Do dogs (Canis lupus familiaris) prefer family?

• We tested the ability of domestic dogs to recognize scents of closely versus distantly related kin.
• Dogs discriminated the scents of sires despite having no familiarity with sires.
• Male dogs spent more time investigating the scents of distantly related females.
• Sex of subject and scent is important when testing kin discrimination in dogs.

Kin recognition requires the ability to discriminate between one’s own genetic relatives and non-relatives. There are two mechanisms that aid in kin discrimination: phenotype matching and familiarity. Dogs may be a good model for assessing these mechanisms as dogs are a promiscuous social species with a keen sense of smell. Domestic dogs of both sexes were presented with two scents (close kin, distant-kin) and preference was assessed through three measures (latency to approach, number of visits, time spent). Experiment 1 explored the possibility of phenotype matching as subjects had no contact with sires, whose scent was presented alongside a control male's scent. Experiment 2 explored recognition of siblings raised with the subjects and then separated at seven weeks of age. Whereas female dogs in this experiment did not show a statistically significant preference, male dogs showed a preference for distant-kin when presented with sire and female sibling samples.