When you think about it, a human that turns into a wolf or other animal is a bizarre idea. So where on earth has it come from?
When my daughter was little more than a baby and started watching children's television, she was absolutely freaked by programme where the presenters put on and took off masks. She was genuinely terrified, and I think what scared her was the idea of human faces becoming something else. It seems to me this is probably some kind of primeval fear, though which came first, shifter or fear, I'll leave you to decide :)
There is certainly evidence of werewolf stories going back to classical times. Herodotus wrote that the Neuri, a tribe he places to the north-east of Scythia, were all transformed into wolves once every year for several days, and then changed back to their human shape. And in the second century BC, the Greek geographer Pausanius relates the story of Lycaon, who was transformed into a wolf by Zeus as punishment for ritually murdering a child. This has links to many later legends which have werewolves being cursed into existence.
In early European folklore, werewolves can be spotted by certain physical traits, such as the meeting of both eyebrows at the bridge of the nose (anyone seen the film Company of Wolves?), curved fingernails, low-set ears and a swinging stride. Or apparently, if you cut the flesh of a werewolf in his human form, there would be fur in the wound.
Some Swedish accounts said the werewolf could be distinguished by the fact that it ran on three legs, stretching the fourth one backwards to look like a tail.
After returning to their human forms, werewolves are usually documented as becoming weak and debilitated and suffering melancholia and manic depression, through guilt at their crimes.
One reviled practice of medieval European werewolves was the devouring of recently buried corpses, as documented, for example, in the 19th century Annales Medico-psychologiques.Some werewolves were old women who possessed poison-coated claws and could paralyse cattle and children with their gaze. Serbian vulkodlaks traditionally congregated each winter to strip off their wolf skins and hang them from trees. They would then get a hold of another vulkodlaks skin and burn it, releasing from its curse the vulkodlak from whom the skin came. While the Haitian jé-rouges typically try to trick mothers into giving away their children by waking them at night and asking their permission to take their child, to which the disoriented mother might either reply yes or no.
It seems to me that many of these legends can be attributed to basic human fears and anxieties, of something beyond their control threatening them, their food supply or their families. Of course, wolves are not the only shifters of legend, but it's interesting how often they come up and how far their stories have spread.
Marie (with a grateful nod to Wikepedia!)