A dog’s mouth is just as expressive as his eyes and tail. Even though he can’t use his mouth to talk like we humans can, the way that he positions his lips, jaws, and teeth can still speak volumes. As with all other aspects of dog body language, some of the dog’s gestures with his mouth are blatantly obvious, while others need a practiced eye to detect. Knowing what gestures to watch for and what they likely mean can give you a lot of information about what your dog is thinking and feeling in a particular situation. Understanding how your dog is feeling about a person, place, object, or situation can help you predict what he is going to do next. If you can see that your dog is clearly enjoying something, then great! Keep an eye on him to make sure that he continues to have fun, but the interaction can definitely continue. If you think that your dog is uncomfortable, nervous, or afraid of something, it’s best to remove him from the situation as soon as you can before he feels the need to become defensive.

Dogs that are happy and comfortable usually have their mouth closed or slightly open. The muscles around his mouth and jaw will look relaxed. He may be panting gently depending on the outside temperature or how active he has been. His teeth may be visible, but only because his mouth is open. He is not doing anything to actively display his teeth in a threatening manner.

A retriever with a ball
Photo: liz west, via Flickr

Most dogs will lick their lips after eating a meal or drinking water. However, if your dog is constantly licking his lips or flicking out his tongue when there is no food or water present, he might be trying to tell you that something is making him nervous. This is one of the more subtle signals that dogs give to each other and to humans, and it can be very easy to miss if you’re not careful. If you see your dog licking his lips or flicking his tongue, try to pinpoint what it is that’s making him uncomfortable. Try giving him some space and some time to adjust to whatever it is and then let him decide if he wants to interact further or move on to something else.

A tongue flick
Photo: Leonora Enking, via Flickr

Just like humans, dogs yawn when they are tired. However, some dogs will also yawn when they are nervous about someone or something. “Nervous” yawns tend to be a little more exaggerated than “tired” yawns. The yawn is your dog’s way of trying to diffuse some of his nervous energy while also letting another dog or a new person know that he means no harm and would like some space.

A yawning dog
Photo: Matt Chan, via Flickr

Dogs pant for a variety of reasons. Panting is the primary mechanism that dogs use to cool themselves down when it’s hot outside. Some dogs will also pant when they are not feeling well or are in pain. Finally, excessive panting can also be a sign that your dog is nervous about something. Humans experience a similar phenomenon when we get nervous – our heart rates speed up and our breathing becomes rapid and sometimes erratic. Same goes for the dogs. If you look closely to the picture below, you can also see that the muscles around the corners of this dog’s mouth are tense and pulled back as far as they can be, forming “ridges” at the corner of the mouth. Again, do your best to identify what is causing your dog to pant excessively. He might need you to help him cool off, he might need you to take him away from a scary situation, or he might need to see the vet.

a dog panting
Photo: Stella Dauer, via Flickr

Dogs that are extremely nervous or frightened of something will sometimes purse their lips while holding their mouths tense and still. Some dogs will hold this position for a split second and some dogs will hold it longer. Sometimes this gesture is accompanied by a low growl and sometimes the dog is completely silent. This gesture, in all its slight variations, is a warning. Your dog is saying, “Do NOT push me any further or come any closer. If you do, I will snap at you.”

a nervous dog
Photo: SupportPDX, via Flickr

A dog that is baring his teeth is letting you know that he is extremely unhappy with another dog, a person, or the situation that he is in. This gesture is sometimes accompanied by growling and barking, and sometimes the dog is not making any sound at all. For most dogs, baring their teeth is the last warning that they give before they attempt to bite.

A husky with a snarl
Photo: Steve Garner, via Flickr

A dog’s mouth can be extremely telling for that dog’s state of mind. He can express a wide range of emotions with small changes in the way that he holds his teeth, lips, and jaw. Knowing how to “read” the gestures that a dog is making with his mouth will help you stay safe when interacting with him so that you don’t accidentally scare him or upset him to the point that he feels like he needs to bite you. The vast majority of dogs will not escalate to a bite if their initial warnings are observed and respected. As always, it’s important to remember to take the context of the situation and the other aspects of canine body language (e.g. eyes and tail) into account when trying to determine what your dog is feeling. But, now you know what your dog is trying to say with his mouth without him having to say a word!