Puppy Aggression - Symptoms and Causes of
Aggressive Behavior in Dogs

Puppies are extremely cute and cuddly, but puppy aggression may develop at any time because of genetics or the way people handle and interact with their puppies.

Truth is, the most teachable phases of puppyhood tend to pass quickly, and puppy owners must try to make the best out of this brief window of opportunity.

Puppy and dog aggression can be triggered by a variety of circumstances; however, knowing the underlying cause of your puppy's aggression is ultimately the key to reducing and resolving the problem.

Understanding Puppy and Dog Aggression

While genetics play a role in how a puppy will develop when it comes to temperament, it is also true that puppies are blank slates when they are born. A great part of the way puppies interact with people and other dogs will be shaped through life experiences.

Puppies learn most about the world around them during the brief window of opportunity which opens at 3 weeks of age and closes around 16 to 20 weeks. In the first 8 weeks of puppy's life, interaction with its mother and litter mates plays a major role in shaping puppy's personality. After 8 weeks, both breeders and owners play a primary role in providing the puppy with proper socialization.

However, it is important to understand that puppy aggression may sometimes also have a genetic basis. A predisposition for fearful, anxious and general aggressive behavior may never be totally overcome; however, proper training may significantly change a dog for the better.

Puppy Aggression

Symptoms of Dog Aggression

So, how do you know if your puppy or dog is overly aggressive? Take a look at the following list of dog behaviors.

  1. Biting
  2. Snapping
  3. Growling
  4. Excessive barking
  5. Raised fur along the back of the neck and the ridge of the spine

If you can recognize several of the above behaviors, and they occur frequently, chances are that you have an aggressive puppy or dog.

Puppy Aggression Candidates

While all puppies have the potential for acting aggressively in the right circumstances, it is also true that some puppies are more predisposed than others to develop aggression.

For instance, some breeds of dogs may be predisposed to choosing aggression as their primary line of defense when dealing with problems. It is also true that bad breeding practices may cause a tendency for aggression to be passed down from one generation to another.

Among a litter of puppies there may be specimens more predisposed to assertive and aggressive behaviors. This ultimately explains why reputable breeders are quite selective when it comes to matching up puppies with owners.

Puppies removed too early from their mother and litter-mates may also develop aggressive traits because they have missed out important life lessons such as bite inhibition and other important social behaviors. There is also proof that poorly socialized puppies are also more likely to react fearfully to unfamiliar people and dogs. However, puppy aggression in many circumstances may be triggered by the incorrect interactions between dog and owner.

Factors that Influence Aggressive Behavior

What causes aggression in puppies and dogs?

There are many factors at play. A puppy may react defensively when cornered or frightened by an owner, especially if the owner has resorted to physical punishment in the past.

Some puppies may become resource guarders, lashing out the moment a person or dog gets too close to their toys, bones or food.

Other puppies, on the other hand, may be assertive in nature and react aggressively when they feel their social status is being challenged.

It is not uncommon for older puppies to act aggressively when other dogs or people invade their perceived territory. These dogs are protecting their turf and some are even willing to bite in order to defend it.

In some cases, drives and instincts may kick in causing aggressive behaviors in dogs. For instance, predatory drive may escalate into biting when the dog is allowed to chase small animals or herding instincts may cause a puppy from strong working lines to chase and bite the ankles of children.

Finally, some puppies may exhibit signs of dog on dog aggression, including gender aggression (male vs. male, female vs. female).


It is important for a dog owner to recognize actual puppy aggression from normal play. Most puppies engage in nipping behaviors as they grow, and it is ultimately the owner's priority to teach a puppy good bite inhibition.

Puppy Aggression Treatment Options

Puppies suffering from aggressive behavior have a higher chance for recovery when the behavior is caught early.

The aid of a professional dog trainer or behaviorist is highly recommended especially in severe puppy aggression cases. A behavior modification program may sometimes benefit puppies displaying the early signs of aggression. Mild cases may improve by enrolling the puppy in a dog obedience training school and managing its environment.

If a puppy is deemed unsafe in a household with children, rehoming the puppy may be the safest and best option. When purchased from a reputable breeder, aggressive puppies and dogs may be returned back to the breeder.

If at any time you are concerned about your puppy's behavior taking a turn for the worst, don't hesitate to seek out help. While it is true that genetics may impose some limitations when it comes to how much you can change behavior, it is also true that when caught early, appropriate training can make changes happen to some extent.

Regardless of the cause, never underestimate puppy aggression; left untreated it tends to get worse not better.

Here is a brief video that talks about some of the things we just covered in this article...

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Puppy Training

For more advice on how to stop puppy aggression, I highly recommend you read and follow this dog training guide. You'll find lots of information on dealing with many behavioral problems, including dog and puppy aggression.


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