In June, a 55-year-old mother, an employee of the Montreal transit system, was mauled to death in her own backyard by a dog authorities identified as a pit bull.

Christiane Vadnais's untimely death touched off a debate that has raged for decades in cities across the country and around the world: What to do with pit bulls?

Ten days after Vadnais died, the mayor of Montreal announced Montreal would change its bylaw to ban new ownership of the dogs. At the height of the pandemonium, it was revealed the dog may not have been a pit bull.

The city says the ban, which will come into effect Monday, will keep its residents safe. Opponents say Montreal is on the wrong side of history and that it's been proven breed-specific legislation doesn't work.

Montreal isn't the first Canadian city or province to ban pit bulls. So what has history taught us about outlawing pit bulls?

Whether the laws are effective depends on each jurisdiction's stated goal. Some say they work, some that they can't be enforced, and others prefer to target all dog owners regardless of breed.

Getting it right

The key to making good policy is to first correctly identify the problem at hand and what you want to achieve with the bylaws tackling it, said Erich Hartmann, intergovernmental practice lead at the Mowat Centre in Toronto.

"If you don't identify the problem correctly, then odds are you're going to end up solving the wrong problem," he said.

"When it comes to something like banning pitbulls, if you identify the policy problem as 'we need to ban pit bulls,' the policy options are set out for you," Hartmann said.

Dogs and their owners protested in Montreal over the pit bull ban. (Radio-Canada) "But if you step back and try to figure out if the problem is we want to reduce the number of pit bull bites, or we want to eliminate the amount of pit bull bites, that opens up more window of opportunity on how to solve the problem.".

Evidence is also crucial, he said.

"Decisions are made without evidence all the time, but good decisions are rarely made without evidence," he said.

And every policy should include a way to measure whether it's working.

Winnipeg

A series of pit bull attacks, including one on a nine-year-old girl who had to be hospitalized and needed hundreds of stitches to her face, spurred Winnipeg to ban the dogs in 1990.

CBC's Simon Gardner's report from November 1989 on the Pit Bull attack on nine year old Candace Allard 1:55

The goal, according to a city spokesperson, was to protect people from the pit bulls and to protect the dogs from irresponsible pet owners.

The city says pit bull attacks have gone down since the ban was implemented.

A 2012 study out of the University of Manitoba concluded that breed-specific legislation in cities and towns across Manitoba may have helped decrease the number of hospitalizations due to dog bites in those places, especially in young people.

Edmonton

Edmonton had a pit bull ban, but repealed it in 2012 after a comprehensive survey of how other cities handled the issue, combined with pressure from the animal community activists who said breed-specific bans aren't the way to go, said Keith Scott, coordinator for animal control officers.

"It was quite difficult to try and enforce," he said.

Edmonton preferred to focus on dogs' behaviour, not the breed. Scott said he's seen many severe bites from dogs that weren't pit bulls, but that don't get the same kind of attention and media coverage.

Edmonton's bylaw requires dogs to be licensed, spayed or neutered and leashed, and its bylaw includes clauses for dealing with dogs that chase, bite or attack people or animals.

Scott said the city receives between 400 and 600 dog bite, chase or attack-related complaints each year and that, on average, that hasn't changed. Pit bull type dogs are close to the top of the list of perpetrators.

Calgary

Calgary has never had a ban, because it holds the owners, not the animal, responsible for their dog's behaviour. To that end, the city offers free training and obedience classes.

Under the city's responsible pet ownership bylaw, owners can be fined up to $1,500 if their dog chases, attacks, bites or injures a person or animal.

Terrier-type dogs (which include American Staffordshire terriers and Staffordshire bull terriers, usually defined as pit bulls), accounted for the third-most number of bites in 2015, behind herding dogs (shepherds, border collies, sheepdogs) and working dogs (mastiff, husky, Rottweiler, Great Dane).

Ontario

Ontario's pit bull ban, called the Dog Owners' Liability Act, came into effect in 2005.

"We heard very clearly from Ontarians that they wanted to be protected from pit bull attacks," said Brendan Crawley, spokesman for Ontario's Ministry of the Attorney General.

Crawley said there are now fewer pit bulls in Ontario "and, consequently, fewer opportunities for a vicious attack by a pit bull."

The ministry is responsible for the law, but does not keep statistics on dog bites. It's up to municipalities to enforce it, and, by extension, to figure out whether it's working.

Ottawa doesn't enforce the law and isn't shy about it – it says so right on the city website.

In a statement, a city spokesperson said breed-specific legislation targets well-behaved dogs while excluding many poorly behaved dogs from other breeds.

Toronto dog owner Toni Baxter's dog, a pit bull, was bitten by another pit bull in June. (CBC)

Ottawa prefers to enforce its bylaw, which forces owners to register their dogs, use leashes and includes provisions on how to deal with aggressive dogs.

The city receives an average of 450 bite reports annually, and about two per cent, equivalent to about nine, involve alleged pit bulls.

In Toronto, the ban is enforced as written. When asked whether the ban was working, Elizabeth Glibbery, manager of Toronto Animal Services, said the number of registered pit bulls has decreased since the ban was implemented, and the number of dog bites has held steady since 2005.

Lucy the pit bull had to be flown to P.E.I. from Fort McMurray when her owners realized they'd have to drive through Ontario, where there is a pit bull ban. (CBC)

Paul Di Salvo, spokesman for Toronto Public Health, said the number of reports of dog biting incidents rose in Toronto from 1,028 in 2010 to 1,442 in 2015.

He added that since Jan. 1, 2015, when the breed of the animal is known, the three most frequently reported breeds involved in dog biting incidents are German shepherds, huskies, and golden retrievers.