Adult mice voluntarily progress to nicotine dependence in an oral self-selection assay

► Modified two-bottle choice assay of nicotine consumption. ► The nicotine consumed by mouse strains and sexes diverged over 7 weeks. ► C57BL/6J females drank over 70% of their fluid volume from the nicotine bottle. ► C57BL/6J mice voluntarily drank enough nicotine to become nicotine dependent. ► First model of voluntary oral nicotine consumption leading to nicotine dependence.