Not sure how it works so it may not be the same for everyone, but the first review of Predator I see on IMDB is a review that has this to say:
"The first deaths suggest vengeance if not some sort of ritual, but later ones suggest that the alien may be feeding off of his (or her) victims. Oddly enough, it is not until the awful Predator 2 that we learn that it kills for sport."
This hurt to read. Nowhere in the movie is it even hinted at a possibility the Predator feeds off his victims. The movie makes it clear the Predator is there for trophies and the characters know it.
Stuff like this make me mad.
