Understanding fight-or-flight in dogs

When something startles or scares you, what’s your instinct? Do you flee as fast as your legs will carry you? Do you swing a punch before you can think twice? Or do you scream? These are all instinctive behaviors–and we all have different instinctive responses based on a variety of things like the environment, our histories, our neurochemical makeup, and so on.

Well, the same is true for our dogs. When faced with something scary, our dogs will all react instinctively in a way unique to them.

Let’s dig into this automatic response called fight-or-flight in dogs, starting with some basic definitions.

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What is fight or flight in dogs?

Anyone who has ever taken high school biology can probably give a pretty decent definition of the fight-or-flight response, something like: When frightened, most animals will either fight or flee.

But what does that really mean?

Here’s the dictionary.com definition: “the instinctive physiological response to a threatening situation, which readies one either to resist forcibly or to run away.”

Two key words here:

• instinctive: you don’t consciously control your response
• physiological: your body just jumps in and moves before your brain can override it

In other words, when your dog experiences fear, his or her body simply reacts without thought for self-preservation.

The fear can come from anything from the vacuum cleaner to another dog to physical threat and so on.

Regardless of what causes the fear, and regardless of whether or not your dog goes into fight or flight, it’s vital to realize your dog isn’t in control of this response and therefore should not be punished for it.

Gasp, what? Punished for being scared? We’ll get into this more in a minute, but think about how many people use punishment when a dog aggresses, even though we just established that it’s an instinctive physiological response to fear.

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Have you heard of fight, flight, freeze, and fawn?

Sometimes called the 4 F’s. I’ve also heard of 5 or 6 different F’s, including fight, flight, freeze, fawn, fine, and faint. In humans they’re often referred to as the trauma response.

Some responses more prevalent in other animals. Think of animals that play dead (my favorite: google the hognose snake) or find other ways to hide from predators (like ostriches).

Freezing and fawning do happen to our dogs, too.

If you see a dog freeze, his body tenses up and his muscles become tight. Dogs usually freeze to give themselves a second to then think and react. Fawning is fearful behavior that tries to appease the person scaring them. This is the dog who tucks his tail and turns over to show his belly. Fawning also includes behaviors like excessive licking or pawing.

Do certain dog breeds experience fight-or-flight more than others?

Socialization, training, environment, trauma experiences, and individual temperament are all likely more important than a specific breed when it comes to how a dog responds to fear.

This is purely anecdotal evidence, but over the years I’ve had three distinct pit-bull-type-mixes with three wildly different fear responses.

Emmett, who purportedly came from a potential abuse situation, was abandoned in the woods, then sheltered for almost two years before we adopted him, was afraid of nothing. Literally nothing. He never really exhibited a fear response because, well, he never seemed to get scared.

Cooper, who came to us at 8 weeks old and never had a bad experience in his life, was terrified of absolutely everything. His response was all fight. He’d launch up on his hind legs and bark and snarl his little face off.

Penny, who we’ve had for less than a year and is a huge mix of hound and pit bull from a hoarding situation, is also scared of lots and lots of things, but her instinct is to cower, to crouch low to the ground and skitter away as fast as she can.

Of course, this is a small sample size and is just a series of strung-together stories, but it’s important to realize that breed is less important than personality and life experience.

That said, according to some research, there are breeds more prone to stress, which can make them more sensitive to instinctive fight-or-flight responses since they’re already more tightly-wound.

A fascinating study from University of Helsinki looked at aggression in more than 13,000 pure bred dogs and concluded that age (older dogs), gender (male dogs), lifestyle factors (like if the dog was the owner’s first dog), and so on all had an impact, as did breed and body size (smaller dogs were more aggressive than medium and large dogs, but medium and large dogs were tied.) And, also, as we’ve been discussing, “Highly fearful dogs had over five times higher odds of aggressive behaviour than non-fearful dogs and moderately fearful dogs also had a higher odds of aggressive behaviour than non-fearful dogs.”

Is this a bad behavior?

Remember my earlier point? Punishing or “correcting” these responses simply doesn’t make sense because the reactions are instinctive and physiological and emerge as a response to fear.

Fear shouldn’t be punished or corrected.

Sadly, it happens all the time.

And does jerking, pinching, or shocking a dog stop that fearful, aggressive response? Of course not, and more often it results in an even bigger response from the dog.

This is why it’s so, so important to understand fight-or-flight in dogs.

Many dogs suffer needlessly because their people don’t understand that the behavior isn’t “bad” or even intentional. Instead of trying to figure out how to correct the fearful response, let’s instead change our mindset to: How can I help my dog process fear?

How do I get my dog out of fight or flight mode?

We understand if your dog is pancaking and trying to scurry away, she’s scared.

Hopefully by now we also understand that a dog lunging and barking and snapping is also scared.

So, what do you do?

Well, that’s where things start to become more complex. For some dogs, a little bit of time and exposure can help. Penny, for instance, started out terrified of the hallway between our kitchen and living room. We let it go without any direct intervention, and over the course of a few months, she overcame that fear all on her own.

Does that always happen?

Nope.

In fact, it usually takes a lot of direct intervention with a counter-conditioning program combined with positive reinforcement training to make headway with fear. It’s rarely ever quick and it’s almost never easy, as Cooper as this years-long vacuum story demonstrates.

And sometimes, despite all your best intentions and hard work, your dog might not ever overcome a specific fear. Then, it comes down to management.

Regardless, the best thing you can do if you see your dog going into a trauma response is to help him find a place to feel safe, give him lots of time (and possibly treats), and reassurance.

Then, once your pup is over the response, formulate a plan to work on whatever it was that scared your dog.

resources for when you need to formulate a plan:

Fired Up, Frantic, and Freaked Out

From Fearful to Fear Free: A Positive Program to Free Your Dog from Anxiety, Fears, and Phobias

Bark!: The Science of Helping Your Anxious, Fearful, or Reactive Dog <– I haven’t actually read this one yet because it just came out, but from all the reviews from people I respect and admire, I know it’s going to be good. Can’t wait to dig in!

Bottom line: Understanding fight-or-flight in dogs is VITAL for helping your dog live well

I’ve written about reactive dogs for many, many years. I’ll like a few posts below if you want to expand on that topic.

However, a recent conversation spurred me to write this post because it became clear to me that not everyone fully understands that reactive behavior is an unintentional, instinctive, physiological reaction to fear. We need to understand the why of our dog’s behavior before we can begin to attempt to change it. If we don’t know why our dog does something, we’re merely guessing at how to “fix” it, and in the case of fight-or-flight responses, our dogs pay the price as people try to punish the response out of them.

But… I’m curious…

Is your dog more prone to fight, flight, freeze, or fawn? Do you have a go-to strategy to help your pup emerge from this fear response? Let me know in the comments!

Read more posts about reactivity to dig more into that topic. Here are a few to get you started:

What I wish you knew about my reactive dog

Glacial progress adds up when training reactive dogs

Being responsible for a reactive dog

And here’s a free printable training tracker if you want to monitor your dog’s progress as you work through a behavior.

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If you enjoyed this post, you’ll probably enjoy my forthcoming book, For the Love of Dog, from Regalo Press in 2025. It’s chock full of the latest research in canine cognition combined with stories of my dogs to bring the data to life.

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