Large Study Finds No Evidence for "Black Dog Syndrome"

A study of over 16,000 adoptable dogs finds black dogs don’t take longer to be adopted after all.

A black French Bulldog relaxing on her bed
Photo: Istvan Csak/Shutterstock

By Zazie Todd, PhD

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Understanding what people look for in adoptable dogs can make a big difference to animal shelters. It makes sense to target promotions in order to stop dogs having lengthy stays. But you can only do this if you know what people want. 

The idea that black dogs wait longer for a new home than dogs of other colours has been around for a while. New research by Heather Svoboda and Christy Hoffman (Canisius College) suggests it does not exist, at least at the two shelters they surveyed.

Christy Hoffman told me, “We did not find evidence of Black Dog Syndrome, but we did find that shelter outcomes tended to be worse for brindle dogs and, not surprisingly, bully breeds. A relatively recent paper by Brown et al. (2013) also concluded black dogs do not have worse than average shelter outcomes. I wonder if, perhaps, Black Dog Syndrome was never a problem, or if all the marketing efforts to promote black dogs have actually reversed the trend.

Black dogs did not take longer to be adopted at either of the two shelters taking part in this study. In fact, brindle dogs had a longer wait at both shelters, and multi-colour dogs also took longer at one of the shelters. Black dogs were not more likely to be euthanized. Age and breed group were more important than coat colour when it came to adoptability.

Even though all the dogs in the study were adults, the younger ones were still adopted more quickly. Females were adopted faster than males.

Does 'black dog syndrome' exist? This large study found no evidence that black dogs - like this French Bulldog - take longer to be adopted from shelters.
Photo: Irinia Kozorog/Shutterstock
The bully breeds took longest to be adopted at both shelters, and were more likely to be euthanized or considered untreatable-unhealthy. This is in contrast to the earlier work by Brown et al which – while also finding no evidence for Black Dog Syndrome – did not find bully breeds waited longer for a new home. 

At both shelters Terriers and Toy breeds were adopted most quickly, but there were some differences in the relative popularity of other breeds.

Svoboda and Hoffman suggest shelters take a look at their own data to find out which dogs wait longest at their location. They can then devise targeted promotional strategies to help increase adoption rates and reduce euthanasia.

One of the great things about this study is the size of the dataset: 16,692 dogs over four years at two animal shelters in the Pacific NorthWest. Because puppies and young dogs are already known to be adopted faster, they focussed on dogs over 1 year old, and less than 13. Dogs that came in and were adopted out between 1st Jan 2009 and 31st December 2012, and for whom all the necessary data was available, were included in the study. 

The results are especially interesting given different intake policies. Shelter A, which houses over 100 dogs, has a managed intake policy, which means they decide which animals to take. About half their dogs come from other shelters and 30% are surrendered by their owner. Shelter B has space for 60 dogs, and is ‘open admission’ which means they take any animal. Owner surrenders and strays make up 60% of their intake, with most of the rest coming from other shelters.

The average length of time a dog was available for adoption at shelter A was 7 days, and 10 days at shelter B.

This study shows the importance of looking closely at adoption data, and the results will surprise many people.

What do you look for when adopting a dog? 

Zazie Todd, PhD, is the award-winning author of Wag: The Science of Making Your Dog Happy and Purr: The Science of Making Your Cat Happy. She is the creator of the popular blog, Companion Animal Psychology, writes The Pawsitive Post premium newsletter, and also has a column at Psychology Today. Todd lives in Maple Ridge, BC, with her husband, one dog, and two cats. 

Useful links:

Brown, W., Davidson, J., & Zuefle, M. (2013). Effects of Phenotypic Characteristics on the Length of Stay of Dogs at Two No Kill Animal Shelters Journal of Applied Animal Welfare Science, 16 (1), 2-18 DOI: 10.1080/10888705.2013.740967
Svoboda, H., & Hoffman, C. (2015). Investigating the role of coat colour, age, sex, and breed on outcomes for dogs at two animal shelters in the United States Animal Welfare, 24 (4), 497-506 DOI: 10.7120/09627286.24.4.497

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