A study of guinea pig vocalizations: With particular reference to mother-infant interactions.

Guinea pig vocalizations were investigated. The behaviour of the guinea pig was observed in a wide variety of situations, and from these samples of vocalizations were recorded, analysed on a sonagraph and classified on the basis of their physical structure. Eleven basic calls were isolated, these were the chut, chutter, whine, low whistle, whistle, squeal, tweet, scream, chirrup, purr and drrr. A series of playback experiments was conducted; from this, general observations and a detailed study of mother-infant interactions, five functional categories of calls were suggested. These were: calls increasing physical proximity, greeting and proximity-maintaining calls, proximity-regaining calls, distress calls and alarm calls. Within the context of maternal behaviour it was found that lactating females, unlike virgin females, responded vocally to proximity-regaining calls of infants and showed searching behaviour. Females did not appear to respond preferentially to the calls of their own young but the possibility that females recognized their own young, entirely by voice, could not be excluded. An exmaination of the ways in which vocalizations are used in mother-infant interactions indicated that the incidence of most calls made by both mothers and infants changed over the post-partum period, and in this situation specific calls were found to be associated with particular forms of behaviour. In general, vocal responsiveness of the female towards her young declined as the suckling period waned, and this paralleled a decline in other forms of maternal responsiveness. Infant animals showed no similar decrease in vocal responsiveness to the mother during the observation period. The part played by exteroceptive stimuli in controlling maternal behaviour in the guinea pig was considered and discussed in relation to other rodents.