Why Do Dogs Wag Their Tails?

Brittany Grenus, DVM
By Brittany Grenus, DVM on May 17, 2023
close-up of a corgi's rear-end holding his tail high

One of the biggest misconceptions about dogs is that a wagging tail means the dog is friendly. While it certainly can mean this, there are a multitude of reasons dogs wag their tails.

At the most basic level, a wagging tail simply means the dog is responding to something in their environment. They are trying to convey how they are feeling about what is happening, and that can help people understand what kind of interaction the dog is attempting to have.

The dog could be experiencing any number of feelings—and some might conflict with one another. This means you can’t assume a dog is friendly or wants to engage with you just because they’re wagging their tail.

There are many factors that need to be considered when assessing a dog’s tail wag, including the presence of other behavioral clues. Attention should always be paid to the dog’s entire body language, not just the tail.

How to Read a Dog’s Tail Wag

Because dogs use their tails to communicate different emotions, the feeling being conveyed depends on two factors: the tail position and the speed of the wag.

If a dog’s tail wag is thought of as their way of talking, then the positions of their tail can be thought of as words. The speed at which they’re wagging their tail can then be compared to how loud their voice is. The faster the tail wag, the louder the voice.

But can be tricky to see, depending on the dog’s anatomy. The average dog’s “relaxed” tail position may hang down by their heels. But there are some breeds whose natural tail position is upright, and others that don’t have tails at all. 

Pay attention to the tail’s base. This reveals the ever-important tail set (or position). Once the angle of the tail is noted, assessing the wag completes the picture and helps you determine what kind of emotion the dog is feeling.

What Does It Mean When Dogs Wag Their Tails?

The tail’s position could be considered reflective of the dog’s general mood (scared, excited, concerned, curious, happy, or angry). The wag indicates the intensity of that emotion. The more exaggerated or extreme, the more intense they’re feeling.

For example, let’s say a dog with an average-length tail is approaching you. The base of their tail is raised slightly just past parallel to the ground. The wagging could be described as moderate speed, full, sweeping, and loose. The tail position tells us the dog is feeling relaxed and the exaggerated movement of the tail from side to side indicates that the dog is approaching with the intention of engaging in a positive social interaction with you.

Here are several emotions a dog can convey through wagging their tail.

infographic depicting illustrated dogs wagging their tail and what it means

Happy/Friendly

When a dog is expressing happiness or friendliness, their tail is often in a neutral position (the base of the tail is parallel to the ground). It can also be in a slightly upward or downward position and wagging at a moderate speed.

Their tail is relaxed and wagging in full, sweeping side-to-side movements. It may even be wagging in a circular motion known as a “circle wag” or “helicopter tail.” (Though, some dogs can have a helicopter tail when they’re feeling anxious, aroused, or agitated. Again, it’s important to remember that no one body part communicates the whole story!)

The more excited a dog is, the faster their tail typically wags. When dogs are excited and friendly, they will sometimes also wag their hips or even their whole body, from their shoulders down to their tail. This is frequently observed in dogs with short, nub-like tails. They sometimes wiggle the entire back end of their bodies!

Curious

When a dog is curious about something, such as when they find a new smell, their tail is typically held straight out behind them. This may or may not be associated with a tail wag—the tail is often held still, but it won’t look stiff or tense. They may also be standing with an alert posture with their ears perked up, potentially with wrinkles visible on their foreheads.

Relaxed

A dog that is relaxed will stand with a tail that’s void of tension and not wagging. They will only start moving their tail when an emotion is sparked by an environmental change.

Appeasing/Submissive/Fearful

Before describing an appeasing, submissive, or fearful tail wag, it’s important to note that all these forms likely have an element of fear, vulnerability, or uncertainty. It’s important to pick up on the cues a dog is giving to avoid heightening the situation.

Submissive dogs will often lower their tail or tuck it between their legs. This is typically done because the dog feels threatened and does not want to be harmed. This tail position is telling other dogs (and people!) that they need time and space to work through the discomfort. A submissive tail position may or may not be associated with a tail wag.

If a dog has their tail tucked tightly between their legs and is wagging the tip in a tight fast motion, this is typically indicative of the dog experiencing a fear response and wanting to pacify another dog. Many dogs show signs of submission when they’re scared as a survival strategy.

Because the speed of a tail wag is reflective of how intense the dog’s feelings are, a submissive tail wag can be thought of as a dog saying, “Please don’t hurt me!” If a dog is exhibiting this sign, it’s best to stop approaching or interacting with them.

Allow the dog to approach when they are feeling safer. And remember: a dog moving forward with a tucked tail wagging low and tightly may not be an invitation for interaction.

Aggressive/Threatening

A dog moving closer to exhibiting aggressive behavior will move their tail into a vertical position that often arches over their back. The tail will be very stiff and may or may not be moving.

If a dog’s tail is in this position, it means they are preparing for an interaction that involves agonistic behaviors. The tighter and faster the tail movement, the more agitated the dog is.

If a dog is showing signs of feeling threatened, action needs to be taken to change the environment immediately. The dog should not be approached because it’s likely they will attempt to bite if a human or animal tries to interact with them in this state. If the dog can’t be removed from the situation, the people, other animals, or events causing the dog’s distress should be.

In addition to the high, stiff tail, other signs dogs may exhibit include:

  • Stiff body pointing at the target

  • Staring with wide eyes

  • Pinning or flattening their ears

  • Closing their mouth with tension in the lips

  • Standing perfectly still/freezing

  • Moving forward in slow motion

  • Exposure of canines

  • Growling

  • Lunging

Avoidance

When dogs don’t want to interact at all, they typically stop wagging their tail and move away. They may even exhibit displacement behaviors like self-grooming or sniffing the ground. A more direct translation of these behaviors is, “please leave me alone,” or “please calm down.”

At this stage, this isn’t associated with aggression; it’s just the dog’s way of requesting to be left alone. However, if the dog is approached, the avoidance signals may transition to submission or aggression, depending on the dog. Heed the dog’s request and do not approach unless absolutely necessary. If you are able to give the dog some space, they may willing come to you after some time.

Right-Sided vs. Left-Sided Tail Wagging

Scientists have also discovered there is a difference between a more right-sided versus left-sided tail wagging. Dogs conveying more positive emotions will wag their tail slightly to the right, while dogs that are conveying more negative emotions will wag their tail slightly to the left.

Dogs that are wagging their tail slightly to the right tend to be friendlier and exhibit other behaviors indicating a willingness to interact socially. Dogs that are wagging their tails slightly to the left tend to be more stressed or anxious and exhibit avoidance or escape tendencies when presented with social opportunities.

How Do Dogs Without Tails Communicate?

Because dogs communicate so many different emotions with their tail, how do dogs without tails communicate? Just like humans, they use vocalizations and body language.

With or without a tail, here are just a few ways that dogs use their voice and body language to communicate their emotions:

  • Vocalizations: barking, growling, snarling, whimpering, whining, crying, howling

  • Facial expressions

  • Moving their tongue, such as lip-licking

  • Eye position

  • Ear position: flattened, perked up, relaxed, pinned

  • Stance/posture: hunched, cowering, play bowing, hackles raised, stiff/frozen, body weight shifting forward or back

  • Movement: stiff/frozen, lying down, walking around, lunging, “tip-toeing,” moving backward, turning head away

Learning how to speak “tail” can be complicated, but the most important thing to remember is that just because a dog is wagging their tail, it does not necessarily mean they are friendly.

Keep in mind this is just one body part dogs use to communicate emotion. Always ask the pet parent before approaching and petting their dog. And even if they say yes, take a look at the dog’s posture yourself. If you see anything that gives you pause, it’s OK to decline.

Featured Image: Adobe/e-Kis


Brittany Grenus, DVM

WRITTEN BY

Brittany Grenus, DVM

Veterinarian

Dr. Brittany Grenus graduated from Tufts Cummings School of Veterinary Medicine in 2018 with her doctorate in veterinary medicine and a...


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