Pit Bull Awareness Part 2: Statistics, Misidentification and Genetics

Thoughtful pit bull laying on the floor.
Thoughtful pit bull.
(Photo by Mikorad on Pixabay under CC0.)

If you haven’t read Part 1 of this series on pit bull awareness, I invite you to go here for a brief glimpse of the different breeds that make up the pit bull family and their history – long ago through recent.


Dog Bite Statistics.

There are certainly plenty of statistics available today on dog bites – all of them ugly, disturbing and confusing.

Dogs Bite.

DogsBite.org reports several studies, all of them based on news reports. One study done by Merritt Clifton of Animals 24/7 was a compilation of American and Canadian news accounts of dog bites between 1982 and 2014. This attributed 76% of attacks resulting in fatalities and 86% of attacks resulting in maiming to the Molosser breeds (please see this article referred to in  Part 1 of this series for a list of the specific breeds).

Dogs Bite compiled a report of their own on 88 fatalities between 2006 and 2008, again based on news reports. This study reported 52 of these deaths (or 59%) due to “pit bull type” dogs.

Another report by Dogs Bite on the 34 fatalities in 2015 attributed 28 of them to pit bulls.

Center for Disease Control (CDC).

Data and calculator - generating statistics.
Generating statistics.
(Photo by Kaboompics at Pixabay under CC0)

In a 20-year study by the CDC of 327 dog bite fatalities between 1979 and 1998, some breed information was available for only 238 of these. With the data available, it has been claimed by some sources that 67% of the deaths were due to pit bulls and Rottweilers.

However, the CDC says of the study that:

it does not identify specific breeds that are most likely to bite or kill

and indicated that relying on media coverage of the fatalities presented a biased view of the animals involved and that they were more likely to be “ascribed to breeds with a reputation for aggression.”

American Veterinary Medical Association (AVMA).

The American Veterinary Medicine Association (AVMA) Task Force on Canine Aggression and Human-Canine Interaction published a study (A Community Approach to Dog Bite Prevention) in the Journal of American Veterinary Medical Association (JAVMA) in June 2001. In it they stated that:

Dog bite statistics are not really statistics, and they do not give an accurate picture of dogs that bite.”

Another report by AVMA published in JAVMA in 2013 researched fatal dog bites between the years 2000 and 2009 (Co-occurrence of potentially preventable factors in 256 dog bite-related fatalities in the United States (2000-2009)). Unlike other reports, this study was based on law enforcement, animal control, and investigator reports rather than media reports. They found reliable identification of dog breed possible in only 18% of incidents.

In a 2014 literature review by the AVMA Animal Welfare Division (Dog Bite Risk and Prevention: The Role of Breed), the AVMA concluded that breed was a poor sole predictor of dog bites. Referring to pit bulls specifically:

“controlled studies have not identified this breed group as disproportionately dangerous.”


“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.”

American Canine Foundation.

Pie chart data.
Pie chart data.
(Photo by OpenClipart on Pixabay under CC0.)

In a study reported by the American Canine Foundation on fatal dog attacks during the 40-year period between 1965 to 2005, it is mentioned that 32% of them were caused by two or more dogs together.


Is your head spinning yet with conflicting information? I’m sorry. But these last two mentions are well worth your time to read in full.

Steffen Baldwin of the Animal Cruelty Task Force of Ohio wrote this article (The Lies, Damn Lies and Statistics Behind Dog Bites) for the Huffington Post. The title of the article says much of it, but still he spells everything out very eloquently.

Sara Logan Wilson of The Canine Journal has written a great article here which provides information on why dogs bite, how to prevent dog bites and some things to consider when looking for your next dog. She also gives these final statistics:

  • 7 million dog bites occur in this country yearly, of which approximately 386,000 require medical treatment, half of them children.
  • 92% of fatal dog attacks involved male dogs, 94% of which were not neutered.
  • 25% involved chained dogs.
  • 75% of these occurred on the victim’s property and most knew the responsible dog.



Eye looking - visual identification.
Visual identification.
(Photo by Geralt on Pixabay under CC0).

Do you sense a theme here in all this confusion?

According to Wikipedia:

“variation amongst “bully breed” dogs makes it difficult for anyone, even experts, to visually identify them as distinct from “non-pit bulls.”

SinDelle wrote an article for Pet Helpful (Ten Breeds Most Commonly Mistaken for Pit Bulls) detailing some of the specific breeds most likely to be confused for pit bulls.

This study (Inconsistent Identification of Pit Bull-Type Dogs by Shelter Staff) reported in The Veterinary Journal in November of 2015 examined the accuracy of visual identification of pit bull type dogs. The study involved 120 dogs in four Florida animal shelters (30 per shelter) and 16 shelter workers (4 per shelter, all of them with at least three years of experience). These individuals were asked to identify the breeds of the 30 animals selected. The purpose was to measure agreement in pit bull designation of the dogs and then do DNA analysis to determine true breed. It showed:

  • Only moderate agreement of breed designation between staff members.
  • One in five dogs identified genetically of pit bull heritage were missed by all staff.
  • One in three with no genetic heritage were identified as pit bull breed by at least one staff member.
  • Only 8% of genetically true pit bulls were correctly identified.

These statistics from Canine Journal make the results of the above study especially significant and disturbing:

  • 40% of dogs in shelters are bully breeds.
  • 60% of all dogs in shelters will be euthanized.
  • 22% of shelters routinely euthanize all pit bulls.


The Role of Genetics in Behavior?

DNA under magnifying glass.
Genetics as a contribution to behavior?
(Photo by Geralt (modified from Peggy_Marco) at Pixabay under CC0.)

Since a poor gene pool and intensive breeding for aggression is much of the argument used to justify current policy and treatment of pit bull-type dogs, it makes sense to look at it briefly here.

With over 19,000 identified genes in dogs (slightly fewer than the human’s 21,000), this quote from Human Illnesses on behavioral genetics would seem to be purely common sense:

“It is especially hard to link genes to most types of behavior, because most are complex and are determined by more than one gene.”

In this review article on the genetics of canine behavior (“Behaviour Genetics in the Domestic Dog,” Unkoping University, Unkoping, Sweden),  Mia Persson states:

“Behavior, regardless of innate or learned, is always a product of both genetic and environmental factors.”

Kristina Lotz of I Love Dogs interviewed Dr. Jerry Klein, DVM (Nature Versus Nurture: Is Your Dog’s Personality Learned or Genetic?), supervising veterinarian at Chicago Veterinary Emergency & Specialty Center. Dr. Klein is also a breeder of award winning Afghan hounds and judge on several occasions at Westminster Kennel Club shows. With his diverse background and ability to consider dog genetics from several different angles, his opinion on nature versus nurture was:

“Your influence will shape your dog’s personality just as much as their genetics.”

Matt Bershadker, President and CEO of ASPCA, says of genetics in his blog post, Shining a Light on Shelter Myths:

“While bloodlines and histories are useful tools to assess an animal’s value, they are limited in terms of predicting behavior.”

The Animal Farm Foundation’s awesome infographic has done a terrific job at explaining what a tiny amount of genes we see expressed when looking at a dog and how much variability there can be even within a litter of puppies.  I urge you to click through and read the whole graphic. (Click here to see a larger version (easier to read) in PDF form).


Infographic: All Dogs are Individuals
by Animal Farm Foundation

Click to see the full image


Final Thoughts.

So we’ve waded through many of the statistics driving current treatment and perception of pit bulls – and I’ll admit that they are pretty horrific at first glance. We have also looked at how difficult it is to correctly identify these dogs – even by professionals – without genetic testing. And yet dogs continue to be euthanized in large numbers based on their appearance every day …

In the first part of this series we looked at their history, and pit bull-type dogs have been bred for animal aggression for hundreds of years – that much is true. So we looked at the role that genetics plays in behavior. That role independent of training and life experience isn’t very convincing as a predictor of behavior.

In the last part of this series, we’ll look at environment as a contributor to behavior, public policy recommendations by several different groups, and finally the characteristics and personality of the “pit bull.”


In the meantime, I’ll leave you with this as a reminder of the heroes that pit bulls are …

Thanks to Leighann0007 for this video on YouTube.


And this – which really doesn’t belong here but I have included it anyway.

I think all of us could use something to smile about after all the statistics and quotes. I dare you not to smile at this!

Thanks to Karen Erbach for this happy video on YouTube.


A special thank you to the above-mentioned photographers and creatives for making their work available for use.


My sources for this article are listed below for further reading.

Sources/Further Reading







American Veterinary Medical Association Task Force on Canine Aggression and Human-Canine Interactions. “A Community Approach to Dog Bite Prevention.” Journal of the American Veterinary Medical Association, Volume 218, Number 11, June 1, 2001.

Patronek, GJ (2013). “Co-occurrence of potentially preventable factors in 256 dog bite-related fatalities in the United States (2000-2009).” Journal of the American Veterinary Medical Association 243 (12):1726-36.







K.R. Olson, J.K. Levy, …., M.S. Zimmerman. “Inconsistent identification of pit bull-type dogs by shelter staff.” The Veterinary Journal, November 2015, Volume 206 (2):197-202. (http://www.sciencedirect.com/science/article/pii/S109002331500310X)










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