Composer Craig Safan wrote an original score for this film and was replaced at the last minute by future Academy Award winner James Horner, who had only 12 days to write and record his score.
Dustin Hoffman seriously wanted to play the role of Dewey Wilson, but was refused the part by director Michael Wadleigh who really wanted to work with Albert Finney, who was his favorite actor. It was the only time in his career that Hoffman was rejected for a part.
The film was the first movie to use a thermographic visual photographic look to represent the point-of-view of a character, in this case, the wolfen. The type of effect shot has been used in a number of movies to show the POV of a character, usually villainous, like a beast. One notable example of the popularizing of this kind of visual effects perspective is its use in the "Predator" films.
First filmed adaptation of a Whitley Strieber novel. Others that would follow would be "The Hunger (1983)" a couple of years after then later "Communion (1989)."
Director Michael Wadleigh's cut of the film that he handed to the studio in Febuary 1980 before his removal from the film in post-production, was over four and a half hours.