Although perhaps not as common in California, many residents of San Diego are probably still at least somewhat familiar with the notion that some breeds of dogs are inherently more dangerous than others. In some states and cities, special laws even exist that impose additional restrictions and rules on owners of dogs thought to have dangerous breeding and are thus more prone inflict serious dog bites.
There is some truth to the idea of breeding having to do with the frequency and severity of a dog bite in that some animals are bred to be smaller than others. A miniature poodle is going to be less likely to inflict a serious dog bite simply because the dog is too small too do so. Of course, if the dog is around young children, a serious bite is possible.
It is also true that, historically, some dogs have been bred to defend territory or to attack and bite other animals. However, these types of dogs are typically also bred to be fiercely loyal to people, meaning they are less likely to bite a person with whom they are familiar. Moreover, other types of dogs, those with no breeding for violence, have bitten and sometimes even killed their victims.
Although there have been some studies which have ranked the dangerous propensity of dog breeds, the conclusions of these studies have been questioned. Many experts believe that there is no such thing as a dangerous dog breed, and that it is owners who bear the responsibility when a dog bites. An owner must make sure that all dogs, no matter the breed, get proper care and socialization, including good dog training. Furthermore, even the best trained dogs need close and consistent supervision, as every dog has a bite potential.