Evidence for cache surveillance by a scatter-hoarding rodent

Abstract

The mechanisms by which food-hoarding animals are capable of remembering the locations of numerous cached food items over long time spans has been the focus of intensive research. The ‘memory enhancement hypothesis’ states that hoarders reinforce spatial memory of their caches by repeatedly revisiting cache sites, yet no study has documented this behaviour in wild animals. We investigated whether scatter-hoarding Central American agoutis, Dasyprocta punctata, actively survey their seed caches. We placed remote cameras at sites where seeds were buried by known individuals and at nearby random locations to compare the behaviour and visiting rates between owners and naive individuals. We found that cache owners were almost four times more likely to walk near their cache than to walk past random locations. Moreover, cache owners that passed in front of a cache camera were more than twice as likely to approach their caches than were naive individuals but half as likely to excavate the seed when interacting with the cache. We conclude that agoutis remember the location of cached seeds, are aware of their ownership and actively survey their caches. Surveillance could serve to monitor cache theft and food quality as well as enhance spatial memory of cache locations; thus, this behaviour could have important fitness benefits and may be exhibited by other scatter-hoarding animals.