What Causes Dog Reactivity?

When we talk about reactive behaviour, it’s easy to focus on what we see — the barking, lunging, growling, or sudden outbursts. But these behaviours are really just the symptoms. The cause lies deeper, in the dog’s emotional state.

Reactivity isn’t about a “bad” dog or a disobedient one. It’s a dog who’s struggling to cope with a situation and using the only communication tools they feel they have at that moment. Here are the four core reactivity types, the emotional roots that commonly drive reactive behaviour.

Fear-Based Reactivity:

Fear is one of the most common reasons dogs become reactive.

A dog who feels unsure, threatened, or overwhelmed may bark or lunge to increase distance or keep the trigger away.

Frustration Reactivity:

This happens when a dog wants to access something but can’t.

Leads, fences, gates, and other barriers create restriction, tension and prevent natural movement or communication. Other dogs or people not engaging in or stopping play interactions or other forms of interaction can also lead to a frustrated response. When frustration peaks, the dog may jump, growl, bark, lunge, or bite because what they need in that moment is not happening or not happening quick enough.

Guarding Reactivity:

Some dogs react when they feel the need to guard resources. This could be their person, their space, their home, food, or something of high value to them.

Guarding behaviour is a normal response for dogs in a lot of contexts, but this can be exacerbated due to genetic predisposition, lack of positive socialisation, or due to a lack of confidence.

Conflicted Reactivity:

A conflicted dog feels multiple emotions at once. Usually, interested but uncomfortable.

This internal push-and-pull can lead to sudden, or unpredictable reactions because the dog wants to interact with the trigger, but doesn’t ultimately feel safe.

If we only try to suppress reactive behaviour, nothing changes, the dog still feels the emotion. To truly help reduce reactive behaviour, we need to address the emotions driving the reaction, build their confidence, give them coping strategies, and help them feel safe in challenging situations. With the right support, their reactivity can improve significantly and many dogs go on to enjoy calm, happy and more manageable interactions with the world.