Honor’s Thesis, Cognitive Science, UC Berkeley. “Keep Your Enemies Close”. Submitted in August 2016. 30 pp.
Fox squirrels ( Sciurus niger) are scatterhoarders who spread out their food stores to reduce the chance of pilferage by competitors. Fox squirrels within a population often have overlapping home ranges, but how they decide exactly where to store their caches is unknown. We hypothesized that fox squirrels have a preference for cache areas that are relatively private in that they do not overlap with common areas; this provides protection from pilferers. In this study, we collected both home range and caching locations utilizing geographical positioning systems for 11 squirrels on the UC Berkeley campus. Using ArcGIS, we generated home range and cache area polygons, which we could use to measure the areas used by squirrels and estimate squirrel density. This population’s home ranges were found to overlap extensively, but the size of the cache areas used by one unique individual were significantly larger than shared cache areas ( p < 0.0001). This suggests that this population of squirrels preferentially use private cache areas even though they all have overlapping home areas.