It is a common belief that when a dog wags their tail, it means they are welcoming, friendly and happy to see you. Yet, this is not completely true. As a dog parent, you should make yourself familiar with canine body language to read your pet’s behavior better.

Dogs use their tails to communicate but not only in a positive manner. Dog tail wags generally means a willingness to interact, not necessary that the dog is friendly. By moving their tails in a certain position, they can also try to express their fear, anger or insecurity. Therefore, tail movements might communicate different things, depending on, e.g. the dog’s mood or the situation the dog is facing.

Breed specifics

Tail positions and motions can differ between dog breeds, for example, greyhounds carry their long tails low while pugs have tiny curly tails always pointing upward. The majority of dogs hang their tails down near their hocks or heels. By observing the position and movement of your dog’s tail, you can try to define the dog’s emotional state.

Tail positions

According to the American Society for the Prevention of Cruelty to Animals, when the dog is feeling relaxed, their tail is in its natural position – in the middle height of their body.

A tail held up higher than normal suggests the dog is curious or alerted.

If a dog is stressed or anxious, they will keep their tail lowered between their legs and when they are scared they will hide the tail under their body.

However, a vertical tail indicates aggression or a dominant attitude.

Dog tails wags


Tail wags

A small tail wag indicates a welcoming gesture while broad means that the dog is friendly. This one is associated with a happy dog, especially when the dog’s butt moves back and forth within their body.

A slow tail wag could convey that a dog is insecure about a situation, no matter if the tail is positioned high or low. It only suggests that the dog is unsure about how to react.

High-speed tail movements which might seem like vibrations, signify that the dog is going to take some action, most probably in a negative way – attack, chase or bite.

When the tail is completely stiff, it’s not a good sign, this might state hostility. Generally, a dog is more open to a friendly interaction when their tail is moving.

Additionally, it has been scientifically proven that if the dog is wagging their tail to the right, they’re experiencing positive emotions while to the left – they are feeling bad about something. The fact is that the brain’s left hemisphere controls the right side of the body and vice versa.

Research on the approach-avoidance behaviour of various animals shows that the left hemisphere is associated with positive feelings and the right one with negative-avoidance feelings.

Dog tails wags


The experiment

The experiment by A neuroscientist, Giorgio Vallortigara, and two veterinary doctors, Angelo Quaranta and Marcello Siniscalchi conducted an interesting experiment which draws similar conclusions. The researchers gathered 30 dogs of different breeds and put them individually in a cage equipped with cameras in order to track motions of dogs’ tails. The pets were introduced to four different interactions – with their owner, an unknown person, a cat and a dominant dog.

When the dogs saw their parents, their tails began to eagerly wag with a bias to the right side of their bodies. When they met a new person, their tails were also wagging more to the right yet not so intensively. While seeing a cat, their bodies reacted with right-turned but slow and reserved tail wags. This behavior indicates that the dogs are curious and alerted at the same time. When an unfamiliar, alfa dog entered the room, the dogs’ tails position turned with a bias to the left side of their bodies, suggesting negative feelings.


As a dog parent, always keep in mind that tail wags can have different meanings, depending on the situation your dog is facing, people or animals your dog is meeting or their surroundings. Before decoding your dog’s behavior, consider the bigger picture – a full body language. Don’t forget that tail is one of your dog’s main communication tools so it’s crucial to learn their language in different contexts.

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