He growls, stiffens, reacts (reactivity)
Your dog growls, freezes, barks or lunges towards a trigger? That is emotion spilling over, not defiance and not nastiness. Never punish the growl: it is his only warning before a bite. Rule out pain with your vet first, then work below his tolerance threshold, at a distance big enough for him to stay calm.
Reactive is not the same as aggressive
A reactive dog reacts strongly to a trigger (another dog, a passer-by, a motorbike): he barks, pulls, stiffens. He is not trying to hurt anyone, it is an overflow coming out. The most common cause is fear: the dog has discovered that barking or threatening makes the thing that worries him back off, and since it works every time, he does it again. Then comes frustration (on the lead, he can neither go and see nor move away, so the tension builds), and pain. Most so-called “aggressive” dogs are in fact frightened dogs bluffing to be left alone.
Working below the reaction threshold
Bring the emotion down, do not correct it: everything hinges on the right distance, with a trigger you control.
Find his threshold
His threshold is the distance at which he can see the trigger but is still able to eat, look at you and walk on. As long as he takes the treat, you are at the right distance. Work with a trigger you control, such as a friend and their calm dog stationed at a distance of your choosing, never chance encounters forced on you at the street corner.
Always keep a margin
Too close, and he tips over. Back away with calm steps, keeping your dog close to you, widen the angle, change the rhythm, without bolting or yanking the lead. Moving away before the explosion is not weakness, it is what stops him escalating.
Pair the trigger with something good
The moment he spots the other dog or the person, say a short, happy word, a cheerful “yes!” that announces “that's good, the reward is coming”, then give a high-value treat. Little by little, the trigger comes to announce good news instead of danger.
Keep moving, do not freeze
In movement, most of the tension drops away. Walk on at the same pace, without staring at the trigger or snapping the lead tight.
Keep a plan B
If he escalates anyway, turn calmly, move away, and start again further off. A reaction is not naughtiness to be punished, it is the sign that you were too close, too fast. And if you cannot manage that distance, or if the reactions are already well established, this is the moment to call a professional rather than pushing on alone.
Keep the lead loose in all circumstances, not only when another dog crosses your path: a lead that goes tight passes on your tension and “confirms” to your dog that there is danger. Keep a soft hand, and take distance in advance rather than pulling. A 5-metre long line gives the movement and the options that a short lead rules out.
Passing head-on on the lead
- A head-on pass is a risky situation: two dogs head to head, a posture close to a fighting stance.
- Walk on and widen the angle, letting your dog move aside himself if he needs to.
- If the pavement is too narrow to step aside, cross the road, turn back, or position yourself between your dog and the other one to screen him.
- If he is only reactive on the lead but relaxed off it, it is frustration: give him enough chances to meet other dogs off-lead for that frustration to settle.
The postman rings at the door
- Keep the dog indoors, never alone on guard at the gate: left alone at the fence, he learns that shouting is enough to drive the stranger away, and that feeds his reactivity.
- You are the one who deals with it: you go out, take the parcel, come back in, then have a bit of play. The doorbell becomes good news.
- Now and then, ask someone close to you to ring instead of letting themselves in with their keys: the bell then also gets linked to someone he loves.
He growls at a guest who is already inside
- Do not punish him: by growling at your guest, he is saying he needs space. Punishing him in front of the guest only adds stress to an already tense scene.
- Call him calmly away, into another room or onto his bed, or keep him on a long line indoors to avoid any contact he has not chosen.
- Ask your guest to ignore him: no outstretched hand, no staring, no approach. It is up to the dog to decide whether he comes to the guest, never the other way round.
- If it happens at every visit, get support: it is one of the most common reasons owners consult a behaviourist.
He stiffens over his bowl or his toy
- First, listen to the warning: the moment he guards and growls, do not approach, let him finish in peace, and never take anything back from him by force. Forcing an approach is exactly what creates the defensive bite.
- Keep everyone at a distance: move children and other pets away, and wait until he has let go of his own accord before picking anything up.
- If he freezes, bares his teeth or has already nipped to guard something, resource guarding is well established: this is a job for a professional, do not improvise any exercise yourself.
- For prevention only, when things are calm: if your dog is relaxed and does not care about the object, teach him the swap at a distance. You walk past without stopping, you drop something better on the floor, you move away. Your passing announces a bonus, never a loss.
There is a child around
- Never let a child eat, run or shout next to a dog who is eating or holding a toy, nor lean over him or hug him.
- Always supervise dog and child moments, even with a dog you know well: it is the lack of supervision, not the dog's nastiness, that comes up most often in these bites.
The kit that helps (and the kit that makes it worse)
Before you head out to work with your dog, get what you need ready.
0 / 4When to hand over to a professional
You can carry on at home
- The reaction stays moderate: he tenses up, he barks, but he recovers quickly as soon as you put distance back in.
- You can read his threshold and keep a margin before he explodes.
- No bite, no hard nip, and the vet has ruled out pain.
Get support
- If he has already bitten or nipped, or if he reacts with no warning signal at all, see a professional quickly: do not let the situation settle in.
- The reactivity is intense, daily, or turns into panic.
- There are children at home, or you feel out of your depth: a trainer or a veterinary behaviourist using positive methods takes over.
- While you wait for the appointment, cut down the chances of a reaction: avoid the situations that make him explode, keep your distance, and be especially careful with children at home (never alone with him, no access to his bowl or his toys while he is eating or chewing).
- AVSAB — Position Statement on Humane Dog Training (2021)
- Herron, Shofer & Reisner — Survey of the use and outcome of confrontational and non-confrontational training methods (2009)
- Ziv — The effects of using aversive training methods in dogs: a review (2017)
- Vieira de Castro A. C. et coll. — Does training method matter? Evidence for the negative impact of aversive-based methods on companion dog welfare, PLOS ONE (2020)
- China, Mills & Cooper — Efficacy of dog training with and without remote electronic collars (2020)
- Reisner I. R., Shofer F. S. & Nance M. L. — Behavioral assessment of child-directed canine aggression, Injury Prevention (2007)
- WSAVA Global Pain Council — Guidelines for the recognition, assessment and treatment of pain (2022)
Going further
Frequently asked questions
Why does my dog growl?
Growling is communicating, not being nasty: your dog is saying “I need space”. Behind it there is often fear, discomfort, a resource to protect or pain. Do not punish him, it is his warning before the bite. If the growl is new, or appears when you touch him, start with the vet to rule out pain.
Why does a dog growl at a person?
Most often out of fear, or because he feels trapped and pushed to his limit: a stranger leaning over him, staring at him or stroking him against his will. Sometimes it is to guard his bowl or a toy, or because he is in pain. He warns before he bites. Give him distance and never force contact on him.
How do you calm an aggressive dog?
In the moment: add distance, walk on calmly without staring or yanking the lead, and do not shout. Underneath, you do not “calm” him, you teach him again below the threshold: as soon as he spots the trigger without panicking, mark it with a “yes!” and reward him, so that the trigger becomes good news. Rule out pain first, and get support if the reaction is marked.
What should you do when faced with an aggressive dog?
If it is a dog you do not know coming towards you, become “a tree”: stay still, arms folded in front of you and hands together, do not shout, do not run, do not stare at him, look away, then move off slowly. Panicked running and shouting wind the dog up. If it is your own dog, it is distance, calm, zero aversives, and the help of a professional using positive methods.
Is my dog aggressive or just reactive?
Reactive means reacting strongly (barking, pulling, stiffening), often out of fear or frustration, with no intent to hurt. Aggressive means trying to push something away through threat or a bite. Most dogs labelled “aggressive” are frightened dogs who have learned that threatening makes things back off. In both cases, you work below the threshold, never with a tool or a method that hurts.
My dog has suddenly become aggressive, why?
A genuinely sudden change points first to pain or illness: head to the vet first. Otherwise, the small early signs (stiffness, avoidance, little growls) had often been there for a while, without you seeing them. Then you go back to working below the threshold, rewarding calm, never punishing.
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