Factual error: Early in the movie, the Predator is standing still while cloaked as an ant crawls across its leg. A rat grabs and eats the ant, then a snake strikes the rat. The snake starts to crawl away, then suddenly senses the Predator and gets startled, rattling its tail. However, rattlesnakes are pit vipers. They see heat. So even cloaked, the snake should have already seen the Predator standing there and known. Predator cloaks do not cloak from heat vision. (00:13:30)
Suggested correction: If you watch closely, the rattlesnake is initially distracted by a mouse. However, as the predator moves closer (even while cloaked), the snake becomes agitated and rears up in a defensive "S" posture. The reason the snake doesn't strike immediately isn't necessarily that the predator is hidden from its heat vision; it's that the predator is a giant, unfamiliar heat source that isn't moving aggressively yet. The snake is essentially "sizing up" a massive predator it can see perfectly well.
That is not how pit vipers behave. Unless the predator would be behind glass, it would be aware of body heat coming from it, and as a larger source than that rat, it would be defensive. It is in captivity where the feeding response can override this, as seen by handlers. But not in the wild, where the snake would not be used to a large heat source providing food.
Factual error: The movie is set in the Northern Great Plains of the United States, and the tribe is identified as Comanche, but the Comanche were located in the Southern Great Plains, across present-day northwestern Texas, eastern New Mexico, southeastern Colorado, southwestern Kansas, and western Oklahoma.
