The development of social preferences in the voles Microtus montanus and Microtus canicaudus: Effects of cross-fostering

Abstract

Litters of Microtus montanus and Microtus canicaudus were cross-fostered for 28 days postpartum. Upon reaching sexual maturity, they were tested for social preferences by giving them a 48-hr choice test between individuals of the opposite sex of the two species. The test animals had free access to the stimulus animals. The major results were as follows: (1) M. montanus males reared by natural parents showed a preference for conspecific females, while fostered males showed no preference; (2) M. montanus females reared by natural parents showed no discrimination between males, while fostered females preferred males of the foster species; and (3) M. canicaudus females showed no discrimination between males when reared both by natural or foster parents. It is likely that the discriminations shown were based on olfactory cues, but this was not specifically examined in these experiments. It is concluded that, at least in M. montanus, a behavioral isolating mechanism may be established by early experience with the parents.