Debunking the Myth

Debunking the Myth That

Breed Predicts Aggression  
  

Many people believe certain dog breeds are inherently aggressive, but research increasingly shows this is a misconception. While breed may influence general tendencies, it is far from the only, or strongest, predictor of aggressive behaviour.

Although domestic dogs descend from wolves, which have a higher natural propensity for aggressive behaviour, many generations of selective breeding have resulted in the calmer, more sociable dogs we know today. Aggression is a complex trait influenced by multiple genetic and environmental factors, including maternal effects, sex, age, neuter status, litter size, guardian (e.g. pet-parent) personality, and their interactions.

As a veterinarian, I’m constantly reminded how unpredictable animals can be. In my experience a well-socialised dog tends to have better mental health than one that missed pivotal experiences as a puppy or exposed to life-changing trauma. I often meet siblings who have had the same parents, same beginning to life, same guardianship and environment, and still, one individual will be calm with no aggressivity noted at all, while it's sibling will be highly anxious and needs to be muzzled. These can be breeds from Dachshunds, Schnauzers, or Cavoodles to Amstaffs, Kelpies, or Labradors. It highlights to me that there are so many factors that influence behaviour, and this example anecdotally confirms that breed genetics only plays a small role. Interestingly, the same Nature versus Nurture debate we see in humans applies to dogs (and other animals) as well.

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Attacks are more strongly influenced by socialisation, training, environment, health, and guardian behaviour than by breed alone.

Australian Veterinary Association

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Placing rigid restrictions on specific breeds is both scientifically flawed and ethically questionable. Behavioural science confirms: aggression is multi-factorial. Breed identification is often unreliable (even with current DNA testing), and breed has been shown to account for only 10-40% of behavioural variation. Prejudice, or “breedism”, has no place in a animal-loving community built on support, love, and inclusion. 

In Australia, animal welfare bodies like the RSPCA (The Royal Society for the Prevention of Cruelty to Animals) argue that breed-specific legislation is based on confounding assumptions: that certain breeds are inherently dangerous and that appearance reliably predicts risk. Temperament tests consistently show that “restricted breeds” do not differ significantly in behaviour from other dogs. The RSPCA maintains that each dog should be assessed individually, rather than judged by breed.

Similarly, the Australian Veterinary Association critiques breed bans in its report Dangerous Dogs - A Sensible Solution, noting that such bans rarely reduce dog attacks. Instead, attacks are more strongly influenced by socialisation, training, environment, health, and guardian behaviour than by breed alone. For example, New South Wales statistics show American Staffordshire Terriers (Amstaffs) appear most often in dog attack reports, but breed identification was frequently unreliable, deliberately misleading or not reported at all. This data lacked breed verification and any commentary regarding other influencing factors like environment, individual dog temperament, pet parent behaviour and their dog's neuter status.

Decisions based solely on breed can result in prejudice, exclusion and unnecessary euthanasia, leaving genuinely dangerous dogs unidentified in our community. Cross-breeds and mixed ancestry further complicate the picture, and relying on appearance alone risks overlooking or misjudging a dog’s behaviour.

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What This Means for Pet Parents  
  

 Don’t assume aggression, or passivity, based on assumed breed alone.

Prioritise socialisation, positive training, predictable environments, and attentive care.

 When choosing a dog, consider temperament, history, energy levels, and household fit over breed.

  Support evidence-based policies over breed bans, education campaigns, responsible breeding, good guardian behaviour, leash laws, and safe containment are far more effective.

 If your dog shows aggression, it often stems from fear, stress, defensive or protective instinct. As a pet parent or pet guardian, it’s your responsibility to understand your dog’s limitations and ensure environments are safe and suitable for them. Do not place this burden of responsibility on others.