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Why does my dog growl when I wake him up?

Why does my dog growl when I wake him up?

Dogs are like humans in that each reacts differently to different stimuli. For instance, if there are three people sleeping in a room, and you awaken each one of them, you will witness three different reactions. Dogs are the same way.

Some wake up jolly. Others awaken in a ‘still sleepy’ haze. Some awaken feeling grumpy, and some wake up exhibiting dangerous aggression. “Let sleeping dogs lie.” It’s an old piece of folk wisdom, and wisdom it is.

Why does my dog growl when I wake him up?

If your dog growls when you wake him up, it can be due to various reasons from just not wanting to be bothered to suffering from cognitive dysfunction. Let’s look at a few possible causes.


Like humans, dogs need and enjoy their rest. Also, like humans, they do not like to have that rest disturbed and can react in ugly ways when awakened.

Interruption of Nightmares

Dogs have nightmares just like humans do. When we awaken them in the middle of a nightmare, it can leave them in a temporary state of distorted reality, like a drunken haze. In this state, they may not realize what they are doing for a moment or two.


If you startle your dog, this could be why he growls. I mean, no one likes to be taken by surprise that way.

Anxiety and Protection

He may feel anxious, even threatened. He may have a negative association with darkness or nighttime that causes him to think territorially or defensively. The trouble is that when he feels this way, he may act aggressively.

Vision Loss

Dogs can begin to experience a decline in eyesight as they age. This can also occur due to infections, hereditary disorders, or glaucoma, which can eventually lead to blindness.

Your dog can go on the offense at night due to no being able to see well to evaluate a threat. Signs of vision loss can include disorientation, clumsiness, and confusion in new places.

Hearing Loss

With a dog’s age can also come hearing loss. Partial or complete hearing loss can be temporary, or it can be permanent. It can also be caused by infections, inflammation, waxy build-up, or tumors.

Your dog may be aggressive at night because he doesn’t hear you come upon him, and he gets startled by your touch. The sign of hearing loss will be his lack of response to calling his name, commands, the clapping of hands, and other noises.


Some pharmaceuticals can cause issues in dogs. Medications like MAOIs, antipsychotics, and antidepressants that are prescribed for behavioral issues can actually cause aggression or seizures.


Serotonin helps regulate the sleep cycle and emotions. It is a neurotransmitter that, when not functioning correctly, can interrupt, and in some cases reverse, the sleep/wake cycle, in which case the dog will sleep during the day and be awake all night.

Neurological Disorders

Dogs can develop cognitive dysfunction or dementia as they get older. Just as in humans, they can fail to recognize their environment and the people in it, and their sleep cycles can become interrupted.

Signs of a cognitive issue may be aimless wandering, increased vocalization, staring for long periods, changes in appetite, and disorientation.

Why does my dog growl at me when he wakes up?

When you wake up your dog, and he growls at you, it leaves you wondering what you did to provoke him. Well the answer is probably that you did nothing. If it isn’t one of the issues above, it could be:

REM Sleep Behavior Disorder

Humans and dogs experience REM sleep. When you or your dog are in REM sleep, your brains are very active. You will often see movements of the legs or hear noises, but they will be small ones in a normal dog.

This is because motor neurons are paralyzed by part of the brain stem, preventing dogs from actually doing what they see themselves doing in their dreams.

For whatever reason, in dogs with REM sleep behavior disorder, the motor neurons are not paralyzed, and the limb activity during REM sleep is violent, along with possible howling, growling, chewing, biting, or barking.

This happens at night but can also happen during daytime naps. It has nothing to do with their actual surroundings but is hallucinatory.

It is not unheard of for dogs with this illness to run into walls and attack people. These dogs need to sleep in a separate space, in a well-padded, confined area, like a crate.

This will go a long way toward protecting not only your family, but your dog. Your veterinarian may also be able to prescribe medications that can help manages REM sleep behavior disorder.

Seizure Disorder

If your dog growls at you when you wake him up, he may have a seizure disorder. When a dog has a seizure disorder, he cannot be awakened easily, like dreaming dogs.

It isn’t too hard to differentiate between a REM sleep behavioral disorder and a seizure disorder, because dogs having a seizure are non-responsive.

After a seizure, a dog is usually disoriented. Look for panting and drooling. Dogs in a seizure may “go to the bathroom” one or both ways during a seizure, and dreaming dogs will not.

A vet can prescribe anti-seizure medications like Phenobarbital if your dog meets the criteria.

Why do dogs get aggressive when sleepy?

Why do you get aggressive when you’re sleepy? Dogs get tired and irritated, too. When he’s had a full morning, and he’s ready for his afternoon nap, but you want to go to Aunt Edna’s, don’t blame him for getting a little grumpy. Wouldn’t you?

What to do about my dog being aggressive when tired?

Now, you want to know what to do about your dog’s aggression when tired. Here are a few tips.

Never punish him.

Never punish a dog for being aggressive when tired or when awakened. It may be something they cannot even control, and you can make matters even worse.

For instance, if you punish your dog for growling, he may forego the warning altogether and bite without warning.

Provide safe space.

Provide him with a safe sleeping space. Make sure it is away from everything so that nothing and no one can brush up against him and startle him in the night.

Make everyone aware.

Make sure everyone that comes around is aware of your dog’s condition, especially children.

Take him to a vet or a veterinary behaviorist.

No matter what your dog’s problem is, your vet or veterinary behaviorist can help you figure out the best course of action.