Dog Bite | Animal Behavior Expert Witness

Richard H. Polsky, Ph.D. CDBC
Los Angeles, California

“Bringing the science of animal behavior to attorneys”

Animal behavior expert on dog bite attacks

Richard H. Polsky, Ph.D. CDBC
Los Angeles, California

“Bringing the science of animal behavior to attorneys”

Are pit bulls inherently dangerous animals? Expert opinion

pit bull expert opinion
Some pit bull type dogs are genetically programmed for heightened aggressive reactivity to other dogs, but not humans.

New stories about dog bite fatalities and other maulings by pit bulls have engendered the belief the minds of many that pit bulls are inherently vicious and dangerous animals.

As a result, municipalities throughout the world have enacted controversial laws banning pit bulls or imposing restrictions on ownership. Are these laws justified?  Does animal behavior science support the belief that all pit bulls are inherently dangerous or vicious by nature?  Below, I proffer expert opinion based on animal behavior science.

Pit bull nature & animal behavior science

To answer the above questions I turn to the peer-reviewed literature. A few studies are relevant in this regard.

The first study used evidence based on severity of the injury inflicted by a pit bull. The bottom-line conclusion to the study was that pit bulls inflict severe dog bite injury at unusually high rates relative to other type of dogs

The methodology used in the study was questionable, however. Specifically, the study relied on data that identified a pit bull based on the physical characteristics of the dog. An approach like this produces false positives. For example, animal behavior science has  demonstrated that accurately identifying a pit bull based on the physical features of the dog is problematic. The physical features of a pit bull are not unique. Mastiff type dogs look like pit bull type dogs. Hence, this study may have been over-inclusive of pit bulls, which in turn may have skewed the results.

The second study, although published about 30 years ago, is still relevant and remains one of the few peer-reviewed papers that bases its conclusions on established animal behavior science (Are pit bulls different? R. Lockwood and K. Rindy, Anthrozoos, 1988,Vol.1, pp. 2-8.). The findings presented in this paper are consistent with current thinking by canine behavior experts. The authors found that the most striking difference between pit bulls and other breeds is the willingness of some pit bulls to fight other dogs.

The authors concluded that a combination of traits mentioned below may make some pit bulls particularly dangerous. These include:

  • Tendency to attack without provocation;
  • Tendency to attack with persistence;
  • Insensitivity to the social signals from other dogs, particularly with regard to submissive behavior;
  • Tendency to attack without warning;
  • Difficulty in stopping an attack after it is started.  

Note that the above-mentioned traits pertain to dog-on-dog aggression and not human-directed aggression. However, I note that the above mentioned traits also apply to attack-trained police K9s used for suspect apprehension.


Generally, animal behavior experts are universal in the opinion that the above-mentioned behavioral traits may make some pit bulls inherently dangerous animals – but only to other dogs.  In sum, for the sake of  emphasis, these traits are not found in every pit bull type dog, and again to restate, these tendencies apply only to dog-on-dog aggression and not human-directed aggression. These two types of aggression are believed to be motivationally distinct. Nevertheless, it is an open scientific question as to whether these two types of canine aggression are biologically related in some individuals. The answer to this question awaits further research.

Finally, I direct the visitor to learn more about the supposedly inherent dangerous nature of pit bulls elsewhere on this website. 

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