Breed as a Predictor of Risk: Critical Analysis of Pit Bulls

In comparison, a study into the effectiveness of BSL in Manitoba, Canada in 2012, determined that BSL may indeed have resulted in a reduction in dog-bite injury hospitalisations (DBIH), though the outcome of the study has been called into question. Their original Province-wide findings were that – in jurisdictions with BSL – there were “no significant differences in incidence of DBIH between pre-BSL and post-BSL implementation” . Further to those initial findings, and after introducing “temporal and geographic variations” a difference between jurisdictions with BSL and those without was recorded. However, the study compared Winnipeg, a jurisdiction with BSL and a population of 700,000, with Brandon, a jurisdiction without BSL, but with a significantly smaller population of 50,000. It was found that there was a lower hospitalisation rate in Winnipeg after the implementation of BSL compared to that of Brandon, but Rosado et al. (2007) had previously established that such densely populated areas were more likely, per capita, to have fewer dog-bite related injuries. One factor believed to contribute to this difference is that dog owner’s seemed less inclined to allow their dog to roam unattended and off-leash in areas with heavy traffic and few open spaces. Small towns or villages, in comparison, where there are significantly less hazardous situations may invite dog owners to be less strict with their animals, suggesting that the physical environment in a more densely populated area raises people’s awareness of the possible harm to their animals.

The principle argument against BSL is that breed is not an accurate predictor of bite risk, but in fact all dogs are capable of biting: the movement against BSL has been coined ‘Deed not Breed’. This has been demonstrated by several jurisdictions encountering a higher number of dog-bites caused by non-prohibited breeds than their prohibited counterparts, both before and after implementation of BSL: Klaassen et al. (1996) found that in the 3 months prior to the enactment of the 1991 Act, out of 99 dog-bites Alsatians dogs were the most common offender with 24 incidents, and ‘pit bull terriers’, Dobermans and Rottweilers collectively involved with 6 cases. In the immediate three month period after the Act was introduced, Mongrels caused 30 out of the 99 cases, whereas ‘pit bull terriers’, Dobermans and Rottweilers caused 11. It should be noted that the study did not take into account the weighting of dog breeds within the population; if Alsatians were popular during this time period, and therefore there was more of them, this could then contribute to a higher involvement in incidents.

Many in favour of BSL however claim that the ‘pit bull terrier’ has a special characteristic that sets them apart from other breeds, that of having a locking mechanism in their jaw, whereby once it has bitten onto an object (such as an arm) they can lock their jaw in place. However, this has been physiologically proven to be just a popular myth. What this mythical ‘lock-jaw’ is often confused with is the common ‘pit bull terrier’ characteristic of ‘gameness’ or enthusiasm, allowing such ‘fighting dogs’ to maintain an attack and keep hold of their target despite the threat of injury.

Apocryphal rumours regularly portray ‘pit bull terriers’ as inherently more threatening or vicious than other breeds due to a supposed bite force of approximately 2,000 psi (pound-force per square inch); this would rank their bite force as the third highest of all terrestrial animals, trumping even the hippopotamus at 1,800 psi. The suspected origin of this rumour is an incorrect interpretation of data: in a study by Lindner et al. (1995) the bite force of a number of dogs was tested, with the maximum measurements coming in at around 2,000 newtons, and it is believed this number was subsequently taken and incorrectly read as 2,000 psi. There are too many variables to accurately pinpoint the bite force of a specific breed, especially as the ‘pit bull terrier’ is not actually a recognised breed. However, if it is ‘calculated’ that Rottweilers and Siberian Huskies produce a bite force of around 328 and 320 psi respectively, with German Shepherds and Dobermans at 238 and 245 psi, then the ‘pit bull terrier’ ranks below them at 235 psi.