometimes fatal if no action is taken immediately. However, this behavior is preventable if owners avoid being neglectful or abusive to their dogs.