Separation-related behaviour indicates the effect of functional breed selection in dogs (Canis familiaris)

The domestication of dogs resulted in several fundamental behavioural changes as compared to their closest wild living relative, the wolf. While these characteristics are considered to be fairly robust across dogs, dog breeds themselves manifest apparently strong behavioural differences. Thus far the functional roots of breed-specific behaviours are still less understood and supported by empirical research. We hypothesized that historical selection for the level of working interaction intimacy with their handlers, may have resulted in the fundamental differences between the main working dog types and their behavioural reactions when separated from their owner. In our study, dogs from breeds that were originally selected for either cooperative or independent work tasks, were tested in a short outdoor separation test. We included dogs with and without owner-reported separation-related disorder (SRD) to both groups. We found that SRD-status and the breed type were in significant association with various stress related behaviours during separation from the owner. Dogs from cooperative working breeds with SRD barked more frequently, meanwhile barking was less prevalent in independent breeds and also in cooperative breeds without owner-reported SRD symptoms. General movement (showing the dogs' intention to follow or find the disappearing, then absent owner) was uniformly strongest in cooperative dogs with SRD. Whining appeared most frequently in dogs with SRD, regardless to the breed type. These are the first results that support a functional evolutionary framework behind the association of particular dog breeds with the extent of their stressful reactions to separation from their owner.