Reactivity vs Aggression: Understanding the Difference

For many, a dog barking and lunging looks like the dog is being aggressive, but there’s a difference between a reactive dog and one that’s truly aggressive. Reactivity is about overreactions; aggression is about intent.

A reactive dog is responding to something that feels too big or too close, and they’re trying to increase distance or regain control. Their behaviour might look aggressive, but their goal isn’t to cause harm, it’s to make the situation stop or make the trigger move away.

Aggression, on the other hand, involves a willingness to inflict harm. True aggression is far less common than people think, and many dogs labelled “aggressive” are actually reactive.

That said, care must always be taken with reactive dogs, even if you don’t think they intend to harm. A scared dog may not set out to bite, but if they feel cornered, trapped, or ignored, they may lash out as a last resort.

What Reactivity Looks Like

Reactivity often shows up as:

• Barking, lunging or growling on lead

• Over-focusing or fixating on another dog or person

• Pulling hard towards or away from a trigger

• Shaking, panting, pacing, or whining after an incident

These dogs are not “naughty” or “dominant”, they are normally overwhelmed. It’s like you shouting at someone when they have startled you; it’s an instinctive reaction, not a planned one.

What Aggression Looks Like

Aggression tends to involve a clear intent to threaten, injure or control a situation through force. It may include:

• A confident, stiff, focused body posture before an outburst

• A growl or snarl used to make another back off

• A bite (or attempt to bite) with the aim to make contact

• Quick recovery after the incident

Where a reactive dog often wants the scary thing to go away, an aggressive dog may want to move towards it to assert control or eliminate a perceived threat.

When the Two Overlap

The line between reactivity and aggression isn’t always black and white. A reactive dog who repeatedly feels unsafe and isn’t supported to cope, can eventually cross the threshold into aggressive behaviour. That doesn’t mean they’ve “turned bad”, it means their coping system has shifted and they feel less safe.

Why Understanding the Difference Matters

When we mislabel reactivity as aggression, we risk taking the wrong approach to working through the problem behaviour. A dog acting out of fear or frustration needs to feel safer and learn emotional regulation. By recognising what’s really driving the behaviour, we can work on changing the dog’s emotions which are driving the behaviour.

Moving Forward

If your dog barks, lunges, or growls, it doesn’t always mean they’re dangerous, it often means they’re struggling. With the right approach, they can absolutely learn new ways to cope.

Understanding the difference between reactivity and aggression isn’t just about labels, it’s about empathy. If you’re unsure where your dog fits or how to help them, I offer one-to-one behaviour support to assess what’s really going on and create a plan that builds calm, confidence and trust.