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A Dog's Fight or Flight and Other Stress Responses

When dogs are stressed, their bodies are bombarded with hormones and neurotransmitters that trigger what are known as the four F's of stress: the popular fight-or-flight response, and the less known fool around and freeze responses. Being aware of these responses and their effects on dogs is important, but equally important is managing the dog's environment so that he is prevented from experiencing these negative responses in the first place. Because yes, a little bit of stress is normal when coping with the ups and downs life randomly throws out at dogs, but too much stress, especially if it's the intense, recurrent type, can have an overall negative impact on a dog's health and overall well-being.

scared dog fight or flight

Stress Responses in Dogs

Just like us, when dogs are stressed, they release noradrenaline, adrenaline and cortisol. These neurotransmitters and hormones cause a variety of physiological changes meant to provide a quick boost of energy in hopes of getting the dog quickly out of trouble and up his chances of survival.

These are times where there is little time to think, as one must act quickly.

Physiological changes in stress responses in dogs include: increased heart rate and breathing rate, increased blood pressure, increased muscle tension and increased blood flow to muscles (allowing dogs to sprint into action), increased blood clotting (to prevent excessive blood loss), increased glucose levels (for a quick burst of energy), dilated pupils (to allow dogs to see with more clarity) and lowered threshold for aggression (caution, dogs may bite more easily when stressed!)

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Did you know? The fight and flight response was first described by American physiologist Walter Bradford Cannon in 1920. Canon also developed the concept of homeostasis from the earlier idea of Claude Bernard.

The Flight Response in Dogs 


As the term implies, this response depicts fleeing to avoid a threatening stimulus or event. It's avoidance behavior at best. Dogs may cower, move away, attempt to hide.

Examples include dogs hiding when a thunderstorm rolls in, moving away from a scary open umbrella, pulling on the leash to escape from something perceived as scary.

The flight response can be considered adaptive considering that fleeing can heighten the chances for an animal's survival, possibly preventing himself from sustaining injuries.

 "Fleeing is an excitatory response to fearful arousal that is typically elicited by high levels of fear or the close presence of an intrusive threat."~~Steve Lindsay


The Fight Response in Dogs 

As the term implies, this response depicts a defensive response from a dog who will use aggressive displays in hopes of removing the threatening stimulus.

Dogs may lunge, growl, snap and attempt to bite. Examples include dogs who snap when they are cornered, dogs who lunge at other other dogs, dogs who attack other animals they perceived as threatening.

The fight response is also adaptive considering that it may be used when the animal cannot escape a confrontation and is forced to protect himself.

"Fear elicited fighting occurs in situations involving intense fearful arousal and where flight is blocked by the threatening target."~Steve Lindsay

Freeze Response in Dogs


As the term implies, dogs will freeze when presented with a threatening stimulus or situation.

In dogs, we may see the freeze response when they stop doing things such as when they are reprimanded or stand motionless upon hearing a noise or noticing at a distance an animal or other stimulus that they may fear.

The freeze response is considered adaptive, considering that in the wild, upon spotting a threatening stimulus, remaining motionless allows the animal the opportunity to evaluate the situation and possibly, avoid detection from a predator considering that motion cues in a freezing animal are non-existent.

It's basically "playing 'possum" or in other words, feigning death.

"Freezing is an inhibitory response to fearful arousal that is typically elicited by low levels of stimulation or a distant threat."~Steve Lindsay

dog rolling after bath

Fool Around Response in Dogs

Sometimes, when dogs are under pressure, they may engage in behaviors that may seem out of context. 

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It's a similar reaction to coping mechanisms seen by some people who inappropriately tell a joke at a funeral.

In dogs, the fool around response includes acting plain silly such as jumping, performing play bows, playing and acting over the top at times when they are feeling stressed.

For instance, a dog at the vet's office who starts rolling on the ground or bites the leash in play, may be trying to transfer the focus off of one situation and onto another.

When dogs behave this way, their stress is often not identified as it's not straightforward as a dog who is shaking or growling. Some dogs are labeled just as acting plain silly, or worse, they are reprimanded for being stubborn.

" I don’t know how many dogs came into my office like bullet trains, and ricocheted around my office for a few minutes before they settled down. Their owners would often say “Oh, he’s so friendly” as they leaped on top of me, my desk and my computer. I always saw them as frantic, and was reminded of how I can begin chattering like a mockingbird when I’m nervous." ~Patricia McConnell

A Matter of Choices


What makes a dog choose to fight over flight or some other response? Interestingly, dogs don't always follow a distinct pattern when it comes to freezing, fleeing, fighting and fooling around.

There are specific circumstances that may play a role on whether a dog will be making a subconscious choice of one over the other.

These "chosen" survival reaction may therefore be based on the dog's overall health status, speed, temperament, memories of past experiences, availability of support etc.

For instance, a mother dog with puppies is more likely to engage in fight considering that flight is not an option because it would mean leaving her vulnerable altricial puppies on their own.

An older dog or an animal not feeling well, may as well choose fight rather than flight due to limited mobility or weakness.

Sometimes, breed can also play a role. Some breeds of dogs were selectively bred for having less or more resilience compared to others and their response to stress may reflect that. For instance, beagles may freeze almost to the point of catatonia; whereas, small terriers may respond to fear by barking and running around the fear-eliciting stimulus, explain Jon Bowen and Sarah Heath in the book "Behaviour Problems in Small Animals: Practical Advice for the Veterinary Team."

dog blanket sleep sick

What Happens After? 

It's the ultimate goal of the body to return to a state of normality, what is known as "homeostasis." After enduring an episode of acute stress, the dog's body will therefore work on reaching again a state of balance or equilibrium.

This is when the dog "shakes off" the stress so to relax tight muscles as his breathing rate gradually goes back to normal and his heart rate slows down.

After the fearful event is over, ideally, the dog's body should work to resume a state of normalcy where dogs will be willing to resume eating, drinking, sleeping and playing again and go on their lives (at least until another fear-eliciting episode takes place!)

However, what happens with dogs who are exposed to chronic stress? If the stress continues for some times, burnout may occur as the body starts getting exhausted and this can have negative effects on the body.

Intense and prolonged stress can affect the immune system and cause a host of problems such as skin disorders, digestive disorders and even shortened life spans, explains veterinary behaviorist Gary Landsberg.  

A dog's ability to learn is often affected and dogs may endure in disrupted sleep patterns. Some dogs remain in a perpetual state of hypervigilance and have a hard time relaxing even when nothing is happening. Because of these effects, it's important to reduce stress in dogs and enlist the help of a qualified professional before they become chronic.


  • Neurobiology of the Parental Brain, edited by Robert Bridges, Academic Press; 1 edition (July 29, 2008)
  • Handbook of Applied Dog Behavior and Training, Etiology and Assessment By Steve Lindsay, Iowa State University Press; Volume One edition (January 31, 2000)

Photo Credits:

  • Michael Gil, Discipline!, No Dogs were harmed in the taking of this picture! CCBY2.0

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