Vampires are one of the main horror legends and are rivalled only by their furry counterparts the werewolf. Also dubbed lycanthropes, werewolves are shape-shifting humans that turn into a wolf when the moon is full. In some legends you may find run-offs of the werewolf, such as the were-leopard, the were-panther, the were-tiger etc. but the werewolf is the most commmon and true to horror form.
As one of the oldest legends of human monsters in recorded history, werewolves have origins in mythology from many different cultures. One of the most historical is from an early Native American tribe who believed in a spirit God named Wisakachek who was a shape-shifter that commonly took the form of a wolf and lived in the woods. The Native American legends discusses that Wisakachek approached two boys from a tribe as a hungry stranger, who they gave a meat from a deer they had just killed to. When he returned a week later he learnt they were starving and hadn't caught anything else, so made a deal to share his power of shape-shifting with them as long as they didn't hurt a human in their form and they agreed. One day, after an intense argument, one of the boys killed another boy in their tribe out of anger in their wolf form. Wisakachek was so furious that he removed their power of being able to transform at will and forced the ancient ruling of the moon to dictate their change. 1
Another long-standing myth of the werewolf says that the origin went all the way back to an Ancient Roman myth in 1AD which was written by a Roman philosopher named Ovid. In the story, dubbed Metamorphasis, the Roman King Lycaon offended the Roman Gods by serving human meat to them at dinner. The Supreme leader of the Gods, Jupiter, punished King Lycaon by turning him into a werewolf so that he can continue his abomination of eating human flesh. 2
Since these tales of myths and legends are popular in many cultures, the story of the werewolf continued to evolve until eventually the mid-century European societies started to finger-point people as being werewolves in the same way that witch trials took place. It has been officially documented in history that many people were trialled as werewolves, including a serial killer team made up of a Pierre Burgot and Michel Verdun who were executed in 1521 for being werewolves. In 1573 a Frenchmen named Gilles Garnier was documented as being executed for being a werewolf, who was a serial killer known as the "Werewolf of Dole". One of the most infamous cases of a werewolf execution took place in Germany to a man named Peter Stumpp who was supposedly caught by his neighbours in his wolf form, which was controlled by a "wolf girfle" he was seen taking on and off. Peter confessed to murder, rape, and cannabalism when confronted, after killing his son and eating his brains, and both his mistress and his daughter were tortured and executed with him because he had raped them both. 2
Since the hysteria of suspicious finger-pointing died down in the medieval century, skeptics put the hysteria down to an onset of rabies and the known increase of wolves being in the area, and the werewolf then became folklore in the emerging Gothic horror genre thanks to Bram Stoker's Dracula and Mary Shelley's Frankenstein. Werewolf fiction as a genre became pre-modern precedents in medieval romances and continued to become a major player in horror literature and popular culture today.
In popular culture it is rare not to find a werewolf peppered into the same vampire fiction that beholds the current generation. Unlike some unique forms of vampires seen in movies and TV shows today, the modern day werewolf has stayed fairly true to it's full-moon shape shifting form. From the painful skin-shedding of the character of Peter Rumancek in the TV show Hemlock Grove, the sexy naked rival gangs depicted as Alcide Herveaux in True Blood, the super-cool basketball playing Scott Howard in the 80's movie Teen Wolf, the Native American tribe depiction in the Twilight series, and the twist of the classic protrayls of Little Red Riding Hood in both Once Upon A Time and Red Riding Hood, werwolves always turn at the night of the full moon, always eat human flesh, and can be stopped with a silver bullet.
Luckily though, in this modern age Werewolves are unlikely to be the main reason someone engages in a cannabalistic nature. Unlike the stories of people living amongst us today drinking people's blood, it is more likely to be a case of an actual wolf attack, rather than someone claiming to be a werewolf.