"Variability in behaviour has a wider range within a breed than between breeds. Within the discipline of psychobiology and animal behaviour there is no data from empirically supported studies, published in refereed scientific literature, to support the idea that one breed of dog is `vicious.' The adult behaviour of a domestic dog is determined overwhelmingly by its experiential history, environmental management and training." - Dr. Mary Lee Nitschke, Ph.D. "There is no scientific proof that genetics cause a breed of dog to be aggressive, vicious or dangerous." - testimony from Standing Committee on amendments to the Dog Owners Liability Act. 2005
It is more common than not to hear 'pit bulls' referred to as "dog-aggressive". In fact, they aren't. Some may become fearful around other dogs due to a lack of proper socialization. But this happens with all breeds of dogs, not just 'pit bulls'. Unfortunately, this lack of socialization is frequently encouraged by those who fancy themselves 'pit bull' experts.
So why are so many 'pit bulls' involved in attacks on other dogs? Well, the answer is, they aren't necessarily involved more often than any other breed. For instance, Rottweilers are probably involved in just as many attacks on other dogs, yet they were not bred for dog fighting. They were bred to herd cattle and work as guardians. If put to the test, most people would have to honestly answer that it is not 'pit bulls' involved in most of the dog biting incidents in their communities. Some, maybe. But just as many Labradors, Goldens, Dalmations, Jack Russells, Poodles, etc. also stand accused of biting other dogs.