Exploring the existence and potential underpinnings of dog–human and horse–human attachment bonds

• Dog–human dyads align with all our features of an attachment bond.
• Horse–human dyads show variable alignment with attachment theory.
• Emotional intelligence may mediate animal–human attachment bonds.

This article reviews evidence for the existence of attachment bonds directed toward humans in dog–human and horse–human dyads. It explores each species’ alignment with the four features of a typical attachment bond: separation-related distress, safe haven, secure base and proximity seeking. While dog–human dyads show evidence of each of these, there is limited alignment for horse–human dyads. These differences are discussed in the light of the different selection paths of domestic dogs and horses as well as the different contexts in which the two species interact with humans. The role of emotional intelligence in humans as a potential mediator for human–animal relationships, attachment or otherwise, is also examined. Finally, future studies, which may clarify the interplay between attachment, human–animal relationships and emotional intelligence, are proposed. Such avenues of research may help us explore the concepts of trust and bonding that are often said to occur at the dog-human and horse-human interface.