Growth and reproductive parameters of bonnet monkey (Macaca radiata)

The present paper summarizes some of the important biological and physiological data recorded over a 30-year period on the biology of bonnet monkeys in captivity. Data on sexual maturity, menstrual cyclicity, general behaviour, endocrine profile, reproductive physiology, gestation, parturition, postpartum amenorrhoea in the female, and sexual maturity, hormone profile, and seasonal variation in sperm count of the male monkeys are presented. In addition to the biological values, weights of selected organs, vertebral and dental pattern are also presented. Menarche occurred at an age of 36+/-4 months and the first conception in the colony occurred at an age of 54+/-4 months. The average menstrual cycle length was 28+/-4.3 days. Majority of monkeys did not cycle regularly during March-June during which the temperature reached a peak. The pregnancy index of the colony was 80% with controlled breeding. The gestation period was 166+/-5 days with 6-7 months postpartum amenorrhoea. Males attained sexual maturity by the age of 6-7 years and exhibited the characteristic nocturnal surge of serum testosterone at this age and sperm concentration ranged from 116-799 millions/ejaculate