The exploratory locomotor activity of rats differs between groups, and the results suggest the involvement of a seasonal factor. The body weight and the state of satiety do not appear to influence the locomotor activity. The individual activities of rats are correlated in subsequent tests only if the period between the tests is not long. The foehn wind changes the locomotor activity in the second test, depending on the animals' experience. No correlation between the native locomotor activity and cortical and striatal binding sites for [3H]prazosin and [3H]spiroperidol was found.