Defining Canine Aggression

Defining Canine Aggression

“The aggressor always had a purpose behind his attack; he wanted something to be done, some object to be surrendered by the defender.”

~Mahatma Gandhi

Scott and Fuller described aggressive behavior as agonistic behavior that included “…patterns of barking, growling, biting, running away, or rolling on the back and yelping.” All these patterns serve specific functions with a common general function forming a “…loose relationship to each other.” When one combines all these loose patterns it forms a “behavior system” and taken together this forms a “…group of related behavior patterns having a common general function” (Scott and Fuller, 1965).

In current veterinary literature, many definitions as well as categories for aggression are proposed. Reisner (1998) says, “[o]ne researcher has suggested that aggression is a harmful stimulus directed toward a subject, with evidence of intent and arousal, and toward which the target responds aversively.” According to Reisner (1998), this definition excludes play, but would include the “…repertoire of postural threats preceding some bites”, i.e. direct stare, stiffening, erect posture, baring teeth, growling, barking, ‘bunting’, lunging and snapping.

Others conclude dogs are predators, thus it is necessary to include agonistic behavior in their entire repertoire. Beaver (1999) says, “clinically” aggression is described as “…one or more…distance-increasing behaviors…expressed in an agonistic way as the dog asserted itself at the expense of someone else” and considers it a “threat of harmful behavior directed toward an individual.”

Is aggression a problem?

Whether one considers canine agonistic behavior normal, abnormal, acceptable or unacceptable will greatly depend on an individual’s point of view. According to scientists, canine aggression is a normal behavior and according to Beaver (1999), “…represents a normal expression of distance-increasing vocal and postural communication.”

Typically, there are several ways to approach and define a problem behavior. First, one should have a clear understanding of what normal behavior patterns are for any particular species and that normal behavior may be expressed inappropriately depending on the environment. Second, one should consider a clients “…cultural and personal preferences and normative judgments” since they may impact the client’s “attitudes and expectations, scientific understanding, societal mores [customs] about animal behavior, and costs…associated with the dog’s behavior (Lindsay, 2001).

An ethogram is a compilation of normal dog behavior. The dog ethogram compiled by Lindsay (2001) provides “…an abbreviated catalog of significant functional systems and species-typical behavior patterns” and can be useful when assessing a dogs behavior problem. Additionally, one should consider the cause of the behavior (etiology), the descriptive features of the behavior and function the behavior may serve the animal. Understanding the precipitating stimuli (antecedents) and significance (consequence) the behavior may serve the animal may all be necessary in determining a plan for intervention.

Finally, one may want to include assessment of the dog’s quality of life, the client’s needs, relationship and bonding issues as well as the client’s safety.

The origins of ethology are deeply rooted in the works of Charles Darwin. In his book, The Expression of the Emotions in Man and Animals (1872/1965), he “described and catalogued” the most common social displays exhibited by dogs. According to Lindsay (2001), “[h]e argued that social animals, including dogs, evolve innate species-typical communication systems to meet habitual social demands placed upon them.”

Why communication is important

When one decides to work with dogs and particularly aggressive dogs that person should have some idea how to read dogs. According to Aloff (2002), understanding what dogs are communicating and our ability in recognizing their signals may mean, “…the difference between a dog you have to euthanize and one you can work with.” This is a rather important distinction when a dog’s life is in your hands coupled with emotional trauma an owner may be feeling.

Through careful observation, that may include personal observation by the behavior consultant, observing the interaction between the owner and dog, taking a video or still photographs and getting a detailed historical background could all be helpful in predicting the behavior, applying the proper training methods, management and identifying the dogs emotional state.

Context – where and when does it occur?

Determining the context the behavior takes place in may also be important in determining the intent of the dog’s motivation. For instance, if my dog is eating and I happen to walk past him and he freezes, this is a good beginning indicator he’s uncomfortable with my presence. Any further action by me to move any closer will probably elicit another clear signal indicating an increasing emotional response to my presence. He may slightly retract his lips and might even include a low growl. Anyone not heeding to this warning is asking to be bitten.

So context serves as part of our identifying clues when determining what type of aggressive behavior we are observing as well as accompanying signals.

Invoking Stimuli – what causes an aggressive response?

Commonly referred to as triggers these invoking stimuli are the leading indicators for changes in a dogs’ emotional state. These specific stimuli are commonly identified as early precursors to aggressive responses. Identifying these precursors or stimuli play an important role in developing plans to modify aggressive responses. Avoiding these known triggers that stimulate aggressive responses are important for changing the dogs’ perception of the negatively viewed stimulus. Continued rehearsal will only reinforce aggressive responses so recognition and avoidance are imperative for any modification plan.

Communicative Signals –dogs communicate avoidance, escape and control behavior

Signals are ritualized patterns of behavior. We commonly recognize two sets of ritualized patterns of behavior. The first set is agonistic or assertive behavior used to increase distance. The second set is appeasement or submissive behavior and used to decrease distance. Agonistic or assertive behavior is commonly associated with gaining and/or maintaining resources or establishing physical or social distance. The appeasement or submissive behaviors are commonly used to inhibit aggression or invite interaction.

Cutoff signals usually indicate conflicting motivations and may include “escape intentions…et-epimeletic intentions…or displacement activities” (Lindsay, 2000). He says, “…the cutoff is an expressive compromise between fighting and fleeing” saying further the “…apparent function of the cutoff movement is to suspend sensory contact momentarily with the arousing stimulus” attempting to avoid any further escalation toward a fight and avoid a “chase attack” if the animal chose to flee. Cutoff behavior has “relaxing effects” and appears to “…influence the opponent to reciprocate in kind” leading to mutual compromise rather than submission (Lindsay, 2001).

The function of cutoff signals is to “postpone or break off agonistic conflict” says Lindsay (2000). He says cutoff behavior referred to by Tinbergen is a “compromise movement” rather than a “submissive gesture” used as an “opportunity to call a draw or walk away without further conflict and potential injury to the contestants.”

Dogs use displacement activities “to distract [themselves] from an unfamiliar or unpleasant situation, particularly when…unable to cope, according to Aloff (2002).

Calming signals are used “to communicate non-aggressive intent. According to Aloff (2002), dogs use these signals with known, unknowns and during play when play escalates and the dog is uncomfortable continuing at that level.

Most dogs understand these behaviors; however, some dogs are better at using these signals than others. Lindsay (2001) says, “an important factor in the development of interspecific (dog-dog) aggression is the quality and quantity of early socialization.” Ideally, the best time to remove puppies from the litter is around 7-8 weeks of age. Puppies removed before 7-8 weeks and even those removed during the ideal time “may become socially intolerant toward other dogs” as adults, because they lacked sufficient early exposure to other dogs, which compromised their social skills.

Communication signals may become maladaptive according to James (1949) who described a “more or less stable social hierarchy developing among most litters by 12 weeks of age and is comprised of three groups, 1.) a very aggressive-dominant group; 2.) a mid-group termed sub-dominate; and 3.) an inhibited-submissive group. The social interaction between these groups may predispose individuals to use aggression toward other dogs according to how they learned to use these signals, i.e. a puppy from the inhibited-submissive group may learn that using aggressive signals works to fend off threats from higher-ranking individuals. Contrary to this, a more assertive puppy may learn their behavior is successful in gaining and controlling resources and social situations. The outcome is puppies from the submissive group tend to be more socially intolerant and the assertive individuals more aggressive and unyielding as adults. The mid-group tends to be more socially tolerant resulting from learning to use both submissive (yielding) and agonistic (assertive) behavior more successfully (Lindsay, 2001 & 2002).

Function of aggressive behavior

Generally, aggression is classified by its function often reflecting what purpose an aggressive response may serve. According to Lindsay (2001), aggression serves an “adaptive effort to establish and control” vital resources or situational events and most often when other means are ineffective.

It is Lindsay’s (2001) opinion that often when we classify aggressive behavior based on function and motivation we fail to provide a “consistent functional framework for analyzing aggressive behavior.” He says, “[a]ggression is not merely a passive response to circumstances” but rather serves as an “active and purposive effort aimed at obtaining various ends” using either “assertion of threats or attack.” It should further be emphasized that understanding and controlling aggression requires “recognizing that it is motivated and emitted under the influence of both emotional (reflexive) and purposive (instrumental) components.”

Aggression includes the “presence of significant setting events [contexts and motivation]…transient emotional establishing operations [frustration, irritability, anxiety]…and an evocative target or situation…which the threat or attack is directed” (Lindsay, 2001).

There may be instances when an attack is purely reflexive in cases of rage, but in most instances, aggression is directed at “controlling the behavioral trajectory of another whose interests or intentions conflict or collide with the aggressor’s interests or intentions” (Lindsay, 2001).

Classifications (Lindsay, 2001)

According to Lindsay (2001), he compiled the following list, referred to as “descriptive and functional characteristics of aggression,” and appears as his classifications for aggressive behavior.

Avoidance-motivated – socially insecure, and incompetent

Control-related – lacking boundaries, social inhibitions, often occurring in defense of locations and objects, and most often observed in male dogs.

Dysfunctional – explosive behavior, characterized by low threshold, may be related to PTSD.

Fear related – attacks associated with indications of fear type responses and associated postures.

Idiopathic – unknown, may be epilepsy.

Instrumental – learned aggression, either through classical or instrumental, but may be any situation or stimuli.

Intermale/Interfemale – often appears during sexual maturity, usually provoked by close proximity issues, usually this occurs between same sex individuals and less common in opposites.

Irritable – may be associated with pain, injury, most often associated with veterinary and grooming procedures, but may be observed during stressful situations, over-crowding, frustration, punishment, pain and deprivation. Includes threats, biting and scratching indicating a need to escape.

Low threshold – seems to have no apparent provocation or warning, often associated with dominance aggression. Form of dysfunctional often occurring where normal inhibitions and central control over aggressive behavior is compromised, sometimes referred to as “episodic dyscontrol syndrome.” Springer rage syndrome could be an example.

Maternal – may include inanimate objects during pseudopregnancy. During normal maternal care, it often occurs in relation the nesting area and offspring and usually directed toward strangers.

Pathophysiological – characterized by acute onset, and lacking poorly defined triggers, may be hormonal, genetic related or pathology. Hypothyroidism, neurological disorders and epilepsy could be considered.

Playful – may be directed toward owner that may be characterized as excessive mouthiness, biting hands and clothing. Associated with competition, learning and socialization.

Possessive – often provoked in competitive situations, sometimes is characterized as dominance aggression. It begins in puppyhood and observed during the entire life cycle.

Predatory – is distinguished by lack of affective arousal, often directed toward prey type stimuli and most often triggered by fast moving objects.

Protective – usually in the context of a socially significant other and does not occur during any other context.

Redirected – occurs when aggression is blocked toward a preferred target and in exchange is directed to a more locally available one.

Territorial defense – directed toward targets intruding on an established territory.

Trained – aggressive behavior that has purposively been taught such as police dogs, characterized by the control of specific releasing and inhibitory cues.

Xenopic – aggression directed toward strangers regardless of situation or territorial priority.


Aloff, Brenda. Aggression In Dogs.

WA: Dogwise. 2002.

Beaver, Bonnie V. Canine Behavior: A Guide for Veterinarians

PA: Saunders. 1999.

Lindsay, Steven R. Handbook of applied dog behavior and training. 2 Vols.

Iowa: Iowa SP. 2000. Vol. 1.

Lindsay, Steven R. Handout of applied dog behavior and training. 2 Vols.

Iowa: Iowa SP. 2001. Vol.2.

Reisner, I. (1998). Canine aggression: neurobiology, behavior and management. Retrieved from

Copyright – with exception of other authors, when noted, all materials are copyrighted.

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