Dog Wagging Tail In Sleep – [4 Possible Reasons & Considerations]

You have just finished your work and suddenly notice your dog curled up in a corner. It looks so peaceful while sleeping. You take out your phone to record a video of your dog when you see your dog wagging tail in sleep. Now you must be wondering why it is wagging its tail in sleep. Is it normal? That is where we come in handy.

There is a common misconception that if a dog is wagging its tail, it must be happy. While it is true in some cases, but it is not the only reason. Unlike humans, dogs cannot talk. And they communicate with us by wagging their tails. Here, we will guide you through why dogs wag their tail and what you can do about it.

Dog Wagging Tail In SleeP

Dog Wagging Tail In Sleep – Everything You Need To Know

Dog Wagging Tail In Sleep - Everything You Need To Know

Dogs love to sleep. Similar to humans, they also dream while sleeping. Maybe they are dreaming about getting extra treats or playing all day with a ball.

Why Does A Dog Wag It’s Tail In Sleep?

Why Does A Dog Wag It's Tail In Sleep

One of the best ways a dog can communicate is by wagging its tail. A dog tries to convey its message with its body language by wagging its tails. A wag of tail works well for dogs. As they are more dependent on vision, dogs can discern various types of tail wags.

According to scientists, evolution development has made dog’s tails more visible and thus enhancing their communication. Wagging a tail is like making a facial expression. Just like our facial expression does not always reflect what we are truly feeling. Similarly, a wag of tail can mean different things. A swinging tail acts as an indicator of a dog’s mood.

Dogs wag their tails when they are in a deep sleep. In their deepest stage of sleep, they experience “Rapid Eye Movement” (REM). Humans also show this type of behavior.

We dream during REM sleep, and similar to us dogs also dream during this deepest stage of sleep. Often in these times, dogs show many dreams like behavior which also includes wagging their tails. Wagging a tail while sleeping means experiencing fear, happiness, anxiety, or others; they are just acting upon it.

Reason 1 – Curiosity

If the tail’s position is straight and rigid, it means your dog is curious about something. Perhaps it is dreaming about chasing a butterfly, and all its attention is on the butterfly. It is focused, and its attention is high, eagerly waiting for the next move of its opponent’s move. When dogs identify prey, they point at them with their paws, and their tails become erect and high.

This tendency can be found even in humans. Humans also move their ears in the speaker’s direction when they try to listen to something carefully. Dogs will imitate what they do in the daytime when sleeping, especially if they have been trained to do these things.

Reason 2 – Submissive

Normally a dog keeps its tail in a neutral position. It is neither high nor long. But if you notice that your dog has moved its tail from neutral to a lower position. This might indicate that your dog is submissive and definitely not a threat.

When a dog sees something as a threat, it either lowers its tail position to act submissive or keeps its tail tucked between rear legs to indicate that it is scared. This also means he is surrendering and asking not to be attacked or harmed in any way.

Dogs lower their tail while being submissive is because this position reduces the scent coming from the anal glans and permits the dogs to stay hidden. If you notice your dog’s tail is lower than usual in sleep, it probably dreams of a hostile environment or recalling some past similar experience.

Reason 3 – Happiness

Your dog is swinging its tail energetically most likely means it is excited or it is greeting you in a friendly way. When you come home after a long day of work or if you give your dog its favorite treat, one thing you will notice is that it is moving its tail rapidly from back and forth to this side to that side.

If it is really exciting, it will even form a circle trying to chase its tail. An energetic wagging of the tail just means your dog is really content, and it cannot contain its happiness. Your dog swinging its tail in sleep can mean it is really happy to see you and greet you. Or perhaps, your dog is dreaming about a delicious meal it had for dinner.

Reason 4 – Aggression

A wagging tail moving from the neutral position to arching vertically over the back can indicate that your dog is aggressive. The higher it moves up its tail, the bigger the threat. When a dog’s tail is in a high position, it releases more of its scent from its anal glands. Thus, indicating the dog is marking its territory and is ready to attack if someone crosses the line.

If you notice your dog’s tail is way up than usual, it is probably experiencing some sort of nightmare. Remember, do not wake your dog while it is experiencing a nightmare. When you wake your dog up from a nightmare, just like us, it will not realize it was dreaming. And they can react aggressively and can even bite you.

What Can You Do?

Dreams are still a mystery to us. Scientists could not decipher why we dream or what is the reason behind our dreams. Same with dogs, we cannot be truly sure if they are dreaming or not. But we can guess if they are dreaming by their tail position and directions.

If you notice similar positions stated above in your dog, do not wake them up. If your dog is enjoying a good dream, let your pup enjoy it. Your dog can eat all the extra treats in its dream. But if you are suspecting your dog is having a nightmare because of its sleeping positions that indicates aggression, fear.

Naturally, you would want to wake them. Do not try to wake them from their nightmares. Dogs get aggressive if you wake them up from their sleep. When your dog suddenly gets up from its sleep, it can be scared, and it will take a few moments to realize that it was dreaming. Just like us, they take a moment to adjust.

But waking up your dog suddenly, especially from a nightmare, can have seriously damaging consequences. Even the gentlest dog can bite out of fear if you wake them up suddenly. If you see your dog is in distress while sleeping, wait for it to wake up. And once it wakes up, you can comfort it.

Another thing you can do is, create a cozy, warm sleeping place for your dog. Unhygienic, dark areas are prone to giving more nightmares.

Your Dog’s Sleeping Positions And Habits Tell A Lot About Them

Your Dog's Sleeping Positions And Habits Tell A Lot About Them

A dog’s sleeping position and habits are a window into the dog’s personality. It tells us if they prefer lying around or if they snore, how much time they spend sleeping, and many other things. Following are a few of the most typical dog sleeping postures and their explanations –


This means that dogs are very comfortable in their relationships and also that they like staying near their human (or another dog). These dogs get along very well with humans and can be stuck up.

On Their Side

This is the most comfortable position for lying down and sleeping for your dog. Additionally, it is a positive indication that your dog is comfortable among people.

Paws Up In The Air

This position is a sure sign of your dog’s insecurity or aggression towards his human and other dogs. In this position, your dog is showing off his strength or may be trying to intimidate others.

Sprawled Out on The Tummy

This position is indicative of lazy and sloth-like dogs. The dog was probably allowed to lounge around too much or is recovering from surgery.

Curled Up

Dogs in this position are usually showing love and affection to your family. In certain situations, these dogs may also be nervous or insecure in their environment.

Dogs Wag Their Tail During The REM Sleep Cycle

Dogs Wag Their Tail During The REM Sleep Cycle

When they are in REM sleep, dogs often wag their tails while they are sleeping. Dogs sleep deeply during this period of their sleep cycle. While they are comfortable and content, or when they are dreaming, dogs will wag their tails.

Your dog’s brain is very active in this REM sleep cycle, and the tail wagging that occurs during this period of sleep may be a way for your dog to alert you to what he or she is dreaming.

For example, if you are a frequent visitor to your neighbors and you take your dog along with you, your dog might be dreaming of greeting their neighbor. Your dog might also be dreaming about doing some fun activities with the family and will wag his or her tail while he or she is asleep.

Final Words

Dogs express their feelings by wagging their tails and other body movements. It is similar to our facial expressions. During sleep, our facial expressions change depending on the context of the dream. Similarly, dogs try to communicate with their body movements.

Dogs spend 10% of their sleeping time in the REM stage of sleep. In this stage, dreams can occur. Whether your dog is having a good dream or a nightmare, do not disturb them. Let your dog fight its own battle in its dreamland.

Now that you know what the movement of a dog’s tail might indicate, next time your dog is asleep, pay attention. Who knows, you might be able to interpret what the dream is about! I hope now you understand what to do when your dog wagging tail in sleep.


1.Do Dogs Wag Their Tail If They Are Happy?

Ans: According to studies, dogs wag their tails in the right direction if they are excited or happy, and they shift it to the left if they feel scared.

The scientific reason behind this is that the left side of the brain is known for controlling the movement of the right side of the body and the right side of the brain does the opposite of that.

2.Should I Wake Up My Dog From Its Sleep?

Ans: If you see your dog is in distress, even though it is tempting but do not disturb them. Disturbing dogs while sleeping can lead to serious consequences. Wait for it to wake up. Once it wakes up, then you can comfort it.

3.Why Does My Dog Wag Its Tail Frequently In Its Sleep?

Ans: Dogs, particularly puppies and elder dogs, wag their tails during REM sleep. This indicates that your dog is in the deepest stage of sleep and probably dreaming of something.

4.Why Does My Dog Wag His Tail When He Sleeps?

Ans: During deep sleep, your dog may exhibit twitching, wagging, leg kicks, and faint barks or moans. These actions indicate that your dog is sleeping well and deeply. For instance, puppies and older dogs tend to move more often as they sleep.

5.Do Breed And Age Affect How Dogs Dream?

Ans: Yes, age and breed have an impact on a dog’s dreaming. Dogs who have been bred for guarding, hunting, or herding show more activity during sleep in the part of their brain that regulates those activities. It is possible that dogs who are bred to have low energy levels, like terriers, show less brain activity during sleep.

Age also has an impact on a dog’s dreaming. Older dogs have been shown to have more intense and vivid dreams than young dogs.

6.Why Do Dogs Wag Their Tails In Their Sleep?

Ans: While it’s not completely understood. Many people believe that dogs wag their tails in their sleep because they are trying to communicate with their owners. Some scientists even hypothesize that tail wagging is a communication between humans and canines akin to sign language.

The process by which this occurs is still largely unknown. But it seems likely that when dogs feel secure and content within the family unit, they will subconsciously signal this through the movement of their tail. This may help reassure the owner or calm them down if they agitate or are nervous.

Leave a Comment