Why Does My Dog Wag Its Tail?

When your dog is wagging its tail then it means he is excited, trying to maintain balance or wants to communicate something. Dogs also wag their tail to show respect and love for their owners.

Well, we all love it when our best friends welcome us home with a wagging tail after a long day’s work. You might have noticed that your dog has a unique but complicated communication system based on the position and movement of their tails.

Not many of us care about the position of their pet’s tails or body language. We simply assume that a wagging tail is a welcoming sign.

So don’t be surprised when the pet you assumed was happy to see you suddenly became aggressive. Before I got to research about these animals and their communication process, I always assumed, like everyone else, a wag means they are happy.

We are also aware when it is between the legs and under their belly, it means they are scared.

Dog Tail Wagging Meaning

There is more to the position than the general information, which we consistently based on an assumption, about what they are communicating as they wag this body part. If you speak to dog trainers, they will explain a lot about different positions. For example, you will learn that it could communicate their emotional state.

According to the American Association for the Prevention of Animal Abuse, when they relax, the tail will be in a “natural” position. They use them to communicate strong emotions such as anger, happiness, and agitation.

The sign that may appear as a happy pet may easily bite you because you read the signs incorrectly. Unfortunately, there is no science to wagging.

Whenever we see them swinging it, we think “well, there is a friend.” These hairy bones have many uses other than simply being swung left and right. Initially, we all understood that the goal of this part is to provide balance. It is true because it protects the animal from falling over when running around and taking sudden bends.

As they walk, climb or jump in narrow buildings, they will need the tail to obtain a balance. Over time, humanity came to understand its other significance – communication. The natural position varies according to the species. For example, many of these animals will hang them near the heels or hocks.

However, species like the pugs have it curled upwards while the greyhounds position theirs slightly between their legs.

If they are submissive or nervous you may notice that it will be below its natural position and whenever they are scared it will be under the body. On the other hand, once it is above the normal position it is an indication that something just aroused them. A vertical tail may indicate aggression.

The moment a tail is held straight out, it shows the dog is attracted to something that makes them curious. As our best friends swing them it is commonly a sign of excitement, the more it wags the higher their enthusiasm about something.

It is the reason they will wag them faster than normal when playing or just noticed you are back home.

In 2007, researchers discovered that the way a dog shakes their tail also provides clues to their emotions. Specifically, they presented findings that showed that swinging to the right indicates positive emotions and a swing to the left indicates negative emotions.

Interestingly, in another 2013 survey, it was noted that dogs could understand the asymmetrical movement of other dogs’ tails. It means your pet will understand another dog just by observing its movement.

Dog Waging its Tail is a Means of Communication?

As people, we are good listeners because speech is the foundation of human communication. On the other hand, dogs are different they are observers since they cannot speak. Since they cannot use verbal communication, they communicate more using body language.

They will take specific poses, move or position their ears, frown, or move their eyebrow, and wag the tail.

Wagging will always work best for them. It is because their visions, canines, tend to pay attention to movement than colors and details.

For example, you will notice that your pet may notice something before you get to know about it. It is only when they bark or become unsettled that you realize something is up.

For us, colors and details are more important as we make decisions or react based on the information we receive from such observations. Dogs are different as their information comes from movement observation; something moves, and your friend will immediately notice it!

Evolution has also played a significant role as it helps to produce a more pronounced tail, which is visible. Some have variations in color like light spikes or dark that appear clear and very thick. All of these features emphasize on swinging and improve communication.

Messages They Send When Wagging Their Tails

Before getting excited about the movement of your best friend’s tail, we ought to recognize that the neutral or natural position varies from one species to another. Most dogs have one that will hang down close to their heels as they relax.

However, some dogs, like the Beagle, keep them vertical. Others, like Greyhounds and Whippets, will curl them under their bellies.

Some like the Boston terrier and the Pug have a tail that coils against their bodies and they do not swing at all. I would admit that it would be way difficult to understand how such species communicate.

A Few Tips on Tail Positioning

Steadiness or distress – whenever these animals pay attention they will keep their ears upright and raise their tails. The movement you notice this behavior, I advise that you stay away because they will be watching as they get ready to confront whatever it is that made them steady.

A negotiation approach – well we like negotiation, guess what! So do our pets. The same happens among dogs especially when they stop wagging and suddenly freeze. It could mean they expect to divert a threat but not with aggression. It happens every time a stranger pats them and their reaction will mean that they are not interested in interacting with them.

They may become aggressive – dogs are not happy all the time and swinging tails may come as a warning more than an invitation. For example, as they move it from a neutral position to a vertical position, it may mean that they plan to be aggressive.

As it gets higher so are the chances of you getting attacked almost immediately. They will also raise them to releases a scent from their anal glands that seek to mark their territory when they notice an aggressive dog or a stranger.

A sign of submission – whenever your best friend moves their tails from a neutral position to a lower position, they may be showing you that they are not a threat. If it happens in the presence of another dog then they are being submissive.

They show curiosity – every time these animals are curious about something, the presence of whatever it is will cause them to hold their tails straight in a horizontal position.

They are just happy – we react differently once we are happy, perhaps we may dance around or sing. For dogs, it a little different. They can jump around, “dance,” when happy but you will not fail to notice them swinging their tails.

Wagging the Tail While Sleeping

You may have noticed your pet acting weird in their sleep. Many times they bark, growl or kick while sleeping. Similar to us, dogs dream! Mine is notorious for waging her tail when sleeping. I have always wondered what makes her do that, perhaps she is dreaming of us playing catch.

It’s a funny thing to watch them dream. Sometimes they may begin to tremble and move their feet and tail.

Mine acts as though she just saw a squirrel and it is time to run around chasing it. Nonetheless, many times it’s like the squirrel managed to get away. I know this from how she makes a disappointed growl and continue sleeping.

You may not know if they are dreaming while sleeping while until after you notice the obvious signs. They do not fully describe their experience during the dream but you can make various guesses based on their reactions during their sleep.

The time the brain is most active is during the REM sleep. It is not all organisms that sleep into the REM rounds. However, mammals have the capacity to get sleep. As mammals, dogs are observed to have similar brainwaves to human beings.

Similar to our REM sleep, dogs have shown to spend equal time like us, which allows them to have dreams about their daily events.

Common behaviors that occur while they are sleeping include facial twitching, wagging tails, low screams or backs, foot movements, whimpers, and whines.

Unless you find a way to teach someone to you how to talk to these lovely creatures, you will always be amazed at what they are dreaming about. In many cases, it is remarkable watching them dream.

Wagging the Tail While Sleeping

Does the Wagging Speed Matter?

  1. Friendliness – it is common that as they wag the tails they are being friendly towards us and they enjoy our company.
  2. Excitement – the faster they wag their tails, the more excited they have become and are willing to continue doing whatever it is that excites them. Sometimes they may do it so fast that you may think it is vibrating.
  3. Aggression – be careful as they wag it fast and vertically, it could mean they perceive you as a threat and could become aggressive.
  4. Insecurity – they can notice whenever something is wrong or the moment a stranger shows up. They will act tense and wag the tail slowly and slightly showing their insecurity.

Even if the direction of the swing is important, the communication of these animals remains to be very complicated. Studies have shown that dogs swing their tails to the right when they are happy or confident, and when they are scared, they move around while keeping them under their belly.

The left side of your dog’s brain takes control of the movement of the right side, and vice versa. Therefore, as the tails move to the right, it means the left side of the brain is activated and by moving it to the left, the right side of the brain is activated.

The happy dog leans their tails to the right as the left side of the brain is associated with positive emotions such as love and tranquility.

Also, the right half of the brain is associated with negative emotions such as fear and depression, so a frightened dog will swing it to the left.

Moreover, behavioral avoidance studies in other animals show that the left hemisphere is associated with positive proximity and that the right hemisphere is associated with negative avoidance.


I hope you have learned a lot about this behavior that many owners will simply assume they understand. Dogs are our best friends and they are here to stay until the end but not knowing them may risk our friendship. We may make assumptions that lead to decisions that end up stressing our friends due to limited knowledge.

As noted, our pets have tails for many reasons other than showing us how excited or alert they can be all the time. These parts of their bodies are useful for non-verbal communication since it is their only means of passing information.

We should pay more attention to how they position these parts and the reactions that follow such as ear positioning, facial expressions, and the sounds they make.


  1. https://psycnet.apa.org/record/2017-51520-001
  2. https://www.vdt.ugent.be/sites/default/files/art72402.pdf

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