CVMA | Documents | Legislation Concerning Vicious Dogs – Position Statement

Legislation Concerning Vicious Dogs – Position Statement

March 31, 2010


“The Canadian Veterinary Medical Association (CVMA) supports vicious dog legislation provided that it does not refer to a specific breed. This legislation should be directed at fostering the safety and protection of the general public from dogs classified as vicious. The CVMA encourages and supports responsible pet ownership.”


1. Dogs may show aggression that can be either appropriate or inappropriate. Appropriate aggression is a normal behaviour where an animal exhibits aggression that is in context with the degree of danger or threat to the dog. Dogs that show appropriate aggressive behaviour will exhibit a complete behavioural sequence which includes:

a) A warning (growling, lip lifting, barking);

b) A pause to observe the other individual’s response;

c) Action (bite only if the dog has interpreted the situation/person as dangerous), and release.

If the dog does not interpret the situation/person as dangerous, or is reassured or “in agreement” with the individual’s response to the warning, it could choose to end the aggressive sequence after the warning without further action.

2. A vicious dog is classified as any dog that is inappropriately aggressive and when unprovoked, bites or attacks a human or another animal, either on public or private property. Dogs that show inappropriate aggressive behaviour will have an altered behaviour sequence (no warning prior to the bite; no release of the bite; warning and bite without a pause between the two events, etc). Other indications of inappropriate aggressive behaviour are:

a) The aggressive behaviour cannot be justified or explained given the circumstances (inappropriate for the context, for example, not related to self-defence or because of pain or threat to the animal);

b) The frequency of aggressive events is excessive for the context;

c) The severity of the bite is excessive for the context.

3. Vicious dogs, regardless of breed, are a significant threat to humans and other animals. The CVMA recognizes that some possible causes of inappropriate aggression in dogs are improper methods of genetic selection, training and/or rearing (1). Pet ownership bears a responsibility to be familiar with and understand inherent differences of dog breeds. The CVMA encourages anyone considering pet ownership to discuss the selection process and breed differences with a veterinarian (2).

4. The CVMA recommends that municipal and provincial governments that are considering vicious dog legislation consult the model municipal bylaws proposed by the National Companion Animal Coalition (3).


  1. Overall KL. Clinical Behavioral Medicine for Small Animals. St. Louis, Missouri Mosby Publ, 1997;
  2. CVMA Code of Practice for Canadian Kennel Operations. Canadian Veterinary Medical Association, Ottawa, Ontario, May 2007;
  3. National Companion Animal Coalition. Sample Municipal Bylaw Regulating the Keeping and Controlling of Companion Animals. 1999. Available on the CVMA Web site at

(Revised March 2010)