Male rats usually defecate more and ambulate less than females in the open-field test. A strain of hooded rats is described in which the sex difference in defecation is the reverse of the usual one (males defecating less), but the sex difference in ambulation takes the usual direction. This strain was also investigated in a two-way active avoidance situation, in which males usually perform worse than females. The sex difference in the hooded rats was found again to be the reverse of the usual one, males performing better. This result suggests that the sex difference in two-way active avoidance reflects sex differences in fearfulness (as measured by open-field defecation), not in activity (as measured by ambulation).