Characteristics of the menstrual cycle in nonhuman primates. III. Timed mating in Macaca arctoides.

Analysis of five years of reproductive data from Macaca arctoides showed the mean menstrual cycle length was 29.9 +/- 4.4 days. Using timed mating, a conception rate of 16.3% was observed. The highest conception rate occurred after matings on day 11 of the cycle. Eight pregnancies went to term and the mean gestation length was 172.4 days. The sex ratio was 137.8 males per 100 females in fetuses obtained on day 100 post-conception.