Common Mistakes: “If He Wags His Tail, He’s Happy”

The tail is one of the body parts with which the dog communicates its state of mind to the world around it. A tail that wags its tail almost always snatches a smile from dog lovers, but in some cases if it is not “read” along with all the other signals that the dog tries (in vain) to give to humans, it can lead to accidents that could have been avoided.

It may have happened to almost all owners to observe a mistrustful behaviour of their dog towards another dog they met on a walk: “Why is my dog afraid? Yet the other wags his tail.” The answer is simple: the dog, through an overall reading of the bodily signals he receives from the other dog, is able to decipher his intentions and state of mind (which we humans can hardly do). By lingering for the moment on the tail we can identify different positions and their meaning while wagging his tail.

High, Intermediate, Low Tail, Between The Legs

The height of the tail is just a clue to the dog’s state of mind. It can mean adrenaline, excitement, readiness, but not just happiness.

A high tail wag accompanied by facial mimicry and body posture is generally a sign of the dog’s confidence and self-esteem. He knows what he’s doing. High tail wagging allows the dog to spread its smell, emitted largely by the glands in the perianal and genital area. The dog’s intentions in this case are not necessarily playful.

A lower wagging wag (until he wags his tail between his legs) progressively indicates insecurity, submission, and fear (in these cases the movement will almost exclusively concern the tip of the tail).

The reason for the eternal misunderstanding between dogs and cats lies right here: the cat’s tail in a naturally high position sends signals of challenge and dominance that are misinterpreted by the dog.

Tail Speed

Even the rhythm of the wagging doesn’t lie.

A slow, cadenced movement indicates in most cases a state of conflictual indecision. The dog is not sure whether he is facing a friend or an opponent in this situation. The reaction of the person in front (man or dog) will lead him to decide how to behave.

A rapid, frenetic movement without a precise cadence, often involving the bum as well, indicates a strong excitement. It can be high or low tail, depending on the degree of safety of the dog. The excitement can be joyful, but also concentration/aggressiveness (hunting dogs often wag their tail quickly when following a trail or prey).

Tail Right Or Left

According to a study conducted by Professor Giorgio Vallortigara, a neuroscientist at the University of Trieste, the dog’s tail tends to lean towards the right side of the body when the dog feels safe and has positive feelings towards something or someone (e.g. wags its tail towards the owner).

On the contrary, the orientation is to the left when the dog feels aversion and feelings of hostility or mistrust, as in the case of meeting a stranger. Vallortigara and colleagues analysed the behavior of 43 dogs of different breeds while looking at images of other dogs, realistic or depicting stylized figures, while wagging their tail to the right, to the left, or while not wagging their tail.


Although it is only a clue to the dog’s state of mind, the way he wags his tail can give us important but not sufficient indications to have a precise picture of the dog’s intentions. An analysis of facial mimicry and posture are essential to avoid any misunderstanding that leads in some cases to avoidable quarrels and bites.