Sex differences in ICR mice in the Morris water maze task.

The Morris water maze (MWM) is one of the most common tasks used to assess spatial learning and memory ability in rodents. Genetic strain and gender are two prominent variants that influence spatial performance. Although it was reported that ICR (Institute of Cancer Research) mice exhibited an unchanged baseline performance in the training phase of the MWM task, this outbred strain has been widely used in learning and memory studies, and little is known regarding the effects of sex on behavioral performance. In this study, we demonstrated that both male and female ICR mice could complete the MWM task. Furthermore, a significant sex difference was observed, with females having shorter escape latencies and longer durations in the target quadrant in both the acquisition and test phases. Our findings emphasize the necessity of careful examination of not only the strain effect on behavioral performance but also the sex effect.