Grey aliens (also referred to as "Greys") are alleged extraterrestrial beings whose existence is promoted in ufological, paranormal, and New Age communities, named for their skin color.
Paranormal claims involving Greys vary in every respect including their nature (ETs, extradimensionals, demons, or machines), origins, moral dispositions, intentions, and physical appearances (even varying in their eponymous skin color). A composite description derived from overlap in claims would have Greys as small-bodied sexless beings with smooth grey skin, enlarged head and large black eyes. The origin of the idea of the Grey is commonly associated with the Betty and Barney Hill abduction claim, although skeptics see precursors in science fiction and earlier paranormal claims.
Greys are typically depicted as gray-skinned diminutive humanoid beings that possess reduced forms of, or completely lack, external human organs such as noses, ears or sex organs. Their bodies are usually depicted as being elongated, having a small chest, and lacking in muscular definition and visible skeletal structure. Their legs are shorter and jointed differently from what one would expect in a human. Their limbs are often depicted as proportionally different from a human's; their humerus and thighs are the same lengths as their forearms and shins, respectively.
Greys are depicted as having unusually large heads in proportion to their bodies. They are depicted as having no hair anywhere on the body, including the face, and no noticeable outer ears or noses, but only small openings or orifices for ears and nostrils. They are depicted as having very small mouths, and very large opaque black eyes with no discernible iris or pupil. Sometimes Greys are alternately depicted as having no noticeable nostrils or mouths.
Among reports of supposed alien encounters, Greys make up approximately 50 percent in Australia, 43 percent in the United States, 90 percent in Canada, 67 percent in Brazil, 20 percent in Continental Europe, and around 12 percent in the United Kingdom
During the early 1980s Greys were linked in popular culture to the alleged crash landing of a flying saucer in Roswell, New Mexico, in 1947, by a number of publications which contained statements from individuals who claimed to have seen the U.S. military handling a number of unusually proportioned, bald, child-sized beings. These individuals claimed that the beings had over-sized heads and slanted eyes—but scant other facial features—during and after the incident.
In 1987, popular novelist Whitley Strieber published the book Communion, in which he describes a number of close encounters he purports to have experienced with Greys and other extraterrestrial beings. The book became a New York Times bestseller, and a film adaption starring Christopher Walken was released in 1989.