Abstract # 34:

Scheduled for Saturday, September 17, 2011 02:45 PM-03:00 PM: Session 8 (Meeting Room 408) Oral Presentation


L. M. Porter1 and P. A. Garber2
1Northern Illinois Univeristy, Department of Anthropology, Dekalb, Illinois, USA, 2University of Illinois, Urbana, Illinois
     In this study we examined the ability of wild saddleback tamarins to integrate spatial information and quantity information in foraging decisions using two complementary methodological approaches: natural observations and controlled field experiments in which platforms baited with different amounts of food (0, 1, or 3 bananas) were located 50-180 meters apart in the group’s home range. Natural field observations of tamarin feeding and ranging behavior (using a GPS unit) were collected at 10 minute intervals over the course of 36 days. We also recorded the location of sleeping sites (n=9) and feeding trees (n=85). From these data, we calculated a circuity index (CI = distance traveled/straight-line distance) to test the degree to which individuals moved directly between sites. Based on an evaluation of 121 travel segments the CI was 1.30, indicating that the monkeys did not take straight-line routes between feeding and resting sites. Our analysis also showed that the monkeys reused particular areas of the forest as nodes or landmarks to reoriented travel. We also conducted a series of field experiments to examine whether tamarins selected feeding sites based on a tradeoff between distance traveled and expected food reward. Overall, our results indicate that S. fuscicollis accurately encoded the spatial relationships among feeding and sleeping sites in their home range, and employed a route-based mental map to navigate between natural and experimental feeding sites.