Up until the 17th century, people thought dogs were little more than unemotional machines that could not feel pain, either emotional or physical. It took behavioral science a long time to move away from that belief. Now, of course, we know that dogs are expressive animals that have a range of emotions. They communicate when they’re feeling happy, sad, nervous, fearful and angry, and use their bodies and faces to convey much of this information. Learning to read that body language is essential.

Related Articles

• Eyes. Dogs’ eyes, their size and shape, and the focus and intensity of their gaze can tell you much about how they’re feeling. A soft, blinky, normal-sized eye indicates a happy and content dog. An overly wide eye may mean that your dog is feeling threatened, while a small or squinting eye may suggest fear or stress.

While your dog may look at you with a relaxed and happy demeanor, the dog that looks at a person or another dog with a direct and hard stare is potentially a threat. Similarly, a dog that looks at something out of the corner of their eye so that much of the white of the eye is apparent — known as whale eye — may be poised for an aggressive outburst.

• Mouth. Did you know that some dogs smile? When dogs are relaxed, they’ll probably display a slightly open mouth. A closed mouth with lip licking may indicate that your dog is anxious or stressed. Exposing teeth is an indication that your dog is fearful or angry.

• Ears. The type of ears a dog has, such as pricked, folded or drooping, will affect the way in which they’re used to communicate feelings. In general, however, when relaxed, dogs will hold their ears naturally. Raised ears indicate alertness. Ears pinned back against the head is a sign of anxiety or fear.

• Tail. There’s a common misconception that a dog with a wagging tail is always friendly. While it can indicate a gregarious and sociable feeling, it can also be something entirely different. The placement of the tail, the type of the wag and the overall body posture need to be considered. Of course, if a dog doesn’t have a tail (or a full tail), the ability to communicate with it is limited. If it’s held naturally and gently wagging side to side, the dog is probably relaxed and happy. A tail held high with a stiff and rapid movement likely indicates a potentially unfriendly dog.

• Body posture. A dog’s body when relaxed and happy is best described as soft, loose or wiggly. When scared, dogs will likely make their body smaller, hunch over and try to move away. When alert, a dog will stand tall, muscles tense.

Having the ability to read what dogs say with their bodies will help you better understand them and what they’re feeling. It will also alert you to respond when they need your intervention. In almost all cases, the best strategy is to move to another environment.

Our dogs have a lot to say to us. We just need to learn how to listen.

Dawn Kovell is the director of behavior and training at Marin Humane, which contributes Tails of Marin articles and welcomes animal-related questions and stories about the people and animals in our community. Go to marinhumane.org, Twitter.com/marinhumane, or email [email protected].