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Keep your eyes on dogs' mouths

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While the eyes may be the mirror to your dog's soul, I spend more time paying attention to the mouth. This is partly because I specialize in helping aggressive dogs, and these animals are armed with the equivalent of steak knives in their mouths.

Eyes may be intense, but no client of mine ever ended up at the hospital or in court because of what the dog's eyes did to them. On top of that compelling reason, the mouth of a dog can give a lot of information about the dog's emotional state and what he is likely to do.

One of the first things I notice about a dog is whether his mouth is open or closed. A relaxed, friendly dog will usually have an open mouth. The typical image of a happy dog is one with a relaxed face whose tongue is hanging a little out of his mouth as his lower jaw rests wide open.

An open mouth on dogs who are overheated tells me nothing about their emotional state because they will have their mouths open to cool down by panting no matter how they are feeling. On the other hand, a dog who is not warm but is nonetheless panting is probably feeling anxious. A dog who is fearful or nervous most often has his mouth tightly shut.

When dogs become emotionally aroused, their mouths reveal a lot about their internal states. Specifically, it is informative to observe the position of the lips and how visible their teeth are. When the corners of a dog's mouth, or commissures, are pulled back tautly, it is a sign that the dog is fearful, and this facial expression is actually called a fear grimace. In a fear grimace, many of the dog's teeth are visible. This posture of the mouth connotes fear rather than the intention to attack. Fearful dogs may still behave aggressively out of panic, but many will take another way out of the situation if possible.

When an aroused dog pushes the commissures forward so that the mouth becomes O-shaped, the signal is a threat called an "offensive pucker." This signal indicates a dog who is willing to go on offense and who is most likely very confident.

Another visual signal involves retracting the lips to bare the front teeth. Showing the teeth in this manner is called a "tooth display." This signal translates best as "I have teeth and I am willing to use them." In other words, a dog who is doing a tooth display is more likely to go on the offensive and behave aggressively than a dog who is not performing this display. Dogs who give a tooth display combined with an offensive pucker are especially likely to behave aggressively. However, many dogs do make threats with one or more of these signals without ever causing injuries.

Is the mouth open or closed? Is the dog panting? Does the dog display an offensive pucker, a fear grimace, or a tooth display? Answering these few questions can reveal a lot about how a dog is feeling and what he might do next.

Karen B. London, Ph.D., is a certified applied animal behaviorist, certified pet dog trainer and author who specializes in the evaluation and treatment of serious behavioral problems, including aggression, in the domestic dog.


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