Growing evidence indicates that spatial abilities are directly correlated to the foraging ecology of a species. There is also evidence that foraging behaviors which require precise spatial memory, such as food-storing, are correlated with changes in the relative volume of brain structures. The foraging behavior, spatial abilities and brain anatomy of three sympatric heteromyid rodents will be compared. The foraging ranges of these species (Dipodomys merriami, Perognathus formosus and Chaetodipus fallax) and their patterns of cache distribution are to be determined over two field seasons in a California field site. Their ability to complete a series of mazes and to relocate their food caches using spatial memory will be measured in the laboratory. Finally, the relative hippocampal volume of each species will be calculated from thin brain sections. Thus, this study will address the question of spatial ability at three levels: the underlying basis in morphology, the organization of spatial ability for different tasks such as finding food and retrieving caches and, finally, the implication of such differences for the structure of desert heteromyid communities. The institutional site for this postdoctoral fellowship project is the University of Pittsburgh.
