Trivia: There are a few major differences between the movie and the book that it is based upon. For instance, the film suggests that the Wolfen may have Native American mythological roots-that they are wolf-like spirits that have taken physical form to hunt people; in the book, they are a separate, intelligent species from humans that preys upon weak, abandoned and likely "unmissed" people. Furthermore, the film suggests that the Wolfen will continue to predate on the forgotten with impunity; per the novel, they have been discovered with their corpses as evidence and open conflict is likely.
Trivia: James Horner would later use the melody of the main theme from this movie as an action motif in 'Aliens'. His villainous music for 'Star Trek II: The Wrath of Khan' is also quite similar.