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Help, My Dog Is Aggressive When Woken Up

Adrienne is a certified dog trainer and former veterinarian assistant who partners with some of the best veterinarians worldwide.

Dogs acting aggressively upon being woken up often react very quickly and without much thinking involved.

Dogs acting aggressively upon being woken up often react very quickly and without much thinking involved.

Sleep Startle Reflex in Dogs

A dog acting aggressively when woken up is something concerning considering the potential for injuries. Although this type of aggression may occur only occasionally, it's an insidious form of aggression because it often occurs without much warning.

Most dogs in an awakened state will try to inform their owners about a situation that is making them uncomfortable. Dogs will typically use their words (growl, bark) and body language (lip licks, yawning, turned head) to inform owners to stop what they are doing and allude to the potential for a bite if their pleads are not taken seriously into consideration.

Startled Reflex to Attack

Dogs acting aggressively upon being woken up often react very quickly and without much thinking involved. They may skip the warning signs they would normally give when in an awakened state. The reaction occurs as a startle response, with the aggressive display appearing almost reflexive.

Owners of such dogs must use the utmost caution, especially if there are children living in the home. Children should be told not to approach when the dog is sleeping. This rule actually applies to all dogs, as dogs who are startled from sleep may bite as a defense mechanism. This is a survival mechanism. As the saying goes, "let a sleeping dog lie."

Dogs exhibiting aggression upon being woken up should be kept in enclosures (crate, x-pen, behind a baby gate in a quiet room where nobody will disturb) during their naps to prevent mishaps.

A Variety of Causes

There can be various causes as to why a dog may act aggressively upon being woken up. If your dog is aggressive when woken up, please seek help from a professional. Start by consulting with your veterinarian.

There are chances this behavior may stem from a medical or neurological issue. Once medical issues have been ruled out, the next step may be consulting with a dog behavior professional such as a veterinary behaviorist (DACVB) or a Certified Applied Animal Behaviorist (CAAB).

Many dogs yawn when startled upon being woken up.

Many dogs yawn when startled upon being woken up.

How Dogs React to Being Awakened

As mentioned, there can be various causes as to why a dog may act aggressively upon being woken up. There is a thin line separating a normal startle response from other situations stemming from behavioral issues, sleep disorders, and neurological issues.

Let's face it: Nobody likes to be awakened from a deep sleep, and that applies to humans as well. However, reactions vary from one individual and another. Some just roll over or turn to the other side, while others may vocalize a response. Among dogs, there may also be a variety of responses based on their individual temperaments.

Minor Startling Reactions

Ideally, a dog awakened by its owner accidentally brushing against his fur may not care or may wake up, lift his head to look around, or just go back to sleep. Many dogs sleep by their owners' feet on purpose so as to be awakened by their owners' movements and stay informed about their whereabouts.

Some dogs may lightly startle upon being woken up, but their startle responses don't involve aggression. The dog may perhaps yawn (not because he's tired but more because he got startled) and then go back to sleep.

Of course, not all dogs react in the same way, and the same dogs may react differently in different situations. For instance, a dog may react aggressively if he was having a bad dream or if he was suddenly startled by a noise he doesn't recognize.

More Significant Reactions

Some dogs may be just grumpy when awakened from napping, and any touch may evoke an episode of growling or snarling. While these dogs may "use their words," there is always a risk for escalation and a potential bite. Some dogs may lead highly stressful lives and may be in deep need of restorative sleep. Living on edge like this makes them startle easily.

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Serious Startle Reactions

Some dogs may act aggressively and go straight to a bite, skipping all the warning signs. These dogs may be startled to such an extent that there is no thinking involved. Obviously, this is a very dangerous situation. All it takes is for the dog owner to accidentally touch the dog for the dog to react quickly and very aggressively.

This form of startle response may be due to behavioral issues but may also stem from medical and neurological issues, and therefore, requires a close evaluation by a veterinarian and/or veterinary behaviorist.

Now, something worth noting is that just because some dogs react this way, it doesn't necessarily mean that they are aggressive dogs. These dogs may be wonderful, sweet dogs when awake. It's just that they may react out of confusion sometimes. Many of these sweet dogs act almost confused and then apologetic once they realize they are in familiar surroundings with their loving owners.

Also, something important and worthy of pointing out is that dogs who react when woken up should never be punished. Firstly, it would be totally unfair to punish these dogs for something they can’t control. Secondly, punishment comes with side effects and only convinces the dog that bad things happen when woken up from sleep. This will only make matters worse.

Dogs may react in various ways upon awakening.

Dogs may react in various ways upon awakening.

Why Is My Dog Aggressive Upon Being Woken Up?

As seen, dogs may react in various ways upon awakening. If your dog is acting aggressively upon being woken up, there may be several dynamics going on.

Important differentials include resource guarding, behavioral issues, sleep disorders, and neurological issues just to name a few. A thorough evaluation and assessment by a veterinarian and/or veterinary behaviorist is a must.

Interruption of Dreaming

Dogs, just as humans, dream. These dreams are not always pleasant, and it can easily happen that their bad dreams may carry on when awakened suddenly. This sudden awakening may cause dogs to distort reality and exhibit decreased impulse control, and possibly aggression, albeit temporarily.

General treatment: As in other cases, avoid waking up your dog when sleeping.

Resource Guarding

Dogs that resource guard sleeping areas typically exhibit aggressive behaviors when dog owners approach them while resting in their sleeping spots, which are highly regarded as valuable places. The aggressive behavior is, therefore, contingent upon the owners approaching rather than upon the dog being awakened.

This behavior has nothing to do with "dominance," the affected dog is just anxious and worried about losing access to his beloved resting place.

General treatment: Seek the aid of a dog behavior professional for safety and correct implementation of desensitization and counter-conditioning exercises for dog resource guarding. The goal is to condition your dog to expect good things when you approach him while he's in his favorite sleeping spot.

Excessive Startle Responses

Some dogs will act aggressively and go straight to a bite, skipping all the warning signs when they are suddenly awakened. These dogs may be startled to such an extent that there is no thinking involved. Obviously, this is a very dangerous situation. All it takes is for the dog owner to accidentally touch the dog for the dog to react quickly and very aggressively.

These dogs are fast to react by biting. This form of impulsivity is often seen in dogs with an underlying pathology such as anxiety. The dog is overreactive due to feeling threatened at a deep level. These are often dogs who are overly anxious and act first and think later. Rather than seeking out more information from their environment which can help them calm down, these dogs react in a way that actually fuels their anxiety.

These dogs may overreact and show disproportionate impulse-based reactions by barking at minimal noises and even at their owners approaching in the dark. They do so without thinking—they just automatically assume that their life is in danger, but they may approach on offense rather than defense.

In some cases, dogs have stopped giving warning signals because they have been punished for exhibiting warning signals in the past. For example, dog owners who punish dogs for growling risk ending up with a dog who bites without warning.

Affected dogs require a thorough examination as they may be suffering from something similar to post-traumatic stress seen in humans, neurological issues, dysregulated sympathetic circuits, heart arrhythmias, etc.

General treatment: This form of startle response requires a close evaluation by a veterinarian or veterinary behaviorist. It is best to keep these dogs in an area away from the chaos (in a crate, x-pen or behind a baby gate) so they don't get bumped by accident by well-meaning owners.

Behavior modification for mild cases may entail tossing the dog a treat every time he is awakened, starting at first with a very light touch done with a long target stick for safety. The goal is to create a positive conditioned emotional response (+CER) upon being touched and awakened from sleep. Obviously, due to safety, this should be only done under the guidance of a dog behavior professional.

Sensory Decline

Worth mentioning is that sometimes dogs who react aggressively upon being awakened are dogs who have lost their sense of hearing. These dogs may get startled upon being woken up in the same fashion as sneaking behind a deaf person.

General treatment: Owners of deaf dogs may be advised to provide their dogs with separate sleeping areas, and for mild cases only, (with the help of a professional) the implementation of exercises meant to reduce startling should the dog need to be woken up.

REM Behavior Disorder

REM behavior disorder is a condition that occurs during a phase of sleep known as REM (Rapid Eye Movement). When dogs with this disorder attack, they do so not intently as part of their brain is turned off.

Here's a brief rundown of what happens. When dogs are in the REM stage of sleep, which is the stage where dreaming takes place, their brain is in a very active state. This is often when you will see dogs moving their legs, vocalizing and moving their ears and tails as if they are really chasing rabbits in their sleep.

While it's true that dogs move during this stage, they can do so only up to a certain extent. A special region of the dog's brain stem paralyzes motor neurons to prevent dogs from getting up and running around "acting out" their dreams.

Now, for some reason, in some dogs, the paralysis of motor neurons during the REM stage of sleep fails to work. The end result is violent motor activity during the REM stage of sleep. There are reports of dogs with this condition who end up running into walls and even bite and attack objects or people around them. Obviously, this puts the dog at risk and puts others around the dog at risk.

General treatment: Affected dogs should be placed during sleep in a confined, well-padded area, such as a crate to prevent any injury to themselves and others around them. Additionally, veterinarians may prescribe medications.

Possible Seizure Disorder

Sometimes, what looks like a dog acting aggressively upon being woken up is actually a dog suffering from a seizure.

One important aspect that helps differentiate a seizure from behavior issues is that dogs having seizures are not responsive and, therefore, you cannot wake them up during a seizure.

General treatment: For seizure disorders, a veterinarian may prescribe anti-seizure medications such as phenobarbital if they occur at a certain frequency.

Preventing Sleep Aggression Issues

The saying "let sleeping dogs lie" offers a world of wisdom when it comes to preventing sleep aggression issues in dogs. Steven Lindsay in the Handbook of Applied Dog Behavior and Training, Procedures and Protocols explains how autoprotective aggression associated with sleeping and resting areas may be triggered by the reactive arousal stemming from being awakened repeatedly.

Soon, a negative emotional response becomes contextualized which is associated with the context of sleeping, and the person startling the dog and waking him up.

Lindsay explains that this could be the making of a dog who exhibits explosive aggression when resting in response to minimal provocation.

So always best to practice caution and let Rover enjoy his restorative REM sleep and catch some zzzs in peace.

Why It's Best to Let Sleeping Dogs Lie

Why It's Best to Let Sleeping Dogs Lie

This article is accurate and true to the best of the author’s knowledge. It is not meant to substitute for diagnosis, prognosis, treatment, prescription, or formal and individualized advice from a veterinary medical professional. Animals exhibiting signs and symptoms of distress should be seen by a veterinarian immediately.

© 2019 Adrienne Farricelli


Peghysue on July 25, 2019:

Thank you for information on various topics

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