Behavioral Differences Between Purebred and Mixed-Breed Dogs

Purebred and mixed-breed dogs have behavioral, demographic, and environmental differences, according to online surveys completed by dog owners. Results of the surveys, recently published recently in PLoS ONE, suggest that mixed-breed dogs may “represent a special group with characteristic behavioral traits,” according to the authors.

Mixed-breed dogs often have complex or unknown ancestry. According to the American Veterinary Medical Association, approximately 53% of dogs in American households are mixed breeds. In other countries, this percentage ranges from 33% (Germany, United Kingdom) to 50% (Australia). Despite the popularity of mixed-breed dogs, few studies have been conducted to examine their behavior.

Several studies have noted behavioral differences between purebreds and mixed breeds. In one study, mixed-breed dogs were found to be more disobedient, nervous, and excitable than purebreds. In contrast, another study found no personality differences between mixed breeds and purebreds. Behavioral comparisons were not the main aim of these studies, however, indicating that the observed differences (or lack thereof) could have reflected other factors, such as dog-keeping practices.

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For the current study, the authors collected data from two online surveys completed by dog owners in Germany. Part 1 of each survey pertained to demographics (dogs and dog owners) and dog-keeping practices. Part 2 of survey 1 focused on 4 behavioral traits: calmness, trainability, sociability (toward other dogs), and boldness. Part 2 of survey 2 pertained to behavioral problems, such as stubbornness and leash pulling.

In total, information on approximately 15,400 dogs (purebred, n = 7700; mixed-breed, n = 7691) was collected.

Behavioral Trait Differences

Compared with purebreds, mixed breeds were significantly less calm and less sociable with other dogs. No significant differences were observed in trainability or boldness. Behavior was significantly more problematic with mixed breeds than purebreds.

Demographic and Dog-Keeping Differences

Of the 20 demographic and dog-keeping factors investigated, 12 were significantly different between dog groups. Several of the significant differences are as follows:

Demography

• Mixed breeds were older and more likely to be female.
• Mixed-breed owners were primarily younger and female with less dog-owning experience.

Dog keeping

• Mixed breeds were older when acquired.
• More mixed breeds were neutered.
• Mixed breeds were primarily indoor-only pets, but they got walked for longer periods than purebreds.

Notably, factors related to commitment to dog ownership (eg, buying gifts, hours spent playing) were not significantly different between dog groups.

Only “neuter status” and “age when acquired” had differences exceeding 10% between dog groups. For the other factors, the magnitude of differences was too small for clinical relevance.

Relationship Between Behavioral Traits and Other Factors

Using linear regression, the authors identified several significant associations between behavioral traits and demographic and dog-keeping factors. Importantly, dog group was significantly associated with several traits: mixed breeds were less calm, more trainable, and had more behavioral problems than purebreds.

Other factors also had significant associations. Compared with younger dogs, older dogs were calmer, less trainable, and less sociable toward other dogs. Compared with males, females were more sociable and had fewer behavioral problems.

The authors mentioned possible genetic and developmental influences on the observed differences. Breeders genetically select for more desirable behaviors in purebred dogs. Developmentally, mixed-breed dogs tend to spend more time in shelters before adoption; the stresses of shelter life could lead to more behavioral problems.

Study Limitations and Conclusion

Owner subjectivity was an important study limitation. Owners of purebreds may have assumed their dogs were behaviorally superior to mixed-breed dogs and thus downplayed problematic behaviors.

Taken together, these survey results highlight the multifactorial differences between mixed-breed and purebred dogs. Such differences suggest that mixed-breeds are more than just “average” dogs.

Dr. JoAnna Pendergrass received her doctorate in veterinary medicine from the Virginia-Maryland College of Veterinary Medicine. Following veterinary school, she completed a postdoctoral fellowship at Emory University’s Yerkes National Primate Research Center. Dr. Pendergrass is the founder and owner of JPen Communications, LLC.