Tail Wagging– what does it mean?

This weekend I went home and visited my adorable, four year-old, lab mix dogs. It was so nice to see her (and my parents). When I first walked in the door, she attacked me with kisses and scratches all over my legs. This reaction was expected but what wasn’t expected was that afterwards she just stared at me and wagged her tail on the ground. Usually, she wags her tail in the air. This caused me to start to wonder why dogs wag their tails and what the different wags mean.

An interesting post talking about why dogs wag their tails explained that it is serves as a signal, a way to communicate with other beings. It explained that a ” dog will only wag its tail when other living beings are around-e.g. a person, another dog, a cat, a horse or perhaps a ball of lint that is moved by a breeze and might seem alive.” A different source added that while they do use their tails to signal happiness, they also use it for anger and annoyance. Every single article I have looked at about this topic emphasized the importance of not assuming a dog is happy/excited when he/she is wagging his/her tail.


In the past, tail wagging has usually been measured through movement and height but recently, there has been a new scientific finding. Apparently the side on which the tail is wagging can say something about the dog’s general mood. Tails wagging more to the right seem to have more positive moods. I found this very hard to believe, it just didn’t make sense to me but after doing some deeper research, I have yet to find a source which says this is untrue. Furthermore, there were a study conducted to support these findings. They took “30 family pets of mixed breed and placed them in a cage equipped with cameras that precisely tracked the angles of their tail wags. Then they were shown four stimuli in the front of the cage: their owner; an unfamiliar human; a cat; and an unfamiliar, dominant dog.” (same article). The dog’s tail reaction with each of the increasingly nerve-wracking stimuli, was consistent with the data.

It is important to know a dog’s natural tail position because this is where it will be if she is relaxed. A nervous dog will generally put her tail low and between her legs and and a happy dog will wave her tail back and forth with increasing speed and force as mood increases.


The same source warns to keep an eye out for dogs with their tails straight up. This could be a sign of aggression or threat. The main way to tell the difference between an angry dog and a dog just wagging her tail is is to look at the rest of the body. It will give clear signals towards the dogs mood through things such as eyes, ears, mouth and posture.

3 thoughts on “Tail Wagging– what does it mean?

  1. Buanafina Maia

    This is an interesting topic to research about. I always thought that if a dog was wagging his tail it was because he was happy. I never stopped to think that maybe it can mean other things too. According to the ASPCA, not only do dogs’ tails tell us about their moods, but also things like the position of their ears, eyes and mouth. So, if you ever see a dog wagging its tail, look out for other signs such as how its eyes, ears and mouth are positioned to tell what kind of mood it is in.

  2. Yu Zhang

    It’s interesting to find that dogs have body language just as humans do; a single waging of tail has so many meanings and can deliver so many different messages if the gesture varies slightly. I was also surprised to see that “Tails wagging more to the right seem to have more positive moods,” and found it hard to believe, but after I read the articlecarefully, it makes sense. “A 2007 study on dog body language that appeared in the journal Current Biology found that the different sides of the dog’s brain dictate the direction of the tail wag.” A dog will wag his tail to the right side when he is feeling happy, positive or confident about approaching something. The left brain, which controls the right side of his body, specializes in behaviors that scientists refer to as “approach” and “energy enrichment.” On the other hand, the dog will wag his tail to the left if he feels scared or wants to bolt from the situation. The right side of a dog’s brain controls feelings of withdrawal and energy expenditure and also controls the left side of his body. In this way, we know the reason is that the right and left side of the brain controls the opposite side of the dog’s body separately.
    However, it’s good that you try to find other evidence regarding the topic and refer to what we talked in class: science can say something is wrong easily, but it’s difficult to prove that something is right.

    Another point I want to mention is that the article you find inform us that “while dogs do use their tails to signal happiness, they also use it for anger and annoyance,” but it doesn’t explain why, nor does it demonstrate studies or researches to back up the point. I’m wondering how people know the dog’s inner feelings when it wag its tail? I’m sure that sometimes the behavior is hard to read, or there won’t be people attacked because of misunderstanding, as you mentioned in the blog. I want to stress that science cannot go without proper proof, and it would be more convincing if you find some studies to substantiate the discoveries.

  3. Alexandra Herr

    I have a 7 year old dog and I have noticed over the years that her tail wagging has peaked. When we first got her, she displayed nervousness, keeping her tail between her legs. When she reached a comfortable age, she was a lot more energetic, wagging her tail constantly. Now that she has reached a bit of an older age, she tends not to wag her tail as much, but just lounges around. I believe this is because of her communicationas this link discusses. This article from Animal Planet says how animals use their tails for communication skills. Perhaps my dog didn’t wag her tail at first because she was shy and she doesn’t wag it as much anymore because she is older and quieter.

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