Shapeshifting is the ability of werewolves, hybrids, and dragons, to change one's shape from human to either wolf or dragon, respectively. To werewolves, the process is activated involuntarily every full moon while others, like hybrids, it can be controlled at will.
During a full moon, a werewolf will unwillingly transform from their human form into their wolf form. The transformation involves the breaking of every bone in the werewolf's body and especially the first transformation can be a slow and very painful process, in time the transformation gets faster and less painful. The transformation, however, can be controlled with only four known ways: pregnancy, hybridization, "evolving" and through the use of magic, via moonlight rings. A pregnant werewolf will not turn for nine months as the transformation would kill the baby, while werewolf-vampire hybrids, evolved werewolves and werewolves wearing moonlight rings can control their transformations at will, regardless of the full moon.
Werewolf-vampire hybrids and Klaus, the Original hybrid, keep all their werewolf abilities but unlike normal werewolves, have also the ability to control their werewolf transformation at will, even during the full moon. Hybrids do not seem to be bound by any former rules concerning their transformations as they can both choose not to transform during the full moon but also keep their wolf forms unusually long. Upon breaking the Hybrid Curse, Elijah informed Klaus that he remained a werewolf for two days after his first transformation.
Most hybrids seem to avoid full transformation due to the pain it causes, preferring partial transformations, manifesting some features of their werewolf forms.
Dragons have the ability to change from their human forms into large, full-fledged dragons while retaining their fire-breathing abilities. Upon transformation, their bodies gain incredible mass, growing in size in mere seconds, scales that cover their skin, a set of horns and a tail, while their arms and hands transform in large wings, giving them the ability to fly. Given the limited information on this species, it seems that the transformation can be controlled at will but it remains unknown if it's bound by any further limitations, such as duration of the transformation.
A kitsune may take on human form, an ability learned when it reaches a certain age - usually 100 years. As a common prerequisite for the transformation, the fox must place reeds, a broad leaf, or a skull over its head. Common forms assumed by kitsune include beautiful women, young girls, or elderly men. These shapes are not limited by the fox's age or gender, and a kitsune can duplicate the appearance of a specific person.
Foxes are particularly renowned for impersonating beautiful women. Common belief in medieval Japan was that any woman encountered alone, especially at dusk or night, could be a fox. In some stories, kitsune have difficulty hiding their tails when they take human form; looking for the tail, perhaps when the fox gets drunk or careless, is a common method of discerning the creature's true nature.
Variants on the theme have the kitsune retain other foxlike traits, such as a coating of fine hair, a fox-shaped shadow, or a reflection that shows its true form. Kitsune-gao or fox-faced refers to human females who have a narrow face with close-set eyes, thin eyebrows, and high cheekbones. Traditionally, this facial structure is considered attractive, and some tales ascribe it to foxes in human form. Kitsune have a fear and hatred of dogs even while in human form, and some become so rattled by the presence of dogs that they revert to the shape of a fox and flee. A particularly devout individual may be able to see through a fox's disguise automatically.
Werewolves are able to shapeshift from their human forms, to a half-human, half-wolf beast form at will. It is implied that werewolves are able to transform into "real" wolves as well.