Both humans and conspecifics provide social support to dog and wolf puppies

Social support can play a crucial role in enabling individuals to cope better with environmental stressors when accompanied by a social partner, but this effect varies strongly across species and often with partner identity. While generally conspecifics can provide social support most effectively, domesticated species might benefit also from the presence of a human partner; even more than their intensively human-socialized wild relatives. Here we set out to compare stress support provided by conspecific and human partners in equally hand-raised and kept wolf, Canis lupus, and dog, Canis lupus familiaris, puppies. Given their similar developmental trajectories and evolutionary background, we expected a similar supportive role of conspecifics in both species. Moreover, we hypothesized that domestication has prepared dogs to benefit from the presence of a human more than wolves, which, however, may be masked when intensive socialization is provided to both species. Therefore, we expected a similar stress buffering effect of a human partner in both dog and wolf puppies. To test this, we had puppies of both species participate in two neophobia tasks and one isolation-reunion-separation task. Although we found no direct differences between the two species when tested with either a conspecific or a human partner, there were a few behavioural differences between wolf and dog puppies suggesting that dogs rely more on humans than wolves. Our present results provide evidence that stress buffering has not evolved anew during the process of domestication, but also that both socialization and domestication might play a role in shaping the extent to which young dogs and wolves rely on their human partners.