Preferential nesting in lemon-scented environment in rats reared on lemon-scented bedding from birth to weaning

Newborn rats (males and females) were reared on lemon scented shavings from birth to weaning. The experienced rats (111 animals) and their controls (135 animals) were tested for lemon odor preference at 21, 51, 81, 111 and 141 days of age. The test box consisted of two preference chambers, containing wood shavings, interconnected by a starting compartment. Shavings of one of the preference chambers were sprinkled with natural lemon juice. The preference ratio was obtained on the basis of the chamber selected for nesting. The results clearly show that (1) sex differences occur in both experienced and control groups of rats and (2) rats reared on lemon scented bedding from birth to weaning acquire a permanent preference for nesting in the lemon scented chamber. The results are consistent with the hypothesis that an imprinting-like process takes place.