EARLY OLFACTORY LEARNING IS INFLUENCED BY SEX IN HAMSTERS BUT NOT RATS

The odor of cedar shavings repels infant and juvenile rats and hamsters reared in pine shavings when animals are tested in a 2-choice situation. Housing male and female infants of either species in cedar shavings for 3 days before testing increases preference for both cedar odor and for a mixture of cedar and conspecific odors. Similar exposure of juvenile male and female rats and male hamsters has little or no significant impact on odor preferences. Housing female hamsters in cedar at either developmental stage equally influences odor preferences. Sex differences may influence the development of early odor-guided behavior in hamsters but not rats. The species differences may have adaptive significance in that the birth of a litter produces a greater environmental change demanding a larger preference adjustment of solitary female hamsters than colonial female rats.