Culture and menstruation the ideal of synchronised tidal, lunar, menstrual and seasonal periodicities whose overall harmony (it is believed) confers spiritual power and fertility. To many, such cultural associations appear persuasive in view of the fact that in humans, the menstrual cycle quite closely approximates the moon's 29.5-day synodic cycle, unlike in chimpanzees (~36 days) or bonobos (~40 days). Statistical information from hunter gatherers is lacking, but where large-scale western studies focus on women's peak reproductive years—removing outlier values—the cycle length gravitates around 29.1–29.5 days, while the figure for women in their thirties shortens toward 28 days. In no extant human population has
The Great Pheromone Myth mice and rats is a vestigial organ in humans. Menstrual synchrony has long been viewed as a physiological phenomenon in humans that could only be explained by the exchange of pheromones among women. He argues, however, that methodological critiques of menstrual cycle research and recent research indicate the menstrual synchrony does not occur among women. Finally, he reviews the literature on human pheromones and argues that there are serious methodological issues in all studies reporting human pheromones and that no human pheromone has ever been definitively identified. His conclusion is that human pheromones are a myth that is driven in