Understanding your dog's body language
Dogs and humans have lived together for thousands of years and we are instinctively able to read most of our moods from each other through body language, facial expressions and voice.
While dogs are alien to human higher feelings such as embarrassment, love, and contempt, they share the same gamut of basic feelings such as happiness, sadness, relief, frustration, and fear as we do. These feelings are essential to the learning process of all animals (including humans), prompting us to behave in ways that turn out to be beneficial to us. For example, fear compels dogs to seek safety, while the positive feelings of contact, grooming, and stroking promote the formation of close relationships with other social dogs and people.
Understanding your dog is key to building a happy, rewarding relationship. The following illustrations should help you learn to recognize your dog's emotions and deepen the bond between you.
Happy

Happiness is one of the easiest feelings to notice because it is so overwhelming! The dog has gentle and unfocused eyesight, his forehead is relaxed, and his ears either hang loosely when he is running, or move back and forth in a sympathetic, friendly manner.
Although the dogs don't smile, some, like this golden retriever, almost seem to grin. His lips are loose, his mouth slightly open, and his tongue protrudes outward as he breathes evenly and gently.
The tail is an excellent indicator of mood. When he rocks it nonchalantly and unhurriedly from side to side at medium height, he is content. When he wags him vigorously, sometimes so vigorously that his entire croup moves, he is excited and happy!
A happy dog is relaxed as he moves, encouraging you to play and join his joy.
Worried

If you know when your dog is upset, you will be more able to calm him down, possibly by distracting him with treats or play.
Your dog's eyes, when concerned, can be wide and staring, they can also be narrowed at times, and your dog will avoid eye contact. You can see the wrinkle or tightness of his forehead, and his ears will point slightly backward if he is listening - positioned to gather information about possible dangers. If his ears are drooping, he may keep them closer to his head than usual.
His mouth will usually be closed, but if he is open his lips will be tense and he may lick them and yawn nervously, even though you know he is not hungry or tired.
Its body and tail are probably still and slightly lowered. Concerned dogs sometimes wag their tail cautiously, but this is not a sign of joy, but a gesture of reassurance. This is why anxiety is often overlooked, so always watch it carefully when it is in a new and challenging situation.
Afraid

Body language in a fearful situation is more obvious than most other emotions and can be more dramatic than the one pictured. Different dogs react differently to fear: some will cower to appear as small as possible, some flip over to show social subordination, others just stand very still, taut to the tips of their hair, and still others bark loudly, bouncing or snarling sticky to the ground.
Eyes may be wide open, gaze darting in all directions, stern and penetrating, or squinting eyes glancing sideways at a perceived threat.
Ears flat against the head that can be lowered and turned to the side.
His lips will be tense and he may lick them or yawn, which further indicates stress or calming down.
His tail will be stationary, lowered or tucked under the belly - between the legs, and the dog will be very focused, he will refuse even his favorite treat and probably will not react to our voice or stroking.
When a dog is scared, its ultimate goal is simply to survive the threat; his body language, facial expression and appetite will return to normal when he feels safe again.
Frustrated

There are different types of frustration, from prolonged frustration with depression (discussed here) to active frustration, which are more acute in response to a specific event, such as when a dog cannot get something that he wants or needs, such as a toy. or the possibility of leaving the house. There is also the frustration that comes from not being able to avoid or run away from something unpleasant.
A frustrated dog will often be tense and his posture will be stiff. He can bark incessantly, run away or even pounce on the object of his frustration. All his senses will be focused on him and he may not listen and respond properly to all your attempts to distract him.
His eyes will be wide open and not blinking, ears raised and listening, and unless he is barking, his lips will be stiff and the corners of his mouth will be pushed forward.
The dog cannot maintain this tension indefinitely, so he will eventually come to terms with frustrating situations or, in chronic cases, will enter a state of powerless depression. This may be misinterpreted as a tacit acceptance, but your dog will need care and affection in these situations to help him relax and act normally again. If you ever observe this behavior in your dog, ask a certified behaviorist for help.
Relieved

The feeling of relief is often most marked in contrast to the previous negative emotional state. It is important to know when your dog is frustrated, anxious or scared, but it is equally important to know when he is relieved and can relax again.
Dogs, just like us, are relieved when sadness or problems leave them, especially when they survive the real threat and fear that comes with it.
You will clearly see the release of tension across your body, from nose to tail. The eyesight will soften, the ears will drop, the head will lower, and the whole body will noticeably calm down.
Some dogs yawn, while the more reserved ones may tilt their heads, avoid eye contact, and seem to be sighing inwardly while remaining generally still. The more extroverted individuals can dust themselves off, make a playful bow, or even run around in euphoria - all of these activities make the tension less intense.
Focused

The focused dog is alert, focusing on something important, such as a ball, a treat, or perhaps you. The illustration shows what your dog should look like when you train him - watching, listening and ready to work with you and earn his reward. He may also be focused on something new as he tries to discover what it is and how to respond to it.
When alert, his eyes are open, attentive, possibly not blinking, and his eyesight slightly intense when he focuses on the object of his interest.
His ears are either turned up to listen or pointed forward, and his mouth can be open or closed with his tongue in the center.
The head will generally be raised as long as there is no intention of chasing something, while it can be lowered and stretched forward.
When he is focused on something pleasant, his whole body may tense in that direction, trembling in anticipation. The body weight will be on the front legs and the tail will be raised and either stationary or wagging excitedly. It is ready for action.
Bad

If you come face to face with a dog that looks like this, you will have to walk very carefully until the danger is dispelled. A bad dog will try to look as big and formidable as possible with a straight and stiff body.
His hair may be fluffed up, especially along the back. His eyesight will be stern, motionless, he will not blink his eyes, his forehead will be wrinkled and tense, and his ears will sometimes be flattened along his head backwards.
The mouth will be open, the lips tense and withdrawn, the nose and mouth will wrinkle showing the teeth.
His whole body is stiff, his tail is held stiff and still, and his weight is pushed forward towards his front paws, ready to lunge or attack.
He will be silent or perhaps growling low and menacingly - a true evil dog does not announce it by screaming. Always avoid provoking the wrong dog. Don't stare at him, scream or make sudden movements, but try to slowly withdraw to a safe place and let him calm down.
Neutral attitude

Hopefully your dog will spend most of his day this way - relaxed, exercised, well fed and comfortable in familiar surroundings. If he is lying down, he will be relaxed and still, but ready to be livened up and interested in what you are doing.
His eyesight is gentle and relaxed, his eyes move smoothly, with no visible sclera, as he observes his immediate surroundings from his comfortable resting place.
His ears are also relaxed and listening freely.
His forehead and eyebrows are wrinkled and free of tension.
The mouth may be closed or slightly open, and when it does not show the readiness to play in the form of a partial smile, its lips and mouth will be relaxed.
The entire body and tail will also be at rest, with no signs of muscle tightening that would indicate readiness to act. He is pleased.