The first demonstration of inbred strain differences in preference drinking in 1959 compared male mice from 5 strains. The data revealed several more subtle differences as well. Within each strain, there were apparent individual differences among animals’ preference ratios. For example, of the four mice in the C3H/NT strain, two were relatively high drinkers and two relatively low, so this strain's “average” drinking had relatively high variability. For preferring strains, preference tended to increase over a period of 2–3 weeks until it settled at a plateau. Whenever the side on which the alcohol bottle was placed on the cage top was switched, there was a temporary reduction in intake of alcohol during the following 1–2 days, but animals quickly reestablished their strain-specific preference ratio (McClearn and Rodgers 1959). Many subsequent studies, published between 1966 and 2004, have employed relatively large panels of inbred strains. A recent review of several of those studies was able to compare relative strain preference ratios for 10% ethanol across decades, laboratories, and small variations in the procedures employed. Despite the inevitable genetic drift due to
