Most Pitbulls Are Mixed-Breed Dogs

Recent studies on the DNA of dogs labeled as 'pitbulls' have found that most dogs visually identified as pitbulls are not pitbull-type dogs by DNA. Among dogs with pitbull-type ancestry, the majority are mixed breed. One study determined that, on average, 60% of dogs visually identified as 'pitbulls' lack DNA from pitbull-type ancestry and are other breeds or mixes altogether. Another study tested the DNA of 249 dogs with pitbull-type ancestry and found that 98% were mixed-breed dogs, with only 2% being purebred. Furthermore, the studies revealed that more than half of the dogs with pitbull-type ancestry had less than a 50% DNA match with breeds included in the pitbull-type category and are therefore, by definition, mixed-breed dogs. A dog needs more than a 50% DNA match with a specific breed to be considered a mix of that breed. For example, a 'Boxer mix' would predominantly have Boxer DNA or at least 50% DNA from Boxer ancestry. If a dog doesn't meet this threshold, it is considered a mixed breed without breed-specific labels. Consequently, these studies determined that most dogs labeled as 'pitbulls' either aren't pitbull-type dogs at all or don't qualify as 'pitbulls' or 'pitbull mixes' since they have less than 50% DNA from pitbull-type ancestry, or another breed predominates their genetic makeup. These findings have significant implications for dog bite statistics, medical studies on dog bites, media reports on dog bites, and breed-specific legislation (BSL).

DNA Results Of Dogs Labeled as 'Pitbulls' 📑

DNA Testing Results

Of dogs with pitbull-type ancestry, on average, 98% are mixed-breed dogs by DNA (not purebred).

98%

Of dogs with pitbull-type ancestry, on average, more than half (>53%) have less than a 50% DNA concentration from pitbull-type ancestry and are therefore, by definition, mixed-breed dogs and not 'pitbulls' or 'pitbull mixes.'

53%

On average, 60% of dogs visually identified as 'pitbulls' are misidentified and lack any DNA from pitbull-type ancestry.

60%

Impact On Dog Bite Statistics and BSL 📊

The findings from these studies hold significant implications for how dog bite-related breed data is used across various contexts, including dog bite statistics, medical research on dog bites, media reporting on dog bite incidents, and breed-specific legislation (BSL). Typically, BSL affects dogs with more than a 50% DNA concentration from breeds listed in breed-specific ordinances. However, these studies suggest that the majority of dogs labeled as 'pitbulls' would not be impacted by BSL if challenged by their owner with DNA evidence. The complexities of accurately identifying a dog's breed are well-known. However, the evidence suggests that using DNA to accurately determine a dog's breed, whether for dogs impacted by BSL due to their appearance, for media reports on dog bite-related incidents, or to support data in dog bite statistics, may very well be BSL's greatest weakness.

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