Visual and auditory cues facilitate cache pilferage of Siberian chipmunks (Tamias sibiricus) under indoor conditions.

Abstract

In the struggle for survival, scatter-hoarding rodents are known to cache food and pilfer the caches of others. The extent to which rodents utilize auditory/visual cues from conspecifics to improve cache-pilfering is unknown. Here, Siberian chipmunks (Tamias sibiricus) were allowed to search for caches of Corylus heterophylla seeds (man-made caches and animal-made caches) after experiencing cues from a conspecific's cache-searching events. For each type of cache, 3 experimental scenarios were presented: (1) alone (control); (2) auditory/visual (hearing and seeing conspecific's cache-searching events); and (3) auditory only (hearing conspecific's cache-searching events only) with random orders. The subjects located man-made caches faster, harvested more caches, and hoarded more seeds both in the auditory/visual and the auditory only treatments compared to the control, while scatter-hoarding more seeds in the auditory/visual treatment but larder-hoarding more seeds in the auditory only treatment. Compared to the control, the animals spent less time locating animal-made caches, harvested more caches, ate fewer seeds, larder-hoarded more seeds and hoarded more seeds in total both in the auditory/visual and the auditory only treatments, while eating more seeds and hoarded fewer seeds in total in the auditory only treatment than in the auditory/visual treatment. The results also show that females spent less time locating the animal-made caches, but they scatter-hoarded fewer seeds than males in the auditory/visual treatment. To the best of our knowledge, this is the first report that visual and/or auditory cues of conspecifics improve cache-pilfering and hoarding in rodents.