Dog bite risk and prevention: the role of breed

1. Breeds implicated in serious bite injuries

In a series of studies, it was found that German Shepherd Dog, Mixed Dog, Bitter Dog, Rottweiler Dog, Jack Russell Terrier and other dogs (Zhou Hound, Shepherd Dog, St. Bernard Dog and Labrador Retriever) were highly representative of bite events.

If you consider only a few cases that cause very serious injury or death, the bulldog will be easier to identify. However, this may be related to the popularity of the breed in the victim community, the reported bias and the treatment of dogs by their owners (for example, fighting dogs in combat). It is worth noting that in some regions of Canada, fatal dog attacks are mainly attributed to sled dogs and Siberian huskies, possibly due to the prevalence of these breeds in regions. See Table 1 for summary of species data related to bite.

2. Controlled studies

The prevalence of particular dog breeds can also change rapidly over time, often influenced by distinct peaks of popularity for specific breeds. It seems that increased popularity is sometimes followed by increases in bite reports in some large breeds. For example there was a distinct peak in American Kennel Club registration of Rottweilers between 1990 and 1995, and they come at the top of the list of ‘biting breeds’ for the first time in studies of bites causing hospitalization in the late 90s and early 2000s. While it must be noted that other fad breeds such as Dalmatians and Irish setters do not seem to make similar appearances, any estimate of breed-based risk must take into account the prevalence of the breed in the population at the time and place of serious biting events.

For example, researchers can compare well-documented bite cases with matched control households. Using this method, one study found that the breeds disproportionately involved in bite injuries requiring medical attention in the Denver area (where pit bull types are not permitted) were the German Shepherd Dog and Chow Chow.

Other studies use estimates of breed prevalence that do not relate specifically to the households where the bites occurred, such as general community surveys, breed registries, licensed dogs or animal shelter populations. A study in Rome, Italy where molloser dogs like mastiff are reputed to be the most dangerous dogs, found they were not disproportionately involved in biting incidents when taking into account their prevalence in the community. These prevalence referenced studies attribute higher risk to the German Shepherd Dog and crosses and various other breeds (mixed breed, Cocker spaniel, Chow Chow, Collie, Doberman, Lhasa Apso, Rottweiler, Springer Spaniel, Shih Tsu, and Poodle).

3. Aggressive breeds

According to the behavior assessment and the owner’s survey, the more aggressive breeds are small and medium-sized dogs, such as shepherd dogs, toy dogs and Spanish hounds. For example, a survey of Canadian general veterinary clients (especially in New Brunswick, Noviascoshe and Prince Edward Island) found that Lhasa Apso, Springer Spaniel and Xuzong were more likely to bite people.

Although dogs may be more aggressive, their size means they are less likely to cause serious bites. In addition to vulnerable individuals or as part of a group attack, this also allows dogs to cause serious or harmful damage to healthy older children or adults. The referral of aggressive problems is closer to the species involved in severe bites, probably because owners are more likely to seek aggressive treatment for dogs big enough to be dangerous. Larger dogs, regardless of breed, are associated with more aggression against humans and other dogs.

Certain large breeds are notably under-represented in bite statistics such as large hounds and retrievers (e.g. Labrador Retrievers and Golden Retrievers)—although even these breeds may have known aggressive subtypes. Results relating to German Shepherd Dogs are mixed, suggesting there may be particularly high variability in this breed, perhaps depending on regional subtypes or ownership factors.

4. Pit bull types

The owner of the Bitter Dog dealt with a strong breed stigma, but the control study did not determine that the population of this breed was a disproportionate risk. The type of Bitter Dog is particularly vague. As a “breed”, it includes a series of lineage breeds, informal type and appearance, and cannot be reliably identified. Visual judgement of dog breeds is not always reliable. The witness may be inclined to think that a dog is of this type.

It should also be taken into account that the incidence of bitdog involvement in serious and fatal attacks may represent a high prevalence in communities that pose a high risk to children, and that young children are the most common victims of serious or fatal attacks. Because the owners of the stigmatized varieties are more likely to participate in criminal and/or violent acts, the correlation of varieties may make the owner’s acts as potential causal factors.

5. Breed bans

In the United States, the most serious dog bite (requiring hospital treatment) is that the victim is a young child, and the dog is not sterile and familiar (belonging to family, family friends or neighbors). Therefore, responsible ownership and supervision are key to reducing the risk of dog bites in the community.

Although some study authors believe that limiting the ownership of certain breeds may reduce injuries (e.g. Bitter Dog type, German Shepherd Dog), it has not been proven that the introduction of a ban on certain breeds will reduce the incidence or severity of bites that occur in the community. Strategies known to lead to a reduction in bite incidents include active enforcement of dog control regulations, which may include breed related regulations.

6. Conclusion

The creation of dogs can cause serious injury and death – it is natural for those who deal with victims to seek solutions to the immediate causes. However, as Duffy et al. (2008) wrote when describing their survey data: “The huge differences within breeds… indicate that it is inappropriate to predict the aggressive behavior tendency of a given dog only based on breeds.” Although breed is a factor, the influence of other factors on individual animals (such as training methods, gender and sterilization status), goals (such as owners and strangers), and dog context retention (such as urban and rural areas) has significant predictive value. In addition, the nature of a variety has also been proved to change with time, geographical location and variety subtype, for example, those varieties raised for conformational display are different from those in field experiments.

Since this breed is the only predictor of poor aggressiveness, and bulldogs were not involved in the control study, it is difficult to support the goal of this breed as the basis for preventing dog bites. If breeds are to be targeted, a group of large breeds will be involved, including German Shepherd Dog and Shepherd Dog hybrids and breeds from different locations.