Discover Why Is Your Dog Wagging Tail In Sleep

dog wagging tail in sleep

Ever found your dog fast asleep while wagging its tail? You may be wondering why is your dog wagging tail in sleep? What’s that about? Is your dog asleep, or are they just faking it? Take a look.

If your dog is wagging their tail in their sleep, it means that they are deeply asleep and in their Rapid Eye Movement (REM) cycle. This crucial stage allows a dog’s body to properly rest and recover, much like we hear about with humans. It involves twitching and other involuntary movements, including yipping, paw twitching, and even changing facial expressions.

What is the connection between a dog’s tail wagging and REM sleep?

Since you’ve seen your dog snooze before with no wagging tail, you might be skeptical. It’s perfectly understandable. However, a wagging tail during sleep is a sign of the REM cycle!

Most humans won’t know that their dog can ag their tail in their sleep because most dogs get their REM cycle sleep while we are gone to work or asleep ourselves. What we witness is our dog’s lighter sleep cycles.

Dogs are naturally light sleepers, which is part of their pack mentality about always “having one eye open” for a threat. They must be thoroughly exhausted to drop into a REM cycle sleep while still, things are going on around them. 

If you notice your dog’s tail wagging while asleep, you’ve succeeded at wearing them out enough that they need to get some serious zzzzs. This is common after a fun walk in the park, a hike, or something that tires your dog out!

Is it normal for a dog to wag its tail while sleeping?

If you’ve never seen your dog wagging its tail while sleeping, you might be concerned — don’t be. While a wagging tail is undoubtedly a sign of REM sleep, there are others, as mentioned above. More common signs of REM sleep include:

  • Paw and leg twitching
  • Facial twitches and expressions
  • Ear twitching
  • Yipping or vocalizing

The odds are that you’ve seen one or more of these at some point in your dog’s life, right? You know how your dog always looks like it’s “running in its sleep”? It’s actually your dog’s REM cycle!

Can a dog wag its tail while dreaming?

Your dog’s REM cycle can often include dreaming, so tail wagging could be a blend of involuntary twitching as they sleep, and because they’re communicating in their dream with their tail, it’ll wag!

You’ll most likely notice that their dream tail wagging is nothing like their normal tail wagging when conscious, but this makes sense. Think about it from the perspective of humans. When humans move or talk in their sleep, their movements are half-relaxed, and their speech slurred. Since their body is physically relaxed, their actions aren’t quite as crisp. A dog’s wagging tail is the same.

In their dream, their dog is wagging their tail like normal. But in their actual body, their movements are slower and more subtle since they are physically relaxed.

Reasons for a dog to wag his tail while sleeping

Tail wagging during sleep is most commonly associated with REM sleep, as we’ve already talked about. However, there are other less common reasons for tail wagging. If you’re curious or concerned, here are the other factors to think about:

  • Dreaming
  • Cold
  • Seizure
  • Faking sleep


We’ve already talked about generally dreaming, but tail wagging in a dream can also help you understand whether your dog has a good dream or a nightmare! Slow wagging and facial twitching often mean that our dog has a pleasant dream. Perhaps one that involves treats and chasing squirrels.

If you notice that your dog is grumbling and their tail movements are sharper and crisper, they could be dealing with a nightmare instead. This is especially if they seem otherwise restless in their movements.

If they have a nightmare, you can wake them up by calling their name safely. While they still will startle awake, you can reassure them with some love and a treat, of course.

You can decide based on what you think is best for your dog’s comfort and stress levels.


Sometimes a dog will wag their tail and twitch if they are cold while asleep. This is especially if they are spawled out rather than curled in a ball to keep their warmth close. You can safely cover your dog with a blanket if you want to, though they may wake up in the process.

If they are doing this often, you might want to consider looking at a new dog bed that helps reserve their warmth or move it closer to a heat source!


If a dog is having a seizure, you’ll notice vibrations rather than wagging. Their limbs will be stiff, their ears will be up, and they even might have their eyes open. If you notice a vibrating tail with that other kind of body language, you’ll want to get them to a vet as soon as possible so that they can assess what’s going on!

It could be an underlying cognition, but it also can be a sign of poisoning or other serious, emergency health problems.

Faking sleep

Yes, seriously! Sometimes dogs will fake sleep, but you can tell by their wagging tail. Why are they faking sleep? Because they think it’s fun and it’ll mot often get them nice positive words and an ear scratch or two.

This isn’t as common as the other options, of course, since dogs will get so excited about “faking sleep so well” that they’ll give themselves away and simply get up to go and find you. You have to admit, it’s rather cute.

Is my dog pretending to sleep or trying to sleep?

When your dog seems to pretend to sleep, it could be that they’re also trying to get to sleep, but they’re getting distracted. A dog lying on their bed and slumbering but wagging their tail when you call their name would be the prime example. They hear you and acknowledge you but don’t necessarily get up to respond. 

Think of it as the human equivalent of “Busy, talk later.” If you call them again, they usually will get up and come and find you, but it’s something to take note of if you don’t need anything from them. After all, you’d hate it too if they woke you up for no reason just when they were settling into a nice nap!

All in all

It’s pretty interesting to learn that dogs have a REM sleep cycle. It’s even more interesting that wagging tails can play a factor in that sleep cycle!

Dogs will often wag their tail, amongst moving other body parts, as part of their REM, or deep sleep, cycle. Occasionally, tail wagging in their sleep can be a sign of dreaming or a seizure and occasionally mean that they aren’t actually sleeping at all! Learn the signs of each to help you understand just what your dog is up to!

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Andre Neves

Hi, I'm Andre and I'm the owner of Sula the Border Collie. I love writing about this amazing dog breed here. I joined the Council to be able to reach and educate more people on the joy of having a pet dog.