What does an aggressive dog look like, some examples? What do we look for when evaluating an aggressive dog?


What does an aggressive dog look like, some examples?

What do we look for when evaluating an aggressive dog?

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.”

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.


Determining the context the behavior takes place in may be important determining intent, 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 Stimulus

Commonly referred to as triggers these stimuli are the leading indicators of a change in a dogs’ emotional state.  These specific stimuli, identified are usually the early precursors to the behavior.  Identifying these precursors or stimuli play an important role in developing plans to modify aggressive behavior.  Avoiding the triggers that stimulate an aggressive response is an important part of changing the dogs’ perception of the negatively viewed stimulus.  Continued rehearsal may reinforce the aggressive response so recognition and avoidance are imperative for any modification plan.

Going back to my earlier example around the food bowl, if I continued my approach and my dog escalated his response by including a slight lip retraction exposing his incisors and emitted a low growl and I backed off, my dog is reinforced for his behavior because it worked.  I was smart to back off, but I would be remiss to my dog if I ignored his 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.  We commonly associate agonistic or assertive behavior 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 usually 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 as a distraction when confronted with unfamiliar or unpleasant situations, specifically when they are “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.

Another reason communication signals may become maladapted is because litters according  to James (1949) “found that a more or less stable social hierarchy develops 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.  On the opposing side, 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).

The following are examples of agonistic behaviors identified in specific context with invoking stimuli:

What does the food-guarding aggressive dog look like?  What signals might he use?

Using a typical food-guarding context including some common triggers, an observer might see the following sequence of behavior.

A dog is conspicuously eating from his/her bowl and an astute owner walks by noticing the dog has stopped eating and is frozen in place.  This is accompanied by a hard stare but not directed toward you, the perceived threat.  If you continued to impose on the dog, he will usually escalate his signals that may include a low growl and may simultaneously retract his lips exposing his teeth.  If this was not enough to ward you off, he may snap, usually an air-snap deliberately delivered.  According to Donaldson (2002), “when dogs intend to bite, they bite…when they intend to snap, they snap” and even a “geriatric” dog is faster than even the most conditioned of athletes.  Considering this capability, any further advance will most likely result in a bite.

I purposely used the word astute to describe the owner, because I would suspect the average dog owner would not be aware of the subtle signs a dog may offer initially.  In this particular context, I do not see a dog offering any cut-off signals, displacement activities or calming signals.  I would suspect to offer these types of behavior would mean the dog would back away rather than continue to defend the object.

What does the control complex (formerly dominance aggression) dog look like?  What signals might he use?

The confident aggressive dog described by Lindsay says, “[d]uring a strong threat, dogs stand tall on their toes with hackles raised, ears erect, and tail held stiffly up.  The body is tense, with the eyes singularly focused on the target, holding it transfixed with a steady and unwavering gaze.”  As the threat continues, the dog will “retract the upper lip back and up to unsheathe the front incisors and large canines” and this “snarling action is often followed by a menacing low growl in immediate preparation for attack.”

This description may apply to many aggressive dogs, but it certainly could apply to a confident assertive dog that has no intention of backing down.  This is how I would describe the control complex aggressive dog.

According to Aloff (2002), dogs classified, as control complex aggressive are “abnormal” saying they are “obsessive about rank order” seeming to think of nothing else.  She defines them as “control freaks” always looking for “slights to their authority or status” and lack any ability to use any “mechanisms for conflict resolution.”  She further says, they “offer little or no warning and the triggers may be inconsistently displayed and broad due to the accumulation of the dog’s irritation level.”

What does the predatory aggressive dog look like?  What signals might he use?

The basic predatory behaviors for the dog are orient/eye/stalk/chase/grab-bite/kill-bite/dissect (Coppinger, 2001).  However, we have altered this pattern through either selective breeding or using the developmental periods to our advantage.  According to Coppinger, just as social motor patterns have developmental periods, so do the predatory motor patterns and if during the time of onset a particular behavior is not reinforced; it drops out of the dogs’ repertoire completely (Coppinger, 2001).

Predatory behavior is distinct, is not motivated by anger, and occurs without signs of sympathetic arousal.  However, some scientists do think it may be affected by “coactive anxious and frustrative influences” ultimately leading to affective aggression.  According to Panksepp, predatory aggression does not “always remain under the control of a single emotional system” and can result from “redirected motivation” (Borchelt et al., 1983) said Lindsay (2001).

Viewed this behavior sequence might include observing what appears to be a dog orientating toward a moving target.  This moving target may be another animal, skate boarder, bicyclist or child wobbling about.  As the dog locks on to the target one might see the dog begin to stalk usually signaled by lowering the front legs and body and slowly moving toward the target, the tail will be slowly moving from side to side, this behavior may include salivating and ends with a swift bite that includes shaking.

Some other forms of aggression with entirely different functions are often confused with predatory aggression.  Most often, these include territorial and redirected says Aloff (2002).  Predatory drift may also occur during an escalation in play behavior when one dog shifts from one emotional state to another.  Aloff (2002) points out there are significant differences between play aggression and predatory aggression when determining what you are observing.

What does the fearful aggressive dog look like?  What signals might he use?

Aggression is usually inhibited by fear and elicits either a freeze or a flight response, however in the case of a dog that is unable to respond appropriately due to restraint the animal may have no other choice but to bite.  These dogs may attempt to control the situation initially by using calming signals or appeasement behavior and if these strategies are not countered with appropriate responses, the fearfully aggressive dog may have no other choice but use aggression.

When the dog is successful in thwarting off a perceived threat the defensive behavior may be reinforced and any future behavior may be triggered by conditioned stimuli associated with the original context resulting in avoidance-motivated aggression.  The avoidance-motivated aggression may appear similar to control complex aggression but differs because it is always defensive rather than offensive.

According to Aloff (2002), “fear and stress often result in aggressive behavior as a symptom of the underlying anxiety” and a dog may in turn express aggression in conjunction with overt fearful behaviors” including avoidance, escape and physiological changes related to the sympathetic branch of the autonomic nervous system (ANS).

The behaviors one might observe related to the arousal of the ANS might include, dilated pupils, activation of the sweat glands, increased heart rate, rapid shallow breathing, change in gut motility, piloerection and loss of control over bowels and bladder.

According to Lindsay (2001), “fear aggression can be differentiated by defensive postures” and approach-avoidance conflict and the following are the general observable behaviors and characteristics.

  • Ears back
  • Tail tucked
  • Nervous snarling
  • Showing teeth
  • Barking – possible repetitive conflict behavior
  • Licking movements – agitation when exposed to eliciting stimuli, such as doorbell, approach of strangers, noisy children, skaters and other similar stimulation or approach of dogs
  • Most likely to threaten or bite when suddenly approached by a fear eliciting person or dog…and escape is prevented
  • Once fear aggression has generalized to avoidance behavior…fear behavior may be replaced…telltale signs of fear may be replaced with increased confidence and reduced latency and occur under minimal provocation
  • Fear related or defensive aggression stands opposite to dominance related or offensive aggression on the agonistic continuum
  • Dominance aggression occurs most often during competitive conflict between conspecifics, stimulated by coactive influences of frustration, irritability, and anger
  • Defensive aggression is most often directed toward another group member or species…under the influence of acute threat, fear or anxiety.
  • Tendency to bite is most often seen by shy or nervous dogs…who have learned to rely on biting as a means of self-defense
  • Fear aggression and dominance aggression may present together in the same dog – bipolar aggression may be a suitable term for this dog…and may depend on context when they alternatively appear


Aloff, Brenda.  Aggression In Dogs.

WA:  Dogwise.  2002.

Coppinger, Raymond, and Lorna Coppinger.  Dogs: a new understanding of canine origin,
behavior and evolution.  Chicago:  Chicago UP, 2001.

Donaldson, Jean.  The Culture Clash.

CA:  James & Kenneth.  1996.

Lindsay, Steven R.  Handbook of applied dog behavior and training.  3 Vols.

Iowa:   Iowa SP.   2000.  Vol. 1.

Lindsay, Steven R.  Handout of applied dog behavior and training.  3 Vols.

Iowa: Iowa SP.  2001.  Vol.2.


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