In dogs, chronic stress may be a reflection of their owner's stress

Dogs are empathetic animals that can sense not only affection but also fear, anger, and stress in their owners. However, the levels of stress experienced by these animals vary from one dog to another and differ depending on their breed and their owner’s personality. The selection of dog breeds for their ability to assist humans may have fostered an emotional bond that, over the long term, has led to stress synchronization between the dog and its owner.   With the health crisis we are currently facing, stress has been nearly omnipresent in our societies for many months. And the animals living alongside us are feeling it too. Researchers at Linköping University wanted to find out whether stress in dogs could be linked to the different people with whom they live. They therefore measured levels of cortisol—the stress hormone—stored in the fur as pedigree dogs of various breeds, some closer to humans than others, grew. At the same time, all animal owners filled out questionnaires about their own personalities and those of their pets. They also answered questions about their day-to-day relationships with their dogs, focusing in particular on their interactions, the degree of attachment, any behavioral issues, and so on. According to the results, the owners’ personalities appear to affect stress levels in breeds selected for hunting, such as the dachshund or the Norwegian Elkhound, but not in primitive breeds—which are more closely related to wolves—such as the Shiba Inu, the Basenji, or the Husky. The researchers also showed that the relationship between dogs and their owners could affect the level of stress experienced by the animals, in both hunting breeds and primitive breeds, although the effect is less pronounced in the latter. Sheepdogs, genetically selected for their ability to collaborate with humans, were, however, the only ones to truly synchronize their stress levels with those of their owners over the long term. Collectively, these data reveal that the effect of chronic stress varies depending on the dog’s breed and the purpose for which it was bred. Overall, stress in primitive breeds is less strongly influenced by their living conditions and their relationship with humans. Hunting dogs, on the other hand, show clear links between their stress and their owners’ personalities, and even the degree of closeness between them. But only herding dogs seem to truly synchronize with their owners’ stress over the long term. This “emotional contagion” could be a consequence of the breeding of herding dogs, which have been selected for their receptiveness and ability to collaborate with humans, and are therefore closer to their owners and better able to sense their owners’ stress.