Could someone please explain what a "pitbull" is?

I have several questions - this story supplies an example of some questions I would like answered. A definitive answer from the Liberal party of Ontario would be great, but I won't hold my breath!
First, here is the article printed in full along with a link to the original article. I will post my questions and comments following the article.

 

Owner pleads for dog on death row

2008-01-02 15:09:22.000

A young Mississauga woman is pleading with Animal Control officials to spare her "docile" pet pit bull cross after the dog was caught running free on Christmas Day.

Gabriela Nowakowska, 20, says authorities have indicated 10-month-old Rambo will be destroyed unless she can prove he is not a purebred pit bull.

She insists the dog poses no threat to the public.

"I trust that dog more than I trust myself," says Nowakowska, after Rambo was picked up by animal control officers following his escape from her Kingsholm Dr. backyard in the Dixie Rd. and Dundas St. E. area. He made his get-away through an open gate.

"They can't just take his life. He's harmless," a tearful Nowakowska said in an interview outside the city's Central Pkwy. W. pound.
A letter she received from Mississauga Animal Control gave her until today to satisfy the pound that her dog is not 100 per cent pit bull.
Nowakowska has visited the animal shelter, travelling by transit or cab, almost every day since her dog was seized to plead with officials to release her pet.

On New Year's Day, when the facility was closed, she posted a letter on the door, pleading for more time to prove her dog is a harmless mixed breed (half pit bull). She attached a petition signed by 20 friends and family members indicating the dog is not vicious.

She has a letter from her veterinarian supporting her case.

Meanwhile, staff at the pound refuse to let her see her dog because they feel that could provoke an anxiety attack for the animal.

Rambo has received a reprieve on his death sentence until Animal Control manager Dulio Rose returns next week from vacation.

In August of 2005, the Ontario government passed Bill 132 that bans pit bulls. Since then, aspects of the Dog Owners' Liability Act, including the definition of a pit bull and the reverse-onus clause requiring owners to prove their dog is not a pit bull, were struck down on a court appeal.

A ruling on how to proceed with the law — whether it should be struck down entirely or reworded — is still pending.

"If I didn't love that dog to death, I wouldn't be doing this," Nowakowska said of her crusade to save Rambo.

Dr. Agnes Cetera of the Applewood Veterinary Hospital said, "we would like to help her (Nowakowka) but we cannot prove right now" that the animal is not a pit bull. It was seen only once, when it was four-months-old.

"You often cannot tell when you see the puppy," the vet said.
Now that the dog is grown, it does look like a pit bull, Nowakowska conceded. One of the original definitions in the legislation, and one which infuriated critics, was that a pit bull was defined as any animal which exhibited typical characteristics of the breed.

In his argument against the law in court, lawyer Clayton Ruby said even veterinarians cannot say for certain what constitutes a pit bull.
"If the vets can't tell, who can tell?" he said. "That's vague legislation. The constitution requires more than that."

Dr. Cetera said she believes, "the animal should not be punished for mistakes people make in training the dog. I don't believe destroying the dog is the only option."

Nowakowska understands why public officials would be concerned about vicious dogs.

"But it's really about how the owner treats and trains the dog. There's no reason to take the life of an innocent dog that's harmless."

- What exactly is a 'pit bull'? Is it similar in definition to the 'tooth fairy'? 

*Definition-- 'Pit bull' - a slang term for a shape of mongrel dog.  

'Toothfairy' - a slang term for a shape of fairy who happens to leave money for lost teeth.

- How does one prove a dog is "not 100% 'pitbull'? Oh, that is easy.. .No registration papers = a mongrel dog.  There are many breeds that could be in the ancestry of a dog and there is no way to prove this ancestry.

- Section 19, the reverse onus portion of the law was struck as unconstitutional; therefore that would mean it is up to the Crown, or in this case the City, to prove the dog's ancestry. How are they going to prove the dog's lineage? There is now a dog's life on the line and an owner who may or may not decide to take legal action against the city. The stakes were just raised on this silly 'pick the breed game'.

- The veterinarian said "you often cannot tell when you see a puppy", referring to breed ID. Oh, so I assume this particular vet feels she can determine beyond a doubt the combination of breeds in a mixed breed dog.

I think not! Picture this, a cute looking Jack Russell terrier meets up with a Viszla down the street. They have a little wine... well you know. Sixty-three days later along come some very cute, short-coated puppies. Get it? These pups go on to new homes and someone who makes a mistake and leaves the gate open. A dog is picked up by Animal Control and the next thing you know it's a 'pit bull' 

Is a vet now qualified to identify the breeds of the sire and dam of this dog, not to mention their parents and so on back for at least five generations? Is it even safe to state the parents were purebreds? What if they were mixed breed dogs as well? What are the chances of that? Pretty darn high, I would think.

Guess what folks, this situation happens frequently! There are hundreds of cases across the province, as we speak. There have been over 2000 dogs killed in the province of Ontario for looking a certain way. They may or may not have done anything wrong (in human terms that is).. they may have just been seen by someone who thought they saw a 'pitbull'!

- Who exactly is qualified to definitively identify breeds of a cross bred dog? Nobody! There is no scientific, objective way to identify the breeds that constitute a mutt. I maintain, if my butt is on the line in a court of law, and my dog's life is at stake I certainly do not want ANYONE playing some silly guessing game of 'pick the breed of the mutt' - especially in view of the sometimes hiliarious breed attributions made by these kinds of witnesses.

- I do have one answer to a statement made toward the end of the article. It was stated in the article "one of the original definitions in the legislation which infuriated critics, was that a 'pit bull' was defined as any animal that exhibited typical characteristics of the breed."

This statement is the understatement of the year!

Why do you think 'CRITICS' would be infuriated by this definition? Because THERE IS NO SUCH THING AS A PITBULL! How does anything exhibit typical characteristics of something that doesn't exist?

Now there is a question for all you science buffs.