Scatter-hoarding animal places more memory on caches with weak odor

Abstract

Although spatial memory and olfaction are crucial for cache recovery, the knowledge of whether scatter-hoarding rodents place different memories on caches with different seed odors is still lacking. We used Siberian chipmunk Tamias sibiricus and peanut kernel system to test how scatter-hoarding rodents trade off spatial memory and olfaction when retrieving paired artificial caches emitting either strong or weak odor. T. sibiricus preferred to first recover caches with strong odor across trials both in the impoverished and enriched environments. With the establishment of spatial memory on the artificial caches following the 5-day trials, time spent on retrieving the two caches significantly decreased. Although strong-odor caches were preferred to be recovered during the trials, T. sibiricus selectively searched the caches previously containing peanut kernel emanating weak odor when the odor cues were removed in the final day test in the impoverished environments, indicating that chipmunks may have associated cache odor and cache location based on previous experience in the trials. However, with the spatial and odor cues removed, all tested chipmunks failed to search the caches previously containing peanut kernels in the enriched conditions, suggesting the importance of spatial memory in directing the cache locations. These data collectively indicate that T. sibiricus may place more memory on their caches emitting weak odor for later recovery. To our best knowledge, this is the first study shows whether scatter-hoarding animals trade off spatial memory on their caches emitting different seed odors, which will help us better understand the mechanisms of cache recovery by scatter-hoarding animals. Although scatter-hoarding animals show advantage over naive animals to relocate their caches based on spatial memory, we lack the knowledge of how scatter-hoarding animals place weight on spatial memory and olfaction during recovery of cached seeds. Our results show first evidence that scatter-hoarding animals tend to place more spatial memory on caches with weak odor. Our results provide new insight into the mechanisms of how scatter-hoarding animals trade off spatial memory on their caches emanating different seed odors, which will help us better understand the mechanisms of cache recovery by scatter-hoarding animals.