Well, 'no supernatural' pretty much eliminates the entire genre, since horror usually makes use of fear of the unknown. Otherwise it's generally labeled a "thriller." There's exceptions, but they're exceptions. Serial killer stories are probably as close as it gets.
Originally Posted by siraks
Amazing book, and technically it isn't a tale of the supernatural, since the creatures are just a lesser-known species of predator, at least within the narrative. The creatures are rather fantastical, though.