Food Hoarding And Pilfering In ICR Mice And Siberian Chipmunks

As an adaptive behavior of animals to seasonal variation of food supplies, food hoarding is beneficial for survival and reproduction of hoarders. Food hoarding behavior of animals successes and evolves only when foods are stored at the time of food abundance, and retrieved during the period of food scarcity. Food hoarders often hoard more foods than they need because their caches are often pilfered by inter- and intra-specifics. Hoarders may regulate their hoarding behaviors to adopt pilferage risks of conspecific individuals, but it is unknown how they respond to monitoring competitions of videos and mirroring images. Animals (e.g., rodents and birds) can use olfaction and spatial memory to search for food and pilfer stores of hoarders, but very few studies have looked at if they can use cues of vision and audition to improve food searching and pilfering.Here, we tested effects of conspecific videos and mirroring images, and cues of vision and audition on food hoarding behavior in Siberian chipmunks (Timias sibiricus) and ICR mice(Mus musculus) under indoor enclosure conditions. We sought to know that:1) whether Siberian chipmunks and ICR mice may have different responses under different competitive conditions of conspecific individuals (conspecific competitors), mirror images (mirroring competitors), videos (video competitors) and non-competitors (control); 2) how Siberian chipmunks use available visual and auditory information to increase probability of food searching and pilfering.ICR mice tended to move foods to the area with low competitive risks for hoarding under the condition of conspecific individuals, whereas they spent more time to touch and stay with conspecific individuals than with mirroring images and conspecific videos. These results suggest that ICR mice adopt different food hoarding strategies and time-budget under different competitive conditions.Siberian chipmunks tended to move foods to the area with low competitive risks for hoarding and reduced moving foods to the area with high competitive risks for hoarding in presence of mirroring competitors; and increased the amount of larder hoarded under the condition of video competition. These results suggest that Siberian chipmunks adopt a variety of cache-protection strategies to reduce the risk of cache pilferage by conspecific individuals and monitoring competitors of videos and mirroring images.As an observer (seeing and hearing actor’s caching activities), Siberian chipmunks cached more food items and reduced the time of searching for the food sources. But as a hearer (hearing but not seeing actor’s caching activities), Siberian chipmunks did not greatly change their behaviors of food foraging and hoarding.. These results suggest that Siberian chipmunks can use visual information, rather than auditory information, to increase the benefits of foraging and pilfering.These findings may be good cues for further studies on strategies of hoarding and pilfering, pilferage avoidance of rodents.