Exploratory Behavior of Male and Female Mice

Kudzia, Angela, Shannon Marchant, and Ph.D. Hill

In many animals males and females differ in exploratory and fear-related behavior. Such behavior is frequently assessed by observing animals in a novel environment. In the present study, 41 laboratory mice were observed in an open-field apparatus, which was an aquarium with a shelter box. It was predicted that males would show more exploration, as measured by time spent out in the open, time in the shelter, or locomotion. Sex differences were tested using one-way ANOVAs. Contrary to predictions, males spent more time sitting (p=0.011) while females tended to locomote more (p=0.08).  There was a trend for more time spent in the shelter by males than females (p=.068).  Therefore our prediction was wrong in that females showed more exploratory behavior than males. The interpretation of these findings is not clear.  One possibility is that the rearing conditions differed for males and females. Females were reared in sibling groups while the males were housed individually after they were six weeks old.