Anthropology, University of Texas at Austin
Thursday 2:00-2:15, Galleria South
When resources are patchy in space and time, an animal gains a selective advantage from the ability to find and relocate food items. In this way, diet may be linked to the evolution of spatial memory, with those animals with more uniform food distributions experiencing different selective pressures than those with patchier distributions. This study contributes to our knowledge of the link between diet and cognitive evolution by assessing how one of the most folivorous New World primate species--mantled howler monkeys (Alouatta palliata)— integrates spatial and temporal knowledge of resource distributions into foraging strategies. Specifically, the movements of mantled howler monkeys in relation to resource distributions were observed over an annual cycle (2743 observation hours) on Barro Colorado Island, Panama. Discrete choice models and agent-based simulations were then compared to observed travel patterns in order to determine whether howler monkeys maximize resources obtained per unit distance traveled or whether their behavior could be explained by less cognitively demanding foraging strategies such as movement to neighborhoods instead of individual trees, sensory travel, and movement along arboreal pathway networks without a predetermined destination. Observed travel yielded greater quantities of resources in shorter distances traveled than all alternative strategies tested. In addition, points of significant directional change did not correlate to sites where the acquisition of new visual or auditory information was likely. Thus, this study suggests that a highly folivorous primate, hypothesized to rely on comparatively dispersed resources, integrates knowledge of spatio-temporal resource distributions in highly efficient foraging strategies.
Funding was provided to M. Hopkins by the following organizations: the National Science Foundation (#0622611), The Wenner-Gren Foundation, the American Association of University Women, The Leakey Foundation, the Smithsonian Tropical Research Institute, and the University of California at Berkeley.