The group's definition of a ptbull would include ptbulls, terriers, saffordshires, bull terriers, American staffordshire terriers, American pitbull terriers, or "a dog that has an appearance and physical characteristics that are substantially similar to any of the aforementioned dogs."

Klar said legislation is pending in parts of the U.S. and Canada where bans on pitbulls were enacted and pitbull owners subsequently came forward to challenge the law. "One of the more famous cases is one in the Supreme Court, where the challenge was rejected," he said.

"And it's interesting what the Supreme Court in the United States said in banning pitbulls: pitbull attacks, unlike other dogs, occur more often, are more severe, and are more likely to result in fatalities. The court also found that pitbulls tend to be stronger than other dogs, often give no warning before attacking and are less willing than other dogs to retreat from an attack, even when they are in considerable pain.

"However, interestingly, the court did not cite any scientific sources for this legal conclusion, meaning there's no reason why that happens, other than a pitbull is a pitbull. And we can't understand why it happens, but it happens."

Klar said a pitbull ban is necessary at the Mackle Road dog run because "we have many small dogs" and "many small children who frequent the dog run and it's a concern for all of us and we're very fearful of a tragedy." Mayor Anthony Housefather said council would be reviewing the request.

"Council will consider what steps we can take or we should take to limit or ban pitbulls from the dog run or impose restrictions on pitbulls, such as wearing a muzzle or other types of possibilities," he said. "Certainly it's something that council is sensitive to, so over the next month we'll try to make a decision as to what we would do with respect to pitbulls and other similarly dangerous breeds."

Pitbulls have a long history, stretching back centuries, as a breed used for dog fighting. According to a study by the Centers for Disease Control in the U.S., one-third of all fatal dog attacks between 1979 and 1998 were caused by pitbull-type dogs.

Two years ago, the province of Ontario made it illegal to import or transport pitbulls through the province. While pitbulls owned prior to that are still allowed, they must be muzzled and tethered on a leash no longer than 1.8 metres. Since 1990, the City of Winnipeg, Man. has had a by-law banning pitbulls on its territory.

In Vancouver, B.C. on Monday morning, a man was arrested in connection to a rash of pitbull attacks around the Vancouver region that had taken place over the last 11 months.