Conspecific pilferage but not presence affects Merriam's kangaroo rat cache strategy

We investigated the effects of pilferage on caching behavior in the Merriam 's kangaroo rat by manipulating two factors associated with pilferage: the presence of a conspecific, and the opportunity for pilferage. In one experi ment we assessed animals in either "Stealer" or "'Victim" roles and measure d changes in caching, space use, and behavior after caches were pilfered. V ictims shifted from a majority scatter-hoarding to a majority larder-hoardi ng strategy after their caches were pilfered by the Stealer. In Experiment 2, we measured changes after exposure to a conspecific when there was no pi lferage, with or without prior exposure to pilferage from Experiment 1. Mer riam's kangaroo rats were vigilant when a conspecific was present, but did not change cache strategy. Prior exposure did not have any major effect on caching or behavior. Food storage is an economic decision that is often mad e by a solitary forager. Our results suggest that social competition noneth eless influences such economic decisions, even in a nonsocial forager.