Trainability and boldness traits differ between dog breed clusters based on conventional breed categories and genetic relatedness

Modern dog breeding has given rise to more than 400 breeds differing both in morphology and behaviour. Traditionally, kennel clubs have utilized an artificial category system based on the morphological similarity and historical function of each dog breed. Behavioural comparisons at the breed-group level produced ambiguous results as to whether the historical function still has an influence on the breed-typical behaviour. Recent genetic studies have uncovered genetic relatedness between dog breeds, which can be independent from their historical function and may offer an alternative explanation of behavioural differences among breeds. This exploratory study aimed to investigate the behaviour profiles of 98 breeds, and the behavioural differences among conventional breed groups based on historical utility and among genetic breed clusters. Owners of 5733 dogs (98 breeds) filled out an online questionnaire in German. Breed trait scores on trainability, boldness, calmness and dog sociability were calculated by averaging the scores of all individuals of the breed. Breeds were ranked on the four traits and a cluster analysis was performed to explore behavioural similarity between breeds. We found that two of the behaviour traits (trainability and boldness) significantly differed both among the conventional and the genetic breed groups. Using the conventional classification we revealed that Herding dogs were more trainable than Hounds, Working dogs, Toy dogs and Non-sporting dogs; Sporting dogs were also more trainable than Non-sporting dogs. In parallel, Terriers were bolder than Hounds and Herding dogs. Regarding genetic relatedness, breeds with ancient Asian or African origin (Ancient breeds) were less trainable than breeds in the Herding/sighthound cluster and the Hunting breeds. Breeds in the Mastiff/terrier cluster were bolder than the Ancient breeds, the breeds in the Herding/sighthound cluster and the Hunting breeds. Six breed clusters were created on the basis of behavioural similarity. All the conventional and genetic groups had representatives in at least three of these clusters. Thus, the behavioural breed clusters showed poor correspondence to both the functional and genetic categorisation, which may reflect the effect of recent selective processes. Behavioural breed clusters can provide a more reliable characterization of the breeds' current typical behaviour. (C) 2011 Elsevier B.V. All rights reserved.