Date of this Version
After interacting with a recently fed "demonstrator" rat (Rattus norvegicus), a naive "observer" rat exhibits substantial enhancement of its preference for whatever food its demonstrator ate. Such social effects on food preference in rats are surprisingly robust and able to reverse both congenital flavor preferences and poison-induced, learned flavor aversions. Analysis of the pheromonal signals emitted by demonstrator rats that alter the food preferences of their observers indicates that experience of CS2 (a substance present in rat breath) together with the odor of a food is sufficient to enhance an observer rat's subsequent preference for the food. Adding CS2 to a food substantially increases intake of that food by both rats and mice (Mus domesticus), suggesting that CS2 could be used to enhance intake of poison baits by rodent pests. Recent analyses of the use by rats of odor trails indicate that additional pheromones attractive to rats remain to be described.