If you google Halloween, you will find that the vast majority of images show the full Moon. This iconography is surprising from an astronomical point of view: There’s a full Moon on Halloween every 19 years, with the next one due in 2020. Humanity has always feared the darkness, and the Moon is the "queen of the night," so it is not too peculiar that our satellite is often linked to evil forces that can supposedly take over man and make them mad.
"Weirdos come out with the full Moon," you must have heard a million times, except there’s not a single trace of evidence based on this claim. In a paper called “Much ado about the full Moon,” two American scientists reviewed 37 studies about the alleged effects of the full Moon showing no correlation between reported criminal offenses or acts of lunacy and our natural satellite.
The belief that the Moon influences the brain comes from the classical world; both Aristotle and Pliny the Elder brought forth the notion that the brain was the organ with the most water and thus can be influenced by the Moon. This belief is not ancient history and was considered plausible even by authors and doctors in recent times. For example, the term lunacy comes from the latin word for Moon, Luna.
The Moon is able to generate tides through gravitational effects because there’s a huge amount of water free to move on the surface of the Earth, but the water in your body is firmly held in place.
The full Moon is often associated with wolves, based on another unfounded myth of wolves howling at the Moon. Wolves obviously do howl but for a variety of reasons, such as assembling the pack, confusing enemies and prey, and to warn other wolves of danger. They have no connection to our natural satellite.
The Moon, madness and wolves are all joined together in the myth of the werewolf. From classical to medieval Europe, rumors of wolf-men roaming the woods, murdering the innocent and leaguing with the devil have been a central feature in European folklore.
The concept of evil animal shapeshifters is not exclusive to Western culture, though. There are myths about were-tigers in Asia, were-hyenas in Africa and were-jaguars in South America. In Europe, the wolf has been the most fearsome predator throughout most of its history, so it’s not surprising it has become a symbol of terror.
Despite the introduction of modern science, the werewolf mythos continued to pass from the middle ages into the modern age. Reports and trials of alleged werewolves continued all the way into the late 17th century; the most famous case is probably Peter Stumpp, a German farmer and alleged serial killer and cannibal known as the Werewolf of Bedburg.
Nineteenth-century Gothic fiction brought new life into the myth, reinstating the concept of werewolves as fearsome creatures and introducing the idea that they are tragic characters, cursed and powerless against the animalistic side within humans.
Throughout the ages, many explanations have been given on what has made people believe in werewolves and were-creatures in general. People who suffer from clinical lycanthropy (lycanthropos is Greek for wolf-man) believe that they can transform or they are non-human animals. It is a rare syndrome, possibly caused by neurological factors. A neuroimaging study on two people diagnosed with clinical lycanthropy highlighted unusual activity within areas of the brain associated with body shape perception. The sufferers might have sincerely felt they were shape-shifting.
Another condition associated with werewolves is hypertrichosis, the abnormal growth of hair over the body. It can be congenital (present from birth) or acquired later in life and can be restricted to certain areas or occur across the entire body. It is an extremely rare condition, with less than 200 cases documented in medical history.
Ignorance, superstition, and a preference for the supernatural rather than rational explanations have fueled our ideas of terrifying creatures lurking in the night. But there are only our fears waiting for us out there, under the pale light of the Moon.
Top image credit: Wannabe Harvest Moon by Rowena, via Flickr. CC BY-ND 2.0
