Your dog lunges at other dogs on the lead

The scene is familiar: a dog that is perfectly calm at home spots another dog in the street and turns into a mess of barking, a taut lead and disapproving looks from strangers. The first thing to understand is that in the overwhelming majority of cases this is not about dominance, not about a bad character, and not about something you did wrong. It is a reaction to not being able to increase distance.

Why specifically on the lead

An off-lead dog meeting another has choices: curve around, look away, move off, sniff the ground and pretend nothing happened. These are the normal signals dogs use to avoid conflict. On a lead all of those options disappear.

• The lead prevents curving around — and curving is exactly how dogs greet each other without tension.
• The dog is attached to a person who tends to walk straight at the other dog. A head-on approach is already a challenge in dog language.
• A tight lead physically changes posture: head up, body leaning forward. From the side that reads as a threat, and the other dog responds accordingly.
• Your tension transmits instantly. You spotted a dog in the distance, held your breath and shortened the lead — and your dog already knows something bad is coming.

Hence the paradox that confuses owners: off lead, or in a play group, the very same dog may get on with others perfectly well. The problem is not other dogs, it is the situation.

The first step everyone skips: pain and equipment

Before tackling behaviour, rule out physical causes. A dog in pain reacts more sharply to everything — that covers hidden joint problems, teeth and ears alike.

• Reactivity appearing suddenly in a previously calm dog is a reason to see a vet, not to look for a trainer.
• A collar that presses on the throat when the lead goes tight adds discomfort at exactly the moment of arousal. A harness is nearly always better from that point of view.
• A retractable lead makes everything worse: it teaches pulling, gives no close control, and snaps taut when the dog lunges. A plain lead of moderate length is far more manageable.
• Badly fitted equipment rubs — and the dog associates the pain with the moment another dog appears.

Distance is the main and almost the only tool

The key concept is the distance at which your dog can still hear you. Closer than that it is no longer learning, will not take treats and does not respond to its name: the brain is busy elsewhere. All the work consists of staying just beyond that line and gradually shrinking it.

1. 1Find your distance. Walk your dog and notice at what range it will still take food from your hand and can look away. That is your working point — often further than you would guess: twenty, thirty, sometimes fifty metres.
2. 2Work only at that distance. When another dog appears, stop or move so that you stay beyond the line.
3. 3The moment your dog notices the other and stays calm, praise and give something good immediately. You are paying for the calm glance, not for a command.
4. 4Repeat many times across many walks. The goal is for another dog appearing to start meaning "something tasty is coming" rather than "something frightening is coming".
5. 5Shrink the distance slowly, a metre at a time, and only once the current one has been stable for several days running.

What to do once the dog has already gone off

The moment your dog is barking, straining and not hearing you is not a teaching moment. There is one job here: get out of the situation with minimum damage.

1. 1Turn around without speaking and walk away. Do not yank — move steadily and confidently, with constant pressure on the lead rather than jerks.
2. 2Increase the distance until the dog can hear you again. Only then say anything.
3. 3Let it sniff the ground. Scent work physiologically lowers arousal faster than any command.
4. 4Do not immediately return along the same route. Give it a few minutes for the arousal to drop.

Bear in mind that after a big reaction a dog stays aroused for a long time — hours, sometimes the rest of the day. So two difficult encounters in a row do far more harm than one. On a bad day it is better to cut the walk short and go somewhere empty.

What you must not do

• Do not punish the barking. The dog is barking out of fear; punishment adds fear and removes the warning — next time it may go straight to a bite with no bark at all.
• Do not force them to "meet and make friends". A head-on introduction on tight leads is the worst possible format, and it is how most fights start.
• Do not shout. Your shouting during arousal merges with the barking and amplifies it.
• Do not jerk the lead or use equipment that causes pain. It may suppress the barking, but it leaves the cause intact — and adds pain to an existing fear of other dogs.
• Do not stand there apologising to the other owner instead of simply moving away. Distance first, conversation afterwards.

How long it takes and what progress looks like

Honestly: months, not weeks. And progress is not linear — there will be days when everything slides back after one bad encounter. That is normal and does not mean you are doing it wrong.

• The first real sign of improvement is not silence but faster recovery. The dog reacted, but settled in thirty seconds instead of five minutes.
• The second is the dog choosing to look away from the other dog and back at you. That is the most valuable thing that can happen.
• The third is the working distance gradually shrinking.
• Keep short notes: date, place, distance, how it went. Progress in this is visible over a month, not in your memory of yesterday.

When to get a professional involved

Get a trainer or behaviour specialist involved if the reaction is directed at people or children, if the dog has already bitten, if you physically cannot hold it, or if several months of work have produced no movement at all. Choose someone who works with rewards and does not offer to "put the dog in its place" — with fear, methods built on suppression buy a short-term effect and long-term consequences.

One piece of context worth knowing: reactivity is more common in shelter dogs, and the reason is straightforward. Life in a kennel means constantly watching other dogs without ever being able to interact with them normally. That is neither a verdict nor a character trait: with calm distance work these dogs change like any others, they simply need a bit more time and predictability.