Is My Dog Reactive or Aggressive? How to Tell the Difference

Most people who ring me saying their dog is aggressive have a frightened dog on their hands. The barking, the lunging, the noise at the end of the lead. It sounds like intent. Then you meet the same dog off lead in a controlled setting and it sniffs another dog, gets bored and wanders off.

That gap matters. Leash reactivity and aggression need different plans, and treating one like the other will slow you right down.

What Does Leash Reactivity Actually Look Like?

Reactivity is emotional overflow. Your dog spots a trigger (another dog, a skateboard, a bin chicken) and the arousal races past what they can handle. There is no plan behind it.

The tells are loud and messy. The noise starts at distance, often before the other dog is anywhere near. The body is upright and busy, hackles up, weight bouncing forward and back. And once the trigger is gone, your dog resets reasonably fast, often shaking off and dropping their nose to the grass.

Reactive dogs usually want one of two things: more distance, or to get to the thing so badly they cannot cope with being held back. Fear and frustration look nearly identical from ten metres away.

What Does Real Aggression Look Like?

Aggression is quieter. It has intent behind it, so it does not need the noise.

Look for stillness before anything happens: a hard freeze, a locked stare, weight shifted forward, a low grumble that never builds into barking. The tension arrives before the display, not after it. An aggressive dog holds that tension long after the other dog has walked past, and takes a long time to settle.

These are not two neat boxes. A reactive dog that gets pushed over threshold week after week can learn that escalation works. That is exactly why reactivity is worth taking seriously early, while it is still just noise.

Why Does the Lead Make It Worse?

Restraint removes options. On lead your dog cannot create distance, cannot arc around the other dog, cannot do any of the polite things dogs do in open space. All they can do is go forward or make noise.

Then the lead tightens. Your tension travels down the lead, your dog feels it, they escalate, you tighten again. Plenty of dogs labelled dog aggressive are perfectly social off lead. The lead is the variable, not the dog.

What to Try Today

Find your dog's number. Take them somewhere you can see other dogs from a long way off, like the edge of an oval or a quiet park, and stand still. Keep backing up until your dog can look at the other dog and then look back at you. Mark that choice and feed it.

Whatever that distance is, write it down. If it is 40 metres today, you have a starting point and something to measure against next week. Most owners have never measured it, so they train too close and wonder why nothing sticks.

Reading the difference between reactivity and aggression properly takes eyes on your dog, not a blog post. If your dog is putting teeth on other dogs, on people, or on you, get help now rather than later. At Walkys Dog Training Academy we work through this in 1:1 sessions and group programs, so you get a plan built around your dog instead of guesswork.