Researchers Lisa Gunter, Rebecca Barber and Clive Wynne at Arizona State University reveal the inaccuracies of breed labeling of shelter dogs in their paper “A canine identity crisis: Genetic breed heritage testing of shelter dogs”. Gunter, Barber and Wynne used the Wisdom Panel Canine DNA Test on more than 900 dogs. The Wisdom Panel uses hundreds of genetic breed markers and identifies the breed signatures found in each dog’s great grandparents. It often indicates five or more breeds that are in a dog’s genetic heritage.
This study revealed higher genetic diversity in shelter dogs than was expected. There were 125 breeds represented in the dogs studied, and less than 5% of the dogs (45) dogs were purebred. Previous estimates of purebred dogs in shelters have been about 25%. That higher number comes from work done over 20 years ago. (It’s possible that the demographics of dogs in shelters have changed, but perhaps they have been rare in shelters all along with many dogs misidentified as purebred dogs.) An additional 12 dogs were identified as a cross of two purebred parents of different breeds.
The most common breeds identified in the genetic tests were American Staffordshire Terrier, Chihuahua and Poodle. The average number of breeds found in each dog was three, though it was not uncommon to find dogs with 5 breeds in their genetic makeup. Often, the amount of a breed in a dog’s genes is too small to be detected by genetic tests. In this study, 87.8% of the dogs had at least one ancestor of unidentifiable breed origin at the great-grandparent level.
When the genetic results were compared to the identifications by shelter staff based on appearance, the agreement was underwhelming. Shelter staff were able to correctly identify one of the breeds in a dog about two-thirds of the time. That means a third of the time, visual identifications of a dog’s breed make-up did not match even one of the up to five breeds identified by genetic testing. The accuracy rate for identifying two breeds found in a dog’s genetic signature was only about 10%.
The results of this research show that attempting to determine a dog’s ancestry based on physical appearance is a dicey endeavor at best and little better than pure guess work in many instances. Dogs with very different heritages can look quite similar to one another. (It’s true for humans, too. I once met a woman at a party after multiple people told each of us that there was someone else at the gathering who looked remarkably similar. When we finally connected, we were both amused to learn that despite our striking resemblance, we did not have similar backgrounds. I’m an Ashkenazi Jew descended from Russian, Romanian, Lithuanian and Polish immigrants while she is half Mexican and half Lebanese.)
So, why do breed labels matter anyway? It's common to want to adopt a dog of a specific breed or to avoid certain breeds, but we need to question the standard practice of visual identification of the breeds of shelter dogs. Besides their inaccuracy, breed identity does not guarantee behavior, size, health, beauty or any of the other traits that people are seeking in a dog. If people adopt a certain breed or breed mix, they often expect something particular of that dog, and that can lead to disappointment.
There is even some evidence that labeling dogs makes people focus more on the cards taped to the front of kennels than to the dogs inside them. It’s far better to choose a dog based on that particular dog’s behavioral and physical characteristics than to make assumptions based on breed or physical resemblance to dogs of a certain breed. Without breed labels—right or wrong—people make their own assessment of the dogs when choosing which one to adopt.
We fall in love with dogs, not breeds. It’s the individual dog who has captured our heart, not the breed or breeds within that dog.