Aggression in Dogs

Aggression in dogs describes behaviour directed at causing another individual—human, dog, or other animal—to move away or stop what they are doing. It exists on a spectrum, from a subtle freeze or hard stare through to growling, snapping, or biting. What an owner observes can vary widely depending on context, the dog's learning history, and what has worked for that dog in the past. Many owners arrive at this page after a specific incident—a snap at a visitor, a fight with another dog, guarding of food or space, or reactivity on the lead. Others are noticing patterns: tension around certain triggers, changes in how their dog responds to handling, or escalation over time. Aggression is not a diagnosis in itself; it is a category of behaviour that can arise from fear, frustration, pain, learned responses, or difficulty processing the environment. This page explores the signals that often precede or accompany aggressive behaviour, the range of factors that can contribute, how the behaviour is assessed, and the approaches—environmental, medical, and behavioural—that may be considered. The aim is to help you understand what you are observing and the shape of the conversation that may follow.