• One Health
  • Pain Management
  • Oncology
  • Geriatric & Palliative Medicine
  • Ophthalmology
  • Anatomic Pathology
  • Poultry Medicine
  • Infectious Diseases
  • Dermatology
  • Theriogenology
  • Nutrition
  • Animal Welfare
  • Radiology
  • Internal Medicine
  • Small Ruminant
  • Cardiology
  • Dentistry
  • Feline Medicine
  • Soft Tissue Surgery
  • Urology/Nephrology
  • Avian & Exotic
  • Preventive Medicine
  • Anesthesiology & Pain Management
  • Integrative & Holistic Medicine
  • Food Animals
  • Behavior
  • Zoo Medicine
  • Toxicology
  • Orthopedics
  • Emergency & Critical Care
  • Equine Medicine
  • Pharmacology
  • Pediatrics
  • Respiratory Medicine
  • Shelter Medicine
  • Parasitology
  • Clinical Pathology
  • Virtual Care
  • Rehabilitation
  • Epidemiology
  • Fish Medicine
  • Diabetes
  • Livestock
  • Endocrinology

Fear aggression in dogs (Proceedings)


Aggression is the most common behavior problem presented to veterinary behaviorists followed anxiety related disorders (separation anxiety, phobias). Traditionally, dominance aggression is most often diagnosed, especially when evaluating owner directed aggression. As a result of the label "dominance" being applied in these cases, owners were often directed to establish themselves as higher ranking over the dog through the use of a variety of physical means (punishment, alpha rolls, leash hangs, pinch and shock collars, etc.).

Aggression is the most common behavior problem presented to veterinary behaviorists followed anxiety related disorders (separation anxiety, phobias). Traditionally, dominance aggression is most often diagnosed, especially when evaluating owner directed aggression. As a result of the label "dominance" being applied in these cases, owners were often directed to establish themselves as higher ranking over the dog through the use of a variety of physical means (punishment, alpha rolls, leash hangs, pinch and shock collars, etc.). Escalation of aggressive responses often followed this approach. By examining the situations in which the aggression occurs, body posture exhibited by the dog and evaluating the early history of the behaviors it becomes evident that not all aggression is related to a question of dominance hierarchy. In many, if not most, of these cases a definite fear component seems to be the driving force behind the aggressive displays. This presentation is meant to clarify terms, differentiate possible diagnoses of aggression and offer thoughts on treatment of fear associated aggression.

Aggression is a normal canine behavior when displayed in the proper context. As a tool, aggression is utilized by dogs for a variety of purposes such as acquisition of food, defense of resource (food, territory, mating access), establishment of pack hierarchy, and self defense when threatened. In addition, submissive displays (averting stares, exposure of the underbelly, urination and retreat) are often utilized when a dog is presented with an overwhelming threat. If these signals are not recognized, a subordinate individual may be forced to rely on aggression (growling, barking, snarling or biting) as a last resort.

When examining these behaviors in the context of human-canine interactions, several factors must be considered. Do dogs and humans communicate in the same manner? While both are social species, methods of exchanging information differ. Often submissive signals are missed by observers not familiar with canine body language. As a result, dogs may be put in a position to use aggression when more subtle signals of submission are missed. Over time, learning can occur such that some dogs will totally abandon these submissive cues and instead more quickly elect to utilize these more offensive strategies to alleviate perceived threats.

Secondly, when punishment is used by humans as a means of exerting dominance, fearful dogs may be forced to respond aggressively while more confident animals may see the use of punishment as an incentive to engage in a so-called "arms race". This involves raising the bar by showing higher and higher degrees of aggression in response to ever increasing levels of punishment. In addition, punishment is often applied in the inconsistently creating an increased anxiety in the fearful animal. Not knowing whether to expect reward or punishment, conflicting emotions result lowering the threshold of reactivity and increasing the chance the dog will resort to the use of aggression.

It also appears that fear can be highly inherited so that fearful, anxious or timid parents can produce a higher number of similarly behaved puppies in a litter. Combine this genetic component with the previously described communication breakdown and the true meaning of nature and nurture can be seen. In addition, failure to positively socialize during the sensitive period (up to 14 weeks of age) results in the genetic prophecy of fearful behavior being fulfilled.


Body posture at the time surrounding the aggressive episode can be most valuable in determining etiology. Typical signs include:

     • Tail dropped or tucked

     • Ears laid back

     • Dorsal Piloerection (evidence of arousal and non-specific for fear)

     • Weight positioned over hind legs, head and neck lowered

     • Gaze dorsally or via sideway glance at target

     • Autonomic responses (urination, defecation, anal sac expression)

     • Lip retraction (Vertical)

This may be the early presentation in a younger dog. Over time, the body language may suggest a more confident dog as it learns to deal with its fear and anxiety by adopting a more offensive strategy:

     • Tail raised

     • Ears forward

     • Piloerection

     • Weight shifted forward with head raised

     • Staring directly at target

     • Lunging at or chasing target

In a fearful animal, the target is often an unfamiliar person or can be a very familiar person when conflict exists. It can be sometimes seen where an initially offensive aggressive dog can revert to a more defensive body posture if the threat does not retreat or is sudden and overwhelming.

The situation often also helps determine etiology.

A typical presentation where fear is induced and has the potential to result in aggression includes:

     • Approach from a stranger while on leash walk (leash can transmit owner anxiety, prevents escape by the dog, and also prevents canine specific communication in cases of Interdog aggression).

     • Situations where persons are bitten on the hand while reaching toward the dog

     • Being bitten on the backside or caudal thighs/feet (common with herding breeds)

     • Secondary to punishment by strangers or owners

     • Commonly seen with strangers entering the home or moving suddenly

     • Young, mobile, active children. Unpredictability breeds anxiety in the dog and can cause biting to prevent movement.

Abuse can cause fearful behavior but commonly is displayed as fear toward a specific trigger as opposed to more generalized responses.

Dominant behavior over another individual normally is not seen until a dog reaches social maturity (12-18 months) whereas fearful behavior is often seen very early (at times as early as 8 weeks of age). Body postures associated with dominance are usually more offensive in appearance, they never have an early defensive presentation and is often associated with control of resources (food, space, items) or secondary to attempts to direct the animal's behavior (commands, pushing, wiping feet, approaches, etc.). Dominant animals can also attempt to block movement of individuals. Dominant behavior can be very calculated and purposeful whereas fear responses are much more sudden and reactionary.

The successful use of aggression in a defensive situation can become a learned behavior. Over time, this response can be used in similar situations with greater confidence. As a result, the aggression can be displayed with increasing efficiency.

The principles of reinforcement and conditioning apply to the use of aggression.

Need to know the situation in which the aggression is occurring and the past history of aggressive behavior in order to make a proper diagnosis. Aggression is not static. Constant interaction of genetics and environmental influences can determine behavior at any one point in time.

Conflict aggression


     • Often Diagnosed as Dominance Aggression

     • Often show submissive posture. Not confident.

     • Ambivalent body language (wagging tail while growling). May show "remorse" after aggression.

     • Conflict occurs when put in confrontational situation or when cannot predict interaction.

     • Dog learns to use aggression to get out of uncomfortable situation and is reinforced

     • Owner directed aggression can occur in fear based situations:

     • Inappropriate use of punishment

     • Attempt to create owner: canine dominance structure in household

     • Inconsistent interactions

Treatment of fear based and conflict behavior

The basis of treatment is to remove exposure to inciting stimuli, utilize counter-conditioning/desensitization and at times prescribe anti anxiety medication.

Removing stimuli – can be accomplished in several ways:

     • Response Substitution - Discontinue all forms of punishment. Focus instead on distraction and redirection of inappropriate behavior to more appropriate responses which can be reinforced.

     • Head Halter – Can be used to help facilitate response substitution with the use of an indoor drag leash. Head halter decreases arousal and allows safe, efficient, non-emotional interruption of problem behaviors.

     • Avoid reinforcement of the behavior by withdrawing in response to aggression or giving positive attention (telling the dog, "it's all right").

     • Have unfamiliar people ignore dog at first greeting to allow more time for the dog to assess the situation without feeling threatened.

     • Identify any fear inducing triggers and avoid. For example, if house has several young children, isolating dog can avoid potentially negative interactions.

     • Increase consistency of owner and dog interaction. Always give a command, wait for a response and reward.

     • Avoid inconsistent, casual interactions by ignoring all attention seeking behaviors. Punishment should never be used.

     • Often called "Nothing in Life is Free" or "No Free Lunch"

Counter conditioning

     • Counter Conditioning is the proactive relaxation techniques in all environments that the dog will be in without presence of offending stimuli.

     • Make use of a palatable treats made available by visitors (while still ignoring dog) as a means of accomplishing Classical Conditioning (associate visitors with positive results).


By using fear inducing triggers that gradually increase exposure while asking for, and rewarding, relaxed behaviors taught during the counter conditioning phase. Examples would be people entering the home or approaches from strangers or unfamiliar dogs.


The use of medication addresses anxiety issues which can accompany fearful behavior. Anti-anxiety medications are indicated when the degree of anxiety is great enough to interfere with the ability to learn as behavior modification techniques are applied. Common side effects include sedation, anorexia, gastrointestinal disturbances, increased aggression and anxiety.

Typical anxiolytics include:

Tricyclic antidepressants (TCA's)

     • Clomipramine (Clomicalm) 2-4 mg/kg BID

     • Amitriptyline (Elavil)1-3 mg/kg BID-TID

Common side effects include:

     • Sedation, anorexia, gastrointestinal disturbances, increased aggression, anxiety and drug tolerance.

Selective serotonin reuptake inhibitors (SSRI's)

     • Fluoxetine (Prozac) 1 mg/kg SID

     • Paroxetine (Paxil) 1 mg/kg SID

Common side effects include:

     • Sedation and anorexia

     • Long half life results in delay (6-8 weeks) to effect

Benzodiazepines (BZD's)

     • Benzodiazepines are contraindicated due to potential for disinhibition of fear and possibly heightening the aggression.


Aggression, even when directed at owners, should not be automatically classified as Dominance Related Aggression. Often, the origin is a fear based response directed at unfamiliar people or, when conflicting signals are displayed by the dog's owners, can also be directed toward more familiar people. Understanding the animal's history and body language can be valuable in making the correct diagnosis. Treatment can include avoiding trigger stimuli, utilizing counter conditioning and desensitization (after grading the stimuli) as well as adding appropriate medication where indicated.

Related Videos
© 2023 MJH Life Sciences

All rights reserved.