How to Train a Reactive Dog

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Shell & Katy Updated 21 April 2023 · 8 Min Read

Shell & Katy are two style-savvy dog mums celebrating the best in pet-friendly living. A pet photographer and dog lifestyle writer, together they share trending pet products, recipes, inspiration and expert tips with discerning dog lovers around the world.

Knowing how to train a reactive dog starts with understanding why the reaction is happening in the first place, and that is rarely what owners assume. This question came to us from a Pretty Fluffy reader:

"Do you have any training advice for reactive dogs? My nearly 10 year old cavoodle has become dog reactive after a bad experience in a doggy daycare. Before this happened she was so lovely to all dogs. Now it's random, one dog will go past and she's ok. But the next dog that walks by, she just loses it!"

If you can relate, the good news is that it is never too late to start. To answer this properly we asked our resident expert, Sydney-based dog behaviourist Sophia Gillis, who has spent over 13 years working with dogs as a behaviourist, veterinary nurse and practice manager. Everything below is hers.

What Is a Reactive Dog?

The term reactive is quite broad, and it doesn't necessarily mean a dog is aggressive or bites. It means being overly stimulated by something and responding in an exaggerated way. A reactive dog is simply one who responds negatively to a noise, a person or another dog. That could look like growling, raised hackles, barking, snarling and lunging forward, and at the far end of the scale, biting.

Reactivity sits on a scale. A dog who barks at runners in the park and a dog who lunges at every passing stranger are both reactive, but they need very different amounts of help.

What Causes Dog Reactivity

Reactivity usually has more than one cause. These are the ones that come up again and again in my consultations:

• Fear, anxiety or frustration in particular situations
• Not being exposed to a wide enough variety of animals, people, weather, locations and noises
• Missing proper, controlled socialization during the critical window of 3 to 16 weeks
• A lack of structure or training from a young age, leaving boundaries and expectations unclear
• Genetics, since some dogs have a much stronger guarding or herding disposition
• Previous trauma or abuse
• A combination of all of the above

There is also a factor almost nobody accounts for: stress accumulates. A dog who coped with the vacuum this morning and a visitor at lunch has spent her reserves, and the fourth small event tips her over. Stress hormones take hours, sometimes days, to clear, so a dog who has had a hard week needs a quiet one. I see the same pattern in small breeds who get labelled aggressive.

Why Is My Dog Getting More Reactive?

This may come as a surprise, but when a dog's behavior deteriorates over time, it is very often shaped by how we respond to it. If you are not responding in a way that helps your dog build a more positive association with the thing they find frightening, the behavior repeats and worsens. Every reaction your dog rehearses makes the next one more likely, which is why training a reactive dog early matters so much.

Why Dogs Lunge and Bark on Leash

This is the one I explain most often in behavioral consultations. If little Otis is as sweet as pie everywhere else and only loses it on a leashed walk, the explanation is simple: his fight, flight or freeze instinct has kicked in.

The Fight, Flight or Freeze Response in Dogs

These are the same innate fear responses we experience in a confronting situation, and in dogs they show up like this:

• Fight: barking, lunging, growling, snarling
• Flight: creeping away, running, trying to hide, cowering
• Freeze: holding completely still, or moving extremely slowly

Here is why the leash matters. If your dog feels threatened, their instinct is to create distance, and that isn't possible when they are tethered to you. So in your dog's eyes, what choice is left? Take a stand. This isn't a real fight stance, though. All your dog is doing by barking and lunging is putting on a brave face and telling the threat to stay away.

Fear drives far more of this than owners realize, and VCA Animal Hospitals notes that a dog who lunges at a threat may look offensive while actually being very fearful. Having a leash-reactive dog does not mean you should start walking your dog off leash. If your dog also refuses to walk or freezes mid-walk, that is the flight or freeze end of the same response.

Reactive vs Aggressive Dogs

Plainly put, you can use either word. One just sounds a lot less negative than the other. Reactivity runs from low to high. A dog barking at passing strangers from your house is reactive. A dog categorized as aggressive by a professional has moved into real aggression, where they attempt to cause injury as a fear response.

My humble opinion? Let's be a little kinder with the words we use to describe frightened and damaged dogs, especially those who experienced trauma through no fault of their own.

Reactive Dog Training Tips From a Behaviorist

Living with a reactive dog can be challenging and upsetting, but with buckets of patience and the right techniques it is possible to help your dog. Effective dog training for reactive dogs is not one exercise, it is a sequence. These are the steps I work through with clients, in order.

1. Identify the trigger and the distance

Before you train anything, get specific. What sets your dog off: other dogs, men in hats, bikes, only off-leash dogs? How close does the trigger have to be? Are there locations where it's worse? Write it down for a week. That distance figure is the most useful number you will collect, because everything else is built on it.

2. Keep your dog under threshold

Every reactive dog has a threshold: the point where the trigger tips them from aware into unable to cope. Below it, your dog notices the trigger but can still hear you and take a treat. Above it, they cannot, and calling their name will not land.

All useful training happens below that line. If your dog's threshold is a trigger half a street away, that is where you work, closing the gap gradually over weeks. Learning to read your dog's body language is not optional here. A fixated stare, raised hackles, a stiff body pointed at the trigger, or frantic back-and-forth movements all mean you are too close.

3. Manage the environment while you train

Management is not training, but training fails without it. While you work, prevent as many over-threshold encounters as you reasonably can: walk at quieter hours, drive somewhere open, block window access at home, or swap a walk for enrichment on a bad day. A well-fitted harness that gives you real control also changes how confident you feel, and your dog reads that.

4. Change the association, not just the behavior

Positively reinforcing the behavior you want is the best way to train any dog. Reward calm, focused behavior with their favorite treats, praise and toys. But with reactivity you are doing something deeper than teaching a cue. You are changing how your dog feels.

The simplest version: at a distance where your dog can see the trigger without reacting, the moment they notice it, start feeding something excellent. Stop the second the trigger goes. Your dog learns that other dogs make chicken appear. You will know it is working when they spot a dog and turn to you expectantly instead of tensing up. The same principle works on a dog who barks at everyone passing the house.

Do this with rewards, not corrections. Aversive tools suppress the outward behavior without changing the fear underneath it, and the American Veterinary Society of Animal Behavior advises against them for exactly that reason.

5. Teach your dog to wear a muzzle

Depending on the severity, this may be necessary. Dogs who have swung toward the aggressive end of reactive should never be off leash around dogs or people they don't know. Keeping them on leash is crucial for their safety and everyone else's. Introduce a muzzle slowly and pair it with food long before you ever need it, so it never becomes a punishment.

6. When to hire a dog trainer for a reactive dog

Look for a dog trainer for reactive dogs who is qualified and force-free, and who can recreate safe scenarios to help your dog build confidence. Controlled socialization is a good example, where a calm space is created for your dog under strict supervision with someone experienced ready to step in.

Get help sooner rather than later if your dog has bitten or come close, if reactions are escalating, or if weeks of work have brought no progress. A trainer can run a full behavioral consultation to find the underlying cause and build a tailored plan. Methods vary, so if you haven't found someone you and your dog are both comfortable with, keep looking.

Can a Reactive Dog Be Trained?

Yes, though it helps to be precise about what success looks like. Reactivity isn't a disease, so it can't be cured as such. It is a behavior that can be modified and reduced to the point of good management.

In practice that means a dog who notices another dog across the road and keeps walking, not a dog who has never felt anything about other dogs at all. Progress is measured in small wins: eating treats on a walk, checking in unprompted, one lap of the block with no reactions. It takes time, patience and consistency, but you can absolutely get there together.

Whether it's reactivity you're dealing with or another concerning behavior, you'll find more expert training advice on Pretty Fluffy, including Sophia's guide to resource guarding in dogs, plus our tips to stop leash pulling, teach your dog not to jump on everyone, and stop puppy jumping and biting.