Different behaviour patterns of mother-infant interaction

In 17 infant rhesus monkeys (Macaca mulatta) four different behaviour patterns of mother-infant interaction (On mother, Nipple, Immobile and Grooming by mother during On) were studied from the end of the first month of life to the beginning of the eighth. For both sexes of infants the mean durations and the mean number of bouts per session (frequency) were correlated for each behaviour; correlations between two different behaviours were also calculated (Spearman rank-order correlation coefficients). The results demonstrate an important fact, namely, that there are almost always significant correlations between frequency and duration both within and between behaviour patterns. In most of the cases, this is so only for analyses within the same sex. In general, neither the frequencies nor the durations of the behaviour of females are highly correlated with the frequencies or durations of the same or different male behaviour patterns. Behavioural frequencies and durations tend to be significantly correlated, but only within the same sex. In addition, two further facts emerge: first, that of all the analysed behaviour patterns, the frequency and the duration of Nipple are influenced by the time that the infant spends On mother and, secondly, that this tendency appears to be dependent on the sex of the infant.