What exactly is a 'pit bull?'

"Pit bull isn't a breed."

The first time that I heard this as a new rescue volunteer, it blew my mind. Of course pit bull is a breed - pit bulls are everywhere! In the 15 years since, though, I've come to understand that there's a lot more nuance to it. 

The term 'pit bull' is a catch-all, encompassing a wide variety of breeds and mixes. While the term itself isn't necessarily negative or used with ill intent, the generalization of such a wide variety of dogs has had damaging consequences for these dogs and the people that love them.

A tricolor american bully with cropped ears sits with a happy, open-mouthed expression in front of a pink background
Reesie of @dill_pickle_and_reesie_pieces

In this article:

1. Pit Bull Breeds

a. Pure breeds

b. Mixed breeds

2. The problem with visual identification

3. The effects of generalization

a. BSL and housing restrictions

b. Dog bites and aggression

c. Pet overpopulation

4. Breaking the stigma

5. References


Pit bull breeds

Pure breeds

There are five breeds that are commonly considered part of the 'pit bull' family.

  • American Pit Bull Terrier
  • American Staffordshire Terrier
  • American Bully
  • Staffordshire Bull Terrier
  • Bull Terrier

Several other breeds are often characterized as 'bully breeds,' though this is not an official classification and opinions will vary.

  • American Bulldog
  • Cane Corso
  • Dogo Argentino
  • Presa Canario
  • Bull Mastiff
  • Rottweiler
  • English Bulldog
  • Boxer

Mixed breeds

Many dogs labelled as a pit bull are, in fact, mixed breed dogs. These dogs' breed make-up may or may not contain some percentage of any of the breeds listed above. In most cases, mixed breed dogs are labelled as pit bulls or 'pit-type' based on visual identification alone; any dog with a big head, short fur, a stocky body, or cosmetic modifications like cropped ears or a docked tail may be labelled as a pit bull. 

The problem with visual identification

In most cases, animal shelter staff, veterinarians, law enforcement officials, other dog professionals, and pet owners are guessing a dog's breed make-up based on visual identification. This is a highly inaccurate practice, especially when it comes to mixed breed dogs.

A study published in 2018 that included over 900 dogs found that shelter staff was able to accurately identify one breed in a dog's breed make-up about 66% of the time - and half of those dogs were pure breed dogs. Staff could accurately identify two or more breeds in a dog's breed make-up only 10% of the time. Other studies have found that the visual identification may be even less accurate, though these studies were conducted with smaller sample sizes.

Visual identification isn't exclusive to animal shelters. Veterinarians will frequently use visual identification to label a client dog with an unknown breed make-up, which can be the determining factor in whether that dog is allowed in a particular housing complex or community or covered by insurance. Law enforcement officials use visual identification in dog bite incidents and when determining if a dog is banned by Breed Specific Legislation. Individual pet owners may use visual identification for their own dog.

No matter who conducts it, visual identification is unreliable at best and can have devastating consequences. 

The effects of generalization

If the term 'pit bull,' 'pit-type,' or 'bully breed' can be used to describe a dozen distinct breeds and any number of mixes, can we really make an accurate generalization about these dogs' behavior?

Even if we only consider the distinct pure breeds listed above, we'll find that they were bred for a wide variety of purposes and have varying breed standards. For example, the American Pit Bull Terrier is relatively small, weighing between 30-60lbs; the American Bulldog is much larger, weighing between 65-125lbs. The Bull Terrier was originally bred to hunt rats; Bull Mastiffs were bred as guardian dogs. 

When we consider mixed breed dogs, things get even more complicated. Because mixed breed dogs have more genetic variation than pure breed dogs, it is difficult, if not impossible, to predict what genetic traits they will have and how that will affect their appearance, health, and behavior. A dog that has two pure breed parents will not necessarily present traits that are consistent with either of those pure breeds. For example, a dog that is an equal mix of Labrador Retriever and Australian Cattle Dog may not possess traits that are associated with either of those breeds, such as appearance, herding instinct, an affinity for water, or genetic disorders commonly associated with those breeds. Considering that most mixed breed dogs have a breed make-up of three or more breeds, it becomes even more difficult to make those predictions.

Assuming that any dog labelled as a pit bull will have the same personality and behaviors is simply untrue. This generalization does a huge disservice to these dogs and their people.

BSL and housing restrictions

Dogs labelled as pit bulls are commonly restricted by apartment complexes, rental management companies, insurance companies, and even entire jurisdictions with Breed Specific Legislation (BSL). This is a result of the negative stigma around pit bulls and the inaccurate assumption that they are more likely to be aggressive.

BSL and housing restrictions can make it extremely difficult to find safe, affordable housing for families with dogs labeled as pit bulls. This often leads to families who would otherwise keep their dog for the entirety of the dog's life making the decision to surrender their dog to a shelter or rehome them in another fashion, putting additional and unnecessary strain on an animal welfare system that is already facing a pet overpopulation crisis. Many dogs have and will continue to die in shelters because there simply is not enough space for all of them.

Additionally, surrendering a beloved pet can cause significant emotional trauma for the humans of the family. Some individuals may choose to sacrifice their own safety and well-being by remaining in an unsafe situation so that they do not have to surrender their dog. Finding housing that allows their dog is a financial burden on many families, and they may incur other fines or penalties should they continue to house their dog in an area in which the dog is not allowed.

We'll explore the wider implications of BSL in a future article.

Dog bites and aggression

Generalizing the behavior of such a wide variety of dogs is simply impossible, and that's especially true when it comes to aggression.

There is no reliable evidence that any of the 'pit bull' breeds are more likely to display aggression or to bite. As of January 2023, the American Temperament Society has tested 36,333 dogs, with 84% passing the test. Of the breeds listed earlier in this article, the Bulldog and Bullmastiff were the only breeds to test below average (72% and 79.2% passing respectively); the rest tested above average. It should be noted that the sample sizes for some breeds are quite small (for example, only 6 American Bullies have been tested, with a 100% pass rate), while others are significantly larger (960 American Pit Bull Terriers have been tested, with 87.6% passing). 

In a dog bite report, the dog's breed is either self-reported by the victim or the dog's owner, or it is determined by a law enforcement official - most often by visual identification. Because we are conditioned to think that pit bulls are more likely to bite than other breeds, a dog with an unknown breed make-up who bites is more likely to be labeled as a pit bull. In fact, breed statistics in relation to dog bites are so inaccurate that the Center for Disease Control (CDC) no longer collects that data and considers targeting a specific breed with dangerous dog laws unproductive.

The CDC, American Veterinary Medical Association (AVMA), International Association of Animal Behavior Consultants (IAABC), American Society for the Prevention of Cruelty to Animals (ASPCA), and countless other organizations have published statements in support of dangerous dog laws that consider an individual dog's behavior and specific circumstances around bite incidents rather than targeting a specific breed of dog.

Pet overpopulation

Pet overpopulation is a complex issue with many causes and no simple fix. Every year, about 4 million dogs will enter the animal welfare system (shelters and rescues). Around 400,000 of them will die. Some will be euthanized for health or behavior issues, but many healthy, happy, behaviorally-sound dogs will lose their lives simply because there isn't enough space for them.

It's hard to say just how many of the dogs in the animal welfare system are pit bulls, but there's no denying that dogs labelled as pit bulls, especially pit-type mixed breeds, make up a large part of most shelter populations.

The negative stigma around pit bulls, housing restrictions, and BSL have a negative impact on adoption rates, which often results in a longer length of stay for any dog labelled as a pit bull. More 'desirable' dogs - pure breeds, "designer" breeds, small dogs, and puppies - are more likely to find homes or refuge in a private rescue, leaving a larger percentage of pit-type dogs on the adoption floor. In an over-crowded, under-funded shelter that has to make space for incoming dogs, the chance that those pit-type dogs will make it out alive rapidly decreases the longer the dog sits in the shelter.

Breaking the stigma

No matter their breed, every dog should be considered as an individual. Making judgements based on a dog's appearance, perceived breed, or even documented breed is a disservice to the dog. 

We're celebrating Pit Bull Awareness Month all month long with pit bull-friendly products and educational resources. Help us combat the stigma around pit bulls by sharing this article and starting conversations about these misunderstood dogs.


American Pit Bull Terrier, Official UKC Breed Standard, United Kennel Club (UKC)

Bully Breeds, Humane Society of Harrisburg Area

A canine identity crisis: Genetic breed heritage testing of shelter dogsLisa M. Gunter, Rebecca T. Barber, Clive D. L. Wynne

Comparison of Adoption Agency Breed Identification and DNA Breed Identification of DogsVictoria L. Voith, Elizabeth Ingram, Katherine Mitsouras  & Kristopher Irizarry

Study reveals genetic diseases of mixed-breed, purebred dogs, American Veterinary Medical Association (AMVA)

Exploratory content analysis of direct-to-consumer pet genomics: What is being marketed and what are consumers saying?, Nikki E. Bennett, et al.

Inconsistent identification of pit bull-type dogs by shelter staff, K.R. Olson, et al.

Dog-Bite-Related Fatalities -- United States, 1995-1996, Center for Disease Control (CDC)

ATTS Breed Statistics, American Temperament Test Society, Inc.

Dangerous animal legislation, American Veterinary Medical Association (AMVA)

Breed-Specific Legislation, International Association of Animal Behavior Consultants (IAABC)

Position Statement on Dangerous Dog Laws, ASPCA

Pet Statistics, ASPCA

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