Little is known about the reproductive biology of spider monkeys (Ateles spp.) even though they are a well known and endangered primate. One of the difficulties faced by researchers is that spider monkey females lack an obvious visual signal of ovulation, making it difficult to identify stages in a female's reproductive cycle. Advances in laboratory techniques now enable researchers to extract hormones from the feces of animals, providing a non-invasive method to investigate the reproductive status of wild animals. I propose to study the reproductive biology of spider monkeys (A. geoffroyi) using a combination of hormonal and behavioral data. A preliminary study will measure hormones in urine and feces in a captive group (San Diego Zoo) to refine the techniques that will be used in the field component of this research project. During the one year field study, fecal samples as well as behavioral and ecological data will be collected from A. geoffroyi on Barro Colorado Island, Panama. Results from this study will provide: 1) the first systematic study of the ovulatory cycle of spider monkey females, 2) information concerning possible environmental effects on reproduction in this species, and 3) the first test of the presence of estrus in female spider monkeys.
