In Ontario if a dog bites someone, its owner is "strictly liable" under the Dog Owners’ Liability Act (R.S.O. 1990, Chapter D.16). Under this law, the person who suffered the damage does not have to prove that the dog’s owner was negligent. An owner is liable even if the owner did not have any knowledge of the dog’s propensity for biting people. All that must be shown under the legislation is that the dog bit or attacked someone, and the owner is automatically liable for the incident.
The Dog Owner’s Liability Actcontains an important exception for a dog that protects its owner’s property. Pursuant to Section 3(2), the owner is not liable if the dog bites or attacks a person that is on the premises committing or intending to commit a criminal act, "unless the keeping of the dog on the premises was unreasonable for the purpose of the protection of persons or property."
In summary, the Ontario dog bite laws make the owners of dogs that liable to the injured person in the majority of cases.