For those of you who don't know, Therianthropy is the ability to transform into an animal. Those who possess this ability are referred to as theriomorphs or therianthropes. The most common type known to Western culture is the lupine theriomorph, the person or other being that changes into a wolf. There are 4 basic types, which I will elaborate on using terminology from Jim Butcher's "Dresden Files":

1. Werewolf - the "classic" lupine theriomorph, this type is simply a person with the power to turn themselves into a wolf. The change is the result of a spell and is performed by the user on the user. The transformation itself changes their physical body, but their mind remains the same. As such their personality and ability to think and reason are fully intact. But they also do not naturally possess a wolf's instincts or reflexes, making it necessary for them to first adjust to and learn to properly use their transformed bodies. The transformed wolf-form is physically like a normal wolf, although often quite bigger and stronger than contemporary wolf species.

2. Hexenwulf - This type is able to transform into a wolf-like beast through the employment of a magical talisman, usually a belt made from a wolf's pelt, that is usually provided by another being, such as a hired sorcerer or a demon with whom the user has made a deal. When using the talisman, it provides an anchor for a spirit of bestial rage, which wraps itself around the human personality. The spirit provides an insulation to keep the person's spirit from being destroyed, as well as helps control the physical wolf-body. Through this protection, the person's human intelligence and reason remain intact; at the same time, the person loses their human inhibitions, making them prone to act on their conscious and unconscious desires without doubts. This is at least partly brought about by the presence of the spirit, which would be too strong to control for most people; the spirit would influence the wearer, suppress their conscience, and even control them more fully. The Hexenwulf's personality, although initally protected from the transformation's effects by the presence of the talisman's spirit, will continually erode and be destroyed over time.

3. Loup-Garou - This type is a person who being that, as the result of a curse, transforms into a wolf-like demon under certain conditions, usually the full moon. At the rise of the full moon, the cursed person transforms into a monster and proceeds to slaughter everything it comes across until either the full moon sets or the sun rises. In their transformed state, they have supernatural speed, power, and ferocity. They are very resistant to any form of injury and recover quickly. Physical injuries sustained heal almost instantly, and they are immune to poisons and drugs, though they can usually be hurt by silver or powerful magic.

4. Lycanthrope - Unlike the other various forms of werewolf, a lycanthrope is not actually a theriomorph. Physically human, they are indistinguishable from a regular person, at least on the surface. They are also unique in that they are usually born this way, not made. A lycanthrope acts as a natural channel for a spirit of rage, which makes them beast-like, but only psychologically, so that they have the minds and souls of beasts. Driven by the spirit, they are more aggressive, stronger, and resistant to disease and injury; wounds heal very quickly, enabling them to survive much more physical damage than a typical human being. They have been known to become even stronger under a full moon, but this more a psychosomatic effect than an element of their condition.

Good to know!