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.