Are Small Dogs More Aggressive Than Large Dogs?

Are you considering adopting a small dog? Maybe you’ve heard small dogs have big personalities packed into tiny bodies. Small dogs tend to have a reputation for being feisty, but are small dogs really more aggressive than big ones? Or is this just an unfair stereotype? Let’s break it down. 

Dogs come in a wide variety of sizes, but the genes that determine size don’t inherently make them more or less aggressive. Below, we dig into the science of canine aggression, what really influences behavior (spoiler: size isn’t everything), and how training and socialization can help any dog — big or small — be their best self. 

Do small dogs show more aggression than large dogs?

While it may seem that smaller dogs are more aggressive than large dogs, that’s actually not the case. There are many factors to consider, such as pet parents’ ability to spot signs of discomfort and stress in their dogs that could lead to aggressive behaviors, perceptions of aggressive behaviors specifically in small dogs, and more. It really boils down to a people problem.

Both pet parents and the general public have struggled to accurately read canine body language and identify pre-bite warning signs. On top of that, people with small dogs are more likely to see their pet’s aggressive behaviors as harmless or even “cute” because these behaviors are less likely to cause significant harm. This perception of small dogs as harmless leads to pet parents tolerating aggressive behaviors in small dogs with less of a desire to pursue training.  

To support your small dogs’ emotional well-being, it is important to better understand body language and underlying emotional motives for aggressive behaviors.

Common aggressive behaviors in small dogs

Despite being more noticeable in large breed dogs, aggressive behaviors in small dogs look very similar. Although lunging, growling, and biting are often seen as aggression, small dogs often show subtler signs of nervousness or discomfort first. 

Some of these signs include:

• Appeasement licking

• Whale eye

• Lip licking

• Turning their head away

• A tight or wrinkled face

• Ears pinned back

• A hunched or curved posture

• Yawning

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Factors that influence small dog aggression

Many factors can influence a small dog’s aggressive tendencies.

Fear

The majority of small dog aggression comes from a place of fear. To make a scary thing go away, smaller dogs will bark, lunge, and growl to create distance. Defensive aggression (or fear-motivated aggression) is the most common type of aggression, and has been shown to take place in response to (or anticipation of) a scary event.

Genetics

Although environmental and social factors play roles in canine aggression, genetics may also shape this behavior. Factors such as breed predisposition, heritability, gene-environment interaction, and hormones can all play a part in an increased risk of aggression. While genetics sets a baseline for behavior, upbringing, training, and socialization significantly shape aggressive tendencies (more on that, below).

Breed purpose

If, for instance, a small dog was originally bred to rush, bite, bark, and chase, it is no surprise that you may be struggling with some reactivity and aggressive behaviors. These dogs are carrying out the behaviors they were bred to perform. To expect them to act any differently without guidance or training is simply unfair. 

Trauma and environment

Dogs who have been attacked by another dog or mistreated by people sometimes develop aggression towards those who remind them of past abuse. In combination with genetics, early life trauma, poor socialization, and stressful living conditions can have lasting effects on a dog's behavior.

Parenting styles

Parenting styles from both mother dogs and human pet parents will impact a dog’s temperament and behavior as they mature into adulthood. Specifically, mother dogs’ maternal behaviors towards their pups are found to have direct impacts on those pups’ physical and social engagement as well as aggressive tendencies as they reach maturity and adulthood. Mother dogs who exhibited more maternal care (physical affection, licking/grooming, sniffing/nuzzling, etc.) had puppies who were more physically engaging, social, and less likely to demonstrate aggressive behaviors in adulthood. 

Similarly, pet parenting styles also impact dog behavior. Dogs with authoritative pet parents (high expectations, high responsiveness) are more likely to be highly social, sensitive to social context, and more successful with problem-solving tasks, in contrast to dogs with authoritarian pet parents (high expectations, low responsiveness) and permissive pet parents (low expectations, low responsiveness).

Socialization and handling

Socialization and handling during a puppy’s socialization period (three to 14 weeks of age) can make a puppy more self-confident, secure, and predictable. Since behavioral challenges are the top reason dogs are relinquished, early training and socialization play a crucial role in saving the lives of countless dogs.

Training and reinforcement

Training and reinforcement histories play major roles in either mitigating or exacerbating aggressive behaviors in dogs. Positive reinforcement training (or giving the dog something they like, such as a treat, when they do something “good”) strengthens desired behaviors, builds trust, and helps dogs learn appropriate ways to interact with the world. 

On the other hand, inconsistent training, punishment-based methods, and reinforcing aggressive responses can escalate aggression, particularly if the dog learns that aggression is an effective strategy to avoid unpleasant situations. Proper training, consistent reinforcement, and early socialization are key to reducing the likelihood of aggressive behavior and promoting a well-adjusted, confident dog.

Age

Age definitely impacts a dog’s likelihood of aggressive tendencies. As dogs get older, they become less social. Like people, senior dogs may become more selective about their friends. Additionally, as your dog ages, they are also more likely to have aches and pains, which could make them more grumpy and less tolerant of triggers.

Size

Being small makes everything in the world seem so big. And realistically, everything has a higher potential to hurt them. Smaller dogs are more likely to get stepped on, trampled over, and picked up. Because fear is the leading cause of aggression in dogs, small dogs, who already have more to fear, have more potential for fear-based aggression. 

Neutering and spaying

Spaying or neutering can potentially reduce aggression in small dogs, especially if the aggression is hormonally driven — but these are not guaranteed solutions. Because not all aggression in dogs is caused by hormones (such as fear-based aggression), it is best to consult your veterinarian.

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How to prevent and manage dog aggression

The best way to prevent dog aggression in any breed, no matter their size, is to start socialization and training as early as possible. Preventing and managing dog aggression is a process that requires consistency, patience, and a combination of proper socialization and positive reinforcement. 

If your dog displays aggressive behaviors, here are the best things you can do.

• Determine what triggers their aggressive behaviors.

• Properly manage triggers early to prevent a reaction.

• Provide adequate and appropriate mental and physical stimulation.

• Seek out the help of a professional trainer who’s skilled in behavior modification.

By focusing on positive, reward-based training and understanding the factors that influence aggressive behavior, you can help your small dog become well-adjusted, confident, and less likely to exhibit aggression.

Commonly asked questions

Are small dogs actually more aggressive, or just more reactive?

Yes, small dogs tend to show more aggressive and reactive behaviors. Some small dogs start out reactive and, when not taken seriously, display more aggressive behaviors. This is why it is so important to listen to our dogs.

Are small dogs aggressive because they’re protective?

Despite the popular belief that dogs are defensive of their people, most dogs are actually responding to the environment from a place of fear or anxiety rather than a protective instinct toward their pet parent. Additionally, dominance theory, which has been historically linked to explanations of protective aggression, has been largely debunked in modern canine behavioral science.

Can proper training eliminate aggressive tendencies?

Yes, training can lessen or even eliminate aggressive tendencies. Dogs are sentient beings with their own experiences and feelings, so there is never a guarantee. But working with the right trainer can be life-changing for both you and your dog.

Why do some small dogs bark more than large dogs?

Some small dogs bark more than large dogs because they’ve got a lot to say. While barking is often viewed as an obnoxious behavior, it’s their way of communicating — and you should listen. Because small-dog pet parents are less likely to seek out professional dog training and address their dogs’ problem behaviors, barking is often more prevalent in small dogs. 

How do I stop my dog from aggressive behavior toward strangers?

The best way to address aggression towards strangers is to figure out why your dog is behaving the way they are, and what purpose that behavior serves. How you address their concerns and modify the undesired behavior is best done with the help of a certified, positive reinforcement trainer. Remember, dog training is an unregulated field, so look for certifications such as CPDT, IAABC, and Fear Free.

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