Humans, throughout history, have feared the dark. Our eyes are not well-adapted to seeing in low light levels and we fear what we cannot see. Our hearing is not as acute as our feline and canine companions. Nor can our sense of smell inform us what may be stalking us in the night.
Almost all of our literature that contains night images is — at least — a bit scary.
Yet, in the normal course of things, most of what is “out there” in the dark is pretty much the same stuff that is there by day. It’s not scarier or more dangerous. We just aren’t sure what it is.
It would seem that the uncertainly — for humans — is the same as frightening. Would anyone like to take a shot at why this is so? Does it go back to caves and lurking saber-toothed tigers? Or is in buried deep in our DNA.