In some Native American legends, a skin-walker is a person with the natural ability to turn into any animal he or she desires. To be able to transform, legend sometimes requires that the skin-walker wears a pelt of the animal. In most cases, this pelt is not used in modern times because it is an obvious sign of them being skin-walkers.
Similar lore can be found in cultures throughout the world and is often referred to as shapeshifting by anthropologists.
Possibly the best documented skinwalker beliefs are those relating to the Navajo yee naaldlooshii (literally "with it, he goes on all fours" in the Navajo language). A yee naaldlooshii is one of several varieties of Navajo witch (specifically an ’ánti’įhnii or practitioner of the Witchery Way, as opposed to a user of curse-objects (’adagąsh) or a practitioner of Frenzy Way (’azhįtee)). Technically, the term refers to an ’ánt’įįhnii who is using his (rarely her) powers to travel in animal form. In some versions, men or women who have attained the highest level of priesthood are called clizyati, "pure evil", when they commit the act of killing a close blood relative (sister, brother, mother, father), incest, or necrophilia. This act is said to destroy their humanity and allow them to fully immerse themselves in the teachings of the Witchery Way.
The ’ánt’įįhnii are human beings who have gained supernatural power by breaking a cultural taboo. Specifically, a person is said to gain the power to become a yee naaldlooshii upon initiation into the Witchery Way. This is done especially via the Navajo equivalent of the 'Black Mass', a perverted "sing" (Navajo ceremonial) used to curse instead of to heal. Both men and women can become ’ánt’įįhnii and therefore possibly skinwalkers, but men are far more numerous. It is generally thought that only childless women can become witches. Not every witch is a skin walker, but every skin walker is a witch. Skinwalkers are said to copy the voices of family members.
Although a skinwalker is most frequently seen as a coyote, wolf, fox, eagle, owl, or crow the yee naaldlooshii is said to have the power to assume the form of any animal they choose, a decision based on what specific abilities are needed. For example, Witches may use a bird form for expedient travel in pursuit, escape, or otherwise. Some Navajo also believe that skinwalkers have the ability to steal the face of a person. The Navajo believe that if you ever lock eyes with a skinwalker, they can project themselves into your body. Alternately, some Navajos believe that if you make eye contact with a skinwalker, your body will freeze up due to the fear of them and the skinwalker will use that fear to gain power and energy.
A skinwalker is usually described as hairy, except for an animal skin. Some Navajos describe them as a perfect version of the animal in question. The skin may just be a mask, like those which are the only garment worn in the witches' sing, which is the opposite of the good sing. Because animal skins are used primarily by skinwalkers, the pelt of animals such as bears, coyotes, wolves, and cougars are considered taboo. Sheepskin and buckskin are probably two of the few hides used by Navajos; the others are not used for ceremonial purposes.
Often, Navajo people will tell of their encounter with a skinwalker, though many hesitate to reveal the story to non-Navajos, or to talk of such things at night. Sometimes the skinwalker will try to break into the house and attack the people inside, and will often bang on the walls of the house, knock on the windows, and climb onto the roofs. Sometimes, a strange, animal-like figure is seen standing outside the window, peering in. Other times, a skinwalker may attack a vehicle and cause a car accident. The skinwalkers are described as being fast, agile, and impossible to catch. Though some attempts have been made to shoot or kill one, they are not usually successful. Sometimes a skinwalker will be tracked down, only to lead to the house of someone known to the tracker. As in European werewolf lore, sometimes a wounded skinwalker will escape, only to have someone turn up later with a similar wound which reveals them to be the witch. It is said that if a Navajo was to know the person behind the skinwalker they had to pronounce the full name, and about three days later that person would either get sick or die for the wrong that they have committed. 
Legend has it skinwalkers can have the power to read human thoughts. They also possess the ability to make any human or animal noise they choose. A skinwalker may use the voice of a relative or the cry of an infant to lure victims out of the safety of their homes; the skin walkers cannot enter a home without invitation.
The yee naaldlooshi are distinguishable in human form because their eyes glow like an animal's. In animal form they can be spotted by moving stiffly and unnaturally, and their eyes do not glow like an animal's.
Skinwalkers use charms to instill fear and control in their victims. Such charms include human bone beads launched by blowguns, which embed themselves beneath the surface of the skin without leaving a mark, and human bone dust which can cause paralysis and heart failure. Skinwalkers have been known to find traces of their victim's hair, wrap it around a pot shard, and place it into a tarantula hole. Even live rattlesnakes are known to be used as charms by the skinwalker. A skinwalker can use anything of personal belongs and use in ceremonial rituals against the person they are doing evil against.
Skin-walkers use a powder called corpse dust, also known as corpse poison, corpse powder, and án't'i, to poison victims. Corpse dust is composed of ground infant bones, preferably twin infants, and bones from the fingertips and back of the skull. The yee naaldlooshi blow it into the faces of their victims, or down the chimney of the victims' home. Soon after the victim breathes the dust the tongue starts to swell and blacken, and they go into convulsions and die.
Totem animals and the art of the Medicine Man
The Navajo people have a very strong emotional bond with the Earth and the plant and animal kingdoms that are so much a part of their everyday lives. Certain animals are more sacred to some individuals, families and tribes. They believe these animals bless, heal or guide the people and become totem animals.
Totem animals are honored with their likeness in the dress, dance, music and artwork of the people. The traits and characteristics of the totem animals were thought to be gifted to the people who developed a deep friendship with the spirits of these helpful creatures. Some individuals believed they developed such a deep connection with nature and her "magic" that they could talk with the plants and animals and bring knowledge of medicine and other healing arts to their tribes. These few adepts became medicine men, healers, or wise ones.
Medicine men were believed to be able to travel to other states of being, through the gifts of their totem animals. They were said to often be seen wearing the skin of the animal that they believed granted them this power and would sometimes be seen in animal form.
Often ancestors and heroes would be said to appear as animals important or sacred to the family or tribe, or as an animal the individual was known for. People especially reported seeing these strangely human animals when receiving good fortune or divine messages. Some believed they would hear the animals speak to them, act as a human would or witness impossible colors or breeds that do not exist.
A medicine man should never be confused with a practitioner of the witchery or frenzy way. In the Navajo culture there is a clear distinction between a witch and a medicine man. Medicine men practice healing arts, blessings and the removal of curses. Any Navajo practicing the witchery way is believed to be evil; the intent of such practice is purely to harm others of their own tribe and rarely people outside of it.
Skin-walkers in popular culture
- In the Sega video game Altered Beast, the main character can shapeshift into one of four beings - werewolf, weredragon, weretiger or a werebear.
- In the film Mortal Kombat: Annihilation, the Native American warrior Nightwolf acted as a Skin-walker by transforming into a wolf. He calls the technique his 'Animality', the knowledge of which has been passed down through Nightwolf's people over generations. He teaches Liu Kang how to perform it as well, but since Liu Kang becomes a Dragon, the technique seems to vary from person to person.
- In the second season of "Smallville", episode "Skinwalker". Clark Kent tries to stop a skinwalker, who is a young native American woman that can assume the form of a white wolf.
- In the third season of Haven, the protagonists pursue a mysterious serial killer, known as the Bolt Gun Killer, whose criminal pattern involves a bolt gun to the base of the victim's neck. It is later discovered that the serial murders were vastly under reported and that the suspect, now believed to be a shapeshifting "Skin-walker troubled", is literally skinning the victims and donning said skins so as to assume their identities.
- Navajo Skinwalkers were mentioned in the movie Arizona Werewolf, a version of which (retitled Werewolf) was shown on Mystery Science Theater 3000. However, the werewolf lore was essentially borrowed from The Wolf Man, and Joe Estevez mispronounced 'yee naaldlooshii' as "yannaglotchy".
- In the novel series The Dresden Files by Jim Butcher, a Skinwalker is the primary villain in Turn Coat, the eleventh book in the series, and is referred to as a "naagloshi", a semi-divine being that used to be a Messenger of the Holy Word.
- The protagonist of Kelley Armstrong's Darkness Rising series, Maya Delaney, is one of the resurgent members of this supernatural race due to genetic modification. Other yee naaldlooshii also include Rafael "Rafe" Martinez and Annabella "Annie" Martinez. Maya displays a number of powers, which include shape-shifting into the form of a Cougar, as well as animal telepathy, and accelerated healing.
- In the graphic novel series Pariah Missouri, the character Toro is a Comanche skin-walker that changes into a bear.
- In the first season of The X-files, episode 19, "Shapes", there is a native American skin-walker who can change into a wolf.
- Several episodes of the TV series Supernatural feature villainous skin-walkers.
- They were also featured on an episode of Lost Tapes.
- In Patricia Briggs Mercy Thompson series, the main character Mercedes Thompson is a "walker" who turns into a coyote, however, it is stated in the novels that she may be something else, as she can take only the one animal form, does not require a pelt, does not seem to have other magical powers, and does not seek to harm others.
- In Kevin Hearnes The Iron Druid Chronicles, Atticus O'Sullivan has to stop two skin walkers in the 4th book, 'Tricked'.
- In the HBO series True Blood many characters are known for this ability such as Tommy Mickens and Luna Garza, who are Shapeshifters too.
- In the book series Experiment in Terror by Karina Halle, the book Red Fox revolves around Skin-walkers.
- In the DarkWorld: SkinWalker series by T.G. Ayer, the books Skin Deep & Lost Soul center around Skin-Walkers.
- In the fictional thriller Thunderhead (novel) by Lincoln Child & Douglas Preston which takes place in the American West regarding archaeology.
- The movie "Skinwalkers", directed by James Isaac (Afterdark Films), revolves around a pack of Skinwalkers trying to get the son of their leader back, so he can taste his blood and become the ultimate skinwalker. But the son himself can provide the "cure".
- Stephen King's The Dark Tower: The Wind Through the Keyhole contains a story-within-the-story which finds young Roland and his friend Jamie De Curry in the town of Debaria on a mission to capture "The Skin-Man", an apparent shape-shifter who terrorizes the town and surrounding areas by transforming into various animals at night and embarking on murderous rampages.
- The first four songs (Side 1) of the untitled second album by the band Tarantula Hawk comprise a song-cycle that is unofficially titled "The Skinwalker Suite".
- The band "Skinwalker" is a drum/synth duo consisting of Gabe Serbian and Joey Karam, both members of the band The Locust.
- The wolf Yenaldooshi as referenced in an episode of the children's series Ben 10, but the creature encountered in the episode was only believed to be one by the characters.
- In George R.R Martin's fantasy series A Song of Ice and Fire, as well as the HBO television adaption Game of Thrones, a select few characters who often have the blood of the First Men are called Skin-Changers or Wargs and can take control of animals, sometimes including humans.
- In Monsters and Mysteries in America, the Skin-walker was a subject in the episode "Desert Wasteland" along with the Thunderbird and both were suspected for many livestock massacres.
- Brady, M.K., Some Kind of Power: Navaho Children's Skinwalker Narratives. (University of Utah Press, Salt Lake City, 1984 ISBN 0-87480-238-5)
- Colm A. Kelleher and George Knapp, Hunt for the Skinwalker. (Paraview Pocket Books, ISBN 1416505210)
- Langley, C., Meeting the Medicine Men: An Englishman's Travels Among the Navajo. (Nicholas Brealey Publishing, London, 2008 ISBN 978-1-85788-507-1)
- Marika, K. Werewolves, Shapeshifters and Skinwalkers. (Sherbourne Press, Los Angeles, 1972)
- The Shapeshifter series by Ali Sparkes
- Teller, J. The Navajo Skinwalker, Witchcraft, & Related Spiritual Phenomena: Spiritual Clues: Orientation to the Evolution of the Circle. (Infinity Horn Publishing, Chinle, AZ, 1997 ISBN 0-9656014-0-4)
- Wall, Leon and William Morgan, Navajo-English Dictionary. (Hippocrene Books, New York City, 1998 ISBN 0-7818-0247-4)