ABC’s Of Dog Behavior: “A” Is For Aggression  

This article may be considered old news to many of you, but I believe it is an important to address training and behavior of dogs. When you first bring home a dog whether it’s your first or your tenth, you will need to train it. A puppy, adult/senior dog, shelter, rescue, or even from a breeder/pet store, you are going to have to train it. Even if a dog is listed as “trained”, you are going to have to train it!

I know all too well from working with shelters and rescues that sometimes people complain that they were mislead, being told a dog was supposed to be trained but then exhibited bad behavior. Sadly dogs are often returned for this reason, but it’s not the dogs fault, it’s not the shelters, rescues or even fosters fault–it’s the owners fault for not having patience! You must take the time to train whatever dog you bring into your home due to this being an entirely new environment with different rules than what they may have been used to. Lots of strange new things and people. As a dog owner, your dog’s behavior plays a key role in making a great family member.

Being that it is Pitbull Awareness Month, and there is a great deal of controversy about whether or not they are aggressive, the behavior topic I would like to discuss today is Aggression.

Let me begin by stating that understanding the cause of a dog’s aggression is essential to assessing and helping both the dog and yourself. The information I am sharing here today is NOT intended to replace the advice of your own Veterinarian. Professional help from a Veterinarian and a skilled behavior expert are key components for treating aggression in dogs. While this condition can be extremely frustrating for owners and for affected animals as well, there are steps that can be taken to address the situation. Euthanasia should never be an automatic “treatment” or “solution” for any behavioral disorders in our pets!!

Aggression is defined as an appropriate or inappropriate threat or challenge that is ultimately resolved by combat or submission. It is one of the most common behavioral problems in dogs. Aggression can occur in any breed, age or gender of dog and can be directed towards people or other animals. It is potentially very destructive, and very dangerous.

Aggression can take a number of forms and be caused by a number of things. Common signs of aggression can include biting, growling, snarling, curling lips, barking, snapping, head and tail up with direct stare, head and tail down with body withdrawn, frantic tail waving, posturing and lunging.

All breeds, ages and genders of dogs can become aggressive. However, very few dogs are born aggressive, and frequently aggressive behavior in dogs is normally a direct result of something else. It is possible for underlying medical conditions to cause or contribute to aggression, such as pain or neurological disorders which must be ruled out before an appropriate treatment protocol can begin.

No matter how gentle a puppy is, abuse, mistreatment, or neglect can cause any dog to suffer behavioral problems, including aggression. Dogs that are raised without proper socialization, nutrition and affection will not know how to act appropriately in social situations involving people and/or other dogs. It is extremely sad to see fear and other forms of aggression in a dog because of an abusive or neglectful background. I have seen this many times first hand and I can tell you it has literally brought me to tears.

Medical causes of canine aggression may include: pain, head trauma, swelling of the brain, rabies, distemper, epilepsy, arthritis and other neurological or painful disorders. Painful dogs may bite their owners without really knowing what they are doing (for example, after being hit by a car or attacked by another dog).

Aggressive behavioral problems are difficult to resolve without the assistance of a specialized trainer or Veterinary Behaviorist. The goals of treating canine aggression is to eliminate the aggressive behaviors and render the dog safer, to enhance human safety and the human-animal bond, to alleviate the anxiety causing the dog’s aggressive behavior and to make the dog and its people happier and calmer. Treatment for aggression involves desensitizing the dog to the stimulus which can be other dogs, threatening people, children approaching their food, etc. and counter-conditioning or rewarding the dog for calm or good behavior. Complete control over the dog, by either the owner or the trainer/behaviorist, is essential for this to work. No amount of advice can provide what your Veterinary Behavioral Specialist can provide to assess and address your dog’s particular situation. However, physical punishment and harsh restraint are strongly discouraged as they usually intensify aggression-based behaviors.

When it comes to puppies, proper socialization to people and to other dogs is critical. Puppies go through major developmental phases between 3 and 12 weeks of age where proper and positive interaction with other animals, people and environments are crucial to helping them develop appropriate solid social character traits. Puppy classes are an excellent way to achieve this socialization while establishing a solid training foundation. If you, the owner, fails during these critical developmental periods, your puppy may not develop the proper skills and behaviors to make it a good household member.


There are many different types of aggression, here are several that I believe are most common:

Fear Aggression

Fear aggression, or defensive aggression, happens when a dog perceives that it is in a threatening situation. The fearful reaction may be normal and appropriate under the circumstance, or it may be phobic. There is no age or gender predisposition for this form of aggression. Fear aggression can be extremely dangerous because it can lead to human harm. Signs of fear aggression include trembling, growling, barking, lip-lifting, snapping, cowering, crouching, backing up, lip-licking and tail tucking. Often, so-called “fear biters” have a history of abuse, and lash out when cornered. I deal with a dog that has these types of issues every day, if you missed my post about her and you want to read it, you can find her story here:


Impulse-Control Aggression also known as Dominance

Dominance aggression in dogs can occur in all breeds and either gender. The clinical signs involve growling, baring teeth, staring, a dominant and forward stance, and/or biting – particularly in response to people staring, reaching towards or over the dog or punishing it inappropriately. This type of aggression is often displayed toward human household members, when reaching for the pet, pushing it off furniture or approaching food or toys.

Interdog Aggression 

Interdog aggression is almost always exhibited between dogs of the same sex. The signs are intense staring, hair raising, growling and challenges, although frequently once a fight starts, the dogs are almost silent. I have seen this first hand, many times, it’s not pretty. Male dogs challenging one another with this type of aggression usually fight until one of them submits. Infights between females are worse, and this sadly is what I have had to deal with between Blossom and other female dogs in my household as well. It has lead to extremely severe injuries. Some cases of this type of aggression have even lead to death. (thankfully never in my home) Interdog aggression becomes dangerous to people only when they try to break up the fight, as the involved dogs are fighting irrespective of pain tolerance.

Territorial/Protection Aggression

This type of canine aggression is characterized by barking, growling, snarling, biting and other aggressive behaviors apparently designed to protect objects or people. It worsens when the dog is behind discrete boundaries, such as in a car or behind a fence. In most cases, these dogs are not aggressive away from their territory.

Food-Related Aggression

Food aggression is characterized by growling and lip-licking if approached, or sometimes even if only looked at, when eating. It often progresses to biting if removal of the food or treat is attempted. Obviously, this can be quite dangerous to people, especially children who may try to play with the dog and do not understand the dog’s verbal and postural warnings.

Dogs are NOT born aggressive!! While there are some breeds that are particularly trainable to a number of behaviors, including aggressive ones, (like our loving PitBulls who are used for fighting) they do not come by aggressiveness on their own. Aggressive dogs are those that have been mistreated, ignored, chained, unsocialized or improperly trained during critical periods of development. Humane training methods under the guidance of a skilled trainer can help nip aggressive behavior in the bud. Consistency, kindness and predictability in managing aggression is critical. Many talented, knowledgeable canine behavior experts are available to help you and your Veterinarian address aggression if you experience any issues with your dog!

It is my hope over time to create a series of articles about dog behaviors so I ask that you please leave me some comments about what you and your dog may need help dealing with and I can try to address those behavioral issues specifically.

Sources and further reading: