Interpreting the Dog’s Mouth

Clues to behavior and emotion
By Karen B. London PhD, September 2009, Updated June 2021

When assessing dogs, I often look at the mouth. With such a strong interest in canine aggression, I have spent a lot of time looking at this part of dogs’ bodies, and wrote about my observations recently in my local newspaper.

The basics of interpreting the internal state of a dog from the mouth involve the following questions: Is the mouth open or closed? Is the dog panting? Does the dog display an offensive pucker, a fear grimace or a tooth display?

The answers can enlighten you about whether a dog is happy and relaxed at the moment, rather than feeling anxious or perhaps fearful. The mouth provides clues about the amount of confidence a dog is feeling as well as the likelihood of going on the offense and behaving in an aggressive way.

 Image: iStock

Karen B. London, Ph.D. is a Certified Applied Animal Behaviorist and Certified Professional Dog Trainer who specializes in working with dogs with serious behavioral issues, including aggression. Karen writes the animal column for the Arizona Daily Sun and is an Adjunct Professor in the Department of Biological Sciences at Northern Arizona University. She is the author of six books about canine training and behavior, including her most recent, Treat Everyone Like a Dog: How a Dog Trainer’s World View Can Improve Your Life