Dog Breeds and Their Behavior

Domestic dogs display an extraordinary level of phenotypic diversity in morphology and behavior. Furthermore, due to breeding practices introduced during the nineteenth century, these phenotypic traits have become relatively ‘fixed’ within breeds, allowing biologists to obtain unique insights regarding the genetic bases of behavioral diversity, and the effects of domestication and artificial selection on temperament. Here we explore differences in behavior among the 30 most popular dog breeds registered with the American Kennel Club based on owner responses to a standardized and validated behavioral questionnaire (CBARQ ). The findings indicate that some breed-associated temperament traits (e.g. fear/anxiety) may be linked to specific gene mutations, while others may represent more general behavioral legacies of ‘ancient’ ancestry, physical deformity, and/or human selection for specific functional abilities. They also suggest that previous efforts to relate dog breed popularity to behavior may have failed due to the confounding effects of body size.