Long-term stress in dogs linked to the owner-dog relationship

Researchers at Linköping University have investigated whether the stress levels of dogs are affected by the people they live with. Stress levels for the past several months can be determined in both dogs and humans by measuring the levels of stress hormone stored in hairs as they grow.

The researchers have collected hair from both dogs and owners, and measured levels of cortisol, the most important stress hormone, in them. They were interested in whether there are differences between different dog breeds. Breeding has led to the genetic selection of different breeds for different tasks. The study included 18 dogs from breeds that have been bred for independent hunting, such as the Swedish elkhound, the Norwegian elkhound, and the dachshund. A second group included dogs from ancient breeds that are genetically more closely related to the wolf than other breeds. This group comprised 24 dogs from breeds such as the shiba inu, the basenji, and the Siberian husky. All owners completed questionnaires about their own personality and that of their dog. They also answered questions about their relationship with their dog, including such matters as how the owner experienced the interaction with the dog, degree of emotional attachment to the dog, and the extent to which owning a dog gave rise to problems.

"The results showed that the owner's personality affected the stress level in hunting dogs, but interestingly enough not in the ancient dogs. In addition, the relationship between the dog and the owner affected the stress level of the dogs. This was the case for both types, but the result was less marked for the ancient dogs," says Lina Roth, senior lecturer in the Department of Physics, Chemistry and Biology at Linköping University.

In a previous study, the same researchers had seen that dogs from herding breeds, which have been genetically selected for their ability to collaborate with humans, mirror the long-term stress level of their owner. When the researchers now added information about the relationship of the herding dogs to their owner, it became clear that the relationship was significant for the long-term stress levels also in these dogs.

The researchers conclude that long-term stress is influenced least strongly by the owner and their relationship to the dog for ancient breeds. The hunting dogs show clear links between both the personality of the owner and their relationship to the dog, but it is only herding dogs that demonstrate the unique synchronisation with the long-term stress in the owner.

"We believe that the synchronisation of stress is a consequence of breeding the herding dogs for collaboration with people, while the relationship to the owner and the owner's personality are important parameters that influence the synchronisation of stress levels," says Lina Roth.