Dog Bite-Related Scientific Studies

The scientific consensus on breed-specific risk is clear: numerous scientific studies have determined that a dog's breed does not determine aggression, bite strength, or its propensity to bite. These studies have also found that breed-specific legislation (BSL) is ineffective, as it fails to reduce dog bites reliably. This consensus is significant because it represents the collective conclusion of the scientific community based on a broad analysis of comprehensive research rather than the findings of isolated, limited-scope studies that may support opposing viewpoints. Below, we provide a selection of 28 studies supporting the consensus on breed-specific risk and BSL, including summaries of their findings.

Controlled studies have not identified pitbull-type dogs as disproportionately dangerous.
As the population of specific breeds increase, bite incidents related to the breeds also increase. This correlation is a result of the larger population size rather than any inherent risk with specific breeds.
"The pit bull type is particularly ambiguous as a breed encompassing a range of pedigree breeds, informal types and appearances that cannot be reliably identified. Visual determination of dog breed is known to not always be reliable and witnesses may be predisposed to assume that a vicious dog is of this type."
"The substantial within-breed variation suggests that it is inappropriate to make predictions about a given dog's propensity for aggressive behavior based solely on its breed."
"Given that breed is a poor sole predictor of aggressiveness and pit bull type dogs are not implicated in controlled studies, it is difficult to support the targeting of this breed as a basis for dog bite prevention."
"It has not been demonstrated that introducing a breed-specific ban will reduce the rate or severity of bite injuries occurring in the community."

After analyzing 15 years of dog bite-related fatalities (DBRFs), the CDC recommends breed-neutral approaches for dog bite prevention and public safety, such the enforcement of animal control laws (e.g., leash and dog-at-large laws) and focusing animal control efforts on irresponsible owners and dogs with a history of aggressive behavior.
Banning specific breeds is "unproductive" because most DBRFs are preventable; furthermore, as the popularity of various breeds changes over time, bite incidents related to the breeds also increase or decrease (e.g., in 1995/1996, Rottweilers were the most commonly reported breed involved in fatal attacks, when their popularity was at a peak).
The CDC acknowledged that the media is prone to inaccurately reporting the breeds of dogs involved in DBRFs.
Note: The CDC stopped tracking breed-specific data for DBRFs in the early 2000s (soon after this and several other CDC studies on DBRFs were completed), as it determined that dog bite prevention is not a breed-specific issue. Furthermore, the CDC cited difficulties inherent to accurate breed identification and to accounting for the complexities of the circumstances surrounding each incident.

After analyzing 43 previous studies on dog bites and dog bite-related injuries, the study determined that breed-neutral strategies are more effective than BSL for reducing dog bites.
For public safety, evidence-based research from multiple studies validates that the most effective animal control policies apply to all dogs, and not just specific breeds.
Breed neutral regulations such as enforcement of leash laws, stray dog control, and addressing dogs with a history of aggressive behavior are the most effective polices for reducing dog bites and improving public safety.

Factors associated with irresponsible ownership and failure to neuter dogs are the primary cause of dog bite-related fatalities, breed is not a relevant factor (breed does not determine risk).
Media reports are a poor source for breed information as there are a high percentage of discrepancies (over 40%) between the breed reported in the media and the subsequent breed identification by animal control; additionally, valid breed determination was only possible in 18% of all incidents.
"Most dog-bite related fatalities (DBRFs) were characterized by coincident, preventable factors; breed was not one of these. Study results supported previous recommendations for multifactorial approaches, instead of single-factor solutions such as breed-specific legislation, for dog bite prevention."

In many of the medical studies analyzed, there were "clear-cut factual errors, misinterpretations, omissions, emotionally loaded language, and exaggerations based on misunderstood or inaccurate statistics."
In many of the medical studies analyzed, there was "misinformation about the significance of breed and breed characteristics."
In many of the medical studies analyzed, due diligence was not performed to accurately or scientifically identify the breed(s) involved in the bite incidents.
The study's discussion notes describes BSL as "panic policy making."

A total of 62 dogs were visually identified as 'pitbulls' in the study, but only 25 had DNA from pitbull-type ancestry - a misidentification rate of 60%.
Visual identification of pitbull-type dogs was highly inconsistent with DNA results, with accuracy ranging from a low of 33% to a high of 75%.
Overall, the mean sensitivity of visual identification of pitbull-type dogs was 50%. This mean sensitivity reflects the frequency of two types of errors: falsely identifying dogs as 'pitbulls' when they did not have DNA from pitbull-type ancestry (60% error rate), and conversely, failing to identify dogs as 'pitbulls' when they did have DNA from pitbull-type ancestry (20% error rate).
"Lack of consistency among shelter staff indicated that visual identification of pitbull-type dogs was unreliable."
"The marked lack of agreement observed among shelter staff members in categorizing the breeds of shelter dogs illustrates that reliable inclusion or exclusion of dogs as 'pitbulls' is not possible, even by experts. This has special significance to the topic of restrictive breed regulations, since such regulations are based on the faulty assumptions that (1) certain breeds or phenotypes are inherently dangerous, and (2) that those breeds and their mixes can be identified by observation. Since injuries from dogs have not decreased following bans on particular breeds, public safety is better served by focusing on recognition and mitigation of risk factors for dog bites."

53% of pitbull-type dogs (133 of 249) had less than a 50% DNA concentration from pitbull-type ancestry, and are therefore by definition mixed-breed dogs (and not 'pitbulls' or 'pitbull mixes').
98% of the pitbull-type dogs were found to be mixed-breed (244 of 249); only 2% (5) were found to be purebred.
Pitbull-type dogs had an average DNA concentration of 43.5% from pitbull-type ancestry (38.5% average in shelter 1 and 48.4% average in shelter 2).
Using appearance to determine breed was once again determined to be highly unreliable with accuracy ranging between 10.4% and 67.7%.
"Thus far, limited empirical data has been published on the effect of BSL on improved public safety; however breed bans in Spain, the Netherlands, Canada, and Italy have failed to decrease bite incidents and a recent study from Ireland found no differences between restricted and non-restricted breeds in the severity of bites inflicted or the likelihood that the bite would need greater medical attention."

After testing and analyzing aggressive behavior in two groups of dogs, breeds commonly subjected to BSL (including Akitas, Dobermans, German Shepherds, Rottweilers, and pitbull-type breeds) and breeds not commonly subjected to BSL (including Beagles, Dalmatians, Golden Retrievers, Greyhounds, and Labrador Retrievers), the study determined that aggressive behavior "did not differ significantly" between the two groups.
The study found that breed doesn't determine aggressive behavior.
The study rejects BSL and concluded that BSL is "unlikely to be an effective instrument for reducing risk."

After testing the temperament of 415 dogs impacted by BSL including Bullmastiffs, Dobermans, Mastiffs, Rottweilers, pitbull-type breeds, and others, the study determined that there was "no indication of dangerousness in specific breeds." The dogs were evaluated for aggression in various situations including dog-human, dog-dog, and dog-environment scenarios.
Specifically, there was no difference in aggression or behavior between pitbull-type breeds, that were subjected to strictest regulations, and other breeds impacted by BSL but subjected to fewer regulations, including Bullmastiffs, Dobermans, Mastiffs, Rottweilers, and other breeds.
"Justification for specific breed lists in the legislation was not shown."

Aggression is strongly linked to an individual dog's experience and environment — aggression is not a trait that can be associated with any specific breed.
The factors associated with increased rates of aggression were not breed-specific and included intact dogs (failure to neuter), a dog's age, and dogs subjected to punishment-based training methods.
"It would be inappropriate to make assumptions about an individual animal's risk of aggression to people based on characteristics such as breed."

There is no difference, in the medical treatment required following a bite or in the type of bite inflicted, between bites by breeds stereotyped as 'dangerous' (breeds targeted by BSL such as German Shepherds, Rottweilers, and pitbull-type dogs) and other breeds of similar sizes and strengths that are not stereotyped as 'dangerous' (breeds such as Boxers, Bulldogs, and Labrador Retrievers).
Bites by breeds not perceived as dangerous (non-legislated breeds) are reported at a significantly lower rate to authorities, leading to misleading data in breed-specific statistics on dog bites.

70% of U.S. residents oppose breed-specific bans / BSL.
The majority prefer breed-neutral approaches for public safety including public education about animal welfare and behavior, stricter leash laws, and harsher penalties for irresponsible dog owners.
"There is growing evidence to suggest that such laws (BSL) are ineffective, negatively impact animal welfare, and, in fact, do little to make communities safer. There are many reasons why breed specific legislation is ineffective, including the misidentification of dog breeds, an issue that has been reported among members of the general public, animal shelter workers, law enforcement officers, and human health care professionals. The fact that most people are unable to accurately identify dog breeds significantly impacts the ability to collect accurate breed-specific bite statistics. As a result, media stories, which influence public perception of different breeds, are often inaccurate and misleading."

96% of veterinarians oppose BSL and overwhelmingly endorse breed-neutral policies, such as public education and stricter leash laws, to reduce the risk of dog bites.
The reasons that veterinarians oppose BSL included: 89% agreed that BSL does not improve public safety; 76% agreed that BSL is a form of government overreach, and 75% agreed that BSL creates an animal welfare issue.
The majority described their experiences with pitbull-type dogs as either "positive" or "very positive."
"There is increasing evidence that suggests that breed bans do not decrease dog bites."

Dog bite incidents are the result of a complex set of factors including dog ownership factors, circumstantial factors, and other factors.
The results of breed risk calculations did not correlate with the breeds targeted by BSL.
"The view that aggressive potential is linked to dog breed is a point of serious concern as a dog's tendency to bite or show aggressive behavior depends on more than just genetics, and other factors such as heredity, experience, socialization and training, health, and victim behavior all play a role. As such, it has been advocated that aggressive potential should be evaluated for dogs individually."

The Dangerous Dogs Act (DDA) in the UK, that bans several breeds including Japanese Tosas, Dogo Argentinos, Fila Brasileiros, and pitbull-type breeds, is ineffective and doesn't reduce the number of dog bite-related injuries.
After analyzing medical records on dog bites before and after the DDA was implemented, the study found that the data "clearly demonstrates little impact" on dog bite-related injuries.
"If legislation aims to reduce and prevent injury from animal bites, in its present form the DDA does little to protect the public."

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Dog Bite-Related SCientific Studies

18%

25

9%

Comprehensive Studies (5)

AMERICAN VETERINARY MEDICAL ASSOCIATION (AVMA)

DOG BITE RISK AND PREVENTION: THE ROLE OF BREED (META-ANALYSIS OF Numerous STUDIES AND SCIENTIFIC RESEARCH)

FINDINGS:

Centers For Disease Control and Prevention (CDC)

Dog-Bite-Related Fatalities

FINDINGS:

Journal OF Injury Prevention

Systematic review of dog bite prevention strategies (META-ANALYSIS OF NUMEROUS STUDIES AND SCIENTIFIC RESEARCH)

FINDINGS:

Journal Of The AMERICAN VETERINARY MEDICAL ASSOCIATION

Co-occurrence of potentially preventable factors in 256 dog bite-related fatalities in the United States

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Journal OF Applied Animal Welfare Science

Defaming Rover: Error-Based Latent Rhetoric in the Medical Literature on Dog Bites

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Breed Identification & DNA (3)

The Veterinary Journal

Inconsistent identification of pit bull-type dogs by shelter staff

FINDINGS:

Public Library of Science (PLOS) ONE Journal

A canine identity crisis: Genetic breed heritage testing of shelter dogs

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Journal of Applied Animal Welfare Science

Comparison of adoption agency breed identification and DNA breed identification of dogs

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Breed-Specific Behavior & Aggression (5)

Journal of Evolutionary Applications

Comparison of behavioural tendencies between "dangerous dogs" and other domestic dog breeds - Evolutionary context and practical implications

FINDINGS:

Science.ORG

Ancestry-inclusive dog genomics challenges popular breed stereotypes

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Journal Of Veterinary Behavior

Is there a difference? Comparison of golden retrievers and dogs affected by breed-specific legislation regarding aggressive behavior

FINDINGS:

Journal of Veterinary Behavior

Is breed-specific legislation justified? Study of the results of the temperament test of Lower Saxony

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Journal of Applied Animal Behavior Science

Human directed aggression in domestic dogs: Occurrence in different contexts and risk factors

FINDINGS:

Bite Strength & Severity (3)

Irish Veterinary Journal

Dog bite injuries to humans and the use of breed-specific legislation: a comparison of bites from legislated and non-legislated dog breeds

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Journal OF Anatomy

Cranial dimensions and forces of biting in the domestic dog

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Frontiers In Veterinary Science Journal

Bite Forces and Their Measurement in Dogs and Cats

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Breed-Specific Legislation (12)

International Journal Of Environmental Research & Public HEalth

US Adults' Perceptions of Dog Breed Bans, Dog Aggression and Breed-Specific Laws

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International Journal Of Environmental Research & Public HEalth

Small Animal Veterinarians’ Perceptions, Experiences, and Views of Common Dog Breeds, Dog Aggression, and Breed-Specific Laws in the United States

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Frontiers in Public Health Journal

Emergency department visits for dog bite injuries in Missouri municipalities with and without breed-specific legislation: a propensity score-matched analysis

FINDINGS:

Animal Law Review Journal

A Quantitative Study of Denver's Breed-Specific Legislation

FINDINGS:

PUBLIC LIBRARY OF SCIENCE (PLOS) ONE Journal

The effect of breed-specific dog legislation on hospital treated dog bites in Odense, Denmark—A time series intervention study

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The Veterinary Journal

Human hospitalisations due to dog bites in Ireland (1998–2013): Implications for current breed specific legislation

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The VETERINARY Journal

Dog bites in The Netherlands: A study of victims, injuries, circumstances and aggressors to support evaluation of breed specific legislation