On March 14th, 2013, Vernon Gladue killed his wife’s ten-pound shih-tzu— “Buttons”—by throwing her against a door frame, shooting it with a BB gun, and strangling it. At issue was whether he had a “lawful excuse”, pursuant to section 445(1)(a) of the Criminal Code:
445. (1) Every one commits an offence who, wilfully and without lawful excuse,
(a) kills, maims, wounds, poisons or injures dogs, birds or animals that are not cattle and are kept for a lawful purpose…
Gladue, who had been drinking, had just got into a lengthy argument with his wife. After about an hour, Gladue tried to kiss Buttons; who responded by biting Gladue’s upper lip, causing a minor bleeding. The fatal attack ensued.
The next day, Gladue sent his wife some text messages, including: “... dog doesn't bite hand that feeds it an (sic) if it does its gone,” and “Dog bit me an (sic) lost ...” and “Because I've told you, any dog that bites its master am (sic) draws blood dies. You get it?”
The Court found that there was room for some physical response to being bitten: “Pulling the dog away and even dropping it would have been fully justifiable in the circumstances (even if it injured the dog)” [para. 87]. However, once Gladue’s actions were fuelled by anger and a clear intent to cause injury, his conduct went beyond any lawful excuse: 2014 ABPC 45.
Gladue also attempted to argue self-defence. The Court, however, found that the self-defence provisions in the Criminal Code apply only to human assailants:
Speaking in non-legal terms, one may well be the victim of a dog's ‘assault’ and have to act in ‘self-defence’. That these terms may be utilized colloquially, however, does not mean that they take on the character or legal force of their Criminal Code counterparts [para. 102].
The Court found support in this interpretation from the cases of R. v. Greeley,  N.J. No. 207 and R. v. Barr,  A.J. No. 1021.
The Court also noted that the scope of “lawful excuse” extends even more broadly than “self-defence”. For one example:
The owner of a pet dog who discovers that the dog suffers from a terminal illness would be justified in having the dog euthanized. Indeed, our society views that as a compassionate response to the dog's plight. The same cannot be said in the context of human beings, however. A parent who discovers that his child suffers from a terminal illness would not be justified in having the child euthanized. Our society would view that as murder.… The policy of our criminal law does not militate in favour of extending Criminal Code provisions relating to ‘Defence of Person’ to animals (or vice versa) for that reason [para. 105].
Similarly, a zookeeper would likely find a lawful excuse in shooting a grizzly bear that was approaching a human infant found within its enclosure. Applied to humans in the “self-defence” context, the same conduct would likely not be permissible: consider a prison guard shooting an inmate that was approaching an infant found within his cell.
In further support of this dichotomy, the Court found that animals are “property”: the offence in question is found within Part XI of the Code, titled “Wilful and Forbidden Acts in Respect of Certain Property”.
Within the context of the Criminal Code, this separation makes good sense for several reasons. As remarked by the Court: “I resist the temptation to consider how the defence of self-defence would apply to this case if it were legally available. Did Gladue assault or even sexually assault Buttons by his unwanted kiss?”