Understanding and Managing Aggression in Dogs

Why is my dog aggressive to strangers and other dogs?

Barking or growling at other dogs or people, lunging on the lead with a full threatening display, this usually comes down to fear. A dog that feels unsafe is reacting with a survival response, the same fight, flight or freeze reflex that shows up in any animal facing a threat. Some dogs default to confronting the trigger (fight), others would rather move away (flight), but a dog trapped on a lead or in a confined space doesn't have that option, leaving a threatening display as the next best thing.

What this looks like

Posturing tall, tensing up, raised hackles, a hard stare, snarling, lip-curling, growling, barking, lunging, air-snapping and, in the worst case, biting are all part of the same threat display. If it works, the scary thing backs off, or an owner drags the dog away, the dog feels relief, and that relief reinforces the behaviour. Next time a similar situation arises, the dog repeats what worked before. Owners often tense up too, shortening the lead, changing their breathing, speaking sharply, which unfortunately adds more stress to an already stressful moment rather than less.

How we approach a reactive dog

The first step is understanding your dog's baseline arousal and anxiety level. A generally easy-going dog who only reacts to specific triggers is a different starting point to a dog who's restless and hyper-alert most of the time; the latter often needs their overall stress level lowered before trigger-specific work can succeed, which is worth discussing with a professional behaviourist and your vet together.

Identifying and working with triggers

Triggers are identified one at a time, the postman, men in dark coats, children on scooters, dogs of a particular size or colour, whatever consistently produces the reaction. Understanding that your dog isn't being naughty, they're genuinely scared, matters here; being someone your dog can trust when frightened is the foundation everything else builds on. Effective approaches include classical and operant counter-conditioning combined with desensitisation, Behaviour Adjustment Training (BAT), the Look-At-That game, and matwork. All of them rely on working below your dog's threshold of reactivity, the distance at which their body language shifts from alert to threatening, since once a dog is already barking or lunging, they're practising the unwanted behaviour rather than learning anything new.

Practical steps that help

Muzzle training, teaching your dog to truly enjoy wearing a muzzle, helps you feel calmer and more in control, which reduces the stress you might otherwise be transmitting down the lead, and signals to others that your dog needs space. It's worth noticing your own reactions too: do you tense up, get embarrassed, or speak sharply when a trigger appears? Being kind to yourself matters as much as being patient with your dog, progress with a reactive dog is rarely a straight line. A skilled, experienced behaviourist can make the difference between ongoing frustration and a clear, workable plan.

Getting the right support

See also our guide on helping fearful dogs. Get in touch to speak with one of our trainers about a reactive dog. Learn more about our aggressive training programme and our emotional enrichment hub. Also see Fear, Anxiety and the Risk of Fear-Based Aggression and Recognising and Easing Anxiety Through Emotional Enrichment.