Several dog breeds, including American Pit Bull Terriers (APBT) are subject to restrictions in many countries. In New Zealand, in many areas (including Auckland) APBTs are classified as a ‘Menacing Breed’ (along with Brazilian Fila, Japanese Tosa, Dogo Argentino, and Presa Canario).
While legislated dogs are now perceived by the public to be more aggressive,1, 2 most likely resulting from negative media and political portrayal of these breeds, research shows no differences between legislated and non-legislated dog breeds for bites, age when bitten, bite location, relationship with the dog, history of aggression, if the dog bites again, or those dogs seeing a trainer or behaviourist.1 In fact, the general perception of American Pit Bull Terriers and similar breeds like the English Staffordshire Terrier was, in the early 1900s, predominantly of safe dogs known for their love of children and often called ‘nanny dogs’.3
Many other studies have shown no difference in aggression between breeds,4 or bite rates or bite severity between breeds,5 and others demonstrate conclusively that there is no genetic or behavioural link between pit-bull terriers and aggression.6
In a German study of a cohort of bull-terrier-type dogs, only one of 37 dogs was found to be bite-aggressive and there was no difference in aggression between the bull-terrier group, Labrador Retrievers, and legislated dogs.7 Other research has shown no specific tendency towards aggression in pit bull terriers,8 and no significant difference in temperament between banned dogs (such as pit bulls) and Labradors,9 or between banned dogs and other breeds.10 Additionally, research conducted in various countries (Denmark,11 Spain,12 Ireland,13 Italy,14) demonstrates that breed-specific legislation does not affect dog bite injury rates. Risk-based statistical analysis (number needed to treat) has also shown that improving public health and safety through BSL is implausible.15
Some genetic determinants may be associated with aggression but these are not breed-specific and pit bulls are not defined by these markers.6 More likely determinants of aggression or behavioural problems in dogs are related to fear and anxiety,4 small body size, children in the home, separation anxiety, and excess energy.6
Some studies (usually based on self-reported dog identification and hospital admissions for bites in areas within the United States), have shown a disproportionate number of dog bites and bite severity by ‘pit bull type’ dogs,16-20 but these studies lack reliability for one or more of the following reasons:
Misidentification of breeds is common
Misidentification of breeds is common.21 It is practically impossible for lay people (or even experts) to determine an exact breed by sight and any dog that exhibits some characteristics of a ‘pit bull type’ are usually labelled a pit bull. For example, in a study of San Diego Humane Society staff, while staff were able to match one breed contributing to a dog’s heritage in 68% of dogs, they could only determine more than one breed in 10% of cases.22 Other research by Viola and colleagues has shown that visual identification of breed matches genetic testing in only ¼ of cases.23 Unsurprisingly, physical appearance isn’t a good indicator of either breed or temperament.23
‘Pit bull’ is used as a breed catch-all
‘Pitbull type’ or ‘bull terrier type’ classifications can include several breeds including APBTs, English Bull Terriers, English Staffordshire Terriers, American Staffordshire Terriers, American Bulldogs, American ‘Bullies,’ and sometimes other breeds and mixes that have similar facial and physical characteristics. For example, a 2018 systematic review found that the most common breed identified in dog bites was the German Shepherd and the second most common were the ‘pitbull types’. However, this grouping included four breeds; American Staffordshire Terrier, American Pit Bull Terrier, Staffordshire Bull Terrier, and American Bully.24 It defies logic to believe that if these were separated by breed that they would rank highly.
Dogs appearing as ‘pit bull-type’ are extremely common
‘Pitbull type’ dogs of various breeds are common in the study areas reporting these results. Thus, given that many dogs are misidentified as pit bulls and the many breeds which can make up ‘pit bull types’ are very popular, it’s completely plausible that they would be a common breed grouping responsible for bites by pure weight of numbers alone. This is also plausible given the numbers of dog bites by other common breeds in areas with breed preferences such as German Shepherds in Germany and sled breeds in Northern Canada.
Neither temperament testing, nor genetic evidence suggests any tendency towards aggression in pit bulls compared to other breeds
Temperament testing, genetic evidence, and other more robust trial and observational evidence show no greater risk associated with pit bulls
Figure 2 | Scientific Reports (nature.com)25
Experts are universally opposed to breed-specific legislation
Research also suggests that most veterinarians are not in favour of breed-specific legislation.26 And most, if not all international organisations for veterinary science, dog and animal behaviour, and animal welfare are opposed to breed-specific legislation including the British Veterinary Association, the Royal Society for the Prevention of Cruelty to Animals in the UK, the American Veterinary Medical Association, the Canadian Veterinary Medical Association, the Australian Veterinary Association, the Federation of Veterinarians of Europe, and the American Bar Association.27 An article in The Veterinary Nurse states “Breed is not a good predictor of risk. But in the UK, under the Dangerous Dogs Act, breed-specific legislation prohibits the ownership of four types of dog despite there being no specific research to demonstrate that they are more aggressive towards people than other dogs.”28 All dogs have the potential to bite, and the severity of the bite is mostly related to bite control and the size of the dog, not the breed. It has been stated in an article in The Canadian Veterinary Journal that “If we want to prevent all bites, there is only one sure way and that is to ban all dogs.”29
Conclusion
Breed-specific legislation is lazy grandstanding and is based on fearmongering and is not in line with the scientific evidence which shows overwhelmingly that breed is not responsible for aggression and temperament of dogs, nor is it reliable as an indicator of dog bites or bite severity. Further, it imposes costs that would be better spent on improving animal welfare and education on reliable strategies and tactics to reduce dog attacks.
References
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