Intraspecific attachment in dogs: is the mother always the mother?

Scientific literature on attachment in domestic dogs has mainly focused on dog bond toward humans. Despite the relevance of social relationships in the canine species, studies on intraspecific attachment are scarce. The aim of the current study was to assess whether in adult dogs the bond toward the mother is different from the bond toward another cohabitant dogs. Seventeen dogs (52.9% females, 38.9±13.3 months old, different breeds) were tested in a modified version of the Ainsworth’s strange situation test where the stranger was played by a female stranger and the attachment figure was played by dogs’ mother, living in the same household. A second sample of 22 dogs (45.5% females, 39.2±26.6 months old, different breeds) underwent the same test with an older cohabitant dog. The duration of dogs’ social and non-social behaviors of the two samples in each episode was compared using the Mann-Whitney U test (p < 0.05). No difference was found between the two groups in the isolation episode; a few differences were observed for non-social behaviors throughout the test. A slight preference for the mother was observed in episodes after reunion (more approach and visual orientation). However, the findings do not fully support the hypothesis that the bond of adult dogs toward conspecifics sharing their daily life is stronger in case the conspecific is their own mother rather than another older dog. Future research should investigate more in depth this kind of bond, its features and its relationship with dog behavior and social life.