Chris Knight has always claimed that the moon played a much larger role in human evolution than is generally thought. This lecture will summarize his overall theory of the origins of religion, ritual, language and symbolic culture. For our distant African ancestors, the moon became crucial from the moment we left the shelter of forest life and began occupying open savanna territory. In this new environment, early humans sought safety in numbers to counter the threat posed by lions and other large cats whose night vision was far superior to ours. Lions prefer to hunt when the moon is dark, which explains why even to this day, hunter-gatherer women choose to sing in chorus at dark moon to keep dangerous predators away. Unlike our ape relatives, women have a menstrual cycle of the length you would predict if synchronizing with the moon had been adaptive in our evolutionary past.