Reproductive parameters in the sooty mangabey (Cercocebus torquatus atys)

Data obtained over a 7.5 year period from a captive group of sooty mangabeys were analyzed to examine the relationship between demographic variables and reproductive events. Perineal swelling and reproductive data collected from 67 females contributed to the analyses. Sexual maturation, as marked by the onset of swelling cycles, was recorded at an average age of 36.4 ± 1.1 (mean ± SEM) months and first parturition at 56.5 ± 1.8 months, indicating a period of adolescent sterility of over 1 year. A total of 198 births were recorded, of which 165 (83.3%) were live births with infant survival to 30 days of age. Both parity and the duration of infant survival influenced interbirth interval, with the shortest interval observed in multiparous females with infants surviving less than 6 months (10.0 ± 0.5 months) and the longest in primiparous females with infants surviving more than 12 months (22.4 ± 1.2 months). Infant survival did not vary significantly according to the age class of the mother. Births and the onset of perineal swellings in young females showed a seasonal distribution, with swelling cycles and conceptions rarely occurring from April through September.