A form of avoidance learning in which the animal quickly develops an aversion towards a novel food or bait. Attempts to eradicate local rat populations by using poison have had limited success, as a result of the rat's proverbial bait shyness. Rats (Rattus norvegicus) and mice (Murinae) tend to avoid unfamiliar foods and to sample them tentatively. A rat that takes a small amount of poisoned food and survives will never touch the same type of food again. This rapid aversive learning is found in many mammals and birds.