Classification of Canine Aggression and Rehab by K9-1

This system of classifying the different categories of aggression that pertains to understanding the most common canine aggression "problems" is based on the recorded behavior of canines that range from undomesticated (such as wolves), domesticated (pet population), and stray and feral populations of dogs. This classification system also attempts to make use of the most common terms used by various professionals in the pet and working dog field.

Rationale for the Standardizing Terms

There is very little consistency in the labeling of aggression in the pet training community in particular. Because of lack of any educational requirements, particularly in the subject area of canine ethology, many terms are used inconsistency despite well studied and recorded behaviors. There is often a huge gap between rhetoric and what actually is considered scientifically accurate.

This can cause much confusion to the general public that often seeks help. Certain aggressive behaviors are often labeled non-aggressive behaviors and vice versa. Also, classifications of aggressive behavior are used very inconsistency and sometimes, going against all known literature, are claimed to be non-existent (as in the case of dominance aggression).

The first step to managing, rehabilitating, or training an aggressive dog is to correctly identify what aggression type is being addressed since plans may greatly vary when the motivation for aggression greatly varies. Below you will find a simple system of classification based on researching past studies, professional literature, and a qualitative analysis of my own work which includes over 20 years of working, high volume, mainly with aggressive canines.

What will be considered aggression?

Aggression is any behavior, which left uninterrupted, may result in a dog bite. Therefore, a behavior such as barking, growling, or even staring may be interpreted as aggression if it is determined to be part of that canine's progression of behaviors that will lead to a bite.

Aggression can be specific to other dogs, humans, other animals, or even objects.

A word about "aggression rehabilitation".

Since many people reading this information are concerned about "rehabilitating" a dog's aggressive behavior, the community must be careful of how this terminology is used.

Rehabilitation means the act of restoring something to its original state.

This comes from the Latin prefix re-, meaning “again” and habitare, meaning “make fit.”

Aggression is very much a natural behavior and the presentation of aggression is mostly dependent on a canine's genetics and age. This will determine how, if left uninterrupted, the dog will behave in different situations.

Aggressive behavior can be interrupted by human intervention through a variety of means, particularly training and management, but this is far from what is considered rehabilitation and will fall into the same category as any other learned behavior and the constraints of maintaining that learned behavior.

The recent surge in "rehabilitated dogs" being adopted out from rescue organizations and then causing significant injury and death afterward is a testament to the importance of understanding the limitations of "rehabilitation".

For instance, if a greyhound has predatory aggression toward cats and a trainer uses an E-collar to shock a dog for trying to chase a cat, the dog is not rehabilitated. The cat aggression is a reflection of the dog's natural behavior and the shock has applied consequences to the natural behavior in that particular situation.  This dog is not technically "rehabilitated" and will likely revert back to its natural behaviors without a handlers knowledge of how to generalize, maintain, and prevent spontaneous recovery of the natural behavior.

Does rehabilitation occur in dog training plans?

Yes, there are many examples of dogs that benefit from true rehabilitation, but it must be considered bringing a dog back to, or as close as possible back to a natural state to be classified as such.  Just like a dog with an injured knee, we can attempt to rehabilitate the knee back to its former state but there will always be limitations that depend on the extent of the damage. The same goes for behavior. With the example above, where the greyhound was shocked for chasing a cat, the greyhound may now show hesitancy to chase an electric rabbit or anything else that vaguely resembles a cat and therefore will need rehab to bring the greyhound to a more natural state where it can perform the duties it once was able to do more naturally.  In some cases, rehab is needed because past experience has caused a dog to refrain from behaviors that promote further natural developments of social skills, work behaviors, and more.

A German Shepherd is raised by an owner who bonks the dog over the head with a rolled up towel for various behaviors the owner wants to interrupt.

The owner then wants to partake in a dog sport with their dog and every time the agitator lifts a stick the dog generalizes, flinches, and loses his grip. The dog is making the association of the raised object with past punishment for his current behavior. The past experience of bonking, in this case, is making it more difficult for the dog to be desensitized to light stick hits on the sport field.

This is when rehabilitation becomes part of the training plan since the dog, in his natural state, did not begin life associating a raised object with punishment and was otherwise more confident with the movement of a human. Will the dog ever completely forget the past? No, but the process of bringing the dog back to a more natural association of lifted objects (neutral) and behavior is rehabilitation.

Sometimes, dogs naturally get more aggressive in certain situations as they mature, even though the dog didn't start off as "aggressive". If there is no evidence of events that may have changed the dog's natural behavior and development it is likely that the progression of aggressive behavior is a product of genetics and maturity. Canine ethology at different life stages as well as breed specific behavior and bloodline specific behavior should always be explored before assuming an alien antagonist to the individual dog's natural behavior.

Understanding different types of aggression is the first step in any plan involving the improvement of problem causing aggression behaviors.

A Classification of Aggression Types:

Dominance Aggression

In all animals, dominance is the first right to limited resources. There is no need to rewrite anything on this term or make it more complicated than a simple definition. It makes classifying an aggression "problem" easier and the plan to rectifying problems easier.

Keep in mind that dominance is designed to reduce aggression. The aggression part is the result of a conflict. Dominance aggression can and does manifest itself between species if the aggression is triggered over the first right of a limited resource.

In the case of dogs, and other social species the most dominant in the group also are the primary leaders. Leadership and dominance are closely related in social animals, but are not the same. It is important to understand the difference for troubleshooting purposes.

Leadership is the decision maker for the group. This does not mean that another member of the group may not suggest an activity or otherwise initiate an activity, but ultimately the leader is the decider of when, what, and if activities are going to happen.

With canines this can include travel, hunting, defending from an outsider, accepting an outsider, playtime, and other interaction.

Conflict over leadership can also trigger aggression in canines. It is uncommon, to hear the term "leadership aggression" because it has historically been lumped into the category of "dominance aggression". These two go hand in hand and since, in my experience, both need to be addressed in order to reduce confusion and conflict in an aggressive dog they should remain lumped together as "dominance aggression" as long as a trainer understands the sub categories within that need to be addressed.

Examples of "dominance aggression" (first right to resource):

  • first right to human or other dog attention
  • first right over food/water
  • first right over a toy
  • first right to a resting place

Right to "lead":

  • aggression when pack/family tries to leave
  • aggression when pack/family member tries to initiate affection
  • aggression when pack/family tries to initiate play
  • aggression when pack/family tries to interrupt an aggressive behavior
  • aggression when pack/family reprimand dog

Resource Guarding

Resource guarding is defensive aggression that is limited to guarding food, water, toys, or other objects that are within the "ownership zone" of under a canine's mouth and between the front legs.  It is not to be confused with "first right" to a resource.  The rules drastically changed once there is ownership of a resource.  This is explained more in this video if you need clarification: Dog Culture Made Simple

It is important to understand that although resource guarding is a common occurrence with dogs that are prone to dominance aggression, it can and often is displayed by dogs as an isolated behavior regardless of social status.

In fact, a study of natural wolf behavior by David Mech has quantified that resource guarding is a natural behavior of all wild wolves and has no correlation with status. A low ranking puppy is just as likely to guard food in the ownership zone as a pack "alpha" from any other pack member.

This type of aggression is not viewed as any form of status challenge and does not typically trigger any kind of retaliation from higher ranking canines.

This is important to note, since this type of behavior should never be interpreted as a "challenge for status" or confirmation that a dog believes he has a dominant status over a person or another dog.

Some dogs naturally have a stronger instinct for this primitive behavior while other dogs have a less intense instinct due largely to selective breeding.

Understanding what the behavior is and what it is not, is an important first step to improving a resource guarding "problem".

Protective aggression/fear aggression

These two are classified in the same section because there is only one key difference between the two for purposes of making training plans easier.

Protective aggression is triggered by the instinct of a dog to defend themselves and other packmates from a threat.

This is a clearly observable behavior in all studies of wild and feral dogs and an instinct that humans have taken advantage of in many working dogs.

The term "fear aggression" is a variance of this behavior which is best used as a classifying term instead of protective aggression when the triggers seem to be irrational or inappropriate triggers for a protective response. There may be some gray area as to what constitutes a rational protective response and what would be considered irrational. Further complicating the terms are the expectations of the handler from the dog. For example, a rottweiler that acts aggressively when a stranger walks within close range on a walk is more likely to be called "protective" and a Labrador is more likely to be called "fearful" for the same behavior.  Therefore, it is somewhat subjective.

Protective Aggression Examples:

  • aggression when a stranger hugs the owner
  • aggression from bitch when stranger handles puppies
  • aggression when a stranger approaches in a "threatening" posture
  • aggression toward a dog that approaches with threatening body postures

Fear aggression Examples:

  • aggression toward most approaching dogs regardless of the posture
  • aggression toward most approaching people regardless of the posture

Fear Biter

The "fear biter" should not be confused with fear aggression. While fear aggression is a proactive "I'm going to get you before you get me or us" behavior, the fear biter is reserved for dogs that only bite in defense and when the flight is not an option.

A typical fear biter may "fear bite" when cornered by a perceived threat, when getting nails clipped, or unable to escape any stimulus that elicits a fearful response from the dog.

Other dogs may bite in the same circumstances, but dependant on the proactive behavior and body language, it may also be associated with protective/fear aggression or even dominance aggression.

The true fear biter will have fearful body language and will prefer flight if there is an option.

Territorial Aggression

Territorial aggression will have a very similar presentation as protective aggression and can, in fact, be very intense.

True territorial aggression is motivated by an instinct to protect the perceived territory from outsiders. This can be the inside of a house, yard, or even a neighborhood that a dog is walked around frequently.

A key indicator of territorial aggression is when a dog is very aggressive toward outsiders (dog or human) when in these areas but otherwise non-aggressive when in new or neutral areas.

Since territorial aggression will have a similar presentation as protective or fear aggression it can be masked by fear aggression if the dog is also acting in a similar manner off property due to fear.  Therefore, a dog that displays aggression on and off property to those that seem to pose little threat may or may not also have a layer of territorial aggression.

Territorial aggression is never directed toward "pack members". Therefore, dogs that protect resting places, crates, food, or rooms in the home from other family members should never be labeled "territorial". Instead, those behaviors need to be correctly identified as dominance or resource guarding. If a dog was territorial aggressive toward a family member, technically the dog would attack the family member as soon as the member entered the yard/home.  Different forms of aggression are motivated by different reasons and therefore must be treated differently to manage any problems successfully.

Wild canines are fiercely territorial, and the biggest killer of wolves are other wolves due to conflict over territory. Humans have taken advantage of this instinct during the domestication of many guardian breeds. However, keep in mind that if a wolf shows aggression toward pack mates within their own territory it isn't territorial aggression. The same goes for domestic dogs.

Another behavior correlated and confused with territorial aggression is Alert Barking. Alerting barking is simply the enhancement of the muffled "woof" sound a wild canine makes to warn other pack mates of a possible threat. Technically it is not considered aggressive behavior since, at the core, the motivation behind the bark is to alert a warning to pack members and not directly threaten.

Predatory Aggression

Most aggressive behavior is motivated by a threat or challenge of some sort to territory, resources, status, self, and pack.

Predatory aggression is related to the instinct to hunt, chase, kill, dissect, and eat.

This instinct has been highly manipulated through domestication to help various breeds perform specialized tasks. Through the selection of suppressing and enhancing certain parts of the behavior, we have created dogs that show the micro-divisions of this instinct in different combinations (see a video explaining this here).  For example, a border collie has strong instinct to stalk and chase, but a lower instinct to bite. This allows the dog to perform the task of herding sheep without causing injury.

When the dog's predatory instinct is showing evidence that it will escalate to a damaging bite it is considered predatory aggression.

Play Aggression

Puppy and dog play, just like all social predatory animals consists of practice predatory behavior and practice fight behavior.

More relaxed body and face postures, as well as the relative restraint during bites, mark the difference between the play and the mature forms of aggression.

Play aggression is used to teach young working dogs techniques before transferring over to more realistic training.

Play aggression can also cause a nuisance and even injury to pet owners and children if not channeled and managed properly. Nonetheless, it is handled differently and should not be confused with any of the mature forms.

Barrier Frustration

This is aggression that manifests itself due to the frustration of not being able to engage with something when restrained by a leash or blocked by a barrier. The frustration itself may be the sole cause of the aggression which will extinguish when there is no longer restraint.  This can also be layered with and exasperate other types of aggression such as predatory, fear, dominance, and territorial aggression. In these cases, there will still be aggression present if the restraint or barrier is removed.

Misdirected aggression, where a dog bites a substitute for an intended target, it is usually the result of barrier frustration layered with another aggressive motivation.

Barrier frustration, just like all types of aggression, is very reliant on genetics and in most cases, this trait has been selectively bred into dogs for a purpose.

A classic example of barrier frustration is the dog sport breeder that chooses the breeding stock based on the ease of training the dogs to bark when restrained.  This is useful during the bark and hold training exercise in IPO. The frustration will look more aggressive and impressive to a judge who is otherwise looking at a dog primarily engaged in play aggression under the layer of frustration.

A puppy from this stock is then purchased by a pet home who inevitably has problems because the dog acts aggressively when restrained from meeting dogs or otherwise has a turbo boost layered over any other aggression "problems" while on a leash or restrained.

Skipping Steps in the Aggression Cycle

Ideally, a dog shows a lot of restraint when acting defensively.  In many situations a dog may accomplish what is needed by just a posture and then escalating accordingly to a growl, snarl, snap at the air, a "hit" where the dog hits a competitor with his teeth but does not injure, and then escalating levels of bites that will cause injury before an all out fight or attack.

Particularly, during resource guarding and normal dominance related conflicts we typically see appropriate restraint and the minimal amount of aggression to resolve the conflicts.  When there is obviously much more aggression than would be necessary for a situation we would say the dog is also "skipping steps in the aggression cycle".

Skipping steps in the aggression cycle, in rare cases, can be the result of intense human punishment for early steps in the cycle, particularly growling.

Usually, genetics is the main culprit and the behavior can be found in bloodlines of many breeds that are otherwise not known for overly aggressive behavior but were haphazardly bred.

In other bloodlines, the behavior was an intentionally selected for trait that gave an advantage to certain working dogs, terriers, and fighting breeds that needed the advantage of a quick bite to excel at their tasks.  Skipping steps in the aggression cycle can also be associated with not responding to signals of surrender and submission after the onset of aggression.

Types of aggression can be layered and exasperated by the influence of the other:

Remember that dogs are multidimensional, and usually show most forms of aggression to various degrees. Always be guarded before deciding a dog has only one kind of "aggression problem", since most problems consist of more than one layer.

Lastly, respect that aggression is natural to a dog and what constitutes a problem in one situation is an asset in a different situation.

Aggression problems are only problems when they cause a problem.

Understanding these "problems" instead of trying to suppress natural behavior should always be the first step in any plan.

Hacks and "quick fix it" plans will always yield bad side effects.

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1 Comment

  1. Everything in one spot.
    I like it.
    Kind of funny in Mech 2000, where he says the, “female would return after sufficiently motivating the male,” and is the, “male showing leadership by provisioning the female or is she by taking charge of the food?”

    Although valid questions, as humans most want to see and understand things in a human context (humanize), however by doing so it makes it harder to see. Humanization of dogs, has lead to many problems for both owner and dog.

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