Foraging and Spatial Memory in Wild Weddell’s Saddleback Tamarins (Saguinus fuscicollis weddelli) When Moving Between Distant and Out-of-Sight Goals

摘要

Two main types of cognitive maps, route-based and coordinate-based, have been proposed to explain how animals navigate through their environments. We examined patterns of feeding and ranging in Weddell’s saddleback tamarins (Saguinus fuscicollis weddelli) in northern Bolivia to assess which type of cognitive map best explains the tamarins’ movement patterns in large-scale space, e.g., when moving between distant and out-of-sight goals. We observed the tamarins for 236 h over the course of 32 d and used a GPS unit to record the location of nighttime sleeping sites and feeding trees and the locations of individuals at 10-min intervals. Based on an evaluation of 109 travel segments of >20 m in which the monkeys traveled from the tree of one major feeding species to another without stopping to rest, forage for insects, or interact with neighbors, we calculated a circuity index (actual distance traveled divided by the straight-line distance) of 1.43. We also plotted the monkeys’ daily movement patterns using GIS software. These analyses showed that tamarin travel was not random, that a limited set of route segments (N = 29) was reused on multiple occasions, and that certain areas of the forest appeared to serve as switch points (N = 9) where the monkeys reoriented travel. These results support the contention that the tamarins encoded the spatial relationships among many feeding and sleeping sites in their home range, and navigated in large-scale space using a route-based spatial representation. These results are consistent with those reported for a variety of primate taxa, suggesting that many primate species reuse a familiar set of travel routes and switch points to orient in large-scale space.