If you're planning a walk in the woods, you may be safest just before your period. A preliminary study suggests that women in the luteal or premenstrual phase of menstruation are quickest at spotting snakes. That could be because the hormones involved can influence the amygdala, part of the brain that deals with fear, researchers say.
In the Japanese study, 60 women around age 30 viewed grids of nine photos; eight were of flowers and one showed a snake. Participants, grouped by their menstrual phases, were asked to touch the snake. On average, those in the luteal phase were able to do so about 200 milliseconds faster than the other groups. The luteal phase starts with ovulation, when women are most fertile—so increased fear might help pregnant women keep out of danger, LiveScience reports.