A werewolf, also known as a lycanthrope (from the Greek lykánthropos: , lykos, "wolf", and , anthropos, "man"), is a mythological or folkloric human with the ability to shapeshift into a wolf or a therianthropic hybrid wolf-like creature, either purposely or after being placed under a curse or affliction (e.g. via a bite or scratch from another werewolf). Early sources for belief in lycanthropy are Petronius and Gervase of Tilbury.