Reproductive biology of female titi monkeys (Callicebus moloch) in captivity.

Titi monkeys (Callicebus spp., Cebidae) are monogamous neotropical primates that live in family-like groups typically consisting of an adult monogamous pair and one or two young. Knowledge about the reproductive biology of this genus is scanty. This study investigated the reproductive biology of female dusky titi monkeys (Callicebus moloch). An initial analysis characterized reproductive parameters of 32 females from a captive colony maintained for 23 years at the California Regional Primate Research Center (CRPRC). The colony records provided data on reproductive parameters such as interbirth intervals, seasonality, age at first pregnancy, and reproductive rate in captivity. Changes in urinary levels of estrone conjugates (E1C) and pregnanediol-3alpha-glucuronide (PdG) were used to characterize major reproductive events. Urine samples from eleven females were collected during 17 months. The endocrine data were used to examine changes associated with cycling, conception, and the post-partum period as well as to determine the duration of the ovarian cycle and gestation length. The analysis of colony records indicated that females whose infant survived through weaning gave birth at intervals remarkably close to one year, while those who lost their offspring showed a significantly shorter interval. As long as they lived within the family group, mature female offspring did not breed. The analysis of the endocrine profiles indicated that after giving birth to a viable offspring, females undergo a relatively prolonged period of anovulation (approx. 6.5 months), followed by 1-3 non-conceptive cycles (approx. 1 month), after which they conceive and gestate (4.3 months).