The 16th century Swedish writer Olaus Magnus says that the Livonian werewolves were initiated by draining a cup of specially prepared beer and repeating a set formula, they routinely transformed themselves into wolves by passing through a certain magic pool, another instance of baptismal rebirth in animal form. Ralston in his Songs of the Russian People gives the form of incantation still familiar in Russia.
The natives of the Siberian plains had specific ceremonies to aid shape-shifting, including the preparation of a heady potion which used both opium and hemlock as ingredients. The Siberians were certainly not alone, and the desire to acquire animal abilities has permeated most, if not all, of the world's cultures.
In South America it is believed that certain sorcerers and witches know how to transform themselves into animal guise such as serpents, leopards, panthers, jackals, bears, coyotes, owls, foxes and other feared creatures. They will do this to do evil to or kill theirs enemy usually by drinking their the blood.
Native American mythology is quite interesting as the metamorphosis is not only viewed as curse but as a way to get closer to Nature and one’s totemic animal. This method would also probably include those who gain such a spirit through meditation or dreams. This is the source for many "spiritual werewolves. Shamanic rituals are often complicated and secret depending on the tribes’ own beliefs. It and can also be apply to other animals.
How to become a werewolf