Survey of Shelter Dog Composition: Mutts vs. Purebreds

Survey of Shelter Dog Composition: Mutts vs. Purebreds

July 2015


A major goal of the National Animal Interest Alliance (NAIA) is to reduce the number of adoptable pets that are euthanized in American animal shelters. The problem of unwanted pets and shelter euthanasia is a multi-faceted problem, however, and to make progress toward effective solutions, we need a clearer understanding of the many issues involved. That is why NAIA focuses its resources on studying the various aspects of the pet marketplace, including pet shelters. This study is dedicated to examining the types of dogs present in today’s animal shelters to help us better understand and define the issues.


It is hard to speak with certainty when discussing American animal shelters. Even the number of pet shelters operating in the US is unknown. Commonly cited estimates
range from 3,500 (based on National Council on Pet Population Study and Policy – NCPPSP – data from the 1990’s) to 6,000 based on numerous websites using various sources(1), with Petfinder weighing in at 5,000.(2) The bottom line is that US animal shelters operate with so little oversight, it is very difficult for people outside the sheltering community to understand much about them.

The agency conferring animal welfare status on animal shelters is the IRS, an agency that determines the tax status of businesses, not an agency associated with animal welfare oversight. Moreover, there are no national agencies that oversee animal shelters, municipal or private, and there are no national laws requiring shelters to report information about the activities they conduct or the animals they take in, place with the public, or transfer to other shelters, rescues or foster homes. This lack of oversight assures that animal shelters can operate with a level of autonomy not enjoyed by many other American businesses or institutions.

The historic role of animal shelters has changed dramatically over the last couple of decades as dog overpopulation has been eliminated in some parts of the country. With reduced pressure to hold and place a shrinking number of local dogs, many shelters, primarily ones in the Northern US, have taken on new roles. A significant number of humane societies and SPCA’s have dealt with the decline in local dogs by importing dogs from outside their region, a practice they call humane relocation(3), which gives them a steady inventory of dogs for the public. Many have worked to acquire or expand their police powers, a testimony perhaps to the popularity of television shows like Animal Planet’s Animal Cops. Some have added or increased their legislative activity, an activity that keeps the shelter and its mission in the public eye, a necessity for organizations that depend on donations from the public. Private shelters in many cities have developed a greater media presence than all other pet related groups combined: veterinarians, kennel clubs, pet stores, dog trainers and private breeders – a situation assuring that their point of view exerts the greatest influence on public opinion.


The purpose of this project is to estimate the size of the purebred population in US animal shelters. The portion most commonly assigned to purebreds is 25%, a number that is disputed as being excessively high by first-hand observers all over the United States. Establishing more accurate information would benefit policy makers who rely on such data when drafting legislation; consumers who consider it when choosing a family dog; and society at large, which forms opinions and attitudes about dogs, based on their perception of such issues. The commonly cited percentage of shelter purebreds is high enough to suggest that purebreds pose a significant problem to local pet population control. It also suggests to consumers that purebred dogs will be available for adoption in local shelters. It is our hope that more accurate information will lead to better pet laws and raise consumer and public awareness about the modern dog marketplace.


Gathering representative shelter population data is challenging given the immense and changing number of animal shelters operating in different regions of the US and their lack of uniformity. Past studies investigating this subject relied on surveys of shelter personnel and on owner statements taken at the time they relinquished their dogs to shelters(4). Unfortunately, these methods have limitations which tend to result in overestimating the number of purebreds. Shelter personnel are rarely breed experts and owners routinely identify Collie-like dogs as Collies, chunky black dogs as Labrador Retrievers and stocky, short-coated, brown dogs as Pit Bulls.(5)

But even if the statistical estimates published in these studies (25% -30%) were fairly accurate in the 1990’s when they were done, the shelter world and dog marketplace have changed substantially since then and these outdated statistics are typically misquoted today(6). The studies they originated from did not attempt to identify the purebreds in shelters available to the public, but the number of purebreds that entered shelters. This distinction is crucially important because, 1) purebreds are reclaimed by their owners at higher rates than mixed breeds, and 2) purebred rescue organizations remove, foster and place a very significant number of the remaining purebreds from shelters.

Our goal is to update the work done in past decades; to provide broader coverage of US shelters; to provide a level of transparency that enables readers to interpret the data in a reasonable way despite the inherent limitations of this type of survey. Here are the major survey elements


According to this study, the number of purebreds in US animal shelters is closer to 5% (5.04%) than to the 25% so commonly cited by national animal organizations and quoted by the media. It is interesting to observe that the number of purebreds in shelters would be 3.3% were it not for two breeds that are overrepresented, Chihuahuas and dogs described as Pit Bulls. Together, these two breeds account for 35% of all purebreds listed by shelters in this study. The public seems to be aware that dogs described as Pit Bulls are overrepresented in American shelters. What is not well known is that Chihuahuas are the single most numerous purebred found in shelters today. Because Chihuahuas are small, attractive to adopters and highly adoptable, their numbers are especially high in shelters that import dogs for adoption. For more detail, see the screen shots and PDF listings for Northeast Animal Shelter in MA, the Humane Society of Utah and Oregon Humane Society in Portland, Oregon, all of which maintain major import operations.

  1. Oxford-Lafayette Humane Society:
  3. See the Shelter Project glossary for terminology:
  4. John C. New Jr., DVM, 2000. Characteristics of Shelter-Relinquished Animals and Their Owners Compared With Animals and Their Owners in US Pet Owning Households: John C. New, Jr., DVM, M. D. Salman, Mike King, Janet M. Scarlett, Philip H. Kass, Jennifer M. Hutchison: and M. D Salman, 1998. Human and Animal Factors Related to the Relinquishment of Dogs and Cats in 12 Selected Animal Shelters in the US: M. D. Salman, John C. New Jr., Janet M. Scarlett, Philip H. Kass, Rebecca Ruch-Gallie and Suzanne Hetts.
  5. Dog breed identification is no basis for shelter policy:
  6. Although some organizations and news sources quote the 1990’s information correctly, many more misstate the original findings, some using the incorrect information to promote shelters over breeders.


Copyright © 2015 National Animal Interest Alliance. All rights reserved.
Website by