Independent of sex, C57Bl/6J mice exhibit low avoidance behavior but high threat memory, 129S1/SvlmJ mice high avoidance and high threat memory, DBA/2J mice low avoidance and low threat memory, and BALB/cJ high avoidance but low threat memory. Sex differences and estrous cycle regulation of behavior are both strain- and assay-dependent. OFT, open field test; EPM, elevated plus maze; E encircled by arrows, regulated by estrous cycle.