The dogs that are most responsible
According to the Clifton study, pit bulls, Rottweilers, Presa Canarios and their mixes are responsible for 74% of attacks that were included in the study, 68% of the attacks upon children, 82% of the attacks upon adults, 65% of the deaths, and 68% of the maimings. In more than two-thirds of the cases included in the study, the life-threatening or fatal attack was apparently the first known dangerous behavior by the animal in question. Clifton states:
If almost any other dog has a bad moment, someone may get bitten, but will not be maimed for life or killed, and the actuarial risk is accordingly reasonable. If a pit bull terrier or a Rottweiler has a bad moment, often someone is maimed or killed--and that has now created off-the-chart actuarial risk, for which the dogs as well as their victims are paying the price.