I saw a pre-release interview with M. Night Shyamalan and he noted that an off- screen sound was edited out of the scene where
Ivy is running from the creature in the wood. It was the part where she was twriling. It was aerial shot. Mr. Shyamalan said the sound was going to result in an R rating for the movie. When he removed the sound, it became PG 13.
So…what was the sound?
I have no idea, though I have two guesses:
Noah killing a small animal i.e. animal screams and bones breaking
Noah becoming aroused