Alcohol drinking is a prototypic complex genetic trait, one that is multigenic, oligogenic, and probably polygenic in nature. Several issues complicate our attempts to understand rodents’ relative avidity for drinking. One main issue is taste. Rodents cannot vomit, and have therefore, presumably through evolutionary pressures, developed exquisite sensitivity to novel flavors, and generally avoid them or approach them with caution. However, they greatly prefer sweet solutions, and the preference for sweet solutions is partially genetically influenced (Boughter Jr and Bachmanov 2007). The genetic contributions to preference for alcohol and sweet solutions are overlapping (Rodgers and McClearn 1964). Novelty per se is another factor that must be considered, as animals differ genetically in their response to novel situations (McClearn 1959). Learning may play a role in changes in consumption over time (Blizard et al. 2008), and ingestion of too much alcohol can lead animals to avoid drinking it when it is later offered again (Belknap et al. 1978). Also, alcohol may be ingested simply because it provides calories (Rodgers et al. 1963). In addition, the role of ethanol metabolism must be
