Sex and experience influence behavioral responses of adult rats to potentiated and nonpotentiated ultrasonic vocalizations of pups.

Responsiveness of adult rodent caretakers to infant rodents is necessary for their survival and proper development. Both olfactory and auditory cues are known to influence adult behavior toward the young. In the present study, we found that adults respond differentially to a recording of potentiated vs. non-potentiated ultrasound vocalizations of a 12-day-old rat pup, either in the presence or absence of olfactory cues. The combination of olfactory and potentiated ultrasonic vocalization produced the greatest effect. Adult behavior was also affected by the adults' sex and parental experience in an interaction. Parental experience of females made them more responsive to the type of ultrasonic vocalization; males were little affected. Female experience, of course, includes the hormonal changes due to pregnancy and lactational state. The results are consistent with a communicatory function for isolation-induced ultrasonic vocalization.