In general, werewolves are humans that change their form, partially or fully, into wolves under the influence of the full moon. In many cases, the change is involuntary, particularly to those who have acquired the werewolf ‘curse’ through heredity or after having been bitten themselves by other werewolves.
For those who have acquired the curse through their own will, such as by entering into a pact with the Devil himself, the change can be done at will and even in the absence of a full moon. It is said that humans who enter into this pact do so out of desperation and often, in an effort to seek revenge for the death of a loved one. In popular European superstition, the Devil is said to appear in the form of a coachman whose carriage is drawn by black steeds. The Devil offers a potion that provides the strength needed to carry out the revenge, in exchange for the person’s soul. The potion is often in the form of a vial, the contents of which are applied to the human skin under the light of a full moon. The transformation into a werewolf will then begin immediately and the human has been completely turned into a werewolf forever.
Werewolves are often portrayed as possessing superhuman strength, comparable to that of a dozen normal grown men. In some cases, the werewolf is portrayed as being invincible and nearly indestructible, with decapitation of its head and removal of its heart as the only surefire way to kill one. In other superstition the weapon of choice is the silver bullet, or other weapons made of silver. The efficacy of silver has often been traced to pagan belief in the power of certain metals to ward off evil spirits (among Irish folk, iron is used to ward off evil fairies).
If wounded in its wolf form, a werewolf will bear the wound once it returns into human guise. In such a way, a werewolf can be detected amidst human populations. This has resulted in the shoot first, ask questions later attitude of people in medieval Europe during times when the belief in such supernatural creatures were strongest. In many cases, real wolves have been killed accidentally as a result of the paranoia.
The psychological condition of a person believing he has turned into a wolf is called lycanthropy. The term lycanthrope has usually been used to technically classify a true werewolf. In medieval Europe, some of the people who exhibited lycanthropy were (it is now believed) victims of a poisoning from a bread mold that often broke out during the same period. Research is continuing to unravel this connection.
Werewolves are only second to vampires in terms of monster popularity. Perhaps, like vampires, belief in humans that turn into wild predatory (and often nocturnal) animals exists in all major world cultures. Many psychologists attribute this to the natural animal instinct that resides in the psyche of all men, an instinct that existed since the dawn of mankind.
In regions of the world where wolves are scarce, or not present at all, humans are sometimes portrayed as transforming into bears, leopards, tigers, or hyenas.
French folklore has another name for the werewolf, loup-garou. As in most of Europe, France experienced an outbreak of loup-garou convictions during the 16th-century.
In modern pop culture, the werewolf has enjoyed much success in the box office, particularly because of its embodiment of the brutal fierceness of nature itself, and the longing of the human spirit to break out like a wild animal.