Here is an older article from a blog called 17 Barks:
http://17barks.blogspot.com/2013/01/pit-bull-behavior-3-distinctions.html
Beginning Paragraph: (Warning, graphic photos at link)
Pit bull behavior: 3 distinctions
This post from a couple years ago has been updated and bumped to the top, as it has become increasingly relevant in the current climate. We see a surreal contrast between, on one hand, the daily toll of disfigured, maimed and mutilated pit bull victims, and on the other hand, the swarms of sociopathic pit bull promoters angrily attacking any news site reporting any news of pit bull attacks, bullying and threatening any who say a word about the pit bull problem.
As pit bull fans like to say, pit bulls are not like other dogs, and we must agree, but not for the reasons they would like. As a natural result of a long, bloody heritage, pit bulls have a set of behaviors and motor patterns which differ from other canines.
Pit bull attacks A/C officer
Those differences emerge often in the following notable pit bull behaviors:
Performing a remarkable escape in order to attack a victim.
Entering a stranger’s house to torture and kill the animals living inside.
Unexpectedly mauling an owner or other family member.
How can we explain this? Do we chalk it up, as the pit bull promoters would have us do, to a problem exclusively of “bad owners”? How then do we explain so many kindly, loving pit bull owners like Darla Napora who have been suddenly betrayed and mauled by their well-treated and well-behaved pit bulls? No, we have to look at the genetic characteristics of the breed - this should be patently obvious. Only someone with a very specific agenda could deny the reality of breed-specific characteristics. Why do pit bull fans refuse to accept or understand the role of genetics in pit bull behavior?
(Continued)
Certainly, we can all agree that pit bulls are canines, along with wolves, coyotes, jackals and domestic dogs, which cover an incredible range of size, shape, temperament and behavior profile. If humans varied in size as much as different breeds of domestic dogs, then adult humans would range in height from about 2 feet tall to 33 feet tall - a remarkable variation!
One marvels at the flexibility of canine DNA, expressed in the sheer variety of characteristics for which domestic dogs have been bred - quite apart from size and shape, a remarkable variety of behavior and temperament is on display. From common ancestors have emerged dogs bred to point at birds, or to retrieve downed birds with soft mouth.
Shepherd types were bred to herd livestock, while the livestock guardians were bred for the complementary role of guarding and protecting livestock. Livestock guardians are remarkable to see in action. For hundreds of years they have had the job of acting independently to protect herds of livestock, using gradually escalated measures - only as much force as is required - to deal with any threat to the flock. Over the past several centuries they have capably performed a difficult role.