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Recognizing Warning Signs Of An Aggressive Puppy

Recognizing aggression in puppies

Puppies are commonly “mouthy” and nibble on an owner’s hands as you play with them and sometimes they will make little growls as they do so, even accidentally break skin if one is not careful. To some degree, this can be normal, as this is behavior they exhibit with one another’s littermates in a litter setting. It is still not necessarily appropriate to get to a certain level and there are proven methods to redirect excessive rough play, but that is not the scope of this article. This article is to help puppy owners recognize and head off true puppy aggression.

It is uncommon for puppies to be truly aggressive, which is why outright aggressive behavior exhibited by puppies can be particularly concerning. Although there are breeds where aggression is more common, make no mistake, aggression is not breed specific.

Case in point, 2 months ago I was about to examine what seemed to be a very friendly 14 week old Labrador Retriever puppy whose demeanor abruptly changed once my technician applied standard gentle restraint for the examination. The puppy’s turn was so sudden, my technician was caught by surprise when the puppy went to bite her face. Seeing this coming, I grabbed the puppy’s muzzle who then proceeded to clamp down on my thumb with its canine tooth puncturing through my nail and refusing to let go, having to pry its jaws open to get her to let go. She tried to clap down again but I pulled away in time, my technician now having the puppy firmly in control.

Most dog oriented people know that Labs are well known for their gentle demeanors, consistently rated as being among the safest breeds to have with children. Yet this puppy was very much an exception to this rule. Let my experience be a lesson to you and do not take breed for granted.

So how to we differentiate normal puppy nipping and teething behavior from aggression? A good starting point is to watch your puppy’s behavior around areas where there is food. Early signs of aggression in puppies include being possessive over toys and food.

Is your puppy protective of his food bowl? Does he growl or snarl as you walk by the food bowl while eating? Does he growl or snap when you reach for the food bowl, even if it’s empty? Does he snatch treats or food out of your hand when not offered? Does your puppy lunge, growl, or snap as you attempt to retrieve a dropped piece of food? Is he protective of the trash recepticle?

Does your puppy assert a claim to any specific piece of furniture in certain rooms of the house, such as a particular chair, couch, or bed? Is your puppy unusually possessive of toys or other items, especially items that may belong to your children?

How does the puppy act when someone, especially someone he does not know, walks into the house or enters a room? Does the puppy react differently when an unfamiliar child comes to the house or bark excessively? 

Does the puppy exhibit an unusually high prey drive by chasing and nipping at anything that is moving? Does he over-react aggressively to playful teasing, sudden movements, awakening from a deep sleep, or being corrected? Is he resentful of being touched? Is there aggressive behavior such as growling and biting when the puppy is picked up?

Also, watch how your puppy reacts to other dogs and puppies. Be sure to watch for signs of a dominant puppy. Does your puppy try to dominate other puppies or adult dogs? That type of early aggression needs to be curbed immediately with training.

If any of the above circumstances resonate with your puppy, my first advice to you is to seek consultation with your veterinarian. Many veterinarians, myself included, are not trainers or behaviorists, but many of us have our pulse on the most effective trainers and the ones that locally have appropriate methods and good reputations.

What prompted me to write this article was a client I saw just yesterday that adopted a beautiful 12 week old mixed breed puppy from a rescue. She had recently lost a very gentle a friendly dog and was ready to open her heart to a new puppy. However, she was dismayed to learn that the puppy quickly began to exhibit troubling aggression and when attempting to correct and redirect, the puppy would worsen. She showed me the many puncture wounds on her hands and ankles from the puppy.

As I examined the puppy, he did not show us any bit of aggression, but behavior in a clinic setting can be very different from behavior at home…and of course, I know this owner to be credible and the bite wounds on her were unmistakable.

I will give you the same advice I gave my client: TAKE ACTION AS QUICKLY AS POSSIBLE. The sooner there is intervention, the higher the likelihood that the situation can be resolved. Conversely, the longer the aggression goes unchecked, the more ingrained the behavior becomes, and the more difficult it becomes to reverse it.

It is possible to modify or change your puppy’s inappropriate behavior by consulting with a responsible dog trainer who applies positive reinforcement, punishment-free training methods. The trainer must have experience working with aggressive dogs. Often, something as simple as strong human leadership and basic obedience training can turn things around.

I am fortunate where I practice to have a local Barkbusters dog behavior therapist. Barkbusters is a company that originated in Australia that started a central training program in the US that standardizes their therapists’ approach. To see if there is a local Barkbusters therapist in your area, you can visit their site at and type in your zip code. For my international readers, there are also Barkbusters therapy programs in the UK, Canada, New Zealand, and Japan.

Whether its Barkbusters or another good training option in your area, seek help for your puppy’s aggressive behavior before tragedy occurs for the human family, the puppy, or both. Even if your aggressive puppy is a small breed, I would implore you to still take action to resolve the aggression. Some of the the worst injuries I have seen have come from small breed dogs, especially to children: lips bitten off, parts of ears bitten off, permanent nerve damage from bites, etc.

Lastly, do not ever be convinced to try to medicate away a puppy’s aggression. Most tricyclic and SSRI anti-depressant medications can actually worsen aggression and make the situation more dangerous. There are circumstances where behavior modification aids such as these are appropriate, but aggression is absolutely not one of them. Natural calming aids like pheromone therapy may be helpful but only in combination with a comprehensive training program.

Dr. Roger Welton is a practicing veterinarian and highly regarded media personality through a number of topics and platforms. He is the author of The Man In The White Coat: A Veterinarian’s Tail Of Love. In addition to being passionate about integrative veterinary medicine for which he is a globally recognized expert, Dr. Welton was also an accomplished college lacrosse player and remains to this day very involved in the sport.  He is president of Maybeck Animal Hospital , general partner of Grant Animal Clinic, and runs the successful veterinary/animal health  blogs Web-DVM and Dr. Roger’s Holistic Veterinary Care.  Dr. Welton fulfills his passion for lacrosse through his lacrosse and sport blog, The Creator’s Game.




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