Patterns of behavior across reproductive states of free-ranging female black-handed spider monkeys (Ateles geoffroyi)

Reports on the behavior of spider monkeys (genus Ateles) describe a suite of 5-6 behaviors that are indicative of an estrous female. This study presents hormonal data as an independent measure of reproductive state to determine if these behaviors are associated with any particular reproductive state or stage of the ovarian cycle. Fecal samples collected from 6 free-ranging female black-handed spider monkeys (Ateles geoffroyi) over the course of 11 months were assayed for estrogen (E1C) and progesterone (PdG) metabolites, using an enzyme immunoassay. Behavioral data collected from the same females were analyzed for patterns associated with different reproductive states. A more detailed analysis of behavioral data associated with reproductively cycling periods determined whether each behavior clustered with copulations or a particular phase in the ovarian cycle. Observations of place-sniffing were more frequent for 4 of 5 females when reproductively cycling. Of all copulations observed, 80% occurred when the female participant was reproductively cycling. In addition, the rates of self-clitoral hold and self-clitoral rub behaviors were significantly higher for 2 of 4 and 4 of 5 of females, respectively, when reproductively cycling. No behavior consistently occurred in association with copulations or with any particular phase in the ovarian cycle. Results from this study suggest that the behaviors tested in this paper can provide some information regarding female spider monkey reproductive state (whether or not she is reproductively cycling), but that they are not indicators of estrus in female spider monkeys.