Oh I never claimed there wasn't a difference in mechanism. There is no difference in affect. I don't know of many dog or cat owners whose animals have been severely injured or killed by sighthounds that thought, "whew, it's a good thing my pet was killed by a Greyhound and not one of those Pit Bulls!" There just happens to be a higher population of dogs that an APBT will willingly engage vs. a typical sighthound, if given the opportunity. Both require a level of management, neither are a fault in their respective breeds, and neither translate to human aggression. And Dogdragoness, you'd be surprised. And none of my dogs are a "ticking DA time bomb." That's implying unpredictability. My dogs are predictably DA. If anything, your dog who selectively decides which dogs they want to maim or kill is the "ticking time bomb."