We tested what social cues mediate the transition from non-parental to parental behavior in male meadow voles, based on our previous findings that postpartum interaction with mate and pups was the most effective social experience for making males paternal. Males housed with their mates and pups for a day were more paternal and less aggressive to unrelated pups than males removed from their mates before parturition. Males housed with their mates, but with the litter removed, interacted with pups but were initially as likely to be aggressive as males with no exposure to mates and pups. These results suggest that the mate facilitates interaction with pups, but exposure to pups accelerates the sensitization process. Twenty-four hours of exposure to chemical cues from the mate and pups (mother and litter in cage with wire mesh floor suspended above male's cage) eliminated male aggression towards pups, but physical contact was necessary to enhance positive interactions with pups. Exposure to chemical cues from parturient mates reduced aggression, whereas cues from non-mates were not effective. These results may explain our previous findings that females keep sires removed during pregnancy out of the nest for about a day after reintroduction (while males become sensitized via chemosignals), and continue repelling unfamiliar males (that would not be sensitized by chemical cues from non-mates).