Intraspecific relationships in adult domestic dogs (Canis familiaris) living in the same household: A comparison of the relationship with the mother and an unrelated older female dog

Abstract There is scientific evidence that adult dogs establish attachment bonds towards human beings. Attachment as behavioural system exists in the puppy-mother relationship, but adult dogs tested with the Ainsworth Strange Situation Test (ASST) have been found to show a preference for the stranger over a conspecific living in the same household. In the current study, 50 adult dogs were tested with an intraspecific version of the ASST where the role of the presumed attachment figure was played by an older female dog living in the same household, 18 being their own mother and 32 being an unrelated older dog. The two groups did not show remarkable differences when compared one to the other. However, the within-group analysis revealed that dogs tested with an household older female dog other than the mother showed a preference for the human stranger, who had a higher ameliorative effect than the companion dog. Dogs tested with their mother instead displayed both social and non-social behaviours in a very similar manner when in the company of the stranger or of the mother after being reunited with them. Considering the peculiar appeal that human beings have to dogs and the differences observed in the current study, it can be concluded that adult dogs showed a stronger bond for the mother. Future research may clarify if this depends on the maternal care and/or on the time spent with the mother since birth.