Compiled by Dr Q Sonntag and peer reviewed by Dr H Zulch

A behavioural perspective


Canine aggression is a common occurrence in veterinary practices. It often results in injury to veterinarians and / or staff members. Most injuries sustained by veterinarians and staff members in this way are caused by a lack of knowledge of canine signalling and communication. A better understanding of these issues, as well as of fear-related aggression, can prevent unnecessary injuries caused by aggressive patients.

What is fear?

In most cases where dogs bite veterinarians, they do so as a result of fear. Pain is a very powerful elicitor of fear. Dogs in the veterinary consulting room often experience pain. Fear is the response shown by an animal when it perceives a threat to its own safety. An unfamiliar environment and strange people are often perceived as threats by dogs. Fear is a reaction to a stressful, dangerous situation. Fear also involves a certain emotion - a feeling of apprehension associated with the fear-evoking stimulus.

Fear can be expressed in different ways by animals:

Freezing: This usually occurs when the threat is of low intensity or distant (inhibitory response).
Fleeing: This is a response to high levels of fear or a threat that is very close (excitatory response).
Fighting: This response occurs in the presence of high intensity fear and when the animal is unable to flee (excitatory response). Fleeing is often blocked by the presence of the threat itself.

The most common fear-eliciting stimuli in dogs and cats are loud noises, unfamiliar people, unfamiliar animals and novel situations. Fear can be an innate response or a learned behaviour, and is often a combination of both.

Fear can be recognised by certain physiological changes as well as body and facial signalling (visual signals) .

Physiological signs or fear are

Hyperpnoea (panting)
Increased viscosity of saliva and decreased salivation
Muscle tremors, shivering, muscle tension
Urination (intense fear)
Defaecation (intense fear)
Anal sac expression (intense fear)

Visual signs of fear are:

Lowering of the body and head
Piloerection (raised hackles)
Tail tucked between the legs
Averting the gaze (avoiding eye contact)
Ears flattened
Corners of mouth retracted
Mouth open, exposing all teeth
Vocalisation (whining, high-pitched barking)
Snarling, growling, snapping

Fear and anxiety

Fear is an acute, adaptive response to a specific situation that is potentially injurious to the animal. Anxiety is a chronic state of sympathetic arousal in response to an expected threat which may or may not be real. Anxious dogs appear tense and are hypervigilant (constantly alert, scanning the environment for potential threats). Chronic anxiety often gives rise to behavioural problems including generalised fears and phobias, unpredictable aggression and compulsive behaviour.

Fear and aggression

When a dog perceives a threat that is in close proximity and from which it cannot escape, it will use certain signals in an attempt to increase the distance between it and the threat. Raised hackles, snarling and growling are all distance-increasing signals and are meant to make the threat go away (see Table 1). If this does not happen and the threat continues to approach or does not go away, the next (and only, from the dog’s perspective) option for the dog is to inflict injury by biting.

The typical consulting room scenario is the dog that finds itself in a strange environment with a strange person. It feels insecure and threatened, tries to jump off the table or escape through the door, is restrained and now effectively can no longer escape the impending threat to its safety. As its critical space is invaded, whether by the physical restraint, being touched all over the body during the examination or having a thermometer inserted, it responds with a warning such as a growl. The examination continues regardless. In some instances, such behaviour is punished with verbal reprimands, further physical restraint or sometimes even physical punishment such as being slapped.

The dog’s suspicion that this person may be a threat is now confirmed, especially in the situation where physical correction is applied. Once the possible threat is perceived to be a real threat, the dog has no other option than to respond by biting in defense of its own safety.

A similar situation occurs in the hospital cage. The fearful dog may not allow anyone to touch it because it perceives the approach as a threat to its safety. The more the handler insists on getting closer, the more threatened the dog feels and the more it is likely to react aggressively.

The veterinarian or handler often reacts to this reflexively by hitting the dog – again a confirmation to the dog that this person is indeed dangerous and thus ample justification, from the dog’s point of view, to escalate the aggressive behaviour. This escalation of aggression may be evident immediately, or at a future visit.

Learned fear and aggression

Dogs can therefore learn to be aggressive to vets because vets often reinforce the notion that they are to be feared by the manner in which they respond to canine fear. Another situation which also often occurs, is that of the owner inadvertently reinforcing fearful and aggressive behaviour by comforting a dog that is growling in the consulting room. It is a perfectly natural human response to do this and clients need to be made aware of the effect this has. The more attention is paid by the client to fearful and aggressive behaviour, the more the undesired behaviour is reinforced. The dog learns that it is appropriate to behave in such a way as it is being rewarded by the owner.

Prevention of fear-related aggression in the veterinary practice (table 1)

At the age of 3 – 16 weeks, puppies are most sensitive to influences from their environment. This is commonly known as the "socialisation period". If they have positive experiences with all the environmental stimuli they may encounter later in their lives (cars, vets, people of different appearances, noises, other dogs, other animals etc) during this period, they are less likely to view these stimuli as dangerous or threatening later in their lives.

If however, during this sensitive age period, they have negative experiences, they learn by association that those situations which are unpleasant or have negative consequences for them, are potentially dangerous.

Veterinarians can play an active role in assisting clients to produce happy, confident dogs by encouraging them to expose their puppies in a positive way to as many environmental stimuli as possible before they are 6 months old.

The veterinarian must ensure that the first experience a puppy has in a veterinary practice is pleasant:

Encourage a no-charge pre-vaccination visit where the vet and veterinary staff play with the puppy and feed it delicious treats (the treats do not need to be big, just tasty).
When the puppy does have to receive an injection, take special care to minimise the chances that the puppy will feel pain: Use new, sharp needles and precede the injection with positive, fun interaction. Desensitise the injection site by rubbing it fairly vigourously before injecting.
Distract the puppy during the injection or other potentially painful procedure with an interesting toy.
Reward the puppy immediately afterwards with a tasty treat if it behaved well.

Encourage owners of new patients, especially puppies, to visit the practice often with the dog when there is no need for a consultation, and to feed treats during such visits or provide other positive experiences such as play and presentation of favourite toys.

Make an effort to invite clients and pets into the consulting room during such visits, simply to show the dog that the consulting room does not always mean unpleasant things. Put the puppy on the table and pet it and give it a treat. Such visits can play an important role in establishing a healthy and mutually beneficial client-veterinarian relationship.

Veterinary practices can offer puppy socialisation classes or once-off puppy parties on their premises to help the puppies make a positive association with the veterinary practice. At the end of each class, the puppies are taken through the consulting room where they can be handled and given treats.

The veterinarian or veterinary staff should explain to clients how their own behaviour can inadvertently reinforce unacceptable canine behaviour. Most people do not understand this concept but fully understand the implications of their actions once it is explained to them in a caring manner. Clients who understand that attention given to a fearful or aggressive dog is in fact positive reinforcement for such behaviour, will take care to change their own behaviour. The client needs to withdraw all physical and verbal interaction with the dog the instant it shows inappropriate behaviour.

First visit – no procedures, no pain, just fun

Take care with first injection – new needle; gentle handling

Reward puppy with treats

Distract puppy with fun toy during any potentially painful procedure

Encourage regular visits in between consultations

Invite client and puppy into consulting room just for fun and pleasant experience

Offer puppy socialisation classes, or once-off puppy parties

Educate clients on how to behave when the patient shows signs of fear and aggression

Table 1: Preventing fear-related aggression in the veterinary practice

Recommendations for dealing with aggressive dogs in the veterinary practice

Dogs that already perceive the veterinarian and / or veterinary staff as a threat need to be handled with care and patience. The person handling the dog should act calmly and in a non-threatening manner, using calming signals to relax the dog.

Calming signals are visual, physical signals (body language) which dogs use in order to avoid conflict. This can be observed when dogs unfamiliar with each other meet and wish to convey to each other that they do not intend an antagonistic interaction. People can use many of these signals to show a dog that they do not wish to engage in conflict (see table 2).

Avoiding direct eye contact

Turning the head away

Turning the body sideways

Keeping the body low – crouching, sitting down

Approaching the dog from the side

Approaching very slowly

Avoiding rapid movements

Table 2: Calming signals which can be used by the veterinarian to calm a fearful dog

The veterinarian can effectively use calming signals to signal to a fearful dog that conflict is not intended and that there is therefore not a real threat.

A slow, calm approach without any threatening body language will help a fearful dog relax. The veterinarian should make a point of avoiding direct eye contact with the dog, approaching the dog from the side with a sideways body posture, avoiding rapid movements and even yawning and licking the lips. A tasty treat can be offered in a slowly outstretched hand while not looking at the dog directly. If the dog refuses this, a treat can be tossed on the ground first. However, highly stressed dogs often do not eat at all. Time and patience, and possibly sedation will be required.

Touching the dog should be postponed until the dog shows trust by eating from the veterinarian’s hand or sniffing and approaching the vet in a calm manner. Very fearful dogs are best examined and treated on the floor rather than on the examination table. Picking up a dog and placing it on a table may be perceived as a threat and exacerbate its fear.

A calm relaxed approach by the veterinarian makes the dog and the client relax and proves to the dog that the perceived threat is not real.

The same approach should be used when retrieving a fearfully aggressive dog from a hospital cage.

The role of physical punishment and force

Physical punishment, jerking the dog on a choke chain and shouting are counterproductive. The veterinarian should avoid such actions as they will only result in heightened fear and / or aggression.

Retaliating to aggression with aggression results in a vicious spiral of increasing aggression and anxiety with no benefit to anybody.

Physical abuse of patients (strangling, beating, helicoptering, long-term muzzling) cannot be justified and will place the veterinarian at risk of being charged with unprofessional conduct and / or animal cruelty.

The use of muzzles

The veterinarian who deals with a fearful or aggressive dog should consider the well-being of the animal and also his or her own safety, as well as that of the client. If a dog is not approachable at all and does not respond favourably to calming signals, the veterinarian should use appropriate methods of restraint. Acceptable methods of restraint would include the use of muzzles and / or pharmacological restraint.

When in doubt, veterinarians are advised to use muzzles to protect themselves and the clients. The veterinarian should make this decision and need not be led by a client insisting that the "dog won’t bite" – in an unfamiliar context, there is no guarantee that a dog will not bite. It is not reasonable for the client to expect the veterinarian to place him- or herself at risk.

Tight-fitting nylon muzzles can only be used for short periods of time (a few minutes) as they restrict panting and thereby affect thermoregulation. They require close contact with the dog’s muzzle to be put on and with an extremely reactive dog this could be risky. Crepe bandage (improvised) muzzles also restrict panting but are easier to apply without getting the hands close to the mouth of the dog.

Basket-type muzzles allow panting and usually even eating and drinking and can be left on for longer periods of time. However, a dog should always be under direct supervision and on a lead when wearing any type of muzzle. Dogs should never be placed unsupervised in a kennel with a muzzle on.

If a dog has a history of aggressive behaviour in the consulting room, it is advisable to request the client to put on a muzzle before entering the veterinary practice. The calmer the dog is when the muzzle is put on, the better.

If the dog is already in the consulting room when the muzzle needs to be used, the veterinarian must use his or her discretion in deciding who should put it on. If the client is unsure or incapable, it is better for the vet to do it.

Dogs with a known history of aggression

Dogs that have a known history of aggression in the veterinary practice should be identified on the patient record and a course of action in handling such patients should be decided upon together with the client:

Clients could be requested to acquire a muzzle and get the dog used to it at home so that the muzzle does not contribute to the stress of visiting the practice.
Dogs could be premedicated with anxiolytic medication before visiting the practice. The longer-acting benzodiazepines like oxazepam (0,2 - 1 mg/kg) or alprazolam (0,125 – 1 mg/kg not exceeding 4 mg/dog) are recommended.
Clients could be referred to a veterinary behaviour practitioner for an objective assessment and appropriate therapeutic approach.

Veterinarians understandably become frustrated with uncooperative, aggressive patients and then often blame the clients for having uncontrollable pets. However, an accusatory attitude towards the client simply alienates the client and certainly does not help the dog. A positive and empathetic approach to address the problem will prevent the breakdown of the veterinarian-client relationship.

Right of refusal of treatment

The veterinarian is entitled to refuse examination and treatment of an extremely aggressive dog. Such cases could be referred to another veterinarian with the agreement of such veterinarian, or the client can be requested to return with the dog at another time, when specific measures can be taken (e.g. prior application of a muzzle or administration of medication).

In the event of an aggressive dog that cannot be controlled at all even if all reasonable measures have been taken, the veterinarian has the right to refuse seeing that patient.

Hospitalisation of aggressive dogs

When an aggressive dog needs to be hospitalised and the veterinarian is unable to provide the necessary care and treatment due to its aggression, the owner, or somebody appointed by the owner with whom the dog is familiar, should be requested to assist in removing the dog from its hospital cage and administering the necessary treatment.

Safety and security

The veterinarian never needs to place him- or herself at risk of being injured. Veterinarians are often injured in the process of preventing patients from escaping. Precautions should be taken to ensure that dogs cannot escape from the practice should they become uncontrollable. Such precautions would include, amongst others, secure gates on cages, secure doors to hospital rooms and consulting rooms, safe outside perimeters of practices and escape-proof windows.

Clients should be encouraged to use proper leads and collars so that dogs cannot escape and place veterinarians and veterinary staff at risk by having to chase and catch such animals. If the veterinarian takes reasonable precautions to prevent escape of animals, it will not be necessary to risk being bitten while retrieving an escaped dog.

Dominance aggression – fact and fiction

There is a misconception that dogs bite vets because they want to exert dominance. Dominance aggression, however, is a problem of resource control within the dog’s social structure in its home. It typically occurs in the dog’s own territory – it is usually directed to people familiar to the dog who are part of the dog’s social system. The aggression is an attempt by the dog to control access to resources. Aggression directed towards people unfamiliar to the dog, like the vet, has to do with a direct threat to the animal’s safety and is the result of fear.


Veterinarians can play a pro-active role in minimising aggressive interaction with patients. Clients appreciate such efforts as it confirms that the veterinarian really does care about the patient. This will result in a more positive vet-client relationship with all the ensuing benefits.


  1. Abrantes, Roger 1997 Dog Language: An encyclopaedia of canine behaviour
  2. Wakan Tanka Publishers, Naperville, Illinois, USA
  3. Lindsay, Steven R 2001 Handbook of applied dog behaviour and training, Volume 1 Iowa State University Press
  4. Lindsay, Steven R 2001 Handbook of applied dog behaviour and training, Volume 2 Iowa State University Press
  5. Overall, Karen L 1997 Clinial behavioral medicine for small animals Mosby
  6. Rugaas, Turid 1997 On talking terms with dogs: Calming signals Legacy By Mail, Inc, Carlsborg, USA

(Published- April 2003, courtesy of Dr  I Sonntag)


Links to African Council websites

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Kenya Veterinary Board

Veterinary Council of Tanzania

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