BSL supporters claim there is something inherently different and more dangerous about certain dog breeds. Increased bite strength or ability to “do more damage” are often cited as reasons to restrict certain categories of dogs.
Research does not support this – the few studies that exist indicate that bite strength is correlated with size of dog, and aggression with individual genetics and environment. Most bite strength numbers are problematic and based on weak or anecdotal data.
A 2016 article on the Canine Animal Psychology Site titled Bite Strength – It’s Not What You Think discussed a study by Dr. Gary Patronek of Tufts University that tracked down sourcs for commonly cited statistics for bite strength by different breeds:
“They looked at papers from 1969 – 2009, and two court cases, that referred to canine bite strength. They went through the literature to trace the statements back to the origin. So what did they find?
‘We tracked each citation to 1 of 7 original sources,’ they write, ‘and did not find verifiable evidence (or data obtained from a controlled experiment) about bite force in any of the articles. In 2 of the original sources, statements about bite force were found, but there were neither data nor a citation to support those statements. In 4 other original sources, none contained any statement or data about bite force, despite being cited by other scientific articles as though they had. The final original source was not a scientific article at all, but a newspaper article that again provided no source for the data presented.’ [references omitted for ease of reading – see link below]
In other words, there is no evidence for the statement that a pit bull, or any other kind of dog, has a bite strength of 1800 or even 2000 PSI.”
Patronek’s study, published in the Journal of Veterinary Behaviour, can be read in full here.