Notes

The American Temperament Test Society provides testing around the country for dog breeds and provides a passing score for the entire breed, based on the percentage of passed over failed within total number of that particular breed tested. As of March 2001, the American Pit Bull Terrier has a current passing rate of 82.3% which makes him one of the top 5 most stable breed of dog in the country. Pitbulls are the second most tolerant breed tested by ATTS, after only golden retreivers. Any dog can be made vicious, it isn't the breed it is the person that owns the dog; that is like blaming the gun for shooting someone.
Pit Bull” is NOT a breed. It is a generic term often used to describe all dogs with similar traits and characteristics often known by the public as Pit Bulls
In almost every measure, out of the 35 most common breeds, Chihuahuas were reported as the most aggressive, especially toward bigger dogs they have not seen before. But before Chihuahua owners start picketing, none of the breeds were particularly aggressive. Chihuahuas peaked out at being moderately aggressive on some measures but were usually on the “sometimes aggressive” end of the spectrum. They only stood out because most other breeds—including pugs, collies and King Charles Cavalier Spaniels—were “seldom aggressive” or “never aggressive.”The American Pit Bull Terrier—a breed often portrayed as highly aggressive—consistently ranked as one of the least aggressive dogs, with the exception being toward new dogs, where it was still below Miniature Schnauzers. This could be because pit bull owners are conscious of the bias against the breed when self-reporting, but it does agree with the American Temperament Test Society, which also has found that American Pit Bull Terriers were among the most tolerant breeds.This is problematic, since not only does the evidence suggest that pit bulls are not more aggressive toward people than other breeds, but few people even know what pit bulls are. American Staffordshire Terriers, Staffordshire Bull Terriers, American Pit Bull Terriers, and mixes of any of these breeds all can be called a pit bull, and even people who are familiar with pit bull breeds can have trouble identifying them. In several recent studies, workers at shelters misidentified dogs’ breeds 50 to 87 percent of the time. When DNA tests identified a dog’s dominant breed as Dalmatian, shelter workers called it a terrier. When the dog was mostly Alaskan malamute, they called it an Australian shepherd dog.Breed misidentification plays a significant role in the stigma attached to pitbulls. It's difficult even for experts to properly identify a breed of dog. A study published in the Journal of Applied Animal Welfare Science ($$) found that "87.5% of the dogs identified by an adoption agency as having specific breeds in their ancestry did not have all of those breeds detected by DNA analysis.”For most of the 114 years since the American pitbull terrier was first recognized by the United Kennel Club, the breed was rightly seen as the perfect “nanny dog” for children because of its friendly nature, loyalty and stability.Since the 1980s, the media have falsely portrayed the pitbull as a bloodthirsty monster, inherently more dangerous than other strong breeds of dog. There is absolutely no factual basis for that narrative, but it's led to a vicious cycle in which people who want a badass dog to fight, or to guard property, or to intimidate rival gangs tend to choose pitbulls (or Rottweilers, another much-maligned breed). Pitbulls are the dog of choice for irresponsible breeders, dog-fighters, people who want a tough-looking dog to tie up in their yard and those who refuse to have their male dogs fixed because they think those big, swinging balls makes them look tough by proxy (86 percent of fatal canine attacks involve an unneutered male, according to the American Humane Society).A 2009 study in the Journal of Forensic Science ($$), found that the owners of vicious dogs, regardless of the breed, had “significantly more criminal behaviors than other dog owners.” The researchers added that “vicious dog owners were higher in sensation seeking and primary psychopathy,” and concluded that “vicious dog ownership may be a simple marker of broader social deviance.” And according to the ASPCA, “Pit Bulls often attract the worst kind of dog ownersAll of those human failings lead to poorly socialized and potentially aggressive dogs. It is because pitbulls are disproportionately favored by these kinds of owners that they're responsible for a statistically outsized share of serious attacks on humans. These incidents are then reported – and very often misreported – with breathless sensationalism by the media, and the cycle continuesMeanwhile, advocates say that pitbulls are the most frequentlyabused, tortured, abandoned and euthanized breed of dog in the United States. Shelters across the country are overflowing with pitbull mixes. Because of their stigma, they're often difficult to adopt out; a ride to the shelter is almost always a one-way trip for pitties.Pitbulls do not have special “locking jaws” – that's pure mythology. They don't demonstrate some sort of special shaking action when they bite – all dogs display similar biting behavior. Pitbulls do not exert an unusual amount of bite-force for their size. Multiple studies have found that bite force correlates to body-weight, and tests of three breeds conducted by National Geographic found that the American pitbull terrier exerted less bite-force than German shepherds or Rottweilers.
While they have been a favorite of dog-fighters for a century, pitbulls weren't originally bred for fighting. According to the United Kennel Club, sometime in the 19th century European breeders began crossing various terriers with bulldogs in search of a breed that had the former's enthusiasm and the latter's stamina and strength. The pitbull breeds that resulted were then imported and embraced “as catch dogs for semi-wild cattle and hogs, to hunt, to drive livestock, and as family companions.” (UKC also notes that pitbulls “have always been noted for their love of children,” but aren't “the best choice for a guard dog since they are extremely friendly, even with strangers.”)As Karen Delise details in her book, in the 19th century, bloodhounds were believed to be inherently vicious, having a taste for human blood. “Eventually,” she writes, “these bloodhounds fell from view, and we pushed other dogs into the spotlight, including the German Shepherd dog and the Doberman Pinscher.” (Dobermans were widely believed to have abnormally small brains, turning them into mindless killers, but this, like the pitbull's “locking jaws,” was simply a myth.) Other breeds that have haunted the popular imagination in the past include mastiffs and Newfoundlands. In Canada, Siberian huskies have often played the role of killer-hound.