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Definitive Guide: What Is Dog Reactivity?

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David Adams

November 30, 2022

Dog Reactivity

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* All Sniffspot articles are reviewed by certified trainers for quality, please see bottom of article for details *

Do you have a reactive dog or suspect you may have one? You’re not alone!

Reactivity is common in dogs. Your dog barking, growling, lunging, or otherwise acting “out of control” on walks or out in public can feel embarrassing — but it’s important to remember that your pup is having a hard time, not trying to give you a hard time.

Sniffspot is committed to providing reactive dog guardians with safe spaces for off-leash exercise as well as up-to-date, trustworthy resources on how to help your sensitive dog feel better about the world around them (and therefore act better, too, in a way that enables you to enjoy more experiences together).

In this guide, we’ll go over what dog reactivity is and isn’t, what causes reactivity, and what to do if your dog is showing signs of reactivity.

What is reactivity in a pet dog?

The American Kennel Club defines reactive dogs as “[dogs] that overreact to certain things or situations.” This means that a dog’s reaction to a certain stimulus is excessive or out of proportion with the situation.

Reactivity generally encompasses a range of undesirable aggressive or defensive behaviors (barking, growling, lunging, jumping, pulling, and so on) in situations that typically don’t warrant them in our minds (triggers are behaving normally in a non threatening way) but that are overwhelming or scary to our dogs.

Reactivity is very common: Our own research shows that 75% of dog owners say they have a dog that shows some signs of reactivity.

What causes dog reactivity?

According to the AKC, “genetics, lack of proper socialization, or a combination of the two can cause reactivity.”

Nature and nurture both play a role in dog reactivity

The “nature versus nurture” debate is at play here. It’s tough to determine what is caused by genetics and what is caused by your dog’s environment, lack of socialization, or potentially traumatic past experiences.

For example, if a dog is born to a mother who is reactive to certain stimuli, he will likely become reactive to the same stimuli. However, it’s difficult to say whether this is straightforward genetics, or whether the dog learned this behavior as a puppy by watching his mother. In a puppy’s early life, especially the first twelve weeks, socialization is critical. If a dog is not properly socialized during this time and is observing a parent with reactive behavior, she might become reactive.

Applied animal behaviorist and author Patricia McConnell writes that dog reactivity can be caused by caused by psychological trauma and compares reactivity to soldiers with PTSD: “Just as a veteran soldier with PTSD can react to a loud noise by throwing herself to the ground, dogs with their alarm systems fixed on HIGH are usually quick to startle to an abrupt noise, or panic when unfamiliar dogs appear.”

The general consensus is that genetics may play a part in dog reactivity — and it’s also likely a conditioned behavioral response. In pet dogs, aggressive behavior on leash can usually be identified as either fear-based leash reactivity or frustration-based leash reactivity.

Fear-based dog reactivity

Fear-based dog reactivity is often caused when nervous or uncertain dogs feel trapped in a certain situation. This causes them to display defensive behaviors that can sometimes be interpreted as aggression (even though the root cause is feeling unsafe).

You can read more about fear aggression in this guide.

Frustration-based leash reactivity

Frustration-based leash reactivity, on the other hand, stems from a dog wanting to interact with something (a person, another dog, an item) that they can’t.

This is common in social dogs who regularly visit dog parks or attend daycare. They love other pets and get frustrated when they aren’t allowed to greet them! That frustration (especially when being held back on a leash) can quickly build into a reactive display. If your dog’s reactivity is limited to when they’re tethered, this article talks about fixing leash reactivity or leash aggression specifically.

Are certain breeds or types of dogs more likely to be reactive?

The answer is tricky. Some breeds have been bred for specific purposes, such as hunting or herding, and this can influence their behavior.

In addition, over the years, different dog breeds have been maligned for alleged tendencies toward reactivity or aggression (think of all the negative press about Pit Bulls, an umbrella term used for an entire group of different breeds, over the last couple of decades). However, there is no scientific evidence that suggests this is true the way mainstream media often portrays it.

Let’s take a deeper look into dog breed and reactivity.

Some breeds have innate instincts that can be linked to reactivity

We bred certain traits into dog breeds over generations and generations. Two examples: Herders are hyper-aware of their surroundings, and terriers have an intense desire to chase prey. So if your Cattle Dog is barking at quick-moving objects or your Jack Russell keeps lunging after rabbits, there’s a chance their reactivity is caused by unmet genetic drives rather than a lack of socialization! (You can read more about training a herding breed specifically in this article.)

Other dogs are just prone to overarousal, independent of breed

Some dogs also struggle with general overarousal even if they aren’t acting on specific breed traits. If your pet can’t seem to settle down even in familiar environments, triggers out in the world can be like the straw that broke the camel’s back — the final stimulus that puts them all the way over their threshold (which is low already) even though the problem is bigger than that one thing.

Any dog breed can become fearful or frustrated

As mentioned above, much pet dog reactivity can be classified as either fear or frustration based.

In an article about leash reactivity (dogs who are reactive while they are on a leash), Sue Brown, MNM, CDBC, CPDT-KA, states “you cannot predict which dogs will be reactive simply by looking at their breed.” She adds that she is not aware of any studies that look at this question.

While more research is needed, it is likely that a dog’s environment and socialization, not breed, are the key factors in reactivity.

What is not dog reactivity?

It can be tough to know what is and is not reactivity. Remember the definition of reactivity: Dogs that overreact to certain things or situations. To be considered reactive, your dog needs to have certain triggers that are consistent over time — the same stimulus provokes a reaction.

Basically: Your puppy who woofs once or twice when startled? They wouldn’t be diagnosed with reactivity. One who barks, growls, and lunges at every other dog they see out on a walk, on the other hand? They would be considered reactive.

Below are a few behaviors that are not reactivity but are commonly confused with it.

Rough play

Though rough play can sometimes seem scary — especially if it’s particularly vocal — it’s a normal part of dog interaction. As long as the play is reciprocal (both parties are into it) and each dog takes turns, there’s no cause for concern.

Puppy nipping

Puppies use their mouths to explore. This often involves nipping, especially during play. While this can be annoying or painful, it is not reactivity. Biting is a normal puppy behavior!

What’s more: Remember that puppyhood can be a tumultuous time. Most trainers would not consider any puppy to be properly reactive until they were several months of age and showing more consistent responses to the world around them.

Resource guarding

Dogs will sometimes guard things that are of value to them, such as food (commonly called “food aggression”), bones, or sleeping areas. This may come with behaviors such as growling or snapping and can thus sometimes be erroneously called reactivity.

However, resource guarding is considered a normal behavior for dogs. It absolutely needs to be managed so that it does not escalate to aggression toward the people living in the house with the dog — there are ways to work through it! — but protecting possessions is a normal canine instinct. In general, resource guarding is not considered a reactive behavior.

Barking or whining when separated from you

This is more accurately classified as “separation anxiety,” not reactivity. You can learn more about separation anxiety in this article and anxiety in general in this one!

A dog barks at his home's front gate, possibly experiencing isolation or separation anxiety

How do I know if my dog is reactive?

Do you think your dog is “aggressive” or notice that they bark, lunge, or have other extreme responses to certain stimuli? You might have a reactive dog.

Look for signs of reactivity


Excessive barking, growling, and whining can be common signs of a reactive dog. For example, does your dog bark for what feels like a long time when he hears a skateboard go by or when the mail carrier comes to the door?

Body language

Body language is also an indicator. Keep an eye on your dog’s body language in different situations. (You can read more about your dog’s body language in this article.)

Notice if your dog shows any signs of anxiety or stress. Some clear indicators could be trying to flee from a stimulus or deciding to charge and lunge at the trigger in hopes of making it go away.

A dog who exhibits stress signals is not automatically a reactive dog — it depends on the exact circumstances. This can be a tricky distinction, but try to determine if the reaction seems like “too much” for the situation. More on this below!

Intensity of reaction

As we mentioned, remember that not all barking or nervous body language is necessarily dog reactivity. It’s natural for our pets to respond to the world around them! Occasional vocalizations or even larger episodes in particularly scary situations (like being startled by an off-leash dog) can be completely normal depending on your dog’s breed and baseline temperament.

What’s important to think about is if your dog’s reaction seems to match the situation at hand or if it seems over the top. If you try to keep your dog from ever barking again, you’re setting yourself up to fail. It’s a natural canine behavior!

If your dog is continually set off by “small” or common things in the environment, though, then it’s definitely worth considering if they have a form of reactivity and how you can help them feel better about the world.

For example: If your dog exhibits stressed body language when cornered by a wild animal, or if they bark a few times when startled by a small child sprinting at them, that reaction is proportional. If your dog is cowering in fear when the cat walks by, though, or freaking out at the mere sight of a stranger down the street, your dog might be reactive. They are having an intense reaction to something that is not actually a danger to them.

Get in touch with a trainer

When in doubt about whether or not your dog’s behavior is considered canine reactivity, get in touch with a professional trainer. They’ll be able to use their years of experience and continuing education to accurately diagnose — and then help you treat — whatever is going on with your pup.

What should I do if my dog is showing signs of reactivity?

How to train through your dog’s reactivity is a huge topic. We’ve put together a separate beginner’s guide with everything you need to know to get started! Below are the key points to keep in mind.

Try to remain calm

First things first: Don’t panic!

As we stated above, many people live with reactive dogs. You can live a full life with a reactive dog — and your reactive dog can have a full life, too.

Figure out what causes your dog’s reactivity

Understand your dog’s triggers and emotions

Spend some time thinking about why your dog barks, growls, and lunges at certain things. Really observe your dog. When are they calm and showing relaxed behavior? When are they reactive? Your pup may have a trigger that’s obvious (mail carriers, people with beards, etc) or it may be harder to spot. (Maybe she wildly barks sometimes and you don’t know why — in this case, try your best to listen, watch and get to the root of it.)

Questions to ask yourself about your dog’s reactivity

  • In what situations is your dog most likely to react? Does a trigger have to be moving in a certain way (directly approaching versus passing on the other side of the street, for example)?
  • How close does a trigger need to be before your dog barks, lunges, growls, or otherwise reacts at it? This is referred to as their threshold distance. If the trigger is farther away than this limit, they’re under threshold and able to take treats normally, sniff the environment, and respond to you with loose body language. Once it breaks their “bubble,” they go into a panicked fight-or-flight mode.
  • Is your dog’s reactivity limited to when they’re on a leash, or does it happen regardless of where they are (loose in the yard, in your home, etc)?
  • Is your dog a social butterfly with their triggers outside of a certain context, or do they always react?
  • Does your dog seem afraid or merely over aroused?

Pay attention to your dog’s body language

As mentioned in the above section on how to know if your dog is reactive, watch for signs of stress in your pup, such as lip licking, facial tension, whale eye (when a dog turns their head but keeps their eyes on you, showing a lot of the whites of their eyes), shaking, or freezing. If you notice your dog showing these signs, note the situation and environment and see if you can get to the bottom of what’s causing them. (You may have to do this several times to be able to notice a pattern.)

You might never have clear answers about what causes your dog’s reactivity

Understanding the root cause of your dog’s reactivity can be difficult — and maybe even impossible for some pets. It’s worth spending some time thinking about it, but don’t dwell if you (or even your trainer, a behavior professional) can’t fully figure it out. Try to make peace with the ambiguity and commit to treating your dog’s behavior.

Meet your dog’s basic needs and keep tabs on their health

It’s always a good idea to evaluate your reactive dog’s basic needs before focusing on specific training situations. Even if your dog’s reactivity is driven by more than a treatable health or fulfillment problem, making sure their needs are met will still help you maximize your training success.

Physical health problems can exacerbate reactivity

Canines are great at hiding discomfort. If your dog is reacting when being touched by people or playing with other dogs — especially if they’re suddenly sensitive in situations they used to tolerate well — there’s a good chance they’re in pain.

Provide enrichment to help fulfill your dog

At its simplest, enrichment provides animals with opportunities to satisfy their innate instincts. Common enrichment activities usually give our dogs the chance to safely dig, sniff, and emulate their predatory behavior sequence (searching, stalking, chasing, fighting, celebrating, and consuming) without causing harm to or disrupting the communities we live in.

You can read more in our Comprehensive Guide to Canine Enrichment article. Get their brains going!

Take care of yourself as your dog’s guardian, too

Living with a reactive dog can be overwhelming — and there’s no shame in admitting that. It’s okay if you’re tired. It’s okay if you miss a training session here and there. It’s okay if you sometimes feel jealous of other dogs and owners who don’t have to worry about the things you’re constantly keeping track of.

Take time to practice self care. You have to fill your own cup before you’re able to give your dog what they need! There will inevitably be setbacks in training your reactive dog — but together you can create more positive associations, as long as you show yourself grace.

Use management strategies to prevent reactive behavior while you work on training your dog

Management is an important part of helping your reactive dog. The more frequently your pet practices their undesirable behaviors in a heightened emotional state, the deeper they ingrain those habits. It’s important to prevent as many reactions as possible so your training can be successful!

Once you know your dog’s triggers, the good news is that you can manage them (to some degree). Take note of everything in and around your home that you can control. Get creative with your dog’s environment to minimize what triggers them.

Just a few management examples to minimize your dog’s exposure to triggers:

  • Carefully consider when you go to an environment and whether it will be too busy for your reactive dog to feel comfortable. It's smart to avoid places with many off-leash dogs, young kids, or other common triggers, especially early on in your reactivity training plan.
  • Put on white noise for dogs who bark when they hear a car or person outside.
  • Cover your windows with film or close the blinds to prevent your dog from barking at triggers outside your living room or office windows throughout the day. You can also use household objects as visual barriers.
  • Drive to a quieter walking route rather than trying to stay in your immediate neighborhood if it’s too overwhelming.
  • Don’t feel guilty about turning around when you see a trigger if you aren’t prepared to train through it. Remember management is your friend!
A reactive dog wears a muzzle as a humane management technique

When management fails, get out of the situation

If you are surprised by a trigger, try to get out of the situation as gracefully as possible. For example, if you are surprised by another dog on a walk and your dog is reactive to other dogs, this might look like making a u-turn or crossing the street. Your exact exit strategy will be different depending what the trigger is.

The important things to remember are that you want to get away from the trigger safely and you do not want to punish your dog (more on that below).

If your dog does react, remember it can take a long time for their nervous system to completely recover. Take it easy for the next few days and up your management game!

Start tackling specific reactivity scenarios

We’ve covered a lot of reactivity treatment foundations. Now for the nitty gritty: What does the actual training to address your dog’s reactivity look like? There are a range of training techniques, methods, and set ups to help your reactive dog feel calmer around their triggers. Most of them involve creating neutral or positive experiences to change their underlying emotions. This process is called behavior modification or behavior rehabilitation.

We’ve compiled a full list in this reactivity training article with comprehensive steps to follow, but below are two key concepts to understand.


Desensitization involves getting our dogs used to their triggers slowly, in small doses that don’t put them over threshold. While it can be difficult to implement in the “real world” (public environments are often unpredictable and we can’t always decide how far away our dogs are from their triggers) it’s a valuable technique in controlled situations. Distance, intensity and duration matter. 

According to the VCA, desensitization means “the gradual exposure to situations or stimuli that would bring on the undesirable behavior, but at a level so low that there is no negative response.” Desensitization and counterconditioning go hand in hand. 


Counter conditioning (CC) is your best friend when you have a reactive dog. What is it? Counter conditioning means “changing the pet’s emotional response, feelings or attitude toward a stimulus,” according to the VCA. 

Counter conditioning is the process of pairing something scary or overwhelming (your reactive dog’s triggers) with something positive (like their favorite treats or toys) to ultimately change their conditioned emotional response over time. CC can be incredibly helpful when working with reactive dogs — but it’s important to be aware of your timing! If you feed your dog before they notice their trigger, you might accidentally teach them that “good things predict scary things” instead of the other way around. You also have to keep up CC consistently or undesirable emotions (and their associated behaviors) can return. 

What counter conditioning might look like in practice

Here are a few steps to begin counterconditioning your dog’s triggers. First, you’ll need lots of high value treats. Take your dog (and your treats) to an area with the dog’s trigger (or where the trigger is likely to appear). Once the trigger appears and the dog clocks it (e.g. you can see the dog observing the trigger, but not yet reacting to it), begin generously rewarding the dog with the high value treats.

An example: perhaps you’re out on a walk with a dog who is reactive to skateboards. You hear a skateboard in the distance, and see your dog’s ears prick up, observing the sound. Now is a great time to reward the dog with the high value treats. The goal here is to change the dog’s association from “skateboarders = bad and scary” to “skateboarders = treats are coming.” 

The process will look different depending on the dog’s triggers, but that is the basic idea. It is very important to start small and go slowly. As with any training process, counterconditioning is likely to take a while, and you will have to do it multiple times across many different sessions. Be patient and celebrate victories, even if they seem small!

What not to do if you have a reactive dog

You should never punish your dog for reactivity. Many people are tempted to do this in an attempt to “correct” the behavior — but dog trainers agree it only makes things worse in the long run. It can instill more fear in your dog and does not deal with the root of their reactivity.

Though it can be difficult to resist the urge to punish in the moment, keep in mind that positive reinforcement is a much more effective strategy. Punishment will only degrade your relationship with your dog.

Further reading and learning

There are countless great resources for how to live with and train a reactive dog! Here are a few that we like.

Sniffspot blogs on canine reactivity

We have an entire blog category devoted to dog reactivity and related problem or unwanted behaviors. One of our primary goals is to be a welcoming community for reactive dogs — that’s why we have specific rules (like gaps between arrivals and transparency about other animals within view) to keep all Sniffpots safe.

Here are a few specific articles:

Other training resources on dog reactivity

Good luck, and remember: you’re not alone. When in doubt, get in touch with a professional force free trainer you trust. And know you can always bring your dog to a Sniffspot for some playtime!

Trainer Review of this Article

There is so much misinformation out there, we want to make sure we only provide the highest quality information to our community. We have all of our articles reviewed by qualified, positive-only trainers.  

This is the trainer that reviewed this article:

Shannon Finch
AnimalKind Training
M.Ed. Humane Education
Karen Pryor Academy Certified Training Partner
Certified Tellington TTouch and TTEAM Practitioner

David Adams photo

David Adams

November 30, 2022

Dog Reactivity

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