Evaluation of the Aggressive Dog: What is a Really Dangerous Dog?
World Small Animal Veterinary Association World Congress Proceedings, 2004
Patrick Pageat, DVM, PhD, Dipl Behaviourist FVS, DECVBM-CA

Vets are used to evaluate the dangerousness of aggressive dogs through non-standardised parameters based on their own experience. Individual opinion, philosophical and emotional criteria seem to play a more important role than ethological and medical arguments. Our emotional image of the dog does not include the possible aggressive behaviour toward humans (except, maybe, those who threat the dog's owner). The evolution of our societies, including our clients, leads us to develop better clinical skills in the evaluation of the aggressive dogs. Because this evaluation occurs very close to the aggression, the owners and the possible witnesses are stressed and sometime unable to bring any consistent information. In such a context, it is crucial for the vet to avoid to be contaminated by the emotions of the clients and a highly professional approach is his only shield. Using results obtained from multicentric clinical observations, we have built a statistically based evaluation which helps the vet in performing an objective and scientifically based evaluation.

The steps of the clinical evaluation--the behaviour examination must begin through a very precise physical examination to detect any physical problem and specially painful lesions, sensorial impairment (e.g., deafness, loss of vision, anosmia, ...) and neurological disorders.

First step--is it a real aggressive behaviour?

Every bite is not always related to aggressive behaviours, some of them are related to impulsive reactions (e.g., trying to catch a moving stimulus: for example your hand or your foot...).

Second step--is the dog socialised with the specie of his victim? This is a crucial question regarding predation related aggressions. Dogs are predators and they usually can hunt any individual of any specie with which they are not socialised. When the dog performs predation related aggression toward humans, it has to be regarded as a highly dangerous dog.

Third step--is it possible to predict the aggressions? The vet has to know if it is possible to identify one or a few inductive stimuli between all the aggressions described by the owners (fearful stimulus, context of hierarchical competition, ...)

Fourth step--if the aggressions seem to be related to social competition, does the bite always occur or does the dog react another way (threats, growls)? Competitive aggressions can be modelized using the dilemma of the volunteer (close to the dilemma of the prisoner). The hierarchical system only works if both members are able to be appeasing (active submission) or submissive (active submission) to decrease the tension. Some behaviour disorders impair this social skill. This hierarchical social skill is very well summarized using a word of the Fuegian Indians: mamihlapinatapai which can be translated as "staying eyes in the eyes hoping the other one will propose something beneficial for both party, but that none of them wants to do by herself".




The threats before the bite


yes, except in dogs with fear aggression or learned aggression

Context identified as competition (for food, sex...)


yes, except for predation

Neurovegetative reactions


Yes, during fear aggression or irritative aggression (less common)

Bite immediately induced by any moving stimulus


No except predation (in this case, the sequence is easy to identify)

Dog socialised with a specie

Dog not socialised with this specie

The dog gets spontaneously in touch with any individual of this specie..

The dog ignores, avoids or is hypervigilant in front of most of the individuals of this specie, except, sometime, some precise individuals (taming).

The dog is able to play with any individual of this specie, whatever the age (juveniles or adults)

Usually, the dog is unable to play with individual of the considered specie, or sometime with some precise individuals (same as above, taming).

Communication from any individual of this specie induces predictable reactions with emotional synchronisation

Communication from the considered specie induces aggressive reactions, avoidance.

Being submissive in an unfavourable context for the evaluated dog

Approaching an unknown group in using appeasing attitudes

Flying away after growling when several individuals are allied against the evaluated dog

Accepting to be examined by the vet before coming at his feet to lye down

Dyssocialised (not been socialized during development), dessocialised


No, usually avoiding attitudes

Yes, but just in front of a threatening group, flies away growling


Sociopathy (hierarchical competition)





Learned Over aggressiveness





Fifth step--self-control of the aggressive reactions. Aggression includes all the threatening attitudes (mimics, growls, postures). Threatening means a self-control of aggression: the dog is able to adapt his level of response to the reactions of his challenger. Thus it is very important to obtain a precise description of what the dog does before biting.

During the bite, the way the dog keeps or modulate the pressure of his jaws is a good way to evaluate the dog's self-control. Until the dog is capable to modulate the pressure of his jaws regarding his challenger's reactions, we can consider the aggression as controlled.

In such a case, the aggression will be considered as reactional, which means it will be possible to suppress it just by controlling the eliciting context.

The final evaluation--is the result of the compilation of all the observed items and will answer the question: is this dog dangerous. It does not take care of the animal's history, which is more interesting to identify the origin of the problem and plan a behaviour therapy.

This evaluation is summarized in the following table.

The vet has always to remember that the final decision owns to his clients, but he has to help them in taking the good one for the dog and for the safety of the other people. Having a clear approach helps the clinician in avoiding the main traps in this crucial evaluation.

Balance of the physical examination and the five steps


Vet's proposal

A physical problem + self-controlled aggression

Depends on the prognosis of the physical problem. Most of the time it is possible to improve the behaviour at this stage

Control the pain if some, treat the physical condition, limit fearful contexts (e.g., physical contacts in painful animals).

A physical problem + uncontrolled aggression

Dangerous dog, poor prognosis, analyse the other parameters of risk (young children, ...)

Strict control of the risk, hospitalizing until owners' decision

Impulsive reaction

Dangerous dog, it is necessary to precise the diagnosis

Complete behaviour examination, refer the case if necessary

Predation related aggression

Dangerous for every individual of the prey specie

Never promise an improvement which

Aggressions with neurovegetative signs

Dangerous dog, necessity of a precise diagnosis

Decrease the threshold for eliciting emotional reactions: interest of non-desinhibiting drugs such as carbamazepine or fluoxetine

Self-controlled competitive aggression

By itself this dog is not really dangerous (predictable aggressions), see the other parameters (children)

The decision takes in account the people living with the dog children, aging people) but it (is possible to treat the dog).

Self-controlled competitive aggression with neurovegetative signs.

This dog could be dangerous (fear reactions)

As above, but it is possible to decrease the threshold for eliciting emotional reactions by using drugs

Uncontrolled competitive aggression (learned aggression without any threatening sign)

Dangerous dog

Advice clearly the owners about the high risk, never prescribe any drug until the owners' decision (increases vet's responsibility in case of further aggressions)


1.  Landsberg G., Hunthausen W., Ackerman L. (2003): Handbook of behavior problems of the dog and cat. Saunders, Toronto, 73-91

2.  Pageat P. (1998): Pathologie du comportement du chien. Editions du Point Vétérinaire, Paris, 108-156

Speaker Information
(click the speaker's name to view other papers and abstracts submitted by this speaker)

Patrick Pageat, DVM, PhD, DBFVS, DECVBM-CA

MAIN : Behavior : Evaluation of the Aggressive Dog
Powered By VIN