1. Most births are singletons (99.4%).
2. The youngest age of conception in a captive born female and male was 20.5 months and 23.5 months, respectively. The mean age at first birth in a group of nine females born in captivity was 40.56 _t 7.82 (S.D.) months.
3. Maximum gestation length is 141 days.
4. Interbirth interval averaged 12.72 ± 5.72 (S.D.) months.
5. A birth peak occurred in October, November, December, and January, but the animals remained reproductively active thoughout the year.
ACKNOWLEDGMENTS
This work was sponsored by the Proyecto, Peruano de Primatologia "Manuel Moro Sommo," supported by the Peruvian Government and the Pan American Health Organization with funds from the letter of understanding ICF/ZNS/010. We also want to thank Ms. Margaret Larned for comments during the preparation of the manuscript.
